mattyjoe

93 4.0 running at 120 degrees. will this damage engine. live in boston temp near 10. thermostat? need help

coloradojeepxjowner

I am guessing that the gauge is faulty, or your thermostat is stuck in the open position.

Jesse Hallum

Cite your authority. How do you KNOW the engine temperature is 120 degrees? IR the engine block and radiator, then report back. Do no rely on a potentially faulty temp gauge. Checking the engine temp using a code scanner is another good method for determing the actual internal block temp.

dave1123

IF you're engine IS running at 120*, the PCM is still running in open loop mode and will probably set codes. It also won't evaporate whatever moisture is sucked in when to cools down, forming sludge.

IMO, it's either a stuck thermostat or a bad guage sensor. You can try the old-school trick of tapping on the thermostat housing when it's cold. If it's just stuck, you'll hear a snap as it closes. It could be blown or just worn out.

Again old-school. Grab and hold the upper radiator hose. If you can hang onto it, it'll feel like warm coffee. If it is too hot to hold, it's up to temp.

OR you can use a infra-red scanner.

I like to pass on the old tricks before they're lost with time.

coloradojeepxjowner

Your old tricks are my first tricks Dave and I am 34

xj_maniac_newb

For now try some cardboard in front of your radiator on the grill or wherever. Should give you a quick temporary fix while you still have to drive it, but again this is only a bandaid.. But as said before make sure you're not getting a false reading before you do anything.

dave1123

Colorado, I'm 68 years young and still sharp of mind, not so much in body. My desire is to teach whoever I can the simple things I have learned over the years. Modern tech is so advanced it sometimes overlooks the obvious. After all, engines still run on the same principles. They're just better controlled.