Thermostat Question

95'BlackP-Finder · Jan 21st, 2007, 11:06 AM

I recently put a thermostat in my 95' Pathfinder after it failed during a very cold time. Anyways, I replaced it with a 180 degree instead of a 170 that came in it from the factory. Now, during the cold weather(20-30) degrees, my coolant hand is only going up to right below the middle, but during an average day temperature of around (50-60) degrees, it's right in the middle where it should be. I was just wondering is this normal and am I getting extra fuel dumped in on the cold days even after hours of driving and a warmed up engine due to the decrease in temperature I'm getting with the 180 thermostat? Peace

**88pathoffroad** · Jan 21st, 2007, 04:57 PM

It will run cooler on cold days, yes. The temp gauge has a different sending unit than the engine temp sensor that the ECU uses. I wouldn't worry about it.

Oldnissanguy · Jan 22nd, 2007, 06:37 AM

I have the same problem on my 97 HB and it's driving me a little nuts. This is the only vehicle I've ever owned that does this and it makes no sense to me. A thermostat is designed, along with the cooling system, to keep the engine operating at a fixed temperature. The only reasons this should vary is if there is something wrong, or inadaquate, with the cooling system or the bypass allows so much coolant to bypass the thermostat that in cold weather it never reaches operating temperature. What am I missing?

95'BlackP-Finder · Jan 22nd, 2007, 09:54 AM

Okay, I think I get it now. So, the engine is running the same temperature as before I changed the thermostat, but the coolant hand sensor is getting a slightly different(cooler) reading. Correct? Is that sensor one of the two on the goose neck, If I'm not mistaking, the first is the hand sensor, and the second is the ECTS? The one the computer uses, Right?--Okay, does this mean I'm running hotter in the Summer though?..Peace and thanks for the replys.

**88pathoffroad** · Jan 23rd, 2007, 01:44 AM

I have no idea. Don't you have a copy of the factory service manual for your 95 yet? The book will tell you which is which, cause I don't know, sorry.

Yagaman · Jan 27th, 2007, 08:37 PM

Most t-stats have a temp they will open at and another temp they will close at. What if your new t-stats are not closing until the temp drops too low? You may see a lower average water temperature in your engine. Check to see if the t-stat you bought was one that regulates on a 5 or 10 degree difference in temp, i.e. 180 degrees +/-5 degrees or 180 degrees +/- 10 degrees.