1996 blazer, 116,000 miles. Sometimes, and it is very random, my engine sounds like a diesel engine when I start. It's very hard to describe but it sounds like the motor is laboring. Hit the gas lightly and it sounds like I stomped on the pedal. Hard to tell if I've lost power because I'm not giving it much gas. It's odd because it's so random. It may do it at 1 stopsign, then not at the next one. Doesn't seem to matter if the engine is hot or cold. I have been keeping track of my gas mileage and I'm getting about 12. I've only had the truck since March and have only put about 4000 miles on it but it is now my only vehicle. Any suggestions would be greatly appreciated.
Thanks,
Jim

 

Sounds like the fan clutch is locking up to me.

 

At the risk of sounding stupid, what's the fan clutch and how can I fix it?

 

Thanks for your suggestion gpgab97. Did a search on the site and found this:

"Check your fan clutch. That's always the first place I check for engine roar. I got a bad fan clutch out of the box for my '93 Jimmy when I replaced the water pump. I had a terrible engine roar and the mileage went down. After I got a second, more functional new fan clutch all returned to normal."

 

After doing some research, I went and turned the fan by hand with the engine cold. Only moved as far as I pushed it and I understand that it should spin freely with a little resistance. Started the engine and the fan was going. Am I correct that it should only blow when the engine is warm? With a high temp of 15 tomorrow and no garage to work in, I think I will take it to a shop tomorrow. How long should the job take for a pro? I'm guessing about an hour? Seems pretty straight forward with the hardest part being getting the part off.

 

I unknowingly "rented" a fan clutch tool from Autozone...it didn't work and so it added a lot of time for me. Honestly it's probably around 40 minutes or so to get set up and take your time doing it right. There are probably a few write ups here on the forum about it, 4 of my blazers had at least some quirk with the clutch, I'm sure I'm not alone. Good time to replace your accesory belt as well as check hoses and water pump weep hole while you are in there.

And another thing...If it's that cold where you are, you may be able to run the truck without the fan at least for the remainder of the winter, to buy some time for warmer weather. I have a friend in Medicine Hat Alaska who took his off permanantly 4 years ago... He doesn't idle much in traffic like i do... lucky bastard.

 

Heat wave today, 32 degrees so I decided to tackle the problem myself. Shoved a block of wood between the pulleys and with a pipe wrench was able to free up the fan clutch. had to fight with it a little but I'm sure it took less time than borrowing a tool. Figured I'd start with the basics and if that didn't work... Guess I got lucky. Anyway the whooshing noise / engine roar is gone. Thanks gpgab97, you nailed it! Good idea to run without a fan for the winter but I'm heading to Lake Havasu, Arizona for the next 4 months. I'm pulling a 5 X 10 enclosed trailer so I can't take any chances. Plugs, wires, rotor, cap and should be good to go.

 

No Problem, glad you were able to complete it not knowing what you were getting into and all. Man, I wish i could go back out to the dunes and lake Havasu. I miss sand rails and late night pallet bonfires...