We were recently asked to pressure test eight cylinder heads.
The operator reported diesel in the coolant system, and sensibly decided that it needed looking at.
It arrived at our workshop, where we blanked the coolant holes tested them all to 3 bar for 30 minutes.
7 of the 8 heads passed this test but the 8th head consistently dropped in pressure.
A crack was found on the outer flange of the exhaust port, which went through to a coolant channel inside.
We recommend this head is replaced.
At present the exhaust gasket may seal the crack to some extent, but it’s only a matter of time before it fails completely.
This is another example of how a relatively small (and often unseen) amount of damage can lead to greater issues if left unchecked.
