L322 4.4 temp gauge over read? Help

Hello all!

This is my first post, please be gentle

I've just changed the thermostat on my wifes 4.4 L322 with the BMW engine - it blew the top hose as the 'stat appeared to be jammed.

There might be wider H/G issues but for now I have another problem...

The temp gauge shoots past the red even with the engine stone cold. You turn the ignition on, the gauge moves to where it should be when cold, pauses and then rockets pas the red section.

I thought that after the hose blew water could have got into a connection somewhere and after cracking as many as I could find and blowing with and air line there's no change.

I've bled the system as per the manual and now I'm at a complete loss.

Can anyone suggest anything?

Thanks!!

this could be as easy as a bad earth, try putting a jump lead from bat earth to engine then turn it on..

j the range said:

this could be as easy as a bad earth, try putting a jump lead from bat earth to engine then turn it on..

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I ran the engine for a couple of seconds just in case it was an air lock that needed to be moved - no joy, but I think that would suggest the earth's are fine?

Hmmmm, I wonder if the pump's gone and it is an air lock around the temp sensor?

That said, I can see water moving in the expension tank with the engine running...

Duke Thrust said:

I ran the engine for a couple of seconds just in case it was an air lock that needed to be moved - no joy, but I think that would suggest the earth's are fine?

Hmmmm, I wonder if the pump's gone and it is an air lock around the temp sensor?

Click to expand...

A running engine is no proof of a sound earth.

Steve_R1979 said:

A running engine is no proof of a sound earth.

Click to expand...

Tried this now, no joy.

Interestingly the needle pauses exactly where I'd expect it to after having been cooling for a while after it's been running for a minute or two.

Something is causing it to go silly, grrr!!

Duff sensor?

I agree with Data. Can't really be a lot else.

It's an odd one - this morning ignition on, it pauses on cold then off the scale. Let it run for a few minutes and then it'll pause on warm and then off the scale.

It's sensing the correct temp and then going silly. For 12 quid a new sensor is a sensible place to start, it just seems so very odd.

Well, changed the sensor and it made no difference.

Took it for a short drive and within a mile all was well and it's behaved since, very odd!

I had it idling for about half a hour and it stayed at a steady temp and the top hose stayed 'pinchable' and wasn't over pressurising.

I did notice that the viscous coupling span very freely even when the engine had been idling all that time - I would have expected it to be a lot stiffer before this point?

They can fail by locking up, but can they also fail by not engaging as well?

Might start another thread...

Duke Thrust said:

Well, changed the sensor and it made no difference.

Took it for a short drive and within a mile all was well and it's behaved since, very odd!

I had it idling for about half a hour and it stayed at a steady temp and the top hose stayed 'pinchable' and wasn't over pressurising.

I did notice that the viscous coupling span very freely even when the engine had been idling all that time - I would have expected it to be a lot stiffer before this point?

They can fail by locking up, but can they also fail by not engaging as well?

Might start another thread...

Click to expand...

The fan viscous coupling can fail either way, seize or fail to drive. With the engine hot stick a rolled up newspaper into the blades (watching your hands or course), if the fan stops it's shagged, it should shred the paper

Top tip ta!

Tried it and I can stop the fan - in fact I can spin it quite freely in the opposite direction