420A LOW Coolant temps

[Dalton63841]

I have a 95 Eagle Talon ESi with the 420A.

Not long ago, I had to replace a bad thermostat, so I thought I'd make the "smart" move and install a Fail-Safe. After installing it, I noticed the coolant temp gauge read slightly lower than usual, but nothing that concerned me. However, for the last couple of weeks, I noticed that it isn't even warming up at all. I have almost no heat from the heater, and my fuel economy is completely TANKED. I did notice that with slower in town driving the gauge will climb about 1/3rd of the way up, but during normal cruising, it climbs at best a quarter of an inch.

Are these the symptoms of a (spontaneously) failed open thermostat? Or something else? At first I was thinking a bad coolant temp sensor(based on the BAD fuel economy), but that seems to be working just fine.

 

[Dsmkauai]

Sounds like the thermostat is hung open. I would take it out and inspect.

 

[Dalton63841]

Sounds like the thermostat is hung open. I would take it out and inspect.

Thanks for that. It SEEMS obvious to me, but I'm at an awkward point where I couldn't even afford a replacement gasket for the next week, so I wanted to get a second opinion before I borrow to fix it.

 

[Dsmkauai]

Was the replacement thermo oem opening point for your car? Also could be the radiator cap. Might want to check that too.

 

[DSM1G90]

Or, did you put in a cooler T-stat? Stock ones ran 195 degrees.

 

[Dsmkauai]

When the fail safe ones fail they stay open FYI.

 

[Dalton63841]

Yea it's a fail-safe, and IIRC, the only fail-safe offered opened at 180F.

I guess the cap is POSSIBLE. The rubber part on the inside looks weather cracked, but it's been like that forever, and it still seems to seal perfectly. I'll probably go with a standard 195F stat and a new cap.

Also, just making sure... Should I put the thermostat in, then the new gasket, or gasket first, or does it matter?

 

[Dsmkauai]

Stat first with jiggle valve pointing up, And then gasket. Just easier that way. I like to use alittle Orange rtv on both sides of gasket, just to help seal and helps it stick in place for install. Just alittle you do not need that much a small bead

 

[Dalton63841]

Stat first with jiggle valve pointing up, And then gasket. Just easier that way. I like to use alittle Orange rtv on both sides of gasket, just to help seal and helps it stick in place for install. Just alittle you do not need that much a small bead

Okay great that's exactly how I did it last time, but I remember being a bit uncertain during the process.