Coolant in the sump. Lots of coolant...

[Trebor]

Just rebuilt a bust engine that had thrown a valve. I had a different head pressure tested and cleaned up, changed all the shells in the lump, new rings and gaskets.
Started it up and idled for about 10mins to check for leaks amd smoke, came up to temperature as normal, normal oil pressure, nothing obvious wrong.
Let it cool and checked the coolant, loads missing... thought it may be filling up the heater matrix's, checked the oil, mayonaise central!!!!!
Took the sump plug off and a good litre of coolant came out before I got any oil.

Any suggestions??? (The lump has been skimmed)

[Tankerman]

Coolant loss!

Compression test sounds like the first move!

[NiftyNev]

Was the oil cooler checked during the rebuild?

Nev.

[Trebor]

The oil cooler has all new gaskets and a good clean... annoying

[tweak'e]

could be head or head gasket. warped block.
the other odd one is crack/holes in the cylinders.

[bryanisaoldgit]

check you aint put a water pipe
on to a oil connection

[Trebor]

check you aint put a water pipe
on to a oil connection

hahahaha you did have me thinking for a moment!