Ok, I've been working on this Blazer for 3 weeks and now have $1500 wrapped up in this and still can't get it fixed.Had a fuel pump, wheel bearing, and intake gasket installed on my 03. Put a new water pump on because she still had the original. When I drove it for the first 5 miles I hit a steep hill and hammer it. Water pump gasket blows, loose all coolant and back in the shop it goes. Pick it up 2 days later and he tells me the thermostat stuck and it built up pressure and blew the gasket. Head down the road and same thing happens on the same hill. New mechanic, very good expensive mechanic, takes a crack at it and I leave his garage and same thing happens on the same hill. Anyone every had anthing similar happen????

 

something sorta like this happened to me on my first blazer years ago. My waterpump kept leaking no matter what. i tried replacing the pumps etc and went through this about 6 times. Finally what i did was get some indian head shellac compound,and 2 gaskets,coated em in it and torqued the bolts down. Didnt have anymore issues. i believe that portion of the block may have been warped or something. it did have over 600k miles on it.

 

well first off I'd quit going up at hill.....lol...sorry just had to say it...

 

Continuing along the thought of chris015....perhaps remove the water pump and check the block for warping in this area. Get a good straight edge and a strong light and check to see how flat the block is across the water pump interface. Also check the waterpump for flatness....it may require some filing as well as the block.

Were both block and water pump surfaces clean and free from oil when RTV was applied?
Is too much RTV being used?
Is the RTV old?
Do you allow 24 hours for the RTV to cure before adding coolant and running engine?
Are the bolts and the holes in the block clean so as to not give a false torque reading?
Are the bolts the proper length..not soo short, not too long?

Just some thoughts...good luck.

 

I ran into a SBC water pump that had the wrong impeller
the blades were in the oposite direction, V belt driven and serpintine usually spin in oposite directions