185 is super rare, one does exist, but does not fit the housing. Programming in the ECU is the issue, if you have a 99-02 they don't throw a code. They had to add that code to satiate the ***** at the CARB.

 

Thank you for the insights and clarification.

 

It's good you're happy with the results, but if you didn't change anything other than the thermostat what you describe suggests more that the old thermostat in your truck wasn't opening at its design temp, or not opening fully, and changing to even a new stock thermometer or even a 180° would have improved the outcomes.

The thermostat sets the lower bound for coolant temp. Once the thermostat is fully open the operating temp depends on other factors, primarily the radiator but also the water pump, and the fan and fan clutch when not at cruising speeds.

 

You are assuming his previous thermostat was working correctly, however a larger percentage do not and what he saw is typical of what you seen when one does not function correctly. The bypass valve does not close fully and coolant bypasses the radiator. Sometimes at higher rpm it will close completely and drive ok at speed, but opens up at idle or low speed and overheats while parked. Other times it sticks open at a single opening, flowing more bypass with more rpm like at highway speed looking like a plugged radiator. I discovered the flaws when others did not because I had five trucks in the yard and could move parts between trucks for testing and verification.

 

FWIW, I wrote "... the old thermostat in your truck wasn't opening at its design temp, or not opening fully ...".

 

Been chasing a small leak for months in the housing. I had the reusable gasket and thought that was bad, but when I went to replace it I noticed the thermostat wasn't fitting into either side of the housing flat like you'd think. So I took my dremel and ground out a little of the side till the thermostat just fit flat and a little below the surface. Put it back together with the reusable gasket and thought it would be good. A couple days later noticed the same little drop of antifreeze under the engine. Thought it must be a bad gasket so I replaced that with rtv and a new paper gasket - a few days later the drip is back. Today I ran the truck up to temp and forced the thermostat housing up so I could watch the underside and after it got warm a little drop of fluid appeared between the port hole and the edge of where the two halves comet together. It's got a crack in the housing. If it were steel I'd just weld it up and grind it flat again. I don't have the equipment to weld aluminum. Has anyone else run into this? It's not even a year old . . .

 

I had something very similar a couple of months back. I chased it for months before I finally found that I had torn my reusable gasket when I changed to a higher temp stat for winter. I thought it was a crack in the housing as well and even reached out to Extinct on it. The lip between the opening and the port hole is so tight that it’s reasonable to expect the latter. I’d encourage you to try again with a proper gasket, or share some photos of the crack.

 

 

Oh wow, definite crack. Looks like the sensor port plug was overtightened a bit. No worries, we will warranty it out for you. Send an email to info@inlinethermostats.com with your order info so I get it sent out to the right address.

 

Thanks Extinct! I appreciate you sending a replacement part. My wife's rover will feel so much better!