Cooling system issue - very confusing... please help!

speedemn · Sep 8, 2009

My car has been showing signs of cooling issues for a while with a consistent "check coolant level" message. On frequent checks the coolant level was fine so I did not bother to add more coolant. I thought that it might have been the coolant level sensor.

A BMW shop did a cooling system test on it and said that it just needed more coolant. The message did not come back after that which was odd.

Today I was idling in heavy traffic with the AC blasting and the coolant temperature gauge started to climb and hit the red zone and flashed "coolant temperature" on the dash. I immediately blasted the heat until I got out of heavy traffic and the temperature reached back to close to normal operating temperature. Once traffic started moving it went back to normal operating temperature and I was able to turn the AC on again without any issues. Then the "check coolant level" message popped up again.

When I got home I noticed the coolant pouring out of the bottom of the coolant expansion tank over the pan at the bottom and on to the road. I checked a few threads here and waited for the car to cool down and the coolant stopped running out. I then parked on a sloped driveway facing up the slope and added more coolant. The tubes out of the rad were empty and I started the car.

The tubes started to fill up again so I ruled out water pump.
The expansion tank was not leaking so I ruled out cracked tank.

I left the car running and turned the AC on to flush out some of the air and it did and the temperature was stable for a while. One thing I noticed is the fan in front of the rad, behind the grille was not spinning. Then soon thereafter the temperature gauge started to rise again and coolant started bubbling over the top again. I shut the car off at this point.

Can anyone shed some light on what needs to be done here?

1. What can I do in the short term to at least drive it again tomorrow to the shop and ensure that I do not do any damage?

2. Once I got some coolant in the car (and purge as much air out of the system as I can without losing more coolant) can I drive it to work and then to the shop or should I go directly to the shop tomorrow? I will not need to use my AC in the morning and I drive all highway with little stop and go traffic to contend with. It is cool in the morning though.

3. What can I expect the shop to tell me? Is this going to break my wallet?

540nj · Sep 8, 2009

Do you still have your original cooling system?? Why risk severe damage when you know about the history of e39 radiator problems?

My 2003 540i6 sprang a slight leak out of the radiator, the next day I was in the shop getting the work done. 65K miles.

You're looking at ~$1000 at the dealer without replacing everything. DIY for the same price replaces most everything.

dave

bmw_n00b13 · Sep 9, 2009

Cooling system rebuild time. It's overdue, actually.

DO NOT DRIVE THE CAR OVERHEATED. This means that if the needle moves past half-way (i.e. to 3/4), STOP the car immediately. The needle is electronically buffered and the temperature in a '99 540 will reach 117°C before the needle moves, which isn't good.

You may have a busted hose, and/or a jammed thermostat; getting it to the shop without a tow may be a problem depending on how far away the shop is.

speedemn · Sep 9, 2009

bmw_n00b13 said:
Cooling system rebuild time. It's overdue, actually.

DO NOT DRIVE THE CAR OVERHEATED. This means that if the needle moves past half-way (i.e. to 3/4), STOP the car immediately. The needle is electronically buffered and the temperature in a '99 540 will reach 117°C before the needle moves, which isn't good.

You may have a busted hose, and/or a jammed thermostat; getting it to the shop without a tow may be a problem depending on how far away the shop is.

When the car is moving the temperature gauge is normal. I went around the block yesterday with the AC blasting after the coolant level was back to normal and it did not overheat but it did leak coolant through the bottom of the expansion tank when I stopped.

The shop is about an hour away on the highway. I can keep an eye on the temperature gauge when I go to the shop and stop at any sign of temperature increase. However I will have no way of knowing if the coolant is leaking out the expansion tank unless I get a "check coolant level" message while driving.

But if the temperature stays in the normal am I okay to continue driving until I get to the shop?

CSMBlack-540i · Sep 9, 2009

speedemn said:
Can anyone shed some light on what needs to be done here?

1. What can I do in the short term to at least drive it again tomorrow to the shop and ensure that I do not do any damage?

2. Once I got some coolant in the car (and purge as much air out of the system as I can without losing more coolant) can I drive it to work and then to the shop or should I go directly to the shop tomorrow? I will not need to use my AC in the morning and I drive all highway with little stop and go traffic to contend with. It is cool in the morning though.

3. What can I expect the shop to tell me? Is this going to break my wallet?

Do yourself a favor and bring it into the shop ASAP. Fill up the expansion tank ALL THE WAY UP before you drive off to the highway. As there no doubt is a leak somewhere since coolant is coming out of the tank BUT if your shop is located more than 5 miles away, I would see about a tow. Especially if you have AAA service or some other towing membership.

From the sounds of it (based on your description) there is a leak in a hose, crack in the expansion tank/radiator or a stuck thermostat. Usually the tell tale sign of a leak is the WHITE residue that dries up around the leak due to the high heat of the engine. You may not see the actual leak when the engine is off because the pressure is decreased when the engine is off. You will break your wallet (depending on how deep your wallet is) if you go to the dealer. Even as a DIY repair expect to spend about $600-$700 on parts. Easily double that at the dealer for a cooling system overhaul. When it comes to the cooling system on the E39s, it is only as good as its weakest link. Replace a hose and the radiator may be not too far behind. Replace the expansion tank only and the water pump may next. While you are at it change the belts too. So if nothing has been replaced as far as you know:

Replace:

1) Water Pump (Hepu Preferred)
2) Thermostat
3) Radiator hoses
4) Radiator if original (sticker on passenger side of radiator will inidicate date of manufacture-most likely a Behr)
5) ALL Cooling Hoses
6) ALL Belts
7) Expansion tank
8) Fan Clutch (if it doesn't spin freely)
9) Fan Blades (avoid MTC)
10) Gaskets (waterpump & Thermostat)
11) Use BMW coolant if possible or ZEREX G05

Finally if you bring it to the shop, expect about 3-4 1/2 hours of work.

Good luck!

mnepitjr · Sep 9, 2009

Ditto Yeah what he said and then keep bleeding the air out till your tired, stop. Let it sit and do it again the next day. That finally worked on mine well sort of until the stupid light came back on and filled it again but this time seems to be fine.

yeocarp · Sep 9, 2009

Really get it looked at as soon as you can. I pushed the limits once driving on a hot engine and ended up with a warped head. It really sucked. Over heating is one thing that needs to be fixed ASAP.

bmw_n00b13 · Sep 9, 2009

If you're bleeding coolant, I wouldn't put the key in the car, let alone move it.

speedemn · Sep 9, 2009

I drove it the 100kms to the shop this morning. I did not use the AC at all on the trip (it was 18-21 degrees celsius outside). I was able to do about 120 km/h on the highway all the way and when traffic slowed to between 10 km/h - 80 km/h I blasted the heat. The temp. gauge did not move from normal at all. When I got to the shop the expansion tank was leaking coolant from the bottom again... not as bad as yesterday afternoon where it was pouring out. But at least it is at the shop now (safe I hope).

- He said that the fact that the tank is leaking means that I will need a new expansion tank right off the bat - there has got to be a crack in it.
- He also recommended replacing the fan clutch since he was able to spin the large fan behind the rad easily with the car turned off.
- He said that he will test the front rad fan to see if it could be an issue since it did not come on when the car started to overheat yesterday.

For the above jobs and the additional coolant that will be needed he quoted about $400 in parts and labour - sound reasonable?

He is generally very good with prices... $600 for parts and labour for inspection II including spark plug replacement. He charged me $140 to install my Dinan CAI, MAF, TB.
But this time I am in a pinch so I wonder if the price is a bit elevated or if $400 is reasonable for those jobs above.

bmw_n00b13 · Sep 9, 2009

I don't think it's too far off***8230;the expansion tank (BMW price) is like $180 alone. Bleeding the cooling system can be a pain as well. You'll find yourself in a pinch again soon, though, as the rest of the system is poised to fail (water pump, tensioners, various hoses, thermostat, etc).

speedemn · Sep 9, 2009

bmw_n00b13 said:
You'll find yourself in a pinch again soon, though, as the rest of the system is poised to fail (water pump, tensioners, various hoses, thermostat, etc).

I asked him about the other parts too and he did not seem to want to push a replacement of all those parts. I will take that shopping list from above and see what he thinks:

1) Water Pump (Hepu Preferred)
2) Thermostat
3) Radiator hoses
4) Radiator if original (sticker on passenger side of radiator will inidicate date of manufacture-most likely a Behr)
5) ALL Cooling Hoses
6) ALL Belts
7) Expansion tank
8) Fan Clutch (if it doesn't spin freely)
9) Fan Blades (avoid MTC)
10) Gaskets (waterpump & Thermostat)
11) Use BMW coolant if possible or ZEREX G05

#7 and #8 is what he will be doing today at least. So for the other items (sans 7 and 8) what should the cost be - parts and labour? About $800 in parts and 4 hrs in labour?

doru · Sep 9, 2009

I paid 25 bux in Calgary for a jug (1 gallon) of OEM BMW coolant.
Bimmerspecialist - Canada, Exp tank is 83.99 bux and fan clutch OEM (Behr) is 141.99

In US you find much cheaper prices, but you have to take in account shipping and duty.
Prolly Jared or Mark will make you better prices?

Mark@EAC · Sep 9, 2009

Jared and I work at EAC Tuning, not ECS.

CSMBlack-540i · Sep 9, 2009

Mark@EACTuning said:
Jared and I work at EAC Tuning, not ECS. Below is a complete listing of parts to do a cooling swap on a 2003 540i.

thanks!

My bad. Easy to get confused when Jared is in OH and so is ECS.

Mark@EAC · Sep 9, 2009

it happens- similar name and all. We forgive you.

bmw_n00b13 · Sep 10, 2009

After duty it US prices get pretty close to the canadian online suppliers, but it's worth checking with EAC; Mark hangs out in the forums and is helpful so I'd prefer to direct business there than other companies.

speedemn · Sep 10, 2009

I will look in to all those links - thanks guys.

I wanted to provide an update to the issues. The shop I take my car too had a look at the car and ended up replacing the coolant expansion tank (it was cracked) and he said that the fan clutch was in bad shape so he replaced that too. The overheating issues are all gone it seems. The fan in front of my rad still does not work though... but it has not posed an issue - and I even had the AC on MAX in idle traffic today.

I then suggested the cooling system overhaul to him and he said that there is no sense in replacing parts that are currently working - only replace what is broken. He has his own 540 and has serviced many customers' 540s and he said in most cases once the initial problematic items are fixed (clutch fan almost always and coolant expansion tank sometimes) that seems to make any cooling issues go away. Very rarely has he ever done a full overhaul. He said that to defer some expenses if I can make it through the winter he will do my front fan next summer.

Thanks for the advice and help through this thread. I will definetly keep a close eye on this thread as I plan for replacement of parts as required. I love this forum!

cn90 · Sep 10, 2009

Your mechanic is a nice guy and tries to save you money but he is dead wrong.
He is correct that one should not replace parts that are not broken.

But Cooling System is the esception. The parts may look good now, but it can explode tomorrow at that age.
Cooling System parts at that age can go any time.
Just don't do long trips far away from home for now.

I don't know about your mechanical skills, but V8 people should do this Cooling Overhaul written by "BlackBMWs":
http://forums.bimmerforums.com/forum/showthread.php?t=1139685

speedemn · Sep 10, 2009

He is well aware of the risks and mentioned them to me himself. He did inspect all the other major components:
- rad (he said it looked good... might have been replaced by 1st owner - who knows... there was no date on it)
- water pump
- fan blades

He said that replacing the fan clutch even thought it was not broken yet was smart in order to prevent an explosion in there. But other components can wait.

BTW I do long trips everyday - I work 100 kms from home... but his shop is 30 kms from my work.

What specifically would be at risk of "explosion" outside of what is controlled by the fan clutch which is now new on my car?

CSMBlack-540i · Sep 11, 2009

Well, from the sounds of it your mechanic is not out to rip you off. NOW. While I am not saying he will, perhaps you have found a very trustworthy mechanic. From my own personal experience, there was this one mechanic a bunch of us trusted in the neighborhood. At some point, the previous owner decided to sell the shop to him and then things changed, he started recommending things I don't think he would have just as a worker before. I guess he had to make back his money somehow. After that he lost a lot of customers, AGAIN, I am not saying your mechanic is like that but who knows how things will remain. I hope FOREVER. Just always be aware and bounce your ideas off the forums members before any work.

Now as far as the cooling system, I would still recommend an overhaul. HOWEVER, I will make a few points

1) If you work 100km from home, and your mechanic is somewhere in between. I guess as long as you can live with another situation like yesterday whereby something else goes on the cooling system and can bring it in and still go to work, it might me ok. You don't want to find yourself in a situation where you are driving on vacation or somewhere far away from a trusty mechanic an wind up getting ripped off because something else goes wrong on the wrong time. If you read through the forums and many forum members, if not all will support this, there simply are too many issues with E39 cooling systems. It is a known fact.

2) Can anything else "explode"? The only thing I can think of is the water pump impeller, one of the drive belt tensioners or fan blade going (yes the fan clutch was replaced be who knows the condition of the fan blades) If this happens while you are on the highway and it seems like most of your driving is on the highway, there is a possibility your hood might be damaged.

3) While I understand the point of saving some money in this day and age and the way the economy is it. Only you can decide if you can live with the idea of the "check coolant" light coming on for a variety of reasons because an overhaul was not done. I believe many on the forum would opt to have the piece of mind that once the overhaul is done properly, it may be the last time you need it done as it will be good for at least another 80,000km or 50,000 miles (depends on how long you plan to keep it). Many on the forum consider the $1,000 a form of insurance that other than the need to flush the coolant ever two years, the cooling system will probably last to the point you sell it.

4) At a minimum, I think it's worthwhile to replace the hoses as they can go at anytime and cause an inconvenience. But then again, it happens like it did yesterday. I am sure you'll just fill up the radiator, and just drive to the mechanic.

My two cents for what it's worth.

Good to hear that you got it done quickly though and hopefully your mechanic stays honest unlike the experience I once had,

Cooling system issue - very confusing... please help!

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