98 S70 Missing Cyl Head Bolt Massize Coolant Leak

sven · Post by **sven** » 05 Jan 2014, 18:49

Hi MVS,

Doing a cylinder head on my mom inlaws 98 S70 NA (burnt valve). Im putting in the coolant tonight and I found this big leak on the side of the cylinder head. Looks like a bolt or some sort of sensor is missing...anybody know what is supposed to be there? If its a bolt, anyone know the size?

Post by **kcodyjr** » 05 Jan 2014, 19:21

I may be wrong, but isn't that where the upper motor mount arm should be?

Post by **cn90** » 05 Jan 2014, 19:25

Likely #27 and #28 in the diagram below:

http://volvopartslisle.com/assembly/331 ... inder-Head

Post by **jimmy57** » 05 Jan 2014, 19:53

A plug with seal goes there. They will remove things that are harmed when they vat the head to clean it. The next question is if the machine shop can find the plug.

Post by **cn90** » 05 Jan 2014, 20:10

I thought that hole (directly above the black heater hose) has threads in it.

Post by **erikv11** » 05 Jan 2014, 20:30

Yes the hole has threads, just like the plug that screws in there.

EDIT: #27 and 28 in the diagram you posted are the threaded plug and the seal, you guys are talking about the same thing.

sven · Post by **sven** » 06 Jan 2014, 10:41

Thanks for the responses. In case this happens to anyone else....The bolt/plug size is M12 1.5
My local Napa had a BMW drain plug that appears to fit perfectly. Cost was $1.89.

Post by **rspi** » 06 Jan 2014, 16:50

I pulled a head recently and that hole did not have a bolt in it. Was the head new?

Post by **burnout8488** » 06 Jan 2014, 22:16

Is that the "bung" that the PCV coolant hose connects to on 99+ models? (Heats the PCV pipe under the intake manifold, coolant flows from it to the thermostat housing)

Post by **abscate** » 07 Jan 2014, 03:10

Another MVStery solved!!