My 2000 OHV 4.0 is overheating, I am thinking it might be the thermostat being stuck. How hard is this to replace? Or do I need to get it to the shop. I just replaced the PCV valve last week and does this have any connection to the new problem. ALso the AC turned off or wouldn't work when the temp got higher. Does this seem right?

 

The thermostat is easy to get too & replace on tis engine.

When it gets hot like it did, roll your windows down, turn the heater & fan on HIGH & sweat a little. The heater will help cool the engine down quickly, in a overheat condition.

Could be a thermostat, bad radiator pressue cap, clogged up cooling system, worn out water pump vanes, plastic bag, or other debris, restricting air flow through the radiator, slipping belt from a weak belt tensioner, worn out fan clutch, or maybe all the oil has drained out of the fan clutch, low cooant level.

So many possibilities, but just some things to ponder.

Yup it's normal for the computer to turn the A/C off in a overtep condition, to try & protect the engine.

We shouldn't be using the A/C when the engine is overheating, as this adds to the cooling systems heat load!!!!!

The PCV valve replacement should'nt figure in, unless one of it's connections has come loose & is causing an overly lean air/fuel mixture condition that the compute can't compensate for, but then I'd suspect you'd hear the engine ping under load, or have other driveability problems that you haven't mentioned.

 

Thanks for the information. Looks like a visit to the shop, I don't have the tools or knowledge to fix this with all the other things that can be making this problem. Better to let a trained mechanic do it. It is the wife's truck so I have to get this right. It could become a monster if I start anything on it. Thanks again.