1996 A6 2.5Tdi Quattro (5cyl) temperature issues

[tut_gareth]

Hi

Having recently discovered that my engine should be running at 90degrees on the gauge and not 50-60degrees i decided to change the thermostat and flush the system then fill with a 60:40 water: coolant (g12 of course) mix. but this has made barely any difference.

I took it for a really good run and it only got to 90degrees after 120 miles of motorway then hard country road driving. only to see the guage go back down to where it has always sat at 50-60degrees once i'd pulled up.

Checking the top rad to engine pipe it was hot. then checked the thermostat to bottom rad that was not very hot atall. there was also no pressure in the header tank ( not sure if that means anything)

The engine has not overheated and runs fine for 203000. but it does appear to run very cool

Also the oil temp guage does not measure........

Has any body got any ideas? or am i worrying over nothing?

Cheers

Gareth

[airevalley]

Hi .
is the gauge correct .
poss look at replacing the temp sensor which picks up the temp of the coolant .
It may be o.k ( coolant temp ) , but the sensor is reading incorrectly .

[tut_gareth]

hi

I have done the work myself so far

Thinking about the sender as the next step

But i'm wondering why the coolant in the header tank doesnt seem that hot and i can remove the cap and theres no real pressure.

Also noticed the heater gets reasonably wam but not as warm as my corrado does( it is a smaller car though)