Head gasket or Liner Issue

[NMEXPAT]

While correcting my low oil pressure problem, I decided to take off the oil sump in order to inspect and clean the oil pick up, as one of the possible causes is a partially blocked system. Good news it was nice and clear.

While I was cleaning the sump gasket surface on the bottom of the block while under the truck I noticed coolant leaking from the bottom of the cylinder (rear cylinder next to starter).

It was tough to photograph, but it was clearly not oil and it was coolant. It had a green color to it, especially when it leaked on to the tarp on the ground.

Personally, I think this means I might have a liner / block issue instead of a head gasket issue. For it to be a head gasket issue, this would mean water would have to get past the piston rings.

What do the guru's think? I'm only a begginer shade tree mechanic that's learning the ropes.

 

[javelinadave]

Head gasket is plausible and much cheaper and easier than a block issue. Skim the head, swap in a new head gasket and pull your pan again after a few miles of driving.

 

[erover82]

Coolant can get past the rings, so it could be several issues. Pull the head and examine it and everything very carefully. Pressure test it if possible.

 

[jymmiejamz]

What cylinder?

 

[NMEXPAT]

What cylinder?

Cylinder #8.

 

[jymmiejamz]

I would take the gamble on doing a head gasket. Cylinders 3,4,5, and 6 do not have any cooling passages that are sealed by a gasket, so if it were one of those you’d have a cracked block.

 

[MountainD]

Curious--were the signs of the coolant in the oil? With a drip, I would expect a lot of both missing coolant and coolant in the oil. So strange that it is so prevalent.

 

[TheOneTen]

Curious--were the signs of the coolant in the oil? With a drip, I would expect a lot of both missing coolant and coolant in the oil. So strange that it is so prevalent.

This is why I'm a huge proponent of UV dyes in various oil and coolant systems - it makes it a LOT easier to debug and diagnose issues (when leaking)

 

[NMEXPAT]

Curious--were the signs of the coolant in the oil? With a drip, I would expect a lot of both missing coolant and coolant in the oil. So strange that it is so prevalent.

Yes. Coolant has gone missing the entire time I owned it. I've replaced water pump and radiator. I've pressure tested the system. I even disconnected the heater core matrix, all in efforts to find the missing coolant.

Oil was never milky. Cold start up no problems. Never excessive white smoke while running.

 

[evilfij]

I can’t tell exactly, but I have seen quite a few with coolant leaks at the back of the head.