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RE: overheating 97 E36 M3

schneller — Fri, 30 May 2008 11:41:23 GMT

I understand that this is a do it yourself forum & I am supposed to lend advice here on how to fix your own car but...To be successful at anything in life & avoid disaster, an individual needs to know when he's in over his head.:w00t:

If you don't understand how a cooling system works, then how can you properly use overheating symptoms to diagnose which components have failed? How comfortable would you be with your doctor if he didn't know anything about the human body, but just started to learn about your ailment over the internet as he began working with you? That's what your doing with your car. Furthermore it's over heating & you continue to drive it! You are gambling with thousands of (your) dollars betting that you can fix your own car with little knowledge or expertise in the area.

While I've seen some do it yourself mechanics successfully replace water pumps & thermostats, I've also replaced many cracked or warped cylinder heads because air wasn't properly bled from the cooling systems & the cars subsequently overheated.

The M50 - S52 engine series is very sensitive to running hot. Kiss the red with the temp gauge & you'll be lucky to not at least lose the head gasket. Keep it in the red for 30 or more seconds & the head will be warped & possibly cracked.

It sounds to me like it's time to consult someone familiar w/ these engines relative to your overheating issue. Call your dealer or check out BIMRS.org for a capable & reputable shop. The corner gas station won't have the knowledge or the tools to set up the VANOS should the cylinder head need to be removed & reinstalled.

Good luck!;)

RE: overheating 97 E36 M3

cowenj1 — Fri, 30 May 2008 09:31:07 GMT

The only way to know if you warped the head, is to take it off and measure, i think. As i said before, i believe you can warp it, and not have related problems right away (that happened to me). So, get that cooling system fixed up, and drive the car. You will have symptoms if you have a leaking head gasket, or cracked head. However, your car might just work. Make sure you get those cooling system parts replaced, so you can enjoy the car for the summer. Its reletively easy work, and inexpensive if you do it yourself. I think i remember getting a "cooling system replacement kit" from one of the popular online BMW parts places for like $250 that included radiator, thermostat, housing, water pump, radiator hoses.

Start with removing and replacing the fan (i think you said it was not working). Once you remove the fan (hardest part of the job), the thermostat houseing and water pump are right there, and easy to reach. Those are 10 minute jobs once the fan is off. If your radiator hasnt cracked yet, and you want to save money and just diagnose the problem, put the car back togather with the new parts above, bleed the cooling system (special procedure, but easy) and test. If your radiator is original, and you have more then 70k miles, i suggest replacing it, as the plastic upper hose connection breaks off and causes immediate overheat.

For more info on cooling system repairs, what breaks, what should be replaced and how often, start browsing bimmerforums.com. There are also tons of DIY articles to help you.

RE: overheating 97 E36 M3

eyelise — Wed, 28 May 2008 13:11:51 GMT

Man I really hope I didn't warp my heads. I haven't driven the car since the problem was identified. Any way I can tell?

Jeff

RE: overheating 97 E36 M3

KenM10759 — Fri, 16 May 2008 11:56:16 GMT

If you are replacing the coolant pump before the fan clutch, you might be replacing the radiator with the fan clutch. If that thing goes, it could blow bits of fan blade through your radiator, into your hood, and lots of other places. There's a number of photos out there of just how much damage an exploded fan can do to a car, don't take chances!

RE: overheating 97 E36 M3

schnoerrmeister — Mon, 12 May 2008 18:28:30 GMT

More to the Cowan entry.....

Mine started using a cup of coolant per run group at DE's. Then it tried to push out the #6 spark plug and started missing in the middle of theh commute on a six day's DE trip to Canada. By watching the level after every run group, and after gently tighening the loose plug to re-gain the ground and get back to 6 cylinders, I had a great week and finally convinced a shop to pull the head and do the work that no leakdown test ever could detect.

It is terrific again. It was not cheap. We made it more bullet proof than ever.

Mark

RE: overheating 97 E36 M3

cowenj1 — Wed, 07 May 2008 15:36:53 GMT

The stock gauge is buffered. I had some overheating issues with mine last year, and installed an aftermarked gauge. The needle on the stock gauge doesnt move from the middle until the car is over 235 degrees. At the 2nd white mark, its even hotter. I would consider that to be an overheat. If it got past that white line, you very well could have a warped head. That happened to mine. Mine was warped for 2 years before i started having additional problems because of it. In other words, you could have head damage, but no signs of it yet.

I would say that if the motor fan is not working, that is a very large problem, and you shouldnt drive the car until you replace it. With no fan, these cars cant idle.

If i were you, i would replace the entire cooling system (as mentioned above), then hope you didnt do head damage. I wont tell you my story because you dont want to hear it.

RE: overheating 97 E36 M3

schneller — Wed, 07 May 2008 10:06:14 GMT

Lot's of good points here...

Cooling problems fall into 2 general areas:

1)Problems w/ coolant circulation
* Water pump, Stuck Thermostat, clogged radiator, failed head gasket, low coolant level

All these will prevent coolant circulation & the car will run hot all the time after warm up.

2) Problems w/ Air flow related to heat liberation from the radiator
* Failed fan clutch, air flow blockage in front of radiator
With a failed fan clutch the car will run hot at idle but cool down once you're moving. Dirt in the radiator fins will make the car run hot all the time, but in all my years of running a Service facility, I have never had that many leaves pile up in front of a BMW Radiator.

Good Luck!;)

RE: overheating 97 E36 M3

eyelise — Tue, 06 May 2008 22:48:56 GMT

I'm going to order the water pump. The car ran hot on the highway which suggests a problem with the pump or radiator. It is a recent development so I'm leaning toward the pump not radiator.

RE: overheating 97 E36 M3

schnoerrmeister — Tue, 06 May 2008 20:52:42 GMT

You are at the time and mileage to do a radiator, water pump, thermostat housing, coolant, etc. If the car got hot enough to do any damage to the head, watch for coolant loss but nothing leaking on the ground. If any head damage might have occurred, you will see white jelly-like stuff under the oil cap or strange colored oil. This will clog things up eventually and can be hard diagnose as a cracked head since is can seal off until the car is at running temperature.

These cars are not the cheapest to keep, but make owning any passionate car near as much fun look extremely costly.

RE: overheating 97 E36 M3

lbarbieri — Tue, 06 May 2008 14:34:38 GMT

Another test you can do is open the expansion tank cap while the car is running. Look in there and you should see a pretty steady stream of coolant being sprayed in there. That's a good indication that your water pump is working. If you don't see a good stream then chances are the water pump is shot. Get it out of there!

Jim is right, all the "stock" water pumps will fail. If you're going to keep the car, spend the money and get the Stewart pump. Jim is also right that you should just replace all the suspect parts, thermostat, radiator, water pump, hoses, expansion tank.

RE: overheating 97 E36 M3

m3jim — Tue, 06 May 2008 08:22:58 GMT

P.S. If you change the thermostat, you need to remove the thermostat housing. This is plastic also, and has been known to split. Replace it with an aluminium housing.... This is one of those 'while you're in there, you might as well....' things.

RE: overheating 97 E36 M3

m3jim — Tue, 06 May 2008 06:58:59 GMT

"Is the bad fan clutch your entire problem?" - I sort of doubt it, but here's how to test. Just go for a drive with the heater off. When you're driving over 20mph, there is more air moving through the radiator than the radiator fan could ever move. (The radiator fan always turns, but it only moves significant air when you're stopped) So, if you drive and it still overheats, there is something wrong besides the fan clutch. I'd vote for either water pump or clogged radiator fins (thermostat is 3rd choice). Pop the clips that hold the radiator in place, and look between the radiator and the air conditioning evaporator coil (the air conditiong radiator). I bet there are all sorts of leaves and dead bugs in there, blocking air flow.

You can get these parts anywhere, your dealer, Turner, UUC... But I got mine from Bimmerworld:

http://store.bimmerworld.com/shared/StoreFront/default.asp?CS=bimmerworl&StoreType=BtoC&Count1=56484401&Count2=973624825&CategoryID=7&Target=products.asp

Jim

RE: overheating 97 E36 M3

eyelise — Mon, 05 May 2008 21:06:09 GMT

tx a bunch, very helful. I know for a fact the fan clutch is gone. The fan spins freely with a finger. Would that be enough to cause the entire problem? There are no leaks at the top of the radiator or plastic overflow bottle. Do I need to have it pressure tested? Where is the best place to buy parts like the water pump?

RE: overheating 97 E36 M3

m3jim — Mon, 05 May 2008 18:04:49 GMT

The cooling system on E36's is probably the car's weakest point. By 80k miles, it's time to do a complete refresh (if you want a 100% reliable solution that you won't have touch for the next 80k miles). Anything else is just a patch, and some other part of the system may go any day.

Problems: Plastic radiator and overflow bottle - The radiator usually fails where the upper radiator hose connects to the radiator. You can replace the radiator with another stock radiator for ~ $150, or you can get an aluminium radiator for $400-$500.

Water Pump. There are at least 3 'stock' water pumps. Some have a metal Impeller, some plastic, and some have a composite. They all fail, the question is just when. I replaced mine with a Stewart aftermarket pump. They flow more and have a lifetime guarantee, but cost $200.

If you're going to do all that, you should probably replace the hoses and belts (since they have to come off anyway).

And check the fan - the fan clutch has been known to fail. With the engine OFF, you can grab the fan and see how easily you can spin it. You should not be able to spin it, you should be able to move it though. If you can spin it, the fan clutch is gone.

If you do drain the fluid, replace it with BMW's Blue Antifreeze fluid. You drive a BMW after all, don't put $5 a gallon PEP Boys stuff in there..... And a bottle of Water Wetter can help also.

You do have a problem because the Temp on my M3 never moves beyond 12:00, no matter how warm it is outside.

Also, if you keep your radiator, it could be blocked. Leaves and other crap can clog up the fins and block airflow. Good Luck. :)

overheating 97 E36 M3

eyelise — Mon, 05 May 2008 12:53:21 GMT

I was at an autocroos Sunday with my new used M3. The engine ran very hot. The temp guage passed the third white line indicator although not into the red and it did not boilover. I checked the coolant lvl and it was fine. Are there any areas that commonly cause overheating in the E36 M3? The engine has 70K and has seen light duty. I was thinking of changing the thermostat incase it was sticking. Obviously the fluid change as well at that time. I hope the radiator is not shot. BTW, I had to put the heater on full blast while cruising on the highway. It definitely kept it from overheating.