What is too hot on thermostat?
 

Took truck on furthest drive ever today since i have owned it for about 30 mins and temp got up to 200. What is a normal temp for you guys running - 350 with Manual fan no shroud.
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Re: What is too hot on thermostat?
 

200 is 12 degrees below boiling so that shouldn't be any problem. Guys are still living in the dark ages where flathead Fords and 216 Chevy sixes had big issues if they got up to the boiling point but a lot of the newer engines are designed to run at the higher temps. Most 500 Cad engines have 205 thermostats and most 75 and later GM small blocks run 195 thermostats from the factory.

On yours if it goes up to just 200 when you are in slow moving traffic and drops back down to just over the rating of the thermostat when you hit the open road I'd say life is pretty good. On my 71 I can't get it hot enough to get good heat out of the heater. I run a 195 thermostat which is factory for the 79 350 in the truck and still freeze my butt off on the highway at low temps.

Re: What is too hot on thermostat?
 

Thanks mr48chev. I will watch it, not sure what stat is in it as I haven't change it since i bought truck. Block is a 70's block.
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Re: What is too hot on thermostat?
 

Put a shroud on the fan it will make a lot of differance and I would put a 192 thermostat in it to give it more radiator time.

Re: What is too hot on thermostat?
 

200 sounds ok to me - if it gets over 210, then I'd start to worry - i.e. check the theromstat, consider a fan shroud, etc. But if it hung steady at 200, I would not worry. Also - were you parked and idling? If that's the case, I really wouldn't worry - go out an get some airflow through the radiator and it'll probably drop below 200 - and you know when you get stuck in traffic, you'll be able to creep back up to 200 and hold steady with no worries.

Re: What is too hot on thermostat?
 

Thx guys
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Re: What is too hot on thermostat?
 

Definitely put a shroud on that!:D It will do wonders sitting in traffic.

Re: What is too hot on thermostat?
 

not to hijack thread but my 91 runs at 210 in hot weather with the air on,but they say it should run that hot.but on a nice cool day runs bout 195.

Re: What is too hot on thermostat?
 

I would run what ever is recommended for your truck. Newer trucks do run hotter than old ones do.

Re: What is too hot on thermostat?
 

i got a similar queston
ive got a 165 thermostat in my truck, watching the temp gauge you can see it open at around 230, then truck runs around 195.
how are the thermostats rated? i would assume theyre rated to open at the temp, ie. my 165 would open at 165 right?
I just think its weird that my thermostat opens so hot, i know its not bad or stuck either because after pulling the motor and rebuilding much of the lower half when i got the truck i had a new 175 in it, thought it wasnt opening b/c it got up so high and i shut it off before it opened thinking it wasnt going open
so i replaced it with a new 165 and was worried again b/c it wasnt opened but then it did around 230. once open the trucks purrs, not too hot, i can touch the block and its never overheated on me.
Is it possible that the temp gauge is wrong? (its an aftermarket PO put in, one on dash doesnt work) could it just be a wrong resistor or something? on a side note, i once left work on a VERY hot day this past summer and before starting the truck it read like 120-130 i think, it was high 90s that day, but id never seen it start not all the way down before after sitting all day (8 hours)so this made me think the gague was wrong. i dont think it would be 30 degrees hotter inside the engine compartment either

Re: What is too hot on thermostat?
 

If the heater or bypass (bigblock) are not in the design location some times the temp at the guage in the head will be 200 but the coolant at the t stat will be cooler. If you are running antifreeze 210 isn't anything to worry about if you have a good pressure cap, the engine is more efficient at 200 degrees as long as it doesn't get too hot

Re: What is too hot on thermostat?
 

Got around to checking stat and per previous owner there wasn't even one in it. I put a 195 in and drove truck around for about 45 mins. Truck ran between 195 and 210 the whole time. Guess it is ok since it never seemed to run past 210?? I did also put a clutch fan on it as the flex fan was just too loud for my taste. Now wondering how accurate the temp gauge in truck is.
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Re: What is too hot on thermostat?
 

I was having issues with my temp gauge reading extremely hot so I installed an engine thermometer in the intake manifold to get an accurate reading. It turned out that when my temp gauge was at 3/4 sweep the engine thermometer only read about 180. I think its because I'm using the stock style temp sender and original gauge with a new 383 crate motor.

Re: What is too hot on thermostat?
 

I was still nervous so when I got off work I put a 180stat in and it seems to be holding around 185/190. Like that better. Guess I need to go ahead and get a fan shroud.
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