Bad fan clutch and no overheat?

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I'm thinking my fan clutch finally went out. It's not cycling anymore with the a.c on. Right now I think it's only occasionally working. So how come the engine isn't overheating at idle? This is my dodge truck in my sig.
 
Diesels need rpm and work to make heat. They tend to run too cold if idling. I fix lots of trucks like yours. If the fan does not work with the ac on it will smoke the compressor.
 
My car had no working fans for a while when I started driving it in february and I did not notice until I got stuck in traffic during a highway trip in may. I really only noticed because I have a scanguage, although to be fair the overheat light did come on eventually. Temperatures are a little different between toronto and houston, but you would be surprised how much heat capacity engines have. Idling does not generate that much heat.
 
Diesels have very high thermal efficiency. I'm sure that the engine is designed to stay cool under extreme loads, so an idling engine is probably nothing for the cooling system in that truck. Also, with 12 Qts. of oil it will take quite a bit of work to make that engine get to a temperature that requires a cooling fan. For what it is worth, I have never heard the cooling fans on the 14.5 Camry. It takes an awful lot for the cooling fans to come on in the 99 Camry and the Prizm.
 
Originally Posted By: Dorian
Diesels have very high thermal efficiency. I'm sure that the engine is designed to stay cool under extreme loads, so an idling engine is probably nothing for the cooling system in that truck. Also, with 12 Qts. of oil it will take quite a bit of work to make that engine get to a temperature that requires a cooling fan. For what it is worth, I have never heard the cooling fans on the 14.5 Camry. It takes an awful lot for the cooling fans to come on in the 99 Camry and the Prizm.
On your 99 Camry, maybe the thermostat is opening too early?

On my 2000, if I idle in a drive thru for more than a minute the fans will kick on for about 20 seconds.

I'm also in Arizona. But it does it when it's cool out too.
 
Nick, I will look into that. If I remember correctly it is the 180*F model. I just looked online, and it appears that the radiator fans turn on when the coolant temperature is above 199*F.
 
Originally Posted By: Chris142
If the fan does not work with the ac on it will smoke the compressor.


This is important; quit using the A/C until it is fixed. The A/C needs a lot more air flow than what the radiator needs to keep the engine from overheating.
 
I know its a different engine but my friends 05 F150 I replaced a bad fan clutch. It never overheated on him (4.6 V8) but he complained about poor A/C performance while stopped and a 'funny smell' on one or two occasions during extended idling which I believe to have been the over pressure valve opening and dumping refrigerant. That opens at like 500+psi or something IIRC.
 
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