I have a 1995 Chevy 1500 with the 5.7L 350 gas motor. Truck has 178,000 miles and has been well maintained since new. The truck runs good and engine temp on gauge is 180-190 while driving, while stopped or moving in traffic, temp gauge goes past the 210 mark but quicky drops back down once I get moving.

I installed a brand new radiator 1 year ago, fresh coolant (green) and new 180 degree stat and I even replace the coolant temp sensor (AC) on the driver side head. I do hear the fan clutch come on when driving. Any help would be appriciated. Thanks.

That looks perfectly normal to me.? I had a '98 CC Dually with Vortec 454. Out in Havasu, 105-110 ambient, It always held 190 (195 therm) - until idling with AC on. It would get to 210 and just sit there. As soon as we started moving it would drop right back down to 190.

Running hot or overheating would be going well over that mark and NOT coming down. From having the same bodystyle - and probably the same radiator/fan setup, I think you are perfectly normal. That range is well within limits of a 195 therm.

210 is normal. If temp goes over 240 then i would worry.

Temp gauge goes past 210 while in traffic and will drop back below 210 once vehicle gets moving.

Temp gauge goes past 210 while in traffic and will drop back below 210 once vehicle gets moving.
Well, if you are still worried about it, this narrows it down to an airflow issue.

Does yours have the aux elect fan in front of everything (just behind the grill)? I would imangine it does, as I am pretty sure it came with the towing package. If so, I would check to see if that is coming on when it is supposed to. IE, stationary with ac on full. When mine would sit at 210 at idle in 110 heat, that aux fan was blowing like crazy.

If it DOESN'T have that fan, I would just make sure your air path is as clear as can be - minimal bugs, hay, bird feathers, whatever. Also make sure the fan clutch is in top shape. If it is leaving out some of it's coupling efficiency it might not be pulling quite enough for your stationary airflow requirements.

No AUX fan behind the grill, radiator and everything in front is clean. How do i check if the fan clutch is working at 100%?

No AUX fan behind the grill, radiator and everything in front is clean. How do i check if the fan clutch is working at 100%?
You might check the wrecking yards for the aux fan. It sure helped keep the AC cool when not moving!

The shade-tree old way of checking a fan clutch is to take an old radiator hose and rub it against the fan as it's idling - when it's hot and the fan clutch would for sure be engaged. If it stops the fan, clutch is no good. If the fan just keeps banging away at the hose, clutch is just fine.

How long has it been since clutch was replaced? I would assume it was done at the time of the new radiator (a year ago?) which means it should be OK. If it's OE, there is not much chance it's any good. ANYTHING that is still OE in the cooling system should be replaced by now.

Thanks for the replies. I will be checking the fan clutch today.

Electrolisis may have eaten up the water pump impeller, of it may be loose on the shaft.

Fan clutch isn't seeping any fluid, there is no play in the fan or water pump shaft and the fan does have resistance when turning it manually. I'm stumped.

old mechanic told me to change fan clutch when radiator got replace, seemed either fanclutch or waterpump had gone out and effected radiator, pump is good if no noise or leaks, fanclutch was hard, it may be slipping when hot and needed to move air.

Fan clutch isn't seeping any fluid, there is no play in the fan or water pump shaft and the fan does have resistance when turning it manually. I'm stumped.
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VC--

You must check the aftermarket 180* f. t-stat...they (regardless of mfg.) are known to be bad, right out of the box. Check it in a pan of water, heated on the kitchen range. Use a thermometer and check the stat for proper operation. You want it to open and shut (on cool down) very smoothly. Some units snap open and snap shut.

Not good.

It sounds to me that you have covered all the bases, with your cooling issue, EXCEPT the t-stat itself.

A ten degree span of smooth operation is perfect.

(begin to open @ 176*---fully open @ 186*)

Good luck.