Hello to all. Great site! In need of a little help. I bought a 2003 blazer ls 4wd last week and have a radiator fan problem. The fan runs loud always. Even after sitting over night and on a cold start the next morning (40 degrees) the fan instantly is running on high. I sound like a have a jet engine roaring thru town and power is lagging. I had a highrider years ago so i know this isnt how the engine should run/sound. I went ahead and replaced the fan clutch today thinking that would solve the problem but it didnt. Im not overheating or really having any cooling issues so im stumped. Ive searched for a fan clutch relay on this site as well as google but havent found a worth while thread. Am i missimg something? Autozone and oriellys couldnt find a relay on there computers so does it not have a relay or replacable switch of some type? Any info would be greatly appreciated. Thanks in advance.

 

Just throwing this out there could be your water pump cause most clutch fans are not electronic so no sensor for them might be wrong but worth a try 1 yr warrenty pump is only 33.99

 

hate to say it but that jet engine launch in the morning is normal.
i have had my blazer for a long time always has done it...most on here will tell ya the same.

its the blazer morning "turbo launch".

there would be no relay for the fan..it is a clutch and 100% mechanically operated.

 

On a cold start, the fan clutch should be fully engaged causing the jet sound.... perfectly normal, if it doesn't do it, there's a problem. Depending on how cold it is, they typically quiet down when engine RPM reaches ~2500 rpm.

 

As above, normal till it warms up. Curious, did you use an OEM clutch. As with all replacement parts, you can get a bad part out of the box.

 

So after going for a long test drive the fan finely shut off. I guess the fluid in the new clutch just needed to warm up a little. Thank god. My mileage went from 11.86 to 16.4 and i finally have power again! Thanks for all the info. Great site.