No Heat + Over Heating ??? I Need Advice Asap

[bolt-on-bandito]

i recently picked up a 95 325i. i bought this car about 3 weeks ago and the heat has been very wierd. it some times works, sometimes dosen't. but either way it takes about 20 minutes to get warm, if it gets warm. i checked the thermostat and it is fine. the o ring is fine. i can't find any leaks in the coolant system except the radiator. i can't pin point the radiator leak, but it's just coming off where the plastic and the metal meet. i am getting a new radiator this week, but what would this be causing the other issues? i have changed the fluids and i know the coolants good.

i am in ohio and it's like 10-20 degrees F, so why is the car over heating? why is the heat not working. is there some kind of heater module that is not working? could it be the heater core? sometimes the temp gauge will spike for a second, then go back to normal opperating temp? but today it would spike to red, and stay there, i had to pull over twice in less then 20 miles.

i could really use some help in trouble shooting this. i assume it's just something not opening up, or some sensor thats blown. no check engine light, only the check coolant warning after i drive.

ANY ADVICE WILL BE GREATLY APPRECIATED. THANKS---MZ

[LmtdSlip]

How did you determine that the thermostat was OK?

Id replace that just for good measure. Did you pull the water pump? Could very well be the pump.

Id think that the pump and thermostat would be logical parts to replace as you would want to change them anyway if you were doing the radiator.

[94black325i]

as far as your heater not heating, I'm really not sure. Under the center vent make sure the rotary knob is all the way set to hot(red). In 10-20F it's gunna take a lil while regardless.

As far as your other probs, it sounds like you need to check/replace your entire cooling system:
-water pump
-radiator
-hoses
-thermostat
-thermostat housing/gasket
-reservoir & cap/gasket


"but today it would spike to red, and stay there"
I sure hope you didn't drive it at red too long!

Now unless you want to spend another 1 - 3k replacing your head gasket, or cylinder head: DO NOT DRIVE THIS CAR! Until you know the cooling system is functioning ok.

To be smart/safe have a mechanic also run a compression test on the engine and check the exhaust for hydrocarbons. Trust me, you want to know that your engine is ok and no coolant is leaking in the combustion chamber.

good luck!

[termignoni]

Make sure that you coolant is bleed right. If you it is isn't it may cause the system not to heat correct or cause damage to the engine. Double check the themostat and make sure it opens and closes correctly. Make sure the waterpump seal is not leaking or the fan in the pump is not cracked or broken off. (you have to pull it off to see it) These are things you should check for the spiking.

[bolt-on-bandito]

i checked the termostat by submerging it into boiling water, and watching it open. it open when hot, and closed when cool. i had the car on a lift this weekend and watched it from under while it ran and the only leak i could see was coming from the radiator. (about 4-5 drops a minute). i am going to replace the radiator, but the heat issues is what boggles me. i know to adjust the heat under the middle interior vent. i know not to drive a car while the temp gauge is spiked. i guess what i am really wondering is would a bad radiator be causing all of this? how would i check the heater core.

as far as checking for my aux fan, i do not think it works. would that throw any kind of check lights? is there a way to test this other then let the car get hot and check if it comes on?

slip, you suggested to check the water pump gasket for leaks, would this cause the overheating and lack of heat in car?

the wierdest thing is i drove this car for about 2 1/2 hours mostly freeway yesterday and never had a problem other then the heat never really coming on. then yesterday my wife and i go to church 20 minutes away mixed freeway and city, and the thing overheats like crazy.

i am going to buy a new radiator, and probably bite the bullet and take it to a trusted mechanic.

thanks for the help.

[bolt-on-bandito]

could this be a cooling sensor, or somthing stupid and little like that? and what is the sesnor in the airbox?(what is it called) why does that have coolant lines going to it? i think i need to replace that.

thanks for all the advice. domestics i know, it's this greman enginerring that is new. :confused:

[LmtdSlip]

I think you would want to remove the pump to be sure that the impellers are intact. The gasket may be fine but the pump may not be moving the water.

[bolt-on-bandito]

okay, i can remove the pump and look at it, what about air in the system. i have this posted in ac ouple of forums, and someone stated air could be the issue. make sense?

what about testing my AUX fan? any means of doing that?

[dfyoung10]

If the pump is damaged, the coolant won't circulate. That would make it heat up whether you are on the freeway or in traffic or just idling. It also would not be an intermittent problem, because the fins would always be broken. so it doesn't sound like the water pump.

Try taking the thermostat out as an experiment. It should not heat up at all. If it still heats, look for something impeding the air circulation. Enough air circulates through the radiator at freeway speeds to cool the radiator without the fan working, but if the fan is off or intermittent, it will heat up at low speeds.

I have also heard of bad lower hoses in which the plys have separated and the pump is sucking the inside of the lower hose closed, thus impeding the coolant circulation. This is a long shot, though.

You can also bypass the coolant/fan switch so the fan runs constantly to see if the fan control is the problem.

[B2M2W]

Okay i just fixed my overheating issues with my 93 325i, the leaking radiator would help the issue of overheating but wouldnt be making it overheat rapidly like that, you can check your auxillary fan by turning the A/C on and listening it turns on and off when the A/C is running. You can also perform a Aux fan override where your fan stays on all the time. If still doesnt work, bleed the system once again, with my car everything was replaced and it was still overheating, i bleed the system 5 times and finally got all the pockets out. Hope this helps, here is the site that will give you directions on the Aux fan override...www.pelicanparts.com...click on bmw....then tech forums on left hand side.

[IBreakStuff]

Double post, please delete this one

[IBreakStuff]

An air bubble in the cooling system. Plain and simple. Did you burp the system when you put new fluid in it? The reason that the temp. gauge flew up like that is beacuse the temp sensor for the gauge sits in the coolant. However, if there is no fluid to touch the bottom sensor part, it will read cold. Under hard acceleration or for other reasons, the pump may "catch" and thrown the really hot coolant that hasn't been circulating onto the sensor, showing the "read/hot" reading. Obviously the leaking radiator is a problem, fix that first. If you re-fill the system and burp it, see if the coolant hoses are hot, both of them to the water pump, the little ones that go to the heater core, etc. If none are hot, it's a stuck thermostat (but you said it opened ((good idea to put a candy thermometer in there next time, as it may have opened at say, 230 degrees which is way too hot))), or a shot water pump. Or not burped correctly. If you get fluid circulating but the heater still doesn't blow hot, it might be a bad heater core. These get plugged and lose their cooling-off capability (they work the opposite of a radiator, their job is to expel heat INTO the cabin). Since your radiator is done for, most likely the heater core is too since they are of the same age and approximately the same coolant going through them. Out of all the readiators I've replaced in the past, the heater core goes quickly afterwards. I haven't done a radiator on my E36 yet, but I know that the heater core is shot in it. There's a lot of tubes and hoses for the coolant throughout the car, which means lots of coolant to drain, which mean tons of places that you have to refill with coolant. I can imagine it's not easy to burp these correctly. Lemme know if this helps/have any more questions.

Bryan

[blueE36]

your headgasket would be my first guess

[bolt-on-bandito]

thank every one for th tips. i replaced my radiator today. i drove home and the temp gauge would go to 1/2 normal temp to 3/4 temp. then back down to 1/2 way. it did this about 6 times in a 10 minute drive. i let the car sit and idle for about 20-30 minutes while i cleaned everything up and it never moved over 1/2 normal temp.

does this mean anything?

when i got hoe it started overheating again so i hardwired my aux fan to a switch in the cabin. it works correctly, turns on when i flip the switch, but the car overheats still. it only about 30 degrees F outside, this it retarded!

i suppose this only leaves my water pump?

as far as burping it, i let it get warm and then unscrewed the bleeder. it steamed for a while, then whistled and i waited till it was all dne. i have done this three times now.

i hooked up all the hoses, and the top and bottom hose all felt warm/hot, so i believe the RAD is doing it's thing. the heater core may be jacked up but would that cause overheating? basically i just want to solve the overheating issue now. then worry about the heat.


new rad, hardwired fan, thermstat checked out (but doesn't mean anything in regard to overheating) flushed the block, 50-50 mix, burped 3 x's !?!

i figured tomarrow i would take out the thermostat and drive it. it should take forever to get warm, but it should stay cool. it it does not then the water pump is the only thing it could be....right? advice?

thanks for all the help.

[B2M2W]

okay one last thing, before you resort to your water pump, the way the temp gauge is reading is sounds like it needs more bleeding, mine did the same thing, okay run the engine and then squeeze the hose(s) on top right and bottom left, squeeze in a pulsating manor to help get some of the air out, these pockets can be a pain, so be paitient but if that still fails then you know what it is. hope this helps

[termignoni]

Your thermostat obviously works because of the hot water test. I would pull the water pump and check the impeller. Before that however, with car the car off. take off the bleeder screw completely off and fill your aux.coolant tank until it flow constantly through the bleeder screw hole. Should be no air bubbles coming out, all coolant. Put bleeder screw and aux tank cap back on and while in the drive way, turn your heater control to max with max heat. Rev the engine to 2000 rpm to circulate coolant through system for 10 minutes. Check the gauge until it reaches the half way point(normal no matter how cold or hot outside). If the temp goes beyond this point, you have to rebleed or check the waterpump.

[bolt-on-bandito]

cool, thanks. i'll keep ya'll informed.

[fun2drive]

One added suggestion. Is your car on level ground or not? When bleeding the system (which by the way I had to add coolant about 2-3 times) I put a couple of 2X4's under the front wheels to get the front up slightly so that it will help the air out of the system.

It sure sounds to me like you still have air in the system. Honestly if you are going to the trouble to pull the water pump you might just replace it.

It sounds like your temp gage is working correctly too and even being cold the engine will overheat with no coolant to take the heat away. I suspect that if the water pump is the problem that the impellor is turning on the shaft sometimes and then not at other times. God forbid if you have a phenolic (plastic) impellor) . Be sure to turn the pulley with on hand and hold the impellor with the other to be sure there is no play what so ever.

Here to help but I do still think the system has air in it unless it has a dreaded head gasket failure. How do you tell? Just ask your wrench to put his gas analyzer around the radiator cap when warmed up, of course be sure to not burn yourself. If it goes nuts when you remove the cap, you have just received bad news...
Good luck and tell us what you find.

[Good Over Evil]

I would vote for 'air in the system'

It seems like airbubbles travel through your system and are causing inconsistancy which means fluctuating temps

When you bleed the system make sure you turn the power on and put your heat blowers on all the way hot and on full blast and then proceed to fill up your tank.

Also, heat not coming on is a sign of a bad thermostat or air bubbles. I'd guess it's air bubbles judging on how your t-stat works.

Anyone know when they stopped using plastic impellers? I would think this problem was solved before 1995 but I cant really remember....

[bolt-on-bandito]

okay last night i hit the wall, i had a new bosch water pump, and a new thermostat in my trunk. more coolant, a pair of m6 bolts and a some music playing. i jacked the car up and let the engine warm up, it started to overheat, i squeezed the hoses, and i had to have bled all of the air out. still overheating. so i knew i had to change the water pump. i started by draining the coolant, and unhooking the fan shroud. next i started to undo the fan bolt. i had my 32 mm cresent, and a screwdriver to hold it into place, i was turning left, but the bolt wouldn't budge, i have taken the fan off like 4 times in the last week. anyway i ended up breaking the pulley.:mad: at this point i had been hunched over for the better part of an hour and still couldn't get the fan off. and now i couldn't even drive the vehicle :mad: so i had to get it towed to a good mechanic i know and let him deal with my headach. frankly i just want it to work, and don't care at this point. i am frustrated because i have done MUCH more complex things on my vehicles, but with this i have had enough. i am hoping all is well, and i don't need a new head gasket.

any idea a good qoute for a head gasket? i am hoping the labor on a water pump, and broken pulley is just a couple hundred. anyway thanks for the help, and i'll keep ya'll informed.

[XThang]

Hi mate,

It sounds like we are on similar boats. But by the sounds of what you say your problem could be a bad heater core.


here is my story:

day1: bought car from a local car dealer 96 528i e39 done 155,000kms so under stat warranty.

day2: drove car for 3 hours in the city then 1/2 on the free way when the car started to show intermittent overheating.

day3:contact car dealer and arrange for car to be taken in for checks. drove car for an additional 50kms with intermittent overheating signs.

day4: brought car back to dealer and had thermostats replaced. car started to overheated again after 10min drive.

day5:brought car back to dealer. this time they say the head gasket is gone and cylinder heads needed to be checked.

day19: got car back!!! very happy, mechanic said the cylinder head warped and needed machining, the block was also drilled, head gasket replaced and some old hoses were replaced......then the car started to overheat again after 20minute drive. took car back to dealer's mechanic. they said the radiator was not bled properly and now it is fine.

day20: car running fine with no overheating problem.

day21: used steptronic on the car. good fun...but then 20minutes later temperature gauge started to rise to red again and the car was loosing fluid....stop the car and check in the engine bay and there were steams spraying from what appears to be the bottom or side of the engine ....... rang the car dealer.

day22: dealer got car towed away to another 'trusted' mechanic.

day23: 'trusted' mechanic now says that the heater core is gone and needed to be replaced. said its a big job and will take and extra week to fix up. I am about to go mad!!!

day24: still no news.....searching for more info on the web.


QUESTIONS:
- with the head gasket replaced should there be any smoke or steam rising from inside the engine (when hot) when you open the oil refill cap?
- is there anything i should be concerned with about an engine that has this major work done to it?

- would it really take 1 week to fix the heater core problem? they said they have to pull out the dash etc..

- should i be concern about the radiator and the water pump now since other components of the cooling system have failed one after another? I guess that if one part of the cooling system fail then an overheating engine would also cause other parts to become defective.

ANY THOUGHTS IS GREATLY APPREACIATED

[bolt-on-bandito]

sorry to hear about your problems, i would make sure that the dealer is footing the bill for all of this, i am not sure how the lwas are where you live, but there are a lot of anti-lemon laws around here that prevent a dealer from selling a vehicle that needs X amount of repairs, without selling it as such.

with all of that said:

i would replace the water pump, and maybe the RAD, depending how old it is. unfortunatley the cooling systems on these vehicles are tricky, and prone to go out. i just know i started with the therm, then the rad, and then i broke parts trying to do the water pump. and this was after drianing/filling the coolant system about 4 times.

do it all at once, and have the peace of mind about it. if the water pump is bad, then the heater core will not recv' fluid, and it will not produce or disperse heat. once i swapped my water pump, the heat was fine. i have read how to take out the heater core, and it does look like a hassle. but not a week. i think i could do it in a long day.

anyway, as far as the steam?? you should get a compression test done to see if the combustion chambers are running somewhat equally. generally there will be some loss after XXXX miles, but that is the best overall way to check the status of the motor/block.

overall, you should be beating down the dealers door unless this is all being paid for by them, hope this helps.

i ended up putting a new RAD, water pump, and therm, plus flushing the block, and obviously new coolant. said and done about $600, but i got an awesome deal on mine, so i am not sweating it. good luck, and let me know how it goes.---MZ

[ImperialDuckM3]

QUESTIONS:
- with the head gasket replaced should there be any smoke or steam rising from inside the engine (when hot) when you open the oil refill cap?
- is there anything i should be concerned with about an engine that has this major work done to it?

- would it really take 1 week to fix the heater core problem? they said they have to pull out the dash etc..

- should i be concern about the radiator and the water pump now since other components of the cooling system have failed one after another? I guess that if one part of the cooling system fail then an overheating engine would also cause other parts to become defective.

ANY THOUGHTS IS GREATLY APPREACIATED

--No, there shouldn't be steam coming out your engine, but smoke it depend on how hard you ran the car.

--None, if it was done correctly.

--It doesn't take weeks to replace the heater core and it doesn't require the removal of the dash-board. Why would they need to replace your heater core?

--Usually the pattern is if you have a failure in the Theomostate, then the Pump is next, and finally your radiator will be fail due extensive overheat.

[Egor328i]

To All Bimmerfest members who have owned an e36 and has had cooling system problems, i just want to say that i completely understand.I just bought my car in May with 75k miles and now heres how my car took a crap.

I was coming back from my grandparents home when i stopped at a rest area, my car had never really warmed up, but when i pulled back onto the highway and got up to about 55 mph in subzero temps. Wham i heard something break and my engine started to knock, fortunately i made it back, but the engine never got hot. when i arrived home i found fan blades all over the engine,and coolant on the ground, green none the less, so i took the car to a mechanic down the road from my house , and it has been in the shop for just under a week.

1st it was a replaced fan blade, 2nd the water pump 3rd factory coolant 4th a new thermostat 5th a new pulley that had been damaged.so today is December 31st and my mech called and said everythings fine,almost . There is no coolant leak, and it runs smooth, but now there is no heat and the engine temp will not go down from 3/4ths. It could be air in the system, or defective parts.he is going to work on it tomorrow Jan 1st, but for tonight i have no car for new years, and instead of going out and having fun this new years eve i am at home putting messages on internet forums, and hoping that my car will be ok.