Car overheated today :(

Z

Zookoo25

Member
Hi guys,

So for the past few weeks I've been having trouble free motoring with the zed :driving: but then today whilst I was parking the car, the temp guage hit the warning redline. Luckily I was home and switched the car off right away to cool down but needless to say I'm quite worried.

I noticed the temp start to climb in heavy traffic today, and it went back down to normal when the car started moving.

Now... I think the culprit is the fan. Thinking about it, I am pretty sure I have never heard it come on. I could be wrong of course. But, once the car cooled down, I tried to get the fan to spin up by switching the car on and turning on the AC. No luck.

So I guess my questions are:

- Is there a way to trigger the fan without actually driving the car (as I don't want to risk it overheating)
- are there any other checks you would make (no signs of leaks on the floor or anything).

Thanks for any help
 
BMWs have the shittest cooling systems of any car I've ever owned. Water pumps, thermostats, radiators, hoses etc should all be treated as consumables and can need replacing every couple of years. I've had issues with almost all of the 7 or 8 BMWs I've owned (apart from the Z4, touch wood!)

The temperature needle should take a maximum of 5 minutes to reach the centre, and then stay there at all times. If it takes ages to reach the middle, dips down while driving or creeps up while stationary, you have a problem.
 
Ouch. Thanks guys. Will get thermostat looked at. Any ideas on whether I can trigger the fan manually and how? Only as I won't be able to get the car looked at for a couple of weeks and in other cars I have driven you could force the engine fan to run by some combination of aircon settings. Useful in case of emergency.
 
I have a R53 Mini Cooper S and that overheated when stuck in traffic once, it was caused by a blown fuse for the fan so it wasn't kicking in. Worth a check.
 
There is a max cooling button on the aircon controls - the snowflake on the temp dial IIRC correctly. Press it, the car should try to freeze hell over. If that doesn't make the fan come on I don't know what will.

That said, doesn't the Z have two fans, one for the engine and one for the aircon ? I have no idea by the way, I just know other cars do.
 
If you leave the engine running idle at home on the drive the fan should eventually kick on once the engine starts to heat up past operating temperatures due to no air cooling. Just keep an eye on your temperature and if the needle is moving up towards the red line without the fan coming on when idling then you have an issue.

You can also just rev the engine a bit to speed up the heating up process once at operating temps.

I had this issue on my old 2.0i, dealer diagnosed it as a control wire for the fan has corroded, stopping it from activating, and they replaced it under warranty.
 
...................... I just posted something similar on the M thread ....... :D

My fan was not kicking in, resulting in amber then red warning lights coming on when stationary ........
Being the person I am, I googled the sh*t out of it and decided to change the Fan and Radiator ...... cost me around 800 quid to get the parts and do it myself.

End result ....... fan was still not kicking in ........

Took it to the dealers ..... got them to plug it in, they eventually found a broken / damaged wire which was causing the problem.
They then did a full health check which turned out ok.

The advice from me then is that before you start spending wads of cash, plug into it and perform a full systems test ...... :thumbsup:

http://www.z4-forum.com/forum/viewtopic.php?f=9&t=65921
 
Hmmm... The plot thickens. It's booked into a garage next week but I'm still trying to self diagnose and have followed a lot of the advice here. Saving money on diagnostics is a Good Thing I reckon!

1- coolant looks good/healthy level and no mayo
2- got it up to temp today and then sat stationary for 10 mins revving the engine. Steady as a rock. No wavering from the midpoint on the temp gauge. Yet, fan did not spin and popping the bonnet, the engine felt ridiculously hot. Radiating heat like crazy. Nothing like other cars I have driven.
3- no combination of air con settings forced the main fan to work. However, air con works fine therefore @bing conclusion is there must be a separate air con fan

Disca said:
If you leave the engine running idle at home on the drive the fan should eventually kick on once the engine starts to heat up past operating temperatures due to no air cooling. Just keep an eye on your temperature and if the needle is moving up towards the red line without the fan coming on when idling then you have an issue.

You can also just rev the engine a bit to speed up the heating up process once at operating temps.

I had this issue on my old 2.0i, dealer diagnosed it as a control wire for the fan has corroded, stopping it from activating, and they replaced it under warranty.
Click to expand...

teamemmenracing said:
...................... I just posted something similar on the M thread ....... :D

My fan was not kicking in, resulting in amber then red warning lights coming on when stationary ........
Being the person I am, I googled the sh*t out of it and decided to change the Fan and Radiator ...... cost me around 800 quid to get the parts and do it myself.

End result ....... fan was still not kicking in ........
Click to expand...

How long did it take whilst stationary to overheat? I was stood still for 10 minutes after I got the car to the midway mark of the temp gauge.
 
Depends on outside air temp etc.

Just sit in the car with the engine revved slightly once its warm and eventually either the fan will come on or the needle will begin to rise above the middle of the temp gauge.

The fan on my car kicks in long before the needle even moves though.

If the needle moves above middle and the fan isn't on then I would say something is stopping it from activating, as I said mine was a corroded control wire that BMW found when I got them to investigate under warranty.
 
Update - sorted.

Turns out the cooling fan WAS buggered and needed a new one. Approx 400quid including the fitting by an independent near me. Luckily car under warrenty still. Now running beautifully - being stuck on the M6 yesterday for 2 hours gave it a good stress test!

In the process I learnt a few things in case anyone else gets a problem - might be obvious to everyone but anyway:

1- running the car heater on hot will blow hot engine air into the cabin. Useful when you are stuck in gridlock traffic and the temp needle is inching close to red. You will roast but it will save the engine. If the cooling can is broke.

2- the cooling fan is triggered by the cold ac as well as the thermostat. So if you ever wanna check, just set the aircon on cold and if the fan starts spinning it's working :)

3- temp gauge doesn't need to move past the centre line to trigger the fan. Seems like it will switch on once the engine is under a certain load.

Hope it's useful.
 
Number 1 was how I managed to survive being stuck when I discovered mine failed too! But it was about 27 degrees and I still had to keep the hot air pumping out :(

That and the roof had to be up else I would have burnt to a crisp!
 
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