Hello all, I recently bought a 99' Blazer with about 100k on it. About 2 weeks ago I came out of the store and noticed a large puddle of antifreeze beneath. I limped home and coolant was low but leak stoped, it was wet at the bottom front of engine with large drips. Intake manifold looks dry from what I can tell, and all hoses look good and new. So I filled it up, ran to normal temp and no leak. Yesterday it starts leaking again, and needed filling up again. What puzzles me is: is it the water pump, or somegthing worse, and why is it on and off, I am in AZ where it is like 110F? If it is the water pump, is that a PIA? I know its tough for you to diagnose, but what do you all think, thanks!!

 

The water pump isn't too difficult to change, but you really should find the source of the leak.

Is the line from the radiator cap location to the coolant reservoir connected? Could the coolant have come from the overflow tube on the coolant reservoir?

 

So, found out with a pressure test it is the water pump. Directions recommend replaceing the fan clutch as well, but that is just more $$ to me right now. As far as replacing WP, I have purchased a new water pump, silicone gasket sealant, and have a fan clutch wrench. Has anyone does this before, any tricks/suggestions. Do you have to put the sealant on both sides of the gaskets it comes with or do you even use the gaskets and just use the sealant? and also it recommends a 24 hour cure. Does that mean I wont be able to run engine for 24 hours as well? THANKS!!

 

I did this about two months ago! Replaced WP, upper and lower hoses, fail safe thermostat and flush. Took me a good half of a day just take your time... the lower hose was stuck on the WP and I left it on and used it as lever to pull the pump off from the front of the engine. I put sealant on both sides of the paper like gasket it was kinda tricky to line up the bolt holes with the gasket but I eventally got it. Do a search there is a lot of info for DIY out there!

 

For ease of lining it up, put two longer bolts of the same size through the water pump opposite of each other and get those threaded first but not all the way slide the WP tight to the block and thread in a few more bolts. Take the long ones out and put the regular ones back in.

Presto! No silicone everywhere.