Todd, did not do a coolant system pressure check as I do not have an AST and eliminated it with the 1st gen radiator cap. Thus their pressure tester did not interface properly.

 

I'm gonna guess that somehow the coolant is seaping through the pores of the metal. Under boost it get sforced through tiny holes that would other wise not be seen.

I would guess that it is a problem taht would have gotten worse until the casting actually gave way and broke off.

Looks like you just hit the lottery on shitty cast plates Michel.

Too bad I was hoping to see engine bay pics.

Get a new plate and get on with the install.

Dave

 

that is weird....

 

The wall between the coolant seals and the water jacket all in good shape. I am not sure what the width should be, but I know that when it gets to small it can collapes causing the seal to fail.



I don't think the water is going though the plate when pressurized, or it would do it with the pressure from the cooling system.



If I was you I would just stop messing with this hidden crack/leak and just spend the money and get a new housing and be done with it. You may never find what the hell is wrong and you will mostly likely have to replace it anyway.



My 2 cents

 

If the teflon seperated from the inner O ring and was pinched it will cause a coolant leak under the same conditions you are talking about. I did this to my last motor and if I drove the car around with no boost I wouldn't loose coolant, but If I boosted it, it would loose coolant. It was not as bad as yours, but was enough that when I let it sit for 2 weeks with no turbo on it, the corner seals rusted causing lost compression. On tear down I found an inner O ring with about a 3mm section of the teflon that was pinched between the plates.

 

So it could be as simple as a coolant O rings change IGY? Would the coolant pressure be enought to push though the slit in the seal?

 

Igy,

So you're saying that during assembly, a ring can get pinched, causing the teflon to separate and ONLY the teflon gets stuck in the wrong spot causing the leak? Or does the pinch cause the teflon to separate and that in itself will cause the leak under boost? My rings did have the teflon separated from the rest of the 0-ring but I was told that is normal upon disassembly. Is this correct? They have the reuseable kind of 0-ring that they say everyone is moving towards now (in the racing community). It's a bit thicker than the standard 0-ring and it's cross section is round as well. All black. Anyone else hear/use them?

Michel

 

It is normal for the teflon to seperate. Yes, only the teflon was pinched, nothing was wrong with the rubber.

 

if you look at the pictures of his port runners, they are barely ported in that area at all, you can still see the small circular land which is present in the stock casting and the 'pores' are actually just the rough cast _original_ surface, it wasnt even ported down enough to remove it. The problem I'm positive is not in the metal photographed on the ports.



I'm still thinking O ring failure or freeze plugs, but if coolant was getting combusted it would be difficult for the freeze plugs to cause this. The only way I can imagine freeze plugs causing combustion of coolant, is if the coolant gets into the oil and eventually supplied to the metering oil pump, and consequently injected for combustion as if it were oil.

 

Your parts look good

have confidence in you self

just take you time and all should be well.

remember ..... vasoline is you best friend when putting it back together