What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

What thermostat should I run on my 383?

N

nsxxtreme

1/2 ton status
Joined
May 9, 2008
Posts
1,049
Reaction score
0
Location
Oregon
What thermostat should I be running? I noticed my temparature was never really increasing so I took apart the thermostat housing and looked at my thermostat. The little valve somehow poped out of the holder and was in there crooked. So it never fully closed. So I went down and bought a 195 thermostat and the thing runs like poo. I imagine that has more to do with my tune being set up for a cooler engine.

So I bought a 160 and it runs way better.

However it can be retuned to run at the higher temp. What are the advantages and disadvantages of runner hotter or cooler?
 
Man, I don't know for sure but 160 sounds too cool. You may be trying this out Nd letting us know. I would say 185/190. But if your 195 was truly making run worse than I'm lost.
 
what truck, year, engine set up is this? What is the tune?

Normally going to a cooler temp T-stat on a fuel injection engine will make it run richer, gaining a little if you run other mods. But tuning the engine to KNOW about the lower T-stat, doesn't really do much other than run cooler. Do you have a manual or electric cooling fan? The clutch on a manual still wont work till 195, by then the truck thinks it's overheating.

Not a fan of running it that cold. I'm with 63, 180*+ is better, the engine works better too, something about a more complete burn.
 
I've seen mention that running consistently at 160 deg will wear everything significantly quicker than 180-195 deg but I can't tell you if that's true. In theory the cooler temp means cooler intake air (assuming your cooling system can keep it that cool) but I can see that parts (piston rings, etc) may not expand like they should if they are limited to a cooler temp.
 
I like 180 at minimum, I like the engine and oil to be running at the temp engineered to run at.

If you have noticed many new vehicle manufactures are running higher temps because they can get away with leaner mixtures. Maybe try a 180 and go from there
 
K85 Octane said:
what truck, year, engine set up is this? What is the tune?
Click to expand...
Make and model of the truck doesn't really matter since the motor isn't even close to stock. But its an 87 blazer. Its the old manual style fan that's pretty much always spinning.

The motor is a 383 with a 54mm TBI 9.8:1 compression ratio. High lift cam. Have been tuning for the last couple weeks but obviously to the cooler temps. :doah:

So it ran like crap with the 195 because of that tune not because the engine doesn't like it. I'd have to retune for the higher temps. I know with the lower temps you can get away with more spark advance because you wont get high temp detonation. But other then that I don't know why you would want one temperature over the other. Kinda hoping some motor building experts could chime in.
 
I've always heard lower temps gives a lil bit more power. higher temps gives u more engine life.
 
EFI likes a hotter temp... keeps them happy and gets them in to closed loop...
 
I run a 160* in my 89' K5 350 TBI and never noticed a real big difference between running that temp as compared to a hotter one. It is nice never having to worry about it overheating in the Texas summer, but being stock would it have any affect on it running that cool? It has electric cooling fans but no other real engine mods. Should I go back with a hotter one for engine life?
 
yup... tbi's like it around 200... I'd bet your mileage is down... engine longevity is best when oil temp is in the 200 to 225 range... tho most don't have an oil temp gauge, I do....
 
higher temp is said to have better fuel economy to help fuel expansion, however to much advance with that will detonate like a diesel, if I was using aluminum heads that would also change what I decided, all in all a 180 would be a good starting point
 
He has aluminum heads.

As far as I know, manufacturers use 190+ to lean the fuel mixture and lower emissions.

If you are going for power, you need lower. 180 Should be the compromise. You could run the 160, but you would have to run the engine hard to keep the oil temp up. Think race engine.
 
I DON'T GIVE A DAMN WHAT YOU USE

just realize your mechanical cooling fan is still set up for 195* operation, getting really tight 200*+. If you tow or pull long grades in heat, it will climb past your T-stat until the fan can help. Hell, even if you are running the AC at a stop light, this can cause problems. If the computer (on FI vehicles!!) is set up to run a lower stat, this will cause the computer to pull power back and try to get the engine in it's temp range, making things only that much worse.
 
K85 Octane said:
I DON'T GIVE A DAMN WHAT YOU USE

just realize your mechanical cooling fan is still set up for 195* operation, getting really tight 200*+. If you tow or pull long grades in heat, it will climb past your T-stat until the fan can help. Hell, even if you are running the AC at a stop light, this can cause problems. If the computer (on FI vehicles!!) is set up to run a lower stat, this will cause the computer to pull power back and try to get the engine in it's temp range, making things only that much worse.
Click to expand...
Not sure what you mean by being set up for 195. The way it was before I could drive it all day long and did and the temp never moved past about 110. Including going up steep hills. So I dont think the mechanical fan cares what thermostat you have in there, it's going to always suck air threw the radiator.

After doing a lot of reading online I think I'm going to stick the 180 thermostat in there. There seems to be a lot of debate on the internet about this but nothing with any real data to back up the claims.
 
nsxxtreme said:
Not sure what you mean by being set up for 195. The way it was before I could drive it all day long and did and the temp never moved past about 110. Including going up steep hills. So I dont think the mechanical fan cares what thermostat you have in there, it's going to always suck air threw the radiator.

After doing a lot of reading online I think I'm going to stick the 180 thermostat in there. There seems to be a lot of debate on the internet about this but nothing with any real data to back up the claims.
Click to expand...

you can say goodbye to that fresh motor running around at 110...
 
ryoken said:
you can say goodbye to that fresh motor running around at 110...
Click to expand...
Thanks for the support :waytogo:

I changed out the thermostat to 180 other then the pinging I get now it runs just fine. Just need to remove more timing from the tune now.
 
just a word of warning is all... I'm a dinosaur, and I have seen this issue before. it's pretty common in the marine biz... it can lead to a wide variety of issues, carbon build-up, etc...
 
You must log in or register to reply here.

Latest Posts

Top Bottom