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E34 (1989 - 1995)

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  #51  
Old 10-18-2012, 07:38 AM
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BMR_LVR BMR_LVR is offline
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Hay Larrick. To the best of my understanding ..... Regarding whether the engine operates at higher temps at idle or at speed, the engine will operate at higher temps at speed. The reason is that, at idle, very little fuel is being burnt. The combustion process is what generates the majority of the heat. Friction of engine components generates a little, but not that much due to the lubrication systems of the engines. When you are driving at speed, much more fuel is being combusted which causes generation of much more heat.
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  #52  
Old 10-18-2012, 08:01 AM
Larrick Larrick is offline
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That makes sense to me. I guess I always had this vision of cars overheating in traffic jams on highways while at idle. But that may from my youth when the road to the beach would back up for miles on a hot day.
My main concern now is the water vapor. I may just be paranoid. I will closely watch the coolant level.
Does anyone agree that a Hydrocarbon test on the coolant is a real and definitive test for a blown head gasket?
If there are no hydrocarbons can you truly be assured that your head gasket is fine?
As you said, when the car is driving, things get hot and the pressure gets high in the cylinders.
Mike the mechanic said that,if thee were a bad head gasket, hydrocarbons would definitely be found in the coolant.
My engine had zero on a test that detects 1 part per million.
Do BMW m50 engines real blow more water vapor than a standard engine as the mechanic stated?
I will continue to worry until I see a constant coolant level for the next few weeks.
That should be the real test.
I will return to this thread at that time to follow up.
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  #53  
Old 10-18-2012, 08:17 AM
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BMR_LVR BMR_LVR is offline
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Some here distrust all mechanics. I am willing to put faith in a mechanic that has shown, through his work, that he knows what he is talking about and is to be trusted. Your mechanic sounds like he knows what he is talking about.

I am not that familiar with the hydrocarbon test, but in theory, what your mechanic said makes perfect sense to me.

One of the key signs that your HG is okay is that you are not having overheats in the presence of the recent cooling system repair. Very frequently a car with a bad HG will overheat even with a properly functioning cooling system.

I hope that you are encouraged by your mechanic's advice and the car's current status and can relax and enjoy the car. Obviously, keep an eye on the coolant level. Check it each day prior to cranking the car when it is stone cold. That way there are no variables (i.e. coolant expansion with heat).
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It's Deja Poo - as in, I've heard this **** before.
Steve

Calypso Red 1992 525i with 200K miles

1991 735i - Sold
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1995 325is - Sold
2000 528i - Sold

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  #54  
Old 10-18-2012, 09:30 AM
robertobaggio20 robertobaggio20 is offline
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Has anyone heard of at HG that is busted in such a way that the coolant in the coolant passages mixes with the engine oil in the engine oil channels ? If so, that could be happening here. Coolant is mixing with the engine oil and going into the sump. There, it heats up, vaporises, and gets expelled through the pcv (positive crankcase ventilation) system, thus producing vapour in the tailpipe. This could be a pathway by which the coolant does not enter the combustion chamber directly through a crack in the cylinder head or a rupture in the hg.

I second Steve. Your dealer's assertion that pressurised combustion chamber gases get pushed into the coolant system if there is such a HG rupture is sound and his test is more precise than off the shelf colour changing solutions. It is unlikely that you have a hg problem. And steve is right again that hg related overheat problems should manifest even with an otherwise refreshed cooling system.

I'm very glad Larrick that this was a stupid wp issue, and you've done the right thing by changing all the stuff that you've done even though even if they were not specifically damaged. This is in the category of long term wear and tear stuff. The only things I'd add would be a new rad cap and a new bleed screw.

M50 engines do not puff vapour through the tailpipe when other cars don't at the same time. Do this... .go for a fast drive on a non-wet day, probably during the afternoon. Then stop the car and let it idle for 5 minutes, then take a look at your tailpipe. It would be best if someone else in a different vehicle would accompany you on your circuit, so that you can compare against that tailpipe.

You must monitor the radiator daily. If it drops to 1/4 within 2 weeks or less of daily driving, you do have a problem. The time your radiator takes to reach the 1/4 mark on the expansion tank while cold, is the key indicator, that will help you determine if you can continue by merely topping up water more regularly, or to just bite the bullet and do a proper repair.



rgds,
Roberto

p.s. Was a pressure test done on your radiator ?
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  #55  
Old 10-18-2012, 09:38 AM
robertobaggio20 robertobaggio20 is offline
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And I'm unsure as to how to specifically ....oh I just got it hmm. I was about to say that its difficult to test if the wp is working without removing it from the engine and looking at it and turning it with your fingers (it should turn fairly easily and there should be no free play along its axle) and I just thought of a simple way.

You'll need two people to do this with, one person sits in the car and alert you once the temperature starts to climb past middle.

1. Fill the radiator with water.
2. Start the engine and bring it to operating temperature.
3. Continue to fill the radiator with water. Bleed the radiator and button it up.
4. Stop the engine (at this point, your engine should be at optemperature (lets use that as a shorthand for 'operating temperature')..
5. Remove the top rad hose at the point where it connects to the radiator, and stick the opening slightly out to the side etc such that you can see coolant flow. If any coolant escapes, wait till that stops.
6. Have the person in the car start the engine.
7. Observe the coolant flow. It should be moving out at a certain rate, if the water pump is working properly with all of its fins intact. Diagnose accordingly.
8. The importance of filling up the radiator with water earlier, should now be clear.

Now.....what would be ideal would be for you to do the above when your wp is working fine, so that you know at what rate coolant should flow out when the wp is working properly. Thus, if you need to do this test for real, you have a benchmark to refer to, and not simply use educated guesses (although frankly that should be sufficient to identify catastrophic wp failure, there should hardly be any coolant flow).

How's that for a quick wp test, Larrick ? Would you mind trying this out and letting us know ? Just for the heck of it.

rgds,
Roberto

Last edited by robertobaggio20; 10-18-2012 at 09:41 AM.
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  #56  
Old 10-18-2012, 05:05 PM
Larrick Larrick is offline
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I agree with everything you say and suggest.
I did change the bleed and the rad cap seems fine.
I would say that with the engine oil clean and a hydrocarbon test negative one could feel confident that the HG is OK.
I still do not like or understand the water vapor. But it may be just fine. It depends upon conditions and comparisons.
I am at a disadvantage because it is not my car and I do not see it very often.
I di disconnect the upper hose and had my son rev the engine and there was flow.
But, as you say, I had no bench mark for a healthy water pump.
I will do the "hose off "procedure and report back on bench mark flow but I would like to wait for a few weeks to monitor the coolant level
without touching the system as is is now.
I may have to call the mechanic and ask the exact condition of the WP when it was initially inspected because the one I received back had no remnants of any impeller.
There were separate pieces in the box of parts he gave me. Perhaps they were still intact but broke off during removal.
When I detached the upper rad hose, I would say that there was some pressure pushing the coolant.
Could convection alone account for that?
There was obviously some movement of coolant or I would have overheated at idle during a 1 1/2 hour idle.
For now, I have given my son strict orders on monitoring the coolant level.
If there is coolant lose and there is not visible leak, then the non contaminated oil and negative hydrocarbon test combination would not rule out a HG problem.
You guys are great and there is a real comfort in having you take such interest in the problems of others.
I feel as I have let you all down a bit by not doing the job myself but I was in a time crunch.
I will report back. Thanks to everyone.
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  #57  
Old 10-18-2012, 09:10 PM
robertobaggio20 robertobaggio20 is offline
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No, convection alone cannot do enough sir. I think your water pump's impellers was probably intact somewhat, but upon inspection, it probably broke away when handled. it was also probably not turning very well...its axle and bearings could be screwed. If you still have it, take it and try to turn it with your hand.

And of course you now how it flows when busted as you checked that. So, may I suggest that you do the wp flow experiment right now instead of a few weeks later? The issue is fresh on our minds now. Secondly, there would be scant coolant loss now anyway as you just fixed everything up. Coolant loss needs to be monitored over a total of 2 months.....too long to wait for an update ! (gentle arm twisting )

If you can spare the time sir. Thank you. And no you have not let anyone down by doing the job yourself. You had time pressures and there's Mrs Larrick's good cooking on the line as well. No to be risked lightly.
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  #58  
Old 10-19-2012, 12:45 AM
robertobaggio20 robertobaggio20 is offline
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I'd like to offer an update that is relevant to this discussion.

With the engine cold, I removed all the belts and ran the engine. I did this to check something else. Thus, the water pump was not active and not pumping coolant around the system. And I don't have a fan clutch

However, despite the engine running for a total of 25 minutes, of which 10 minutes was spent in actual driving at driveway speeds, the engine did not overheat. The needle stayed at centre, or a needle's width to the right, which is normal for my car. It did not move towards the 3/4 mark at all and did not threaten to move as well. The upper rad hose was hot. I took temperatures and there was a drop from the top left of the radiator to the bottom right of the radiator of nearly 15-20 degrees, which is normal. The auxiliary fan did not switch itself on automatically.

I became curious and wanted to see how long this could last, but however, without the belts connected, the battery would be eventually fullly drained, which is not advisable for maintenance free batteries as far as possible.

Thus, I must ammend my earlier comment here that convection does not help in cooling the car. It does indeed !! However, clearly from Larrick's experience, despite the greater amount of cooling that takes place due to onrushing air when the car is in motion as opposed to when it is stationery, the engine produces far more heat while the car is being driven, and so mere convection is insufficient enough to cool the engine. We need water pumps.

So there will be no water pump delete thread under any circumstance.

Last edited by robertobaggio20; 10-19-2012 at 02:31 AM.
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  #59  
Old 10-19-2012, 11:17 AM
Larrick Larrick is offline
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I assume you meant Highway speeds when you wrote driveway speeds. I never got on the highway as it began to heat up when driven on side streets.
It did try and get the speed and rpms up in stretches when I could but it overheated with in 5 to 10 minutes each trial run after sitting at idle for an hour or more
with out overheating.
When I began driving without letting it get to operating temperature, It did not overheat in the 10 minutes which it took me to drive to my house from my son's
and again the next day (10 minutes) to get to the mechanic
It probably would have overheated if I had gone much farther but I don't know.
So our experiences were different in that you did not overheat while driving.
My son is quite reluctant to touch the cooling system right now and I do not want to force him and then have something bad happen
even if it were unrelated...I would get blamed for the problem.
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  #60  
Old 10-19-2012, 09:55 PM
robertobaggio20 robertobaggio20 is offline
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Quote:
Originally Posted by Larrick View Post
I assume you meant Highway speeds when you wrote driveway speeds. I never got on the highway as it began to heat up when driven on side streets.
It did try and get the speed and rpms up in stretches when I could but it overheated with in 5 to 10 minutes each trial run after sitting at idle for an hour or more
with out overheating.
When I began driving without letting it get to operating temperature, It did not overheat in the 10 minutes which it took me to drive to my house from my son's
and again the next day (10 minutes) to get to the mechanic
It probably would have overheated if I had gone much farther but I don't know.
So our experiences were different in that you did not overheat while driving.
My son is quite reluctant to touch the cooling system right now and I do not want to force him and then have something bad happen
even if it were unrelated...I would get blamed for the problem.
No i meant driveway speeds. I just drove the car around the carpark, for like 5 minutes. I kept the rpms low and it did not overheat.

Just for the fun of it, I came back from a long drive, removed the belts, started the engine and kept the rpms at 1500 while parked. The needle moved from just past centre to past the 3/4 mark within 4 minutes. Even if i had the benefit of onrushing air should I have been on the road, I think the engine would overheat in under 10 minutes (assuming that it was starting from optemp first).

So the water pump cannot be dispensed with, unless you intend to keep your car stationary and leave your engine at idle throughout (perhaps as background music) .


rgds,
Roberto
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  #61  
Old 10-21-2012, 08:14 AM
snowsled7 snowsled7 is offline
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Quote:
Originally Posted by robertobaggio20 View Post
Has anyone heard of at HG that is busted in such a way that the coolant in the coolant passages mixes with the engine oil in the engine oil channels ? If so, that could be happening here. Coolant is mixing with the engine oil and going into the sump. There, it heats up, vaporises, and gets expelled through the pcv (positive crankcase ventilation) system, thus producing vapour in the tailpipe. This could be a pathway by which the coolant does not enter the combustion chamber directly through a crack in the cylinder head or a rupture in the hg.

It is quite common for oil and coolant to mix when a headgasket fails. The typical signs are oil in the coolant resevoir and milk color in the engine oil. It can be one or the other or both but, any one means the HG is bad.

How hot do you think your oil gets bobby? Hot enough to vaporize coolant? Of course, if you are fool enough to drive your car around with the cooling system disabled until the gauge reads above the 3/4 mark, then maybe YOUR oil has seen temps like that. For the rest of us non geniuses, our oil temps probably never see 220*F on the street.
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  #62  
Old 10-21-2012, 09:09 AM
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supertech777 supertech777 is offline
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Quote:
Originally Posted by snowsled7 View Post
It is quite common for oil and coolant to mix when a headgasket fails. The typical signs are oil in the coolant resevoir and milk color in the engine oil. It can be one or the other or both but, any one means the HG is bad.

How hot do you think your oil gets bobby? Hot enough to vaporize coolant? Of course, if you are fool enough to drive your car around with the cooling system disabled until the gauge reads above the 3/4 mark, then maybe YOUR oil has seen temps like that. For the rest of us non geniuses, our oil temps probably never see 220*F on the street.
LOL !

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  #63  
Old 10-22-2012, 07:36 AM
robertobaggio20 robertobaggio20 is offline
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Quote:
Originally Posted by snowsled7 View Post
It is quite common for oil and coolant to mix when a headgasket fails. The typical signs are oil in the coolant resevoir and milk color in the engine oil. It can be one or the other or both but, any one means the HG is bad.

How hot do you think your oil gets bobby? Hot enough to vaporize coolant? Of course, if you are fool enough to drive your car around with the cooling system disabled until the gauge reads above the 3/4 mark, then maybe YOUR oil has seen temps like that. For the rest of us non geniuses, our oil temps probably never see 220*F on the street.
Of course oil is hot enough to vapourise coolant or water, or the oil sump environment sees to it anyway....perhaps the air in the oil sump is at a higher temperature than the oil itself or something. There certainly is alot of air turbulence there which aids vaporisation.

If you've ever tried water decarbonisation to clean your combustion chambers (I didn't get reliable results with this thus I've not talked about it here), water will get into your oil due to blowby gases from your combustion chambers, and it will mix and turn a little yellow. Just drive the car for 30 minutes and it will all clear out naturally.

I guess that's part of the safety margins built in by bmw. lol
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  #64  
Old 10-22-2012, 12:51 PM
snowsled7 snowsled7 is offline
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What you are talking about burning off is condensation. What I am saying will not happen, is that with a gasket leaking coolant into the oil, there is no way the oil gets hot enough to burn it off. That is why it becomes a milky color.

Just keep typing bobby, can you even see out of that hole you have dug yourself into anymore?
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  #65  
Old 10-23-2012, 10:17 PM
robertobaggio20 robertobaggio20 is offline
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Quote:
Originally Posted by snowsled7 View Post
What you are talking about burning off is condensation. What I am saying will not happen, is that with a gasket leaking coolant into the oil, there is no way the oil gets hot enough to burn it off. That is why it becomes a milky color.

Just keep typing bobby, can you even see out of that hole you have dug yourself into anymore?
Perhaps you did not read my post carefully. I said my oil turned milky due to something called water decarb that i did on my engine. This is not the same as condensation....condensation, or "free moisture" in oil, diesel or the like, will never exist in sufficient quantities to turn engine oil yellow to any degree visible to the naked eye.

So....when it turned yellow....i drove the car for 30-45 minutes and it came back to the original colour. And this included the oil under the crankcase cap, which was also initially a little yellow. Obviously, the engine oil, and/or the crankcase environment, was hot enough to cause the water in the oil to vapourise, and then get vented through the pcv system along with the usual crankcase gases.

So, imo, when coolant leaks into the crankcase, it can and is still being burned off through vaporisation and being vented off through the pcv system. However, in a HG issue, new coolant is constantly being leaked in while the old coolant is being burned off, so the oil remains milky, unless of course the HG coolant leak is very minor.

Snowy, is it possible for the HG to be busted in such a way that coolant ONLY leaks into the combustion chamber (evidencing itself as more steam/water vapour out the tailpipe), without also leaking into the crankcase ? Or can this only happen in the event of a cracked cylinder head ? Thank you.

Last edited by robertobaggio20; 10-23-2012 at 10:20 PM.
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  #66  
Old 10-23-2012, 10:21 PM
robertobaggio20 robertobaggio20 is offline
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Here's a thread that may point to the reason why Larrick's car is puffing more vapour than it should :

http://www.bimmerfest.com/forums/sho...d.php?t=601993
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  #67  
Old 10-24-2012, 04:45 AM
snowsled7 snowsled7 is offline
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Headgasket leaks can maifest themselves in many different ways. Sometimes, like my old G320 MB with the M104 engine, the leak is a small oil leak externally that never causes a problem. Sometimes the gasket fails and oil and water mix. Sometimes coolant just leaks into the combustion chamber. It may start out that way but in short order the leak is usually enough to taint the oil. When you shut the car off and the pressure in the cooling system rises, coolant will leak into a cylinder, down past the rings and into the crankcase. If you are just burning a little, it is probably only the beginning. Allowing any amount of coolant to mix with the oil will cause major damage in short order if driven. By no means does any of this mean you have a cracked head, usually just a little warped. It takes a serious overheat to crack the head on most BMW's.
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  #68  
Old 10-24-2012, 08:06 AM
coolredlich coolredlich is offline
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I had similar problem with my 93. Turned out crack in head #4 exhaust valve area. No water in oil, but water droplets on oil filler cap. Also compression test showed normal for all cylinders.
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  #69  
Old 10-24-2012, 10:00 AM
robertobaggio20 robertobaggio20 is offline
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Originally Posted by coolredlich View Post
I had similar problem with my 93. Turned out crack in head #4 exhaust valve area. No water in oil, but water droplets on oil filler cap. Also compression test showed normal for all cylinders.
You had a cracked cylinder head and normal compression test results ? How could that be ?
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  #70  
Old 10-24-2012, 05:15 PM
Larrick Larrick is offline
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Question: If the expansion tank is filled higher than the "Cold mark" on the tank, will coolant be lost until the "Cold mark" is attained? If the expansion tank is full were does the coolant expand to?
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  #71  
Old 10-24-2012, 06:17 PM
robertobaggio20 robertobaggio20 is offline
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Question: If the expansion tank is filled higher than the "Cold mark" on the tank, will coolant be lost until the "Cold mark" is attained? If the expansion tank is full were does the coolant expand to?
Answer : Yes. Coolant will eventually be vapourised and vented until enough coolant is lost till it reaches the cold mark in the expansion tank when cold. This may take up to 2 months to happen, however.

Even when coolant reaches the cold mark when cold, it will not overflow sufficiently to reach the hot mark when hot.

The expansion tank is actually an overflow tank. Excess coolant from the main radiator system will overflow and get stored over there. Coolant doesn't really physically expand measureably. Can someone corroborate these two points ? Meannie ? Snowy ? Superdude ? Josh? Where are groupies ?

Last edited by robertobaggio20; 10-24-2012 at 06:23 PM.
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  #72  
Old 10-24-2012, 07:57 PM
Larrick Larrick is offline
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I am assuming that the "Cold mark" is about half way down the expansion tank. It is a raise line just to the inside of the series of raise lines. Is there an actual "Hot mark"?
I ask because when The cooing system was overhauled, the coolant level was very near the top of the tank when Cold.
I just got a look at the coolant (my son had the car over to the house) It was, of course, not cold but the level was a bit lower than it had been at Cold.
It is well above the "Cold mark" though.
It has been one week and about 260 miles.
The engine sounds wonderful and it is running strong.
It was dark out and cool, I did not notice vapor as he left.
How does the coolant escape if there is too much?
Will it push out the cap?
This is the problem with not having the car here.
My son will put a piece of blue tape at the coolant level when it is "Cold" in the morning.
A non BMW question: I hope this is not a violation of some code....
I was changing the oil on my daughters Pontiac Aztek. As I was adding new oil, I noticed a stream of fresh oil pouring out
from the housing which accepts the oil filter. I was not spilling any.
I know that the oil pressure sending unit is in the area so I instinctively started the engine thinking that a check valve or something had opened.
The leak stopped immediately. I was freaked out about letting my daughter drive away so I kept turning the engine on and off to make sure that all was well.
There has always been a small amount of oil emanating from this area, but never enough to even bother checking the oil the often.
I never experienced any thing like this before, and it being an Aztek there is little information.
Has anyone ever experienced any thing like this on any vehicle? I am still shaking my head.
It has been several days and all seems well.
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  #73  
Old 10-24-2012, 08:22 PM
robertobaggio20 robertobaggio20 is offline
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Coolant gets vapourise and builds up in the expansion tank.
As more vapour accumulates, the pressure on the rad cap increases.
Once the pressure exceeds the rad cap's rating, the rad cap vents the excess vapour, and thus reduces the pressure.
The excess vapour that is lost is actually excess coolant that is lost. When the engine is cold, the water level will be slightly lower.
During dozens of cycles of this process taking place (as you drive the car over weeks), coolant levels in the expansion tank move from the full to halfway up the expansion tank when cold.
Thus you saw the coolant level being slightly lower in your car, from where it was one week ago. This is normal.
I think its a fair assumption that the engineers designed the vehicle to eventually reach and stay at the cold mark, assuming everything else is functioning normally. This is because, the Bentley manual recommends changing the coolant once every 2 years, and does not tell you to check and top up coolant every x number of weeks or months.
However, since the practice of checking coolant is part of popular culture, is quick, easy and harmless and at least allows you to look at the coolant levels and reassure yourself that everything is ok, I generally check and (inevitably) top up water once every 1-2 months. I don't worry about it in the intermediate period.
If you are topping up coolant once every 1-2 weeks because they are dropping so fast, then you do indeed have a problem.

As to your daughter's car, I would say that it is abnormal for oil to be coming out of any part of the engine under any circumstances. There is no device that is in charge of venting oil per se. If oil escapes, it is at the very minimum, the result of a gasket or O ring failure, and possibly something worse. Usually of course it is the result of a gasket failure especially on older cars.
If there are no warning lights on the car's dashboard after it has been started, I think its fair to say that all of the physical oil-related engine components are working correctly, and that it is merely a gasket or O ring that has failed.
I wish I had you for a dad.


rgds,
Roberto
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  #74  
Old 10-25-2012, 05:28 AM
snowsled7 snowsled7 is offline
The Ornery Old Man
Location: SW Mountains
 
Join Date: Mar 2012
Posts: 980
Mein Auto: GTI
My coolant res is full, all the time it seems. The car hasn't been driven for 2-3 days and there was still pressure in the cooling system when I went to take the cap off.

Your son did the right thing though, mark it and monitor it. Don't worry, the level will rise when warm, that is normal. It should return to the mark each time when fully cooled.

On the Aztek, ohh my goodness ditch that buggy I would be checking for a valve cover gasket leak. As you refill the oil through the top of the head, oil pools in the valve covers until it fully drains back to the sump. This might explain the sudden leak and the fact that it remians a small leak. I wonder how much fun it will be to do valve cover gaskets on the back side of that V6?
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