I recently purchased a 1973 Mercury Comet GT Coupe from a couple who said they hadn't driven it for a while (maybe 6 months or so). After driving through stop and go Atlanta traffic for 3+ hours and experiencing no problems whatsoever, I was convinced the stock 302 was in perfect condition. About two weeks ago, however, I was driving down the road and the engine started spewing oil from the dip stick (there was no oil on the distributor cap or any other components on the left side of the engine). The alternator was soaked and I had to replace it. What could have caused this huge buildup of oil pressure?
A friend at work has this same problem with a 289 in a 65 Comet ... he hasn't figured it out ... please let me know if you do so I can tell him ...
I'm sure some Certified Nut turner will jump in (hopefully) but I'd check the PCV valve to see if it's functioning correctly.
yeah ... the first think I told him was to remove all the PVC stuff and make sure that wasn't the problem ... didn't help though ....
You're going to want to check for pressure in the crankcase before you do anything. Usually the PCV valve (stands for positive crankcase ventiliation) takes the crankcase gasses and lets them escape into the intake tract. That usually makes for better emissions, cleaner lower end (no chance for dirt to enter through a valve cover) and of course to relieve any pressure that might build up in the lower end. Removing the PCV is not a good idea...unless it is done correctly. Just removing the PCV and capping the valve cover will let pressure build up and will blow the dipstick out every time. At the very minimum, you need one big breather in the one of the valve covers. It'd be better to have a breather in each cover...that will let all of the gasses out. Even better is to hook up a PCV system of some sort...whether it be a stock-type setup or aftermarket or something engineered by yourself...it doesn't matter as long as it lets the crankcase gasses escape.
Put a hose on the dip stick tube. Have someone crank over the engine with the coil wire removed and listen for a huff sound. If you hear such, a piston or rings are broken and not sealing. Another way is to pressurize each cylinder until you find the one that is causing the excess pressure. If that condition exists it's rebuild time.
Too much oil in the engine, plugged PCV system (quite common - replace the filter, hoses and valve and check the baseplate to make sure it isn't plugged.), Cracked piston, broken rings, or blown head gasket. Start by checking the oil level, then the PCV system, then a compression test then a leakdown test. You can skip the compression test and do just the leak down test if you want to.
Too much case pressure. I concur with the rest of the committee. PCV system... Too much oil... Internal engine damage causing combustion pressure escape... (aka: broken ring, head gasket failure, etc...) Good luck with it Dave
i would say broken ring as well. i know a friend had one do that on a (cough) cheby 350. we determined that the engine was junk and replaced it... engines are a dime a dozen in the cheby world, we tore the engine apart and found 2 broken oil rings, 3 broken compression rings and a crack in the cylinder wall. we figured that the combination of all these caused the compression gases to flood the crank case and made the oil go out to the weakest area, the dip stick tube do not quick fix it and plug up the dip stick tube. it will build up and find another way to vent out. get it fixed... my 2 pennies.. good luck
The problem is not caused by the oiling system. Your oil pressure is not too high. The crankcase is never supposed to be under pressure. It vents through the Breather / inlet filter and the PCV system. If oil is being pushed out then you have one of the problems mentioned - ie: broken ring, cracked piston, blown head gasket or way too much oil in the engine.
josh, welcome :Handshake mine did the same thing and the guy that installed my A/C found i had the pcv hose hooked up to a wrong port. he swapped it around and no more ...blow by... i will PM you my phone # and maybe we can get together and check it out. i live on Sgoda rd. off I16. frank check the ..top right corner...of the page for your private message.
