how long does a thermostat last?

[fan of fanboys]

had to change my thermostat impromptu today. was driving, noticed engine running hot, pulled over few miles later at a shop and got the part swapped. went with 170 degree thermo

how long does a thermostat last?

and when I changed did I make a mistake with going with a basic 170 degree model from local parts store or will that be fine? not sure if one of those deals where oem is best

 

[alumarine]

A good quality thermostat lasts a long time. Like 20 years.
OEM spec is 176-183 degrees, known as a 180.

OEM or OEM equivalent is best.
It's possible to buy a good quality non OEM thermostat but they are not inexpensive.

I just used a Gates/Napa 33982 and it looked identical to the OEM and was made in Japan.

 

[fan of fanboys]

A good quality thermostat lasts a long time. Like 20 years.
OEM spec is 176-183 degrees, known as a 180.

OEM or OEM equivalent is best.
It's possible to buy a good quality non OEM thermostat but they are not inexpensive.

I just used a Gates/Napa 33982 and it looked identical to the OEM and was made in Japan.

good info

so should I proactively swap the one I got today or run it until dies and next time use oem?

 

[Kanoe]

Run it until your next scheduled coolant change. Then change the thermostat at the same time. I believe it's every 2-3 years for coolant.

 

[phattyduck]

Also, make sure the jiggle valve is at 6 o'clock instead of the normal 12 o'clock that most engines run. It makes a large difference in the temp that the engine runs (15-20*F), though you can't see it on the stock gauge (that stays constant from ~160*F to 220*F).

-Charlie

 

[mtbtim]

I believe a thermostat can survive the life of the vehicle. It did in my Subaru Outback that I put 325,000 miles on.

Here's something I discovered recently:

I noticed I was running hotter after I put a new thermostat in my rig. I was running between 188-192 for the most part with the old thermostat and running between 192-196 with the new thermostat. Everything was correct with the installation with the jiggle valve at the 6 o'clock position. It was my theory that the new thermostat wasn't opening as far as the old one because the spring on the new one wasn't worn in like the old one.

I took the newer thermostat out of my engine and put the newer and older one in a pot of water and heated them up to test how far they were opening. I used the FSM as a reference to do this. I found out my theory was correct. At the same temperature, the new thermostat was opening 2mm less than the old one. This is a small difference but just enough to cause a 4 degree rise in my coolant temps.

I put the old thermostat back in and I'm now back to running between 188-192. I'm going to keep the old one in there and just have the other one in my rig as a spare in case I run into an overheating issue and suspect the thermostat as the culprit.

 

[JZiggy]

I agree with Tim on this. I replaced my factory thermostat in my 3RZ with 225k. I tested it in hot water and it was beginning to open right at 82C like it's supposed to. The new one was only like $20 so I put the old one in the "spare parts" box.

I would add that the thermostat's life is largely dependent on if the cooling system has been maintained with fresh coolant of correct chemistry.

 

[TheDurk]

I did mine with my timing belt at 120k (which is the interval I chose for TB, plus all parts that touch it). I'll change it again at 240k.

 

[StreetCreeper]

had to change my thermostat impromptu today. was driving, noticed engine running hot, pulled over few miles later at a shop and got the part swapped. went with 170 degree thermo

how long does a thermostat last?

and when I changed did I make a mistake with going with a basic 170 degree model from local parts store or will that be fine? not sure if one of those deals where oem is best

As others have said already, OEM is 180*. As for how long they last? I changed mine at 400,000 miles. Note the time stamps on both. It was made in 1996 and I changed it 20 years later in 2016 — it still worked perfect and I've kept it as a backup which I would swap back in without hesitation should the need ever arise.

​

 

[fan of fanboys]

good info, thanks everyone

I might be swapping out sooner than expected

today was leaving Lowes and green coolant under truck. yay!

the truck has rear heat and the lines running to the back are corroded pretty badly and now leaking. so they will need to be replaced.

owned the truck less than a week! I knew there would need to be something done, was just hoping would be couple months down the road so I can start funding a 4runner fund. not the case it seems

hopefully after this I can go awhile before anything else needing done