Author Topic: E36 overheating (Read 5460 times)

carter1 · « **on:** April 13, 2010, 03:48:50 AM »

Hi All,

Need a little assistance here. I've seen tons of thread so far on this and there do not seem to be any with a solid conclusion.

I have a '96 E36 328i coupe (no A/C) and it's overheating. I suspected a leaking rad for a while and this resulted in it failing (blowing the exp. tank). I changed the T/S and added a new rad and this proved to work fine, apart from it being a PITA to bleed.
On start-up the engine temp slowly rises to mid way on the temp gauge and stays there, T/C clicks open, flow circulates, fan is working, engine stays at mid-temp. However, after about 20mins there is still no heat from the matrix in the cab and the coolant starts to boil up and splutter then the engine temp starts to rise to the point where I have to cut it and start again.

I�ve taken the pump off and it�s fine. It looks brand new, I imagine the prev. owner had it replaced knowing of an issue� At the mo, I suspect it�s the Heater Control Valve, it clicks to hot but is sticky and perhaps it�s clicking back to cold when I fill/bleed the system causing an air pocket? The new part is here so I�ll install it tonight and post how it goes.

I just hope it�s not the head gasket. Anyone had the same issue and solved it? Also, anyone have any solid tips on a thorough system bleed?
Cheers,
M

dinu.negrean · « **Reply #1 on:** April 13, 2010, 03:56:52 PM »

Taking the head off on a 6cylinder would be a real pain. Your car behaves like a car that is not properly bled.

What I did and worked fine is:
"First, check the drain plug on the new radiator to be sure it isn�t loose. Then mix fresh OEM BMW coolant with distilled water at a 50/50 ratio. Slowly pour the mixed coolant into the expansion tank. Keep filling until it spills out of the bleeder screw hole. Partially thread the bleeder screw back in and start the engine. Turn the heater control to full heat and run the engine until it reaches operating temperature, adding coolant to keep the expansion tank topped off. Watch the temp gauge closely and immediately shut the engine off if the needle approaches the red � something is wrong! If you did it right, the needle will point straight up and stay there.Have a helper rev the engine to 2,000rpm and hold it there. Keep adding coolant to the expansion tank and watch the bleed screw. When there are no more air bubbles coming out and it�s a steady stream of coolant, the system is bled. Tighten the bleed screw and shut off the engine."

The last time, I have taken the top hose and poured water inthere untill it filled up, and after that poured in the expanion tank. I have heard several opinions saying water will fill the engine better. Actually no difference from the method I have mentioned above.

Good luck

carter1 · « **Reply #2 on:** April 14, 2010, 02:53:29 AM »

Hi dinu.negrean. Thanks for the tip. I did this last night. I replaced the HCV, flushed the matrix with a hose to check for flow, bled the system, let it cool and bled it again. It ran fine for about 20mins on idle at mid-temp without leaking. I took it for a short spin and there was still no heat from the matrix - I was getting very short 'shots' of heat but few and far between.
It didn't overheat but when I got back, there was water pi33ing from the rad cap. I let it cool, topped it up, went for another drive and it seemed to lose the coolant and overheated. The pressure seems to be pushing the coolant through the cap and not through the matrix.
I spoke to a BMW tech I know and he said it's either a massive airlock for some reason (blockage?) or it's the head taking in air throught the gasket. Lord, I hope not!$$$ Apparently these can pull air through the head gasket and there can be no typical sign of a busted head gasket (milky oil, white smoke or oil in the coolant)...
Cheers, M

Rosales · « **Reply #3 on:** April 14, 2010, 09:44:32 AM »

Quote from: carter1;90846

Apparently these can pull air through the head gasket and there can be no typical sign of a busted head gasket (milky oil, white smoke or oil in the coolant)...
Cheers, M

Would a compression test be able to tell if this is happening? I ran one and the results from the front to back came as this:
1:190
2:200
3:225
4:220

I have replaced a leaky valvecover gasket since, but im not sure it that will play a role.

dinu.negrean · « **Reply #4 on:** April 14, 2010, 06:41:58 PM »

My previous engine had a similar problem, gasket was leaking coolant on cyl 2 and 3, but a lot more on #2. If the gasket creates a connection between coolant pattern and cylinder, you can imagine what kind of pressure does build up each time the cylinder makes the compression phase.

So, judging from the numbers on the test my guess would be 95% chances of a blown headgasket on cyl #1 and moving twards #2

I am in the same situation,except it does not overheat. If I drive it light, up to 2500-3000 rpm, it blows white smoke, and eats coolant, exhaust alway wet. If I drive it hard, the exhaust will be completly dry but pressure builds up in the system and if I open the radiator cap it will throw coolant out.

Any of the above simptoms present?

BlueBMW · « **Reply #5 on:** April 14, 2010, 09:05:49 PM »

If you run the motor with the radiator cap off, do you see any bubbles coming up out of the coolant? That can be a sign of cylinder compression leaking into the coolant system.

carter1 · « **Reply #6 on:** April 15, 2010, 06:53:45 AM »

Thanks for the help all. In response:

- I see no symptoms of a blown head gasket. Nothing odd coming from the exhust.
- Everyone knows what a pita they are to bleed and I do get bubbling but once properly bled, the system works fine.
- I spoke to a tech I know last night and I'm getting a compression test done shortly along with a gas test to check for hydrocarbons in the coolant.

Note: I checked a diagram of the system and it seems that when checking the matrix for a blockage, I was mistaking two 'in' ports for an 'in' and 'out'. The flow was of course find because it was just circulating throught the 2 'in' ports... - there still could be an airlock so I'll find the 'out' and put a hose on this to check flow throught the matrix. I'll keep everyone posted...

Thanks,
M

flyinglizard · « **Reply #7 on:** April 15, 2010, 10:27:26 PM »

Are there any real clean plugs?? White plugs are water vapor cleaning. The plugs should be very even in color. I would guess head gasket, and or corrosion near the sealing ring of the head gasket.
The bursting of the rad should tell of high pressure leaking from the cyl. . maybe.
Tip the car , up and bleed as above. Then fix the head. \
Maybe you will get lucky, try to fix the heat circuit ,as you are doing to get rid of the air.
Good luck. MM

carter1 · « **Reply #8 on:** April 21, 2010, 02:58:01 AM »

Hi All,

New update: I wasn't satisfied that I had sone all I could so I didn't get a 'proper' mechanic in at this stage. So Last night I:

- Took off the rad, T/S, Heater control valve, and waterpump assy.
- Did the thermostat test - passed.
- Replaced the waterpump (Although I couldn't see any issues anyway).
- Flushed water through all the pipes (without any obstuction).
- Checked the HCV - passed.
- Put it all back together, filled it from the matrix side and properly bled it.

After this it seemed to be running fine (apart from breaking the coolant level sensor:mad:). T/S opened and stayed at mid-heat. I idled it for about 15mins and drove it 10mins. When stopped, I noticed a light 'pee' from the expansion tank side (not sure if it was the tank or the cap) and the heater was still not working.

I've got the mechanic coming in and I'm now off to shoot myself...
:confused:

PumpItUp · « **Reply #9 on:** April 21, 2010, 05:35:32 AM »

A bit off topic but, do radiator flush products do anything?
Or is it just for when it gets really bad, and you have chips in your fluid..
Previously I just unbolted the radiator and flushed it out that way

carter1 · « **Reply #10 on:** April 23, 2010, 05:45:05 AM »

I'm still thinking that it may be the head gasket.. Has anyone actually overcome this by replacing it..?

locknload · « **Reply #11 on:** May 25, 2010, 09:46:31 PM »

Happy ending here yet?