h/o guy

Looking to get some inout / direction on a problem I am trying to diagnose. Freshly built 371 engine with roughly 200 miles on it that started putting water in the crankcase. This is a top quality build with Ross Racing aluminum, heads, all ARP hardware, forged pistons, roller rockers etc.. The timing cover/water pump housing has been removed and inspected and that is not the source of the water contamination. Removed all spark plugs and spun the engine and no water in the cylinders.

Head gaskets are Cometic MLS units but with no water in the cylinders, I'm not sure a head gasket is the culprit. Double cheked the head stud torque and no variations or loosening there but I beliece some if not all the head bolts do thread into the water jacket so is it possble that water could be migrating up the threads of a bolt or two and causing this like I have seen happen with big block Chevts before?

Any input would be appreciated.

Grant

sysmg

How about intake manifold water ports leaking into the valley above the camshaft?

h/o guy

Thanks for the reply sysmg but on these engines, the intake doesnt seal the valley of the block so if the water ports at the front of the intake started to leak, it would leak externally and not into the crankcase.

OLDSter Ralph

Who built this engine ? Was the block checked for cracks ?

BillK

I would start out by pulling the valve covers and putting a radiator pressure tester on the radiator and pumping it up to about 25 lbs. If it was leaking around the head studs you should be able to see it.

If you don't see anything there then you probably have no choice but to pull the pan and see if it is leaking from in the block somewhere

One more thing . . . . how much coolant is it actually loosing ? Make sure its not just condensation especially if you are not running it long enough to get everything up to temp.

h/o guy

I built the engine and the block was magnufluxed prior to machining and assembly and all checked out ok. No excessively worn or stripped head bolt threads needing repair and both the block and the aluminum heads were surfaced to the proper RA finish to accept MLS gaskets. I know some folks put a very thin coating of solicone around water jacket holes on Cometic gaskets but these were installed dry as I have done dozens of times before with no issues.

BillK

Cometic gaskets have a coating on them to seal them up. I have never used silicon on them.

The problem with magnaflux is that it wont show a casting porosity or a small pinhole etc. It only shows actual cracks. If it is something like that the only way to find it is to pressure test it. I had an old Buick block years ago that ended up with a small pin hole at the very bottom one of the cylinders after boring it. It never got water in the cylinder, only in the oil

h/o guy

Thanks for the input Bill