Hi






I replaced the temperature sensor and I'm still getting very conflicting numbers? The engine doesn't feel overly hot and taking various readings with an IR gun shows that. But the digital ultra gauge readings show very high temps? Have you heard of this regarding the ultra gauge displays before? I have pressure tested the cooling system, it holds pressure easily for 20 minutes with no significant loss. I'd rather not keeping throwing parts at it Any other suggestions before I proceed? Does the ultra gauge need calibration?
Cheers John

 

Just ordered the inline thermostat from extinct.

 

Sorry, been away from the office for a bit. I think you still probably have a bad sensor. If your engine was that hot the IR gun woudl show it. BTW, best places to shoot for IR temp confirmation are the intake manifold discharge pipe (which you did), intake manifold crossover (where pipe attaches and factory sensor is located), oil pan, block external by motormounts (water jackets), and for radiator diagnosis inlet and outlet hoses.

 

Thanks so much. I'll take some more readings. I'm going to fit the inline thermostat too when it arrives. I'll let you know what I find out. Really appreciate the input.
Cheers John

 

I took more temperature readings. This time on the block itself with an IR gun. It ranged from 170 to highest 188 toward the rear. Pointing it directly at the cylinder jackets. Ultra gauge telling me it's over 220? I'm going to fit inline tonight and see if happens.
Cheers

 

Have you replaced the sensor yet? You said that you got a normal reading shooting the boss where the temp sensor mounts while the UG showed 230. That says you replace the sensor.

 

Yes. I replaced the sensor. Still getting these readings. I also fitted inline stat tonight. I'll start tomorrow as I need some coolant.
Cheers

 

That could also be a bad connection or wire from the sensor.

 

Hi Guys
I fitted the inline t stat and filled the system this morning. Following the extinct write up. I think its cracked it!! I took a few short drives and the temperature did not continually climb as before. The highest I saw for about 2 seconds was 215. Then it would drop to around 202 to 208. Maybe a little higher than perfect, but I'm stocked. All the other times it would just keep climbing. As far as the ultra gauge situation? I'm really not sure. I may in the future fit a temp sensor to the t stat housing and see how that goes. All this being said I really appreciate all of your input. Thank you Extinct for the t stat too. Very happy. I normally work on 60s 70s Classic Mercedes and they have their quirks and things to watch for too. This is a good example for everyone. If this head gasket job was done and I didn't have at least the warning from the ultra gauge something was up, most shops not familiar with the disco 2 cooling problems would have shipped the car, going by the in dash temp.
I'll keep you posted if there's any updates.
Cheers John.