I have a 1997 4x4 chevy blazer. My temperature runs right under 210, on 190 - 195. My fan kicks on often! I am looking to change it, and want it to run cool. I have considered putting a 160 thermostat, but the parts guy said that it could mess with my computer. So im probably going to go with the 180.

My question is what is a good temp for my blazer to be running at? and what is your view on the above?

Leave the 195° T-Stat in there Period.

Your parts guy is right. Your emissions control as well as your mixture etc. is all dependent upon the engine operating temp.

If you run too cold you'll waste gas and get poor performance.

Don't fix it, it ain't broke.

Your fan is not an electric fan so it shouldn't be roaring on and off.

If it is , your fan clutch is gone.

The 195 is better for your engine. The 180 won't hurt your engine and will give you better A/C performance. You should not use a 160 thermostat, they will increase (and sometimes double) engine wear.

1. Today's engines operate at high temperatures to fight combustion by-products and pollution. Lowering the temp below 175-180 won't accomplish this.

2. Engine oils are designed to work over a specific temperature range with optimum performance starting at temperatures that require the coolant to be the very same 175ish range.

3.Your engine forms moisture inside when it cools and condensates on the walls of the inside. This moisture then is washed down into the oil when started and then awaits vaporization by internal temperatures rising enough to bring the moisture to the appropriate corrected vapor point (boiling). If enough moisture is left behind it combines with combustion byproducts to form acids that become dissolved in the oil itself. The oil becomes more acidic as the age of the oil progresses and picks on certain parts eventually. Also moisture will corrode other surfaces. So, it's important to get these engines to a satisfying operating temperature as soon as possible. Usually oil pooling temps are about 30 to 40 degrees higher than the coolant temps. This is a generalised statement and can vary with load and engine design but you can see why you want your oil over 212 degrees to boil out the moiture immediately.

A 160 degree thermostat won't necessarily let your Blazer run cooler. That only means that the thermostat opens at 160 degrees. When your vehicle gets to operating temperator of 190-200 degrees the thermostat isn't going to close again anyway, whether you are running 160 degree or 190 degree thermostat.

The number only means that that is the temp at which the thermostat opens. The flow of coolant is the same, no matter which thermostat you use, they all have the same flow range.

Blazers have extremely efficient cooling systems. Without a thermostat or with one that is stuck open, the temperature will hardly ever rise above 150 degrees. Because of this they will run at the rated temperature of the thermostat and the thermostat will have to open and close regularly to maintain the temperature.

A 160 degree thermostat won't necessarily let your Blazer run cooler. That only means that the thermostat opens at 160 degrees. When your vehicle gets to operating temperator of 190-200 degrees the thermostat isn't going to close again anyway, whether you are running 160 degree or 190 degree thermostat.

The number only means that that is the temp at which the thermostat opens. The flow of coolant is the same, no matter which thermostat you use, they all have the same flow range.

It is set to open at 160 and never allows the coolant to reach its optimal temperature.

That is the whole point, you are pretty well contradicting your own arguement seeing you are saying that it is not allowing the engine to reach 180-195 before it opens.

I'll Say it again, Leave the 190° T-Stat alone.

I had to learn a valuable lesson trying to outsmart the Boys from Detroit. Maybe you have to learn that lesson too.

I live outside of Phoenix where the outside temp reaches as high as 115° F and my A/C works just fine with the 195° T-stat.

Don't fix it it ain't broke.

If you are in the lower half of the 48, you could probably get away with a 180 with no problems.

If you are in the lower half of the 48, you could probably get away with a 180 with no problems.

Why risk it? Instead of band-aiding a possible deeper problem, like poor cooling system maintenance, why wouldn't you want to fix your system so it will operate as designed?

Why risk it? Instead of band-aiding a possible deeper problem, like poor cooling system maintenance, why wouldn't you want to fix your system so it will operate as designed?

If you local temperatures are always above 65f, some people might see a gain in performance and economy with the slightly colder stat.

Sometimes it is so hot the engine just can't cope with the load.

115f in your area is a perfect example. It might be working fine, but the raised coolant temperatures doesn't help your truck at all.

If you local temperatures are always above 65f, some people might see a gain in performance and economy with the slightly colder stat.

Sometimes it is so hot the engine just can't cope with the load.

115f in your area is a perfect example. It might be working fine, but the raised coolant temperatures doesn't help your truck at all.
Contrary to popular belief, Phoenix sees temperatures as low as +30° F in the Winter. That being said, the engines on my two trucks, (93 Blazer and 2000 Jimmy) run a click or two below the 210 mark on the gage year round regardless of the outside temp. The only exception to that is when the A/C is running and I'm stuck in traffic in 115° weather, then it will climb to 210° F.

I'll agree that the 180° T-Stat probably wouldn't hurt anything. But if your swapping out to a colder T-Stat because you simply don't like where the needle sits on the gage, it's wrong. :2cents:

If there is a bonafide reason for running a colder T-Stat, go for it.

Contrary to popular belief, Phoenix sees temperatures as low as +30° F in the Winter. That being said, the engines on my two trucks, (93 Blazer and 2000 Jimmy) run a click or two below the 210 mark on the gage year round regardless of the outside temp. The only exception to that is when the A/C is running and I'm stuck in traffic in 115° weather, then it will climb to 210° F.

I'll agree that the 180° T-Stat probably wouldn't hurt anything. But if your swapping out to a colder T-Stat because you simply don't like where the needle sits on the gage, it's wrong. :2cents:

If there is a bonafide reason for running a colder T-Stat, go for it.

I agree with you there.

Well, I figured the colder the better gas mileage, and on top of that my fan kicks on often.

Well, I figured the colder the better gas mileage, and on top of that my fan kicks on often.

Not necessarily. As explained in this thread, your engine needs to reach a minimum temp to run right. I think the consensus is 175° to 180° minimum. Detroit (GM) defaults to the 195° T-Stat in most cases.

From what you are telling us, your Dash Gage is a click or two (colder) to the left of the 210° mark. If this is right, you are probably running pretty close to normal.

You mentioned your fan kicking on and off before, but you never clarified if your fan is electric or is it running from a fan belt with a fan clutch. While you're at it, have you flushed your system lately or performed any other cooling system maintenance?

If the fan is whooshing on and off all the time you will have to check your fan clutch seeing it is probably shot.

im also having a problem with this my temp guage was always a click or two to the left of 210 now it has been going to 210 and a click to the right causing my fan to engage upon take off (making the truck seem really loud) it is also a clutch fan...

Therefore I changed out the thermostat and now it runs hotter!!!! and when i turn off the truck and watch the guage while the key is turned to acc it goes from like 2 clicks to the right of 210 to like 260 or whatever the bigger line is (3/4 to the max)..

Im confused any suggestions?

thanks

-tom

rad cap, replace it with something that is NOT AC Delco.

Also, it is normal for your coolant temperature to rise for a while after shutting your engine down seeing the block is still hot and there is no coolant running.

IVIr_Evil']im also having a problem with this my temp guage was always a click or two to the left of 210 now it has been going to 210 and a click to the right causing my fan to engage upon take off (making the truck seem really loud) it is also a clutch fan...

Therefore I changed out the thermostat and now it runs hotter!!!! and when i turn off the truck and watch the guage while the key is turned to acc it goes from like 2 clicks to the right of 210 to like 260 or whatever the bigger line is (3/4 to the max)..

Im confused any suggestions?

thanks

-tom

If swapping out your rad cap doesn't work, you might consider a reverse power flush. Dealership will get approx. $75 USD, other garages will probably charge less.

Have your intake manifold gaskets been replaced yet?
Do you seem to be missing coolant without finding spills, drips or puddles under the truck?

Ill try the rad cap... but I don't miss any coolant always at a constant level. My manifold gaskets have not been replaced yet. I think ill try the flush cause it is the original coolant from 1999 I do believe and the truck has 80 thousand miles.. thanks -tom

What is rad cap? Radiator cap?

yes rad cap is a radiator cap

Remeber, NOT Ac Delco

Well, I figured the colder the better gas mileage, and on top of that my fan kicks on often.
if moters werent designed to run "hotter" today, the octaine requirement for moters to run proporly wouldnt have decreaced over the years (ie ask your grandparents what they use to buy as gas) the less octaine the hotter it burns, cool moters take 114 octane and led in them, both making the moter run cooler (yes i know the led was in there to distribute gas with a chemical reaction with led gas and aluminum) but the point is you had a 19x put in at the factory, keep it that way, it aint broke, quit tryen to fix it... someone beat me to it but i just cant say it better myselfe

At about 70k miles we had to replace the anit-freeze in our 2000 4x4 Blazer.

We have also replaced the rad cap (non-AC Delco).

Before we replaced it, I noticed the fluid being a redish color. The garage said the fluid was bad and needed to be replaced so we did. Some of it spilled in our garage and it looks like some sort of acid spill.

I was also told that the radiator fluid the factory puts in their new vehicles is suppose to last up to 100k.

The only reason I can think it didn't last as long could be due to the temperatures in Oklahoma. They range anywhere from 95 to 102 degrees from June to Sept and sometimes into October.

Not sure if this helps or not.

At about 70k miles we had to replace the anit-freeze in our 2000 4x4 Blazer.

We have also replaced the rad cap (non-AC Delco).

Before we replaced it, I noticed the fluid being a redish color. The garage said the fluid was bad and needed to be replaced so we did. Some of it spilled in our garage and it looks like some sort of acid spill.

I was also told that the radiator fluid the factory puts in their new vehicles is suppose to last up to 100k.

The only reason I can think it didn't last as long could be due to the temperatures in Oklahoma. They range anywhere from 95 to 102 degrees from June to Sept and sometimes into October.

Not sure if this helps or not.

OMG DEATH BY DEXCOOL.....

OMG DEATH BY DEXCOOL.....

No actually, the dexcool failure is due to a poor stock rad cap.

http://www.imcool.com/articles/antifreeze-coolant/dexcool-macs2001.htm