KosinTrouble2

Hello,

I have a 2000 Silverado 1500 with 86k. The truck just recently started to overheat when the truck is at idle. Driving it sits at 210 and doesn't have a problem at all, but once it is sitting and running the temperature climbs. The A/C also starts to go out when it starts to overheat. Any idea what this could be? Thermostat? The truck runs like a champ other than this issue.

Any help would be appreciated.

Thank you!

budhayes3

iTrader: (19)

The PCM turns the AC off when the temp rises as a safeguard, so I'm thinking that's directly connected to the overheating problem. I doubt that the thermostat's the problem, or it would overheat all of the time. Since it happens at idle while sitting, I'd be checking the fan clutch first to make sure it's engaged allowing air flow to be sucked across the radiator. Of course check the coolant level first and look for any leaks...also check and make sure that there's no junk in front of the radiator or between the radiator and condenser blocking air flow. The radiator may be plugged also, but that should also cause problems on the highway. Other things that come to mind are possible bad water pump vanes (pretty rare), and leaking water pump to block gaskets (fairly common).

(You didn't mention if you had efans or not, so I just assumed that you have the factory fan clutch...if you do have efans, I'd check and make sure that they're running while your temp guage is rising)

thunder550

iTrader: (70)

Also, have your a/c pressure checked too. If the pressure is low the a/c system will run hotter than normal, and with 6 years and 86K miles it wouldn't hurt just to be sure.

KosinTrouble2

Hello.

I just had a brand new a/c compressor put in about 6 months ago.The a/c runs great, just when the truck starts to warm up the a/c goes.

The truck does not have electric fans.
How would I go about checking the fan clutch? I am new at this..my husband did all the work on this truck and we are seperated now, so I am trying to figure it out. I am pretty merchanically inclined if someone could just point me in the right direction.

I checked the fluid levels and for leaks and everything was ok.

thunder550

iTrader: (70)

Ok, then as budhayes said I would start with the clutch fan, then check for debris/grease & grime in the radiator and condenser blocking airflow, then thermostat, then water pump, then if all else fails try a new radiator.

1ImperialSS

iTrader: (5)

when you say you checked the fluids, did you check the engine oil? if the oil gets lower the engine wil start getting hotter than it should. welcome to the site BTW

KosinTrouble2

I will double check the oil level just to be sure. Can you tell me how to check the clutch fan?

Thanks!

thunder550

iTrader: (70)

When you are accelerating from a stop when you engine is over 200* or so you should be able to hear it, it's pretty loud. After you accelerate and things cool down a little bit you'll hear the noise dissipate and it will sound like the fan is slowing down as the clutch releases.

budhayes3

iTrader: (19)

You can also check the fan clutch with the engine off. Grab the fan and spin it...there should be some drag and it shouldn't spin too easily...maybe 1 1/2 rotations. If the fan spins easily and keeps on going (like 4 or 5 rotations), the clutch is probably shot. Another thing I've done is to use the "cigarette" method (since I'm currently a smoker). With the truck idling at operating temperature, the fan clutch should be engaged, pulling air across the radiator. Hold a cigarette in front of the grille of the truck and see if the smoke gets sucked in through the grille...if it doesn't, either the fan clutch isn't engaged, or there is a blockage on the radiator/condenser/etc. Another test....if you can physically see the fan clutch (once again with the engine off...you may need to hold a mirror down in front of it), look for an oily substance in the center of it. It should be dry...if not, the fluid in the clutch has started leaking out and the clutch needs replacement.

KosinTrouble2

Ok. I will give those a shot! Thank you for all your help, I really appreciate it.