Throwing arms up in exasperation - why running hot?

[fbgh2o]

This is an update and continued request for help on a cooling issue. I apologize for this post, but no one (including the pros) seems to know what to do.

About 10 days ago, the high speed fans came on when the temperature gauge was showing 80C. Additionally, the temperature gauge had been a bit jumpy from time to time (bad grounds -right?). Immediately, I thought that something was up with the gauge. So I cleaned the contacts on the temperature sending unit and also the football shaped connectors on tha back of the instrument pod and presto it was showing 95C to 100C while driving and no more jumping around. The car does not overheat even while idling, just runs hot.

So I have:
- Flushed the coolant and checked for blockages - none
- Added water wetter
- Bled all the air out. I am 99% sure that there is no air in the system - the garage used their vacuum system and also used the nose in the air approach with a pressure tester to verify.
- Changed the thermostat to an 80C one (after a new 90C seemed to make no difference and I suspected it to be bad)
- Replaced the thermoswitch to with a new 85C / 93C one
- Replaced the expansion tank cap
- Checked for leaks under pressure - there are none and there is no coolant loss
- Had my garage check for a head gasket leak - there is none

And still it runs at 95C. Is it possible the gauge is reading 10 to 15C too hot?

That leaves the sender and the gauge. The sender seems to work properly, so before I throw any more money at the problem I am going to test the gauge as per Clark's Garage. I hope it is the gauge - perhaps when I cleaned the "football" in the instrument cluster that I screwed something up? Anyone have any ideas?

Many thanks

[bleu951]

Have you checked the temperature with a non-contact infrared thermometer? What is the real temperature?

If the gauge is telling you the truth, it is time for a new radiator.

[phoenix_iii]

Timing? If it's running lean, it's running hot.



+1 for IR Thermometer. Great for checking brakes (Even braking), etc.