Overheating Sometimes

[murrayafc 6]

Hello

twice now the car has jumped up to about the 3/4 mark on the temp gauge never went into the red. This has happened when I been sitting in traffic for long periods. Drops again and seems fine after that.

I check the coolant level every morning and does not seem to be losing any, checked this morning and when I opened the cap the water came out of the radiator as if the air con was on, car was not on and stone cold and the level seemed alot higher than it was the previous day?

I monitor the temp when driving and it maxes at about 110 and normally sits around the 90 to 106. when the temp needle crept up it was at 114.

So it runs fine 99 per cent of the time. Rad and hoses have been done, its a 2003 E39 525I

I also tested the fan when it was running and warm and could not easily stop it so think this is fine, cant see any obvious leaks anywhere either.

I bled the system and will do it again over the weekend.

Any ideas what might be happening here?

Cheers

[Mad_Max 231]

If the system is properly bled, about the only things i could think that may cause this issue would be the thermostat sticking or possibly the water pump is on it's way out.

[murrayafc 6]

cheers, might be worth doing the water pump and thermostat then, no idea if they have been changed.

[zero 1162]

Properly bleeding these cars can be tricky.

Sometimes you think its bled properly and yet it still has an air pocket.

[Rubix 434]

If coolant/water came out of the expansion tank after it had been sitting and had cooled completely this means that the system was still pressurized, this could be caused by heater control valve being stuck closed, combustion gases in cooling system etc. 
Compression/leak down test it. I speak from experience (luckily mine was just a faulty HCV).

115 is the danger zone for an m54, anywhere from 80-114 is normal.

Edited August 3, 2016 by Rubix

[*Glenn* 854]

Craig... I have just dealt with a problem like this that we repaired last week. Give me a call tomorrow at work in the morning only (09) 2722546

[murrayafc 6]

So to add to this. I did alot of driving the other night and the car jumped up into the red zone, quickly shut it off and waited for it cool down. Started again and got home with the temp gauge center again and not going above 114.

Let the car cool overnight and did another system bleed. took the car for a drive and let it warm up then drove it like it was stolen for a while, temp never went over 100 was sitting between 80 and 97. So looks like bleeding has fixed it but not finished yet, will recheck again over the weekend car is not in use until this is 100 per cent fixed.

Noticed im getting no hot air from the front vents either, demist and footwell are hot..

 

[jom 98]

Are you putting the internal temperature setting to max (32°) before you bleed it? That should clear any air out of the heater.

[murrayafc 6]

Yeah I'm putting it up to 32 and on the 1st fan setting. Have bled it again tonight and no air came out either bleed screw. Will take it for a drive tomorrow and see if it behaves.

[murrayafc 6]

More testing done today and can't get it to rise above 97 now so it's looking good. I am getting heat from the front vents I just never turned the middle wheel up enough (what a dick ha ha)

will take it to work tomorrow and sit on onewa road for 12 hours in the morning so that will be the ultimate test.

[murrayafc 6]

Well the issue has returned. Started to overheat again last night on the way home. caught it in plenty of time so never went passed the 3/4 mark. I watch the temp reading like a hawk and when im getting close to 114 pull over. Only seems to be an issue when im stuck in traffic, both top and bottom rad hoses were hot. Let it cool for a bit and then drove home with heater on full blast and full heat and never rose above 100. Bled the system again this morning and car drove to work perfect not rising above 94. im almost done with it as need something reliable as I drive alot for work and don't really have the cash for a mechanics repair bill on it right now. If the head gasket was gone would it overheat all the time? Thanks for any advise again.

[zero 1162]

If it was head gasket you would most likely be using water.

 

It sounds like you are holding water fine.

As someone else suggested it could be water pump not pumping the water through the system properly. Water pumps with the plastic impeller are a weak point on this engine.

If you are local I can loan you a working second hand water pump to see if that fixes the problem.

If it is then a new waterpump with the stronger metal impellor is only $30 Euro from Schmiedmann.

[murrayafc 6]

Cheers zero. If it was the water pump would this only cause an issue when idle? or if the pump was gone would this be a constant issue even when moving. as it behaves fine when im moving but moving is not something i do alot during the daily commute. Yip its holding water fine.

[*Glenn* 854]

Did you not read my previous post Craig ?

[murrayafc 6]

sorrry glen I missed that, Let me know and I will give you a call

cheers

[*Glenn* 854]

Call now if you like

 

[M3AN 4016]

Check you clutch fan also, your symptoms sound like it's on its way out.

 

[murrayafc 6]

Thanks for all the good advise. I decided to change the fan clutch this morning and results look promising so far. Took it for a drive up to temp and sat idle temp went up but then came down by itself only turning the ac on hot would help before but only briefly. Also I can actually hear the fan kicking in which I couldn't before. Notice now the Front aux fan does not work so that's the next task.

cheers.

[zero 1162]

Craig - rather than throw parts and money at the problem, you are better to take it to Glenn for a proper diagnosis.

[hybrid 1043]

The is a proper bleed proceedure for e39/x5 which requires you to follow it to the letter. Even then you will have stalled air in the system with out a bit of driving around with the heater on full blast.

IT all about catching it before the thermostat opens as not to trap air in the heater system which takes days to get out when it happens. E39 life ... something I dont miss anymore.

[murrayafc 6]

To be fair I'm not throwing parts and money at it, everything pointed to the fan clutch and it failed every test. Was a cheap and easy fix. If it keeps playing up I will take it to Glenn but i don't have the luxury of being able to leave the car with him so it's not as easy.