Thermostat seems to be working overtime

[87ChevyR10]

So tonight, on my home from work, I noticed the needle of the temp is moving quite a bit. Basically hitting the middle tick between 100 and 210. It'll get about a needle width above and drop to about a needle width below. Outside air temp is in the low teens. Seems to me the thermostat is working too much. The heater is producing heat, maybe not as hot as it should be.

So, is this a sign the thermostat is shot or what? Seems to me the engine should be hitting closer to 210, especially when it's cold out.

Thoughts?

 

[glockholiday]

Same thing mine is doing in the cold right now. It's got too much cooling through the radiator so the t-stat is having to throttle almost all the way closed to keep heat in the engine. Then when it opens back up it moves all the really cooled coolant from the radiator into the engine and cools it back down, and over and over.

That's why you see vehicles with winter grill guards to block some air flow so it can run at the proper temp. Like one of these http://www.ram1500diesel.com/forum/...440867572-winter-grill-cover-winterfront2.jpg

A new t-stat might perform better but maybe not.

 

[jetman]

As mentioned by glock, a cover over your grill will help to better modulate the engine temp in cold weather. Right now when my square starts up in the morning, the temp ramps right up to 250F, then themostat opens, dumping temp down to ~110, temp then jogs up and down before eventually settling out ~ 190.

 

[87ChevyR10]

Well if that's the case, then my engine isn't seeing 190*. That middle tick is 155* and that's where the needle hovers around. I may have to take some cardboard from work and use that to block some of the radiator.

 

[glockholiday]

Mine actually runs a needle width over that 1st line but a laser temp gun on the t-stat housing reads around 190.

It could be the temp sending unit, don't think your dash gauge is 100% accurate.

Mine use to run around 200 on the gauge and I swapped the temp sending unit and it reads lower now. I'm thinking of getting another one to see if it'll read different.

 

[adamj]

What temp is your thermostat rated for? I had a stock 195F, but went with a 205F and it does better now in cold weather when the cooling from the radiator becomes too much due to the cold air. I used to have heat loss that affected the heater core's performance when traveling down hill for extended periods of time in the winter. I've kept it in and no overheating in the summer either with the higher temp tstat.

And yes, verify your gauge reading before anything, the sending unit and/or the gauge could be off. My gauge was faulty and was reading about 25 degrees too warm.