Tired of my overheating problem, I decided to replace almost everything in my cooling system. Radiator is on its last leg, hoses were rotting from inside out, rust flakes everywhere. So I broke down and bought a Stewart water pump and figured I would make sure that's one more part of the cooling system that will for sure be working. Took off the water pump and found this gem in my timing cover. Just thought I would share with y'all.

I am very tempted to take this engine out and rebuild it. I am almost certain the tap/well water that was left in the block by the po for over 8 years has coated the block in rust as well that even term-cure can't clear out. Opinions?

 

Oh wow!! Is that a new high volume bypass port? LOL

 

Old Pontiacs V-8s use an aluminum timing cover tgat served as back of water pump housing. Using just water or weak coolant would in time "erode" it from the swirl as water was moved, and first hint was a pin hole causing hot water to be pushed direct into the timing chain cavity, One night my '65 GTO did it, and I was on the road. I changed the oil that first time but refilled coolant with just water. I had had coolant in it at the first drain ... Mechanic there in Danville suggested (just to get home with near 70 miles to go still) to leave the oil in it and just give it time to separate from the water if I stopped again. I stopped at several gas stations to run it up on the lift to just drain the hot water out of the oil pan, then when oil started coming out, I stopped it with a heavy glove on my hand ... then I would refill water and go another 20 miles or so. I was on Rt 29 where I knew every station that would be open at night. Took a couple, maybe three hours or better to get home. Fix was to change the cover, never had an issue with bearings. I fixed same deal on a GF's GTO and another's Firebird.

Where does that huge hole lead to antyway? Was there water in the oil? If there is good oil pressure still, if it was just water in it, I wouldn't "rebuild it" unlesss I needed to replace rusted freeze plugs. I'd just fix the issue and put fresh good oil and good real coolant mix in it and watch it. I would check freeze plugs for signs of leakage or thiness.

 

It just leaks behind the water pump back plate and down to weep hole. Not inside crankcase. I still have a 99 Taurus given to me in 2008. Owner couldn't keep heater core open. After countless flushing's and chemicals, I pulled engine, rust in the block was higher than core plugs. Bad things happen when cooling systems combine iron, copper, aluminum and steel. Had engine and heads hot tanked, replaced radiator and steel heater tubes. Still going after another 100K.

 

Oh you know, just a little bit of weight reduction for the 460!

 

I don't think it really led to anywhere, putting my finger in it, it think it just eroded away, but the cover kept the water in... just coincidence I found it. The PO I got it from ran it on tap/well water on the farm it was at, so who knows how eroded everything is.

 

That is very common on 385 series engines. There should be grooves on the gasket face on the cover that allows water to flow out there which indicates this problem. It’s possible the grooves were filled in with RTV when the pump was last replaced. This hole would not cause your overheating issue.