QuestionHoward,
I own and drive weekly my third MGB. It is a 1978 B, spent alot, looks fantastic, drives great, but I have constant oil leaks. Now I think it is the rear main seal. I do not work on the car, love to drive it, but no time or tools to work on it. I have had every other gasket replaced. The MG shops in the area say the engine must come out to fix a rear engine leak at huge dollars. One guy says you must fix or risk loosing the engine, another guy says just keep an eye on the oil level? Any thought on this subject? Thanks, Joe
AnswerHi Joe,
Oil leaks on a British car? No way! ha! Sorry, didn't mean to make light of your problem. It is a common joke in the industry about British cars.
I was a line mechanic on MG, Triumph, Jaguar, Lotus, Austin Healey and Sunbeam cars from 1960 on up into the late 70s, I had a ASE "Master" + L-1" certification on up till 2001 and was an instructor in two commercial mechanics schools and a "Hot Line" answer-man for mechanics for 15 years.
I am retired now but still tinker with British cars as a hobby and love them. I have accepted that British cars leak oil (at least up into the late 80s)
The amount of leak should determine what you should do about it. A Jag factory rep once told me that if you park a new "E" type Jag on a clean piece of concrete after being driven, that in the morning you will have two spots the size of silver dollars. If you have more than that they will authorize repairs but if less they will not even talk about it even though the car is in warranty.
Your MG has or had a crankcase vent with a restrictor in the valve cover that connected to a hose going to the charcoal canister. Also there is a hose connected to the front lifter galley on the side of the block that vents crankcase pressure into the carb. If either of these systems is clogged up you will get crankcase pressure and excessive oil leaks even with good seals and gaskets. The front side cover is an oil separator/flame trap which in time can clog up. Worn piston rings can also cause crankcase pressure which in turn causes oil leaks at gaskets and seals. A worn out rear main seal or main bearings and seal can also be a cause.
If you run it out of oil you will do permanent excessive damage to the engine. I always told my customers that if you see that your engine is overheating you have minutes before damage is done to the engine. If you loose oil pressure you have seconds before damage is done.
Your answer is, keep oil in it until you find out what is causing the leak. Oil leaks don't damage an engine but when the oil is out, damage is done in seconds.
I hope this gives you a little background to decide what to do and how to go about it.
HMF
http://mg-tri-jag.net
