Question : 94 3.1 SFI acting funny. (coolant)

[3.1Cutty]

Hey guys , I just recetly got a lot of work done on my 94 cutlass. One of which was a new thermostat and coolant flush. Now befor the replacement the car would hear up but not fully , also it would cool off when doing highway speeds. Now with the new thermostat it heats up a few degrees hotter but heres the wierd thing. When the RPMs pick up the gauge cools down to about 50C and when I let off the gas the gauge heats up to where normal operating temp should be , 95C. Now when im going down the highway it sits at a not normal 70C.

I did a test and held the car at 2k rpm in park and same thing!! The car will not heat up and I cant get the fans to kick in....Is it possible that both my temp sensors need replaced?? I bled the air out a 2nd time after my mechanic did the coolant flush just to make sure he didnt miss any. The system has pressure and I just replaced my Rad cap.

Any help would be greatly appreciated!!!!!

Mike

[IsaacHayes]

Did you ever have dexcool or that universal/100k mile coolant in there? There could be a clog... Mine runs on the highway between 1/4 and 0... When in town it reads right below 1/4. I can't recall what those temps were, I'd have to get out my data logger again. Also, to bleed the air properly, you need to get it hot enough that the thermostat opens up. That usually means in cooler weather to rev it in park until it gets warm enough that the thermostat opens, then bleed the air. Also I've found if you have the bleeder open and rev it under the hood a bit it will help spew out more air until it runs pure coolant then close the bleeder.

[3.1Cutty]

Iv only had the car for a little over a month. Hense why I got a lot of maitnence done. To my knowledge 94 was the year befor dexcool , so I dont think so , the coolant that came out was green. Dex is orange right? I put universal green coolant back in. Not the longlife crap. I will bleed it once again with the car at full temp and see what happends. My gauge is in C cause im up here in Canada , so the proper point should be right below 95C which is right in the middle. I put a 195F stat back in. Isaac ,isnt yours running really cold then?

[bszopi]

These engines typically run around 1/4 on the temp scale, and usually worst case around 1/2.

[3.1Cutty]

Ahh I see. Thanks bszopi. So The temp gauge isnt very accurate at all then . Good thing im almost done making my gauge bezel!!! Ill just thow an autometer guage on there and see what its running at.

Thanks for the help guys!!!!!

Mike

[3.1Cutty]

Ordered my Autometer Temp and oil pressure gauges yesterday. Should be here sometime next week.

[Azrael]

Being a 94, your engine will have two coolant temp sensors. The one for the gauges is typically on the rear head. You might even be able to use that port for the autometer gauge.

[IsaacHayes]

The gauges read slowly until it gets around the temp of the thermostat opening, then after that it raises up very quickly on the gauge. So 0-1/4 is like 0-180F or so, and 1/2 is around 200F IIRC. You can also put a 3 wire CTS in the lower intake from a 96 3100 car and run the extra wire from that for your gauge.