Thermostat replacement lessons learned and common mistakes? (3 Viewers)

[2yotanerd]

I’m planning to replace my thermostat in about a week. I’ve never done this before, but it seems pretty straightforward. From what I’ve read, the main thing to watch out for is making sure the jiggle valve is positioned at 12 o’clock.

I’m also planning to replace the hose that connects to the thermostat. Is there anything else I might be missing? Anyone have any lessons learned or tips to share?

I plan on using these part numbers:

90916-03100	Engine Coolant Thermostat
16346-50010	Thermostat Gasket
16572-50150	Radiator Coolant Hose

 

[kbfj621989]

It’s a straight forward job.

I covered up the alternator and drive belt with plastic so as to not get any spilled coolant on these areas.

Check your aluminum surfaces for any pitting.

 

[GTV]

You have reason to believe your thermostat is failing?

 

[2yotanerd]

You have reason to believe your thermostat is failing?

Yes. My coolant temp was at 212 after I drove about 45 miles while gaining about 1400 feet in elevation on the freeway. On the return trip, coolant temp was at 201 just driving in city on flat surfaces. Outside temperature was about 84-88.

 

[GTV]

Yes. My coolant temp was at 212 after I drove about 45 miles while gaining about 1400 feet in elevation on the freeway. On the return trip, coolant temp was at 201 just driving in city on flat surfaces. Outside temperature was about 84-88.

They generally fail in the open position. I'd make sure your radiator is clean and clear of debris before replacing the thermostat.

 

[2yotanerd]

They generally fail in the open position. I'd make sure your radiator is clean and clear of debris before replacing the thermostat.

Gotcha. Thanks for the advice!

 

[Import Driver]

Yes. My coolant temp was at 212 after I drove about 45 miles while gaining about 1400 feet in elevation on the freeway. On the return trip, coolant temp was at 201 just driving in city on flat surfaces. Outside temperature was about 84-88.

Mine was running about 200-210 in just about any temp. I put a new thermostat in and the temps dropped to around 195.
Pretty sure the thermostat was not opening all the way. You're doing what I would do first (assuming your radiator is clean).

 

[OEMGUY0720]

Rule out your coolant temp sensor as well. Thermostat “dot” marker when installed should be in the 12-o’clock position.

 

[Super77]

Yes. My coolant temp was at 212 after I drove about 45 miles while gaining about 1400 feet in elevation on the freeway. On the return trip, coolant temp was at 201 just driving in city on flat surfaces. Outside temperature was about 84-88.

They’re easy enough to bench test with some boiled water and a thermometer. If you find it functions normally, that will clue you into a likely problem elsewhere.

OE thermostats are about $20, so it’s easy to keep a spare on hand.

 

[2yotanerd]

Rule out your coolant temp sensor as well. Thermostat “dot” marker when installed should be in the 12-o’clock position.

How would you test the coolant temp sensor?

 

[OEMGUY0720]

How would you test the coolant temp sensor?

you can by using a multitester and heat source like a heat gun. That part is inexpensive, so to rule that out I just replace them especially chasing an overheating issue.

 

[Trapper50cal]

I learned: No FIPG (orange or black) - the gasket that goes around the t-stat itself expands to seal the two housings (inner and outer)
and that the little jiggle valve goes at the 12 o'clock position.