97 (almost) overheating

97 Rodeo, 3.2L V6 - Now that the weather is nice and warm I turned the AC on while driving from PA to NC. In DC while stuck in traffic I looked down at the temp meter and it was just shy of overheating. I shut the AC off, turned the heat on, and luckily started moving and it dropped slightly. After taking a break and letting things cool I turned the AC back on. The meter went up to about 3/4 Hot, but didn't go any higher for the rest of the trip.

I checked the coolant level and saw it was right on the max line when everything was cool and turned off. So I kept an eye on it all week while driving (w/ no AC) and the meter stayed right about the halfway point. Today I turned the AC on again and up the meter went. When I got back to the hotel, I kept the engine running and took a look under the hood. The radiator fan was spinning, but the coolant reservoir was well above the max line.

The thermostat was just replaced a few months ago. I just added slick50 to the oil last weekend (before this all started), would that have anything to do w/ it? Any ideas?

When was the last time you flushed your radiator?

What kind of miles on your truck?

Maybe the thermostat was defective?

There are 126,000 miles on my rodeo. I have never flushed the radiator...just drained and refilled at about 60,000 and I assumed this was done when the thermostat was replaced at about 123k. Guess we all know what happens when you assume :). Does this sound like a t-stat problem?

HotBacon- you could have a defective clutch fan. Make sure the fan is pulling a good amount of air thru the grille at idle when the truck is hot. Also, if your truck is equipped with an automatic transmission & a/c, you should have an auxiliary electric cooling fan mounted behind the grille and in front of the a/c condensor. Make sure the electric fan is running when the truck is hot & the a/c is on. You really should do a coolant flush every 30K miles on these trucks as well. Slick-50 is a total scam. Users have toasted their engines using this stuff due to the solid "teflon" clogging their oil pump p/up screens. You dont want solids floating around in your oil!
G/luck
Joel

I do have automatic tranny and a/c. The electric cooling fan is sounding like it could be it since I only have a prob w/ the a/c kicking. Is this fan seeable through the grill or is it hidden?

Also, I wish I would've found this forum before I dumped the slick50 in. Thanks for the tip on the 30,000 coolant flush. For some reason I thought it was 60k. I'm sooooo glad I found you guys :)

I do have automatic tranny and a/c. The electric cooling fan is sounding like it could be it since I only have a prob w/ the a/c kicking. Is this fan seeable through the grill or is it hidden?


My Rodeo has A/C and an automatic transmission. The Electric fan is clearly seen right behind the grille (it has a "diamond shaped" screen) on the passenger side. Your 1997 is probably the same. If I remember correctly, the electric fan always came on when I used the A/C.

Dale

Well no "luck" on the a/c fan diagnosis. I rode halfway home (highway) w/ no a/c. The temp meter stayed put at the halfway point. I turned the a/c on and sure enough when I hit the lights and parking lot the meter started to rise. I checked the a/c fan was buzzing away sucking a good bit of air through the grill. ?:(

Well no "luck" on the a/c fan diagnosis. I rode halfway home (highway) w/ no a/c. The temp meter stayed put at the halfway point. I turned the a/c on and sure enough when I hit the lights and parking lot the meter started to rise. I checked the a/c fan was buzzing away sucking a good bit of air through the grill. ?:(

i don't know if this could be the problem but i do know that the coolant should be between min & max & never over max when it's hot. in fact when it's hot, it should be at min or near it.
For some stupid reason if the coolant if overfull she'll over heat something about the fluid not moving fast enough, or not at all... i thought that gas engines was supposed to "put back" the extra fluid but it seems like this isn't the case.