I just replaced a pump using Merc 8503391, with brass impeller and stainless back cover
The back looks like this, with 3 holes on the side where the big hose attaches. The top 2 holes are for the bolts and the third is a water passage
I used Felpro gaskets, assembeled everthing, and when I started it up, water came shooting of the left side bottom right where that bottom hole is located
I thought maybe I forgot to tighten the bolts on that side, or maybe the freeze plug just to the left of that was the problem
Luckily I saved the old pump because I noticed it's older style GM pump (not LS) that only has 4 holes, not 5
It even has a GM part number on the front
Any idea why I would have this one instead? The PO repowered at some point.
On the block itself, there is a hole to line up with the 3rd hole on the gasket and pump but it looks either plugged or not tapped all the way through
The back looks like this, with 3 holes on the side where the big hose attaches. The top 2 holes are for the bolts and the third is a water passage
I used Felpro gaskets, assembeled everthing, and when I started it up, water came shooting of the left side bottom right where that bottom hole is located
I thought maybe I forgot to tighten the bolts on that side, or maybe the freeze plug just to the left of that was the problem
Luckily I saved the old pump because I noticed it's older style GM pump (not LS) that only has 4 holes, not 5
It even has a GM part number on the front
Any idea why I would have this one instead? The PO repowered at some point.
On the block itself, there is a hole to line up with the 3rd hole on the gasket and pump but it looks either plugged or not tapped all the way through