Hey everyone, i have a 1995 chevy blazer with the 4.3 and i just did the thermostat and flushed the dexcool out of my engine. I was wheeling with my one buddy and when we started to go uphill my temp started to rise up to about 230 when we got to the top of the hill, it cooled off once i was able to get speed on level ground but its a little close for comfort for me already having the trans rebuilt. I was thinking it could possibly be the rad cap not holding pressure or maybe my fan clutch isnt pulling air at low speed. Thanks in advance

 

Is the fan shroud completely intact?

Is the area in front of the radiator clear? Leaves and debris can build up between the A/C condenser and the radiator. I have no idea how they get in there, but I know I've pulled lots of leaf debris and other "natural" blockage out of that area on different vehicles.

When was the water pump replaced? When was the fan clutch replaced?

If there is no air blockage, I'd suspect the fan clutch. Those are supposed to be replaced when the water pump is replaced. That doesn't happen nearly as much as it should.

 

Fan shroud has a small crack on the top but it is mostly intact, i don't believe the water pump was ever replaced and the same goes for the fan clutch, the rad is clean but ill have to check in between my condenser and see if i gots some debris in there

 

Fan shroud pieces (top and bottom) are still available and relatively inexpensive. If you replace the upper shroud, the stickers for it are cheap at the $tealership, and do have some useful information on them. Usually the GM Part # is shown on the sticker.

Most likely your fan clutch is weak. Your water pump might be acting up as well. I replace both when either goes out, because, when you have it that far apart, there isn't much added labor to do both. This is especially true if you're replacing the water pump.

A properly functioning fan clutch will have noticeable fan noise (loud enough that my wife says "What's wrong with the fan?" if she's riding with me) in hot summer weather (90F + temperatures) as you take off from a stop after a long traffic light. It's not quite as loud as the first few seconds after you start the engine in the morning, but it's very noticeably louder than normal.

 

Mine doesn't even have a fan shroud at all. With the 180* thermostat I put in it, the temp might get up to the 210* mark, but only sitting in traffic in 100*+ heat. As soon as I'm moving, it goes back down to around 180-190.

I think it's fairly normal for the temp to go up under heavy load. I pulled a trailer loaded down with all my BILs stuff to OK city awhile back. Going up some hills, the temp got up to around 230, and made me very nervous. But once on level ground, it went back down.

I bet the fan shroud I'm missing might've helped. Eventually I'll pick one up at a junkyard. I didn't know you could still get the stickers, that's pretty cool.

 

New shroud pieces aren't that expensive. If anyone needs part numbers, here they are:

• Lower shroud, GM # 15736666, list price $25.40, available online for ~$17.xx (gmpartsdirect.com), and aftermarket knockoffs are less than that.
• Upper shroud, GM # 15133506, list price $17.58, available online for ~$12.xx (gmpartsdirect.com), and aftermarket knockoffs are in the same price range.

Admittedly, used ones are probably $10-$15 for complete shroud, $5-$7 per piece for individual pieces, but that's not a huge savings compared to new.