I had temps showing into 220+ range on a very hot summer day. It was after a heavy trailer pull, then a 10 minute idle. During the pulling, it intermittently would roar cool, but still ran hotter than 205 showing. At idle, it never went into roar mode, and temp gauge ran way high (yet no other signs of overheating). I am researching about going electric fans, and tried to find any options showing in Rockauto with respect to stock electric cooling parts. I did not see any computer controlled fan hubs offered, and I am wondering if they all proved to be unworthy of even a listing in Rockauto? All they are showing is thermal fan options, and I lost an engine to one of those in a different Chevy truck.
Thanks for any suggestions for making the cooling reliable on my 135,000 mile, LS, stock Blazer.

 

I think electric fans are a good option. There are a few threads on repurposing ones from a Chrysler product. However, I'd like to suggest another option to consider at least as a stand-alone option or in addition to electric fans; a supplemental transmission cooler.

I installed a Hayden 699 on my truck because I tow a boat (2,200 lbs total) where it can get hot (100'F +) and I have some tall grades to climb (1,700' in 6 miles). This cooler worked really well. Using a gauge for my transmission fluid temp (Ultraguage) I noticed that the trans-fluid temps were 20'F lower. This cooler has a built-in thermal bypass valve so that the transmission does not get excessively cooled on cold days.

And since you tow, I'd also recommend you consider getting some sort of trans-fluid temp gauge. The heat generated ruins the seals in our transmissions and causes them to leak. This is what happened to me causing my 3/4 clutch pack to fail. The Ultragauge one also allows monitoring other values. If you get this one, be sure to get the one that allows for trans-fluid temp sensing.

Finally, if I remember correctly, my transmission shop guy said that what helps cool a transmission is keeping the engine and transmission speed up. This is because at higher speeds, the trans fluid goes through the cooling lines faster helping with cooling.

And of course, never tow in overdrive!

 

Hey Christine....in your posting above, the comment about never towing in overdrive, I read it the owner's manual to leave trans in 3rd when towing. However, when I am towing a relatively light load and get on the highway, after I am up to 70mph or so, the Check Engine lite will begin to flash, continues to flash until I shift into D...then all is fine. On surface streets, I go back to 3rd.

Have you experienced this?

I agree with adding a trans cooler....I have due to the temps here in Southern Arizona in the Summer even though I do not tow very often.

 

Lanny,

I also tow a small utility trailer and when on the flats and especially when the total weight of the load and trailer is less than maximum load I could put in the Blazer, I'll use overdrive. Although I haven't been in the situation where I would get up to 70 mph with it with my maximum speed being about 60 where I've towed it, mostly 2-lane highways in North Idaho. But I've never had Check Engine Light start flashing as you described. Have you looked up what a flashing CEL might mean? Were any OBD codes stored?

Have you installed a trans cooler? If not, the Hayden 699 is a tight fit but I'm glad I installed it.

 

No codes are set. I think the flashing Check Engine lite is just to get driver' s attention and hopefully the driver takes notice that the vehicle is in 3rd and not D.

Yes, I did install a trans cooler....you missed where I stated that above.

 

It's misfire detection. Could be real - could be false. I'm sure it would have a pending code on the key cycle where light has flashed. Need a better scan tool to read pending codes.

If you have a Bluetooth OBD2 adapter, Torque light is free and will read pending codes.