gellatly

2000 Grand Cherokee 4.7

Noticed today on my way home Jeep was running I'm guessing 230-240 ish

Turned off A/C and the temps dropped 225-230 at Hwy Speeds

Made it home, after it cooled down some checked and the clutch appears good and the relay is good (have replaced that before).

Radiator appears pretty clear/clean - Daily driver and while being 17 years old this Jeep is spotless. Anti-freeze is and should be good as I just flushed it this past winter.

I don't feel like starting to throw parts at it, but can start with a thermostat. Not even sure if that's it as it technically wasn't over heating.

Other ideas?

Thanks

dave1123

A thermostat's only purpose is to restrict the flow of coolant until operating temp is reached. Did this happen on the highway or bogged down in traffic? If all you have is a clutchfan, inching along in traffic won't cool it well enough. I'd do a complete system chemical flush and see if it makes a difference. Be sure to use an aluminum-safe cleaner. Pull the block drain plugs when draining it to get the crap out of the block.

gellatly

Thanks for the reply, I was in stop & go traffic (upper 80's) for probably five miles. Never looked at the temp gauge until shortly after I got on the hwy.

Turned the air off as mentioned, which dropped the temps slightly and drove the 20 miles home. Never got in the red, but wasn't far from it.

I'll flush it today, planning on picking up a new pump and thermostat.

As mentioned the clutch fan and other electric fan were operational when I checked them at home.

blueseasons

How old is the radiator? I have never been able to look at a radiator to see how clear/clean it is. I can't tell if the clutch on a clutch fan is working or not just by looking at it either. I just swapped out my fan clutch on my Chevy, because i saw a cheap one on EBAY and it made a difference in my temperature. I haven't changed it in the 6 years I owned it and it looked fine to me. If it is old i'd look at that as well. Did you look at the front of the vehicle to see if any debri is blocking the air flow? My experience is a water pump is either working or not and if its going out, its leaking.

rangermonroe

I was suffering from the identical thing and resolved it a couple weeks back.

In my case, I changed the fan clutch , but that only helped a little.

My transmission was low by two quarts. That immediately cured the issue. I guess the fluid was getting hotter than the radiator was able to cool down effectively.