Oscillating temperature gauge – solved!

[Chris P]

You may remember that I posted about a problem with the coolant temperature gauge: every time I pressed the clutch pedal, the gauge dropped to zero, to rise quite happily as soon as I released the clutch. I expected the problem to be somewhere near the pedal but, having contorted myself to get down there, I found no wires anywhere near the pedal. Next, I removed the black plastic cover under the bonnet, to see if there was a problem near the master cylinder. Nope. No wires there. This really only left one place: the slave cylinder.

Sure enough, this is where the problem was. Basically, the part of the harness holding the cables running to the coolant temperature sensor and the temperature sensor for the ECU run right by the clutch slave cylinder. Now the piston in the cylinder doesn’t move very far with each use of the clutch (maybe an inch) but every time it was used, it waggled this mini-harness back and forth. I guess it got to the point where the wires were severed but the insulation wasn’t and using the clutch bent the cable enough to separate the strands of the conductor. I took apart the connector fitting onto the sensor (what a job) and rewired it with fresh cable and – lo and behold – all is OK. (I also cable-tied the harness out of the way of the clutch!)

So…next time you have your engine cover off, you might like to think about checking the same cables. I don’t know whether it was just that they were misrouted on mine or whether they’re all like that (in which case, duh!).

Hope this helps somebody.

[Chris T]

Thanks for telling what the problem was; it could be very useful in the future, and pleased that you have been able to find the problem.

[Petevick]

thats exactly what happens to the harness by the near side boot hinge . Gald your sorted and thanks for the useful information Chris.

[iaross]

There is another nugget of gold for Petes howto website. Good work!!

Iain

[Petevick]

Originally Posted by iaross

There is another nugget of gold for Petes howto website. Good work!!

Iain

I should be keeping a record of this really...........*goes off to make a record*

[Chris P]

Thanks for the positive comments. I do have some pictures but I'm not sure how useful they are - kinda difficult to get in there - but with any luck the text tells you enough.

[Petevick]

Originally Posted by Chris P

Thanks for the positive comments. I do have some pictures but I'm not sure how useful they are - kinda difficult to get in there - but with any luck the text tells you enough.

pics are good, can you post them ??, and could I use them on the web site I'm putting together please

[MikeS]

Originally Posted by petevick

I should be keeping a record of this really...........*goes off to make a record*

EMI or DECCA.... ........please say no.





MikeS

[Petevick]

Originally Posted by MikeS

EMI or DECCA.... ........please say no.





MikeS

no............

[Chris P]

Originally Posted by petevick

pics are good, can you post them ??, and could I use them on the web site I'm putting together please

Here they are. Feel free to use them on your tips website, Pete.

This one is a shot of the (bright blue) coolant temperature gauge sensor. The view is from standing on the left hand side of the car looking forward to the heat shield (silver) on the rear bulkhead.


This one is taken from further back on the left hand side, looking down to the top of the clutch master cylinder. You can see the harness that is clonked by the cylinder's piston (black) by the R clip.