MG Car Repair: Oil Pan Gasket Replacement, crankcase pressure, pan gasket

Question
Hello Howard,
I am about to replace the oil pan gasket on my 1980 MGB LE.  It seems like it is a pretty straightforward process, other than maybe some difficulties getting to the bolts.  Before I start I would appreciate any advice from you on the process.  I have not orderded the gasket yet - was planning on ordering from Moss Motors.  I have been palgued with oil leaks and I am hoping this is the last.  A mechanic told me he found a crack in the pan and he put some kind of sealer on it, and said if that doesn't stop it he could weld it.  I plan on inspecting the pan for cracks/leakage when I have it off, and do what I need to do there, but it is leaking aorund the gasket so I thought I would replace it.

Thanks.
Wayne

Answer
Hi Wayne,

The front bolts are a little difficult to get to and on some "B"s I have had to loosen the motor mounts and raise the engine just a little to get a pan off.

You should also check the crankcase vent system to be sure you are not building too much crankcase pressure. Also run a "Dry and Wet" compression test or a "Leak Down" test if you have Leak Down test equipment and compressed air. Either of these two tests tell if you have excessive ring blow by thus causing excess crankcase pressure and thus oil leaks.

If you don't have access to Leak Down test equipment get a simple compression tester and pull all four plugs and run a compression test (throttle wide open) and write down the results. Then squirt 4 or 5 squirts (about a table spoon) of engine oil into each cylinder as you test it again. This second "Wet" test will show higher then the first test but it should not be any more then 10% to 15% higher then the first. This is a test of the rings for blow by.

If you have excessive crankcase pressure and fix the pan leak it will just cause the next place to start leaking.

Any time we would get a car in for oil leaks, that is the first test we run and only if the ring test is ok would we agree to work on leaks. If it fails the crankcase test we would not work on any oil leaks.

Howard