This topic was started under a different thread, but that one got so strung out, I decided to start another one. I tell you, I'm at my whits ends trying to figure my truck out. My truck is still wanting to overheat, not completely but up around 230 to 240. I have a 180 stat in. Here is what I have done: Run the engine without the stat for 10 to 15 minutes. Ran as cool as a cucumber, never would climb past half way; in fact, a little less than half between the 130 and 200 mark. I tested the stat in boiling water and it opens and closes beautifully. Put the stat back in and ran the truck. Same thing, wants to run around 230-240. So, I thought the only thing left is the fan clutch. Bought one of those and put it on. Guess what? Same thing. I have turned the temp. gauge plug in the opposite direction. Still the same. I have run out of options, except one little thing. I'm going to install the old temp. sensor and see what happens. After that, to the shop. Any other thoughts or ideas? This has becoming extremely frustrating, as I had no problems whatsoever with my cooling system before doing all the work I did. I had a 180 stat in before and it ran 180 consistently. Please help with any more ideas. Thanks.

 

I'm just shooting at the moon here, but what about the belt tensioner? If there's not enough tension on the belt, the belt won't spin the water pump pulley.

 

The belt tensioner seems to be just fine. Belt is nice and firm. I will shoot at the moon also and just check it again. Might as well.

 

Well, I just put the old temp. sensor back in and still the same thing. Don't know what else to do. I'm taking it to the shop in the morning and let them figure it out. I get everything all done; truck runs great; fires right up, and something stupid likes this happens. Oh well, that's life.

 

I think your just solved your own problem., you know water starts boiling at 212 F? and if your boiling the the stat and its sitting on the bottom of the pot its getting direct heat from the stove through direct conduction which means its getting hotter then 212F.

 

Not sure exactly what your're saying. I have tried two different stats. Same thing happens all the way around.

 

Grab a thermometer that goes over 200 degrees. Suspend the thermostat in the water, and insert the thermometer. Turn on the heat.......

Watch the water temp, and see at what temp the thermostat starts to open....

 

I put the old stat in which I know worked correctly before I took it out. It does the same thing. It's not the stat. It has to be something else going on.

 

Have you flushed your cooling system?

When I did my intake, and later... when I did my timing chain and gears..... I developed an air pocket.... so the engine would run excessively hot (apparently...). Until I burped the system really well, it was a problem.

 

It sounds like an air pocket somewhere.


Dave