Is it the t-stat, temp gauge or sending unit?

[rlvelin]

I have been noticing lately that the temp gauge never gets past about 110 even after an hour of driving around town. On the highway or interstate it will rise to 180 in what I would consider a normal amount of time, however if I slow down to go through a town or something (25-45 mph) the gauge will drop back down to about 110 again. The weather around here has been fairly cool lately so I was thinking possibly the t-stat isn't fully closing or maybe the gauge or temp sending unit is haveing a problem. Has anyone else seen anything like this and what was found to be the culprit. It think it should be fairly cheap and easy to just replace both the sending unit and t-stat and see if that doesn't fix it but I thought I would see if someone here might know exactly what is wrong or even if this is normal.
Thanks for any help

[andrewfessler]

Based on what you have listed, I would lean towards the t-stat.

However, I had a problem on my truck where the temp would be all over the place, somtimes 0, sometimes 190, other red hot.

I replaced the sending gauge, about $20 and havnt had a problem since.

[m-keith]

Last time I had a t-stat stuck open (non-GM vehicle), the heater took much longer than normal to blow warm air.

[rlvelin]

I did notice this morning that the heater was blowing warm air within minutes after it was started, outside air temp was about 15 degrees F, but the gauge needle had not yet moved. I think I will try replacing the sending unit first since it should be easier to change quickly.

I'm sure I'll find it after looking for a few minutes but do you know where it is and if it is easy to get to? I would like to minimize my time outside since the temp is currently about 5 F with windchill and my garage/shop/wife's storage area is full.

[m-keith]

I don't know off-hand. If no one else chimes in, I'll look it up in my factory shop manual tonight.

[HowieE]

Before I spent any money on a sending unit I would take the stat out and put in a pot of water on the stove and watch it as you bring the pot to a boil. The stat should start to open just as the water starts to show bubbles on the sides of the pot and be completely open before the water comes to a boil. another thing I would look at is the clutch fan to be sure it is not jamed in the engaged position. I say this because you temperatures seam to track your load and the sending unit would not be influenced by load.

[MM9135]

I agree with Howie.

If you can stick a cooking thermometer in the water flow when it is hot can give you a rough idea of where you are at.

[jsa]

T-stat problem,just did mine yesterday.Gauge did not move,but stillhad heat

[rlvelin]

Thanks for the input, now I see the t-stat logic and if I can find one in town will replace this weekend after I clean out the garage and fire up the barrel stove. If for some reason it isn't the t-stat then at least I'll have a spare (it seems that if I have a spare part on hand then I'll never have a problem with that part again).

[andrewfessler]

Originally posted by rlvelin:
I think I will try replacing the sending unit first since it should be easier to change quickly.

I'm sure I'll find it after looking for a few minutes but do you know where it is and if it is easy to get to? I would like to minimize my time outside since the temp is currently about 5 F with windchill and my garage/shop/wife's storage area is full. The sending unit is located on the drivers side of the engine towards the front, below the alternator. I replaced mine without draining the radiator. Lost about 1 quart of coolant.

[turbovair]

Hey Rivelin,
Bring it over to my house. Its 55-60 in the morning and about 80-90 in the afternoon. We can work outside!!!!Just kidding.
A friend of mine recently had the same problem. Changed the stat and the sender at the same time...problem solved.
Greetings from Phoenix!!!!! smile.gif

[rlvelin]

I have an ex-Navy buddy that keeps reminding me of the warm weather in Pheonix and now I get it here too.

Actually I got the garage cleaned out and warmed up to almost 60 and the t-stat changed yesterday. Took about 5 min, just pulled the cover off, removed old t-stat, stuck a rubber ball (raquetball I think) in the t-stat hole, scraped old gasket junk off and swapped in new t-stat and gasket, only lost about 1 quart of antifreeze.

I've only made one trip across town since (note to self: self don't go to walmart on the weekend) but it seems to be fine now. Thanks again for all the advice.

By the way the t-stat was almost $30 everywhere that they had it in stock. Does that sound right?

[BuffaloGuy]

Are you sure you got a high flow t-stat? I didn't, even though the books show it replaces OEM they don't, and boy was I sorry. At high rpm's it would overheat and pulling a load it always overheated.

The difference is very significant. The high flow don't look like the regular t-stats with the button in the center they are a toatlly differnt style. Big, round and the whole thing opens. Kinda hard to explain.
Ken

[rlvelin]

It is very similar in size, shape and operation to the one that I removed, with which I've never had an overheating problem. For $30 it better be a high flow t-stat since I could get a non-high flow from stant that fits for a whole lot less.

As it seems that winter is finally here I don't think I will have a chance to check its cooling efficiency for a while.

I've done some post t-stat transplant shopping and found that Kennedy sells them for $6. If the one that I have swapped in is determined not to be high flow then I will replace it in the spring with one from Kennedy and have learned $30 worth of something in the process.