96' Blazer - Arizona Heat vs S-10 Blazer

1996 Chevy S-10 4x4 Blazer
Rebuilt Engine w/ about 15K miles on it.
New Water Pump installed with rebuild
New T-stat install with rebuild
2 yr old Radiator, flushed at rebuild
Running the 50/50 Ethylene Glycol


I live in Arizona where it will, and does, get to 115F ambient air temperature. Imagine the heat on the blacktop is in the neighborhood of 140F.

Prior to my engine rebuild my truck would never go over 210F at idle. Now I sit in traffic and the engine builds to three ticks to the right of 210F and that concerns me a great deal. not to mention my A/C starts to blow warmer than typical air(yes the A/C system has been checked and is fully charged. My guess it is also related to airflow over the radiator)


When I finally get moving on the road the fan roars like mad and it takes me up to 3500 RPM to get to a comfortable speed. Once there the cooling goes to normal which for my truck is two ticks left of 210F. The truck runs as it had in the past.


Logic tells me that my truck is not sucking air through the radiator sufficiently while at a stop. So I sit the truck at idle in my garage and put a mega fan in front of it to help push air to the radiator. Cooling stays one tick to the right of 210F, but I figure that is cause the mega fan is not pushing enough.

I did the search on here and noted several ways to test the fan clutch. So I gave it a twirl and it does appear to have some resistance on it. How much resistance should be there I am not sure of and cannot find a reference for.


Questions-

1) Does anyone know how many CFMs the stock cooling fan and clutch are supposed to pull? I am curious because I see so many replacement fans that claim to pull 3000-6000 CFMs. Just wondering if it would be worth it to buy a fan that would pull more air than the stock version. Just what is that stock CFM:icon16:

2) Is there a fan/clutch combo that could be recommended to improve over stock?
3) In this high heat, what tempature T-stat would you recommend running 180F or 195F?
4) Assuming I replace the fan and clutch, are there any other recommendations to help a desert dweller keep his truck running cool? Of course answers of “Move to a cooler state” have and will be pondered..lol!!

Try not to flame to hard if I have asked something retarded.

i think you're on the right track. as a rule of thumb if your vehicle overheats at idle it's probably an airflow problem, if it overheats while driving it's probably a coolant flow problem. you can always try cleaning the grill and cowl areas and pressure washing the radiator cooling fins first.

as far as after market fans you can put in an electric fan which will eliminate the roar of the mech fan and supposidly increase gas mileage. there was a post on here a long time ago about putting in a junkyard Taurus electric fan as a retro fit. i'll see if i can find it for you.

The test for a fan clutch is when rad temp gets 0ver 200-205 or kick in tempt it should be kicking in and moving a lot of air.
You should hear and also feel it kick in.
Hold your hand a ft behind it and you should feel a lot of hot air blowing on kick in.
Always stay with a 195 stat.
A 180 will not run any cooler in warm weather.

Some after market make what they call a heavy duty one
But I like the dealer OEM fan clutches.

I am goig to take it over and power wash the radiator to be sure. I will try your suggestion MT about checking airflow. Makes sense..I'll let it idle and watch the temp gauge. When it gets close I'll watch, listen, and feel for the airflow to kick in. I know it does when I drive cause I can hear the roar when I take off from idle. The roar tends to last a while as it is bring the temp back down over the rad coils. I just hope it is pulling suffienctly/efficiently.

I guess the alternative is the E-fan hook up with some fans that pull 10,000CMF at idle....lol now that would be cool:iceslolan

Another thing that may help when sitting in traffic very long is to put it in park an speed the engine up a little.
Other little things like the rad wash out rad fins or rad flush rad and no screen wire for a bug catcher in front of it..
And look in there between the rad and ac condenser.
I have found card board and plastic paper in between them.
And or a electric pusher fan in front of rad.
A few pickup even have them as stock cooling aids.
And last but not least is a larger or extra core rad if it will fit in there.
Ever little bit helps.
Good Luck MT

Well I tested last evening and it for sure kicks on and pulls air. I did look for things that might be blocking the rad or causing hot spots as well as took it and gave it a good washing with a pressure washer.

I was also thinking along the lines of a pusher fan in front of the rad. This might aid at idle if I set it up right. I will look into as well as a larger rad core.

These are all great suggestions and I appreciate all taking the time to look at it. I will work on it and post any upgrades or results I get.

Living in Arizona sure does take a toll on everything due to our heat. Anything we can do to lower the heat is well worth it.:grinyes: