Hot temp/pressure issues; thoughts? 3.0i

bigwinn

bigwinn

Elite
 Lincoln UK
Site Supporter
Yesterday John and I replaced his expansion tank as it went pop on his 3.0

Today the second hand one did exactly the same

Now, are we either really unlucky and a third new one will be OK, or there is something causing the issue further up the food chain?

Other things of note are that the fan isn't running, compared to my 3.0 which spins up from engine switch on

Second question is what stops the fan from running?

We have swapped the fans over, so thats not the issue. We have bridged the green wire and still no change.

Engine doesn't show high temp on the gauge at all

What are peoples thoughts?

Cheers

Stuart
 
I was advised years ago by a garage that replaced the expansion tank on my E36 coupe (M52TuB25) when it popped, to slightly under-fill or keep the coolant at the lowest allowable level in order to compensate for pressure buildup during the summer months and warm temps.
Have done that for 15 years now and never had an issue.
Just a thought.
 
Chris_D said:
I was advised years ago by a garage that replaced the expansion tank on my E36 coupe (M52TuB25) when it popped, to slightly under-fill or keep the coolant at the lowest allowable level in order to compensate for pressure buildup during the summer months and warm temps.
Have done that for 15 years now and never had an issue.
Just a thought.
Click to expand...

Cheers Chris. We did top it off tbf
 
Rockhopper said:
I’d do a sniff test to rule out head gasket failure.
Click to expand...
I would check this too. Seems a bit suspect that the second tank failed so quickly. I hope you get it resolved.
 
enuff_zed said:
bigwinn said:
Zulu4 said:
Hi Stuart,
This guy had a similar problem with the fan not coming on. Turned out to be the fan controller (which is on the fan unit itself).
https://www.bimmerforums.com/forum/showthread.php?2410123-Cooling-Fan-will-not-come-on-2005-Z4-2-5
Click to expand...
If the fan control module is on the fan we have swapped these over already- but there is always the possibility that both may be faulty
Click to expand...
Or the supply to it?
Click to expand...

Yeah I’ll get a multimeter over the feed pins good call

Where is it fed from? DME?
 
Newtis seems to show a power feed and a feed from the DME, but just to a big block labelled fan? No other controller?
 
Not just a big fat airlock stopping circulation? If coolant isn't flowing through the rad or past the temp sensor then it could be the block is getting hot on its own and creating extra pressure.
 
enuff_zed said:
Not just a big fat airlock stopping circulation? If coolant isn't flowing through the rad or past the temp sensor then it could be the block is getting hot on its own and creating extra pressure.
Click to expand...
Its worth a check- I think when we replace the current expansion tank I'll run a hose through it too

Is fuse 61 in the engine bay? Cant see it on the fuse board
 
So the rad fan in my car (an M car) the rad fan is off until either the air con is turned on and the fan runs at lets say 25% then as the temp increaces to the higher set point it then runs (lets asume) 100% it may control but other than puting the temp sensor in a controled temp I can not prove it. the fan runs unlit the temp drops to the lower set point.

I can activate the fan with my code reader to run at full speed and turn the air con on to test the lower speed.

The way mine is wired is there are 2 big wires that are live and negative feed that are live all the time (ign on) there is a 3rd wire that is the feed to the controler this apears to come via the temp sensor with is a NTC type of sensor so it is a 12v in and a veriable volts out to drive the fan controler

My 1 serries has 2 signal wires going to the fan controller and the two big wires
The temp sensor looks to fit almost every BMW they have made looking at realoem
picture of sensor and wiring diagram showing the NTC detail.
Capture cooling.PNG
 
bigwinn said:
enuff_zed said:
Not just a big fat airlock stopping circulation? If coolant isn't flowing through the rad or past the temp sensor then it could be the block is getting hot on its own and creating extra pressure.
Click to expand...
Its worth a check- I think when we replace the current expansion tank I'll run a hose through it too

Is fuse 61 in the engine bay? Cant see it on the fuse board
Click to expand...
Says its a 60A in the 'Power Distribution' ??
 
PDJ said:
So the rad fan in my car (an M car) the rad fan is off until either the air con is turned on and the fan runs at lets say 25% then as the temp increaces to the higher set point it then runs (lets asume) 100% it may control but other than puting the temp sensor in a controled temp I can not prove it. the fan runs unlit the temp drops to the lower set point.

I can activate the fan with my code reader to run at full speed and turn the air con on to test the lower speed.

The way mine is wired is there are 2 big wires that are live and negative feed that are live all the time (ign on) there is a 3rd wire that is the feed to the controler this apears to come via the temp sensor with is a NTC type of sensor so it is a 12v in and a veriable volts out to drive the fan controler

My 1 serries has 2 signal wires going to the fan controller and the two big wires
The temp sensor looks to fit almost every BMW they have made looking at realoem
picture of sensor and wiring diagram showing the NTC detail.
Capture cooling.PNG
Click to expand...

Thanks Paul- I tried to fire the fan using INPA and nothing- I am now leaning (once fuses are checked) toward the sensor being faulty!
 
enuff_zed said:
bigwinn said:
enuff_zed said:
Not just a big fat airlock stopping circulation? If coolant isn't flowing through the rad or past the temp sensor then it could be the block is getting hot on its own and creating extra pressure.
Click to expand...
Its worth a check- I think when we replace the current expansion tank I'll run a hose through it too

Is fuse 61 in the engine bay? Cant see it on the fuse board
Click to expand...
Says its a 60A in the 'Power Distribution' ??
Click to expand...

Seeing this one- not on the main fuse board though

F30A8E97-9908-42CE-A564-6CB61DA94FC5.png
 
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