I usually ask for a Stant brand thermostat myself, never had to return one. I’ve used the NAPA store brand (premium version) a few times too. One of them failed my water bath test, but the others seemed to work ok. I don’t think you need to spend $124 for a thermostat, but avoid the really low cost versions (less than $25), especially if it is a brand you’d never heard before. I always test newly purchased thermostats before installing them. I put them in a pan of water and heat it up on the sto ve, measuring the water temperature to make sure it opens at the specified point. And that it opens to the correct dimension, isn’t opening in a warped configuration, etc.
Wow. You really should have your own Scotty Kilmer type YouTube Channel. Although Scotty once gave me costly bad advice once (had to do with a front end issue) & obviously bad advice another time when he told me I had a leak in my power steering fluid (electric pump). After I posted last time, I noticed there is a $39.99 Napa Thermostat - Safe-T-Stat - OE Temp. The Premium for $29.99 is god enough? Also there are different kinds of gaskets for it, ribbed, thick & thin. It doesn’t come with one? I imagine never reuse the old one.
I don’t think I correctly formatted me last reply to you, so I’m dong it again.
Wow. You really should have your own Scotty Kilmer type YouTube Channel. Although Scotty once gave me costly bad advice once (had to do with a front end issue) & obviously bad advice another time when he told me I had a leak in my power steering fluid (electric pump). After I posted last time, I noticed there is a $39.99 Napa Thermostat - Safe-T-Stat - OE Temp. The Premium for $29.99 is god enough? Also there are different kinds of gaskets for it, ribbed, thick & thin. It doesn’t come with one? I imagine never reuse the old one.
I changed the coolant & will wait to see if the code returns. If it does, I’ll immediately change the thermostat. Thanks for the illustration. That makes perfect sense as to why everything “seems” ok (heater working/gas mileage perfect).
The gasket is for the thermostat housing, not the thermostat itself. There are dozens of different housing styles for the same thermostat, so while it indeed seems odd, you have to purchase the gasket separately to fit your particular car.
Years ago I ran into this gasket problem when replacing the thermostat on my Corolla. They didn’t have one in stock. Their warehouse didn’t have one either. They had to order it, mailed to them from the vendor; the vendor seemed to have run out of the correct size shipping material. It arrived at the parts store in a flat package measuring 3 feet x 3 feet … lol …
The thermostat seal/gasket fits onto the thermostat. Some thermostats come with the seal, Gates for example;
That’s interesting. I don’t think I’ve ever seen a replacement thermostat having a rubber seal. If the thermostat leaks at its outer circumference, it seems like that wouldn’t cause much trouble. Internal leak is all. The ones I’ve replaced sort of twist & lock into the place they fit, held there by friction forces, but probably still leak a little at the outer circumference.
Some thermostats have a small hole in them, and the hole is supposed to be in a certain orientation, usually up. Don’t know what that purpose of that hole is though.
If the thermostat housing gasket leaks, that’s a different matter. That will cause an external leak and eventual loss of coolant.
Thank you. I drove 661 miles last week, since I replaced the radiator fluid & reset the computer. Still one light flashing on the meter (my meter starts with 5 flashing lights), but no codes & of course no check engine light.
I drove 661 miles last week, since I replaced the radiator fluid & reset the computer. Still one light flashing on the meter (my meter starts with 5 flashing lights), but no codes & of course no check engine light. Seems like it always takes a month to figure itself out. This is normal, right? Two 280 mile trips & the rest city driving.
The weather may be too warm for the problem to be detected. If the engine reaches a minimum temperature within a certain amount of time, (8 to 10 minutes) the computer will consider the coolant temperature to be acceptable.
This is a good example of how car-computerization can actually help the owners. Usually when the CEL turns on, the computer gets the blame and is the subject of much derision. But cars of yesteryear – both of mine for example – don’t perform self-tests to check for a stuck-open thermostat. The owner can drive with a stuck open thermostat for thousands of miles, never knowing there’s a problem. Newer cars, that’s a standard self-test, and one that does help even a diy’er car owner keep their car in good repair.
So I should replace the thermostat even if it goes into the green?
Do you agree with Nevada_545 about the weather no longer cold enough to trigger the code?
Hard to say with any certainty The car manufacturers generally don’t provide the specifications for their car’s computer algorithms to that level of granularity. But say the ambient temp was 102 deg F, and the coolant temperature also measured 102 deg F soon after starting the engine. Would you conclude from that data the thermostat was working correctly? Normal coolant temperature when the engine is fully warmed up is usually on the order of 190 deg F to 220 deg F.
The only place I can check the temperature is at the overflow reservoir, since the car does not have a conventional radiator cap. Placing a meat thermometer there, should I expect 190F? Or would that area not get as hot? If not, how can I check the temp?
You read the engine temp on the screen of whatever scan tool or code reader you are using.
I presume your car doesn’t have a coolant temp gauge on the dashboard. The other ways to check the coolant temp are
- a scan tool plugged into the obd II port may be able to display the coolant temp
- an infrared laser thermometer pointed at the metal part of the top of the radiator
I’ll add if I was uncertain whether my car’s thermostat was working, I’d just remove it and test it in a pot of hot water and thermometer on the stove, make sure it opens at the correct temperature, it opens to the correct dimension, and when closed, nothing looks warped or misshapen.
The one I have been using only shows code numbers & dots. I’ll try to find one that has that info. Thank you.
For all that trouble it would seem better to just replace the $12 part and start with a new one!
Thanks. My meter only has codes & dots. I’ll look for one that has more detailed info. In the mean time, I’ll use the laser thermometer now & let you know the temp. I hope all this posting isn’t too bothersome. There was one person who didn’t like it earlier in the thread, but you know I appreciate all your help. Nevada & asem too.