I recently fired up a Chevy 427 for the first time since it last ran in '94. It's been sealed, filled with oil since then. We sprayed WD40 in spark plug holes and hand turned, changed oil and filter prior to firing. After start up it runs fine, no skip, but rolls white smoke out of driver side header and when we pulled #7 cylinder spark plug it leaked oil out. Also when we checked the dipstick oil was milky and it had used at least a quart. Oil was on floor under left header and dripped out after we shut it off. It filled the shop with white smoke. I would appreciate any advice trying to diagnose the problem. Our prognosis is a leaking intake gasket pulling water from jacket and oil from the valley. Any ideas? Thanks.
I think you are right but you won't know until you open it up. I would buy a new complete gasket kit and start over.
Hold on for a second...before you start disassembling the engine. White smoke says automatic trans fluid to me. Just in case...is the engine mated to an automatic transmission? Check to make sure the engine isn't drawing in trans fluid due to a damaged diaphram in the vacuum modulator.
Although I'm sure you know whether it's oil or trans fluid on the floor. And the loss of oil means I'm probably wrong about the trans fluid. It's just that I've seen a car that was burning trans fluid cover half a town in white smoke. It was my town. And my car. Lol.
No sir. It's coupled to a manual trans. I'm certain it's oil on the floor too. And I can see the loss of oil on the dipstick. I appreciate the idea though.
White smoke is from coolant getting in the right side cylinders, same as the milky oil is definitely a sign of coolant contaminating the oil. The white smoke is actually steam!
Well if coolant and oil are mixing then you can have a couple of things wrong. Head gasket could have failed, cracked block or head somewhere over #7, but if the motor ran fine before it went into hibernation then its most likely a blown head gasket. Im guessing this a big block 427, the water jacket in the head is really tight to a few of the runners for the valves and if there was any port work done they can accidently nick into the water jacket. Had that happen on a 402 BBC in a 72 C10.
^^^^ these guys I think have it right. If it were mine I'd rip those heads off, carefully, and try to preserve the gaskets so you can see the issue. I'm hoping it's the gaskets.
I think it could be a combination of 2 issues. The white smoke, would mean to me that you have a coolant leak some place. White milky coloured oil, also screams of water getting into the oil through a crack or badly fitted gasket. I would pull the head on the left side and check for a leak at the head gasket. If you have antifreeze in your coolant, I would also want to get some clean oil circulated through the engine as soon as possible, to protect the bearings. I hope it isn't a cracked block. Bob
Oh...steam...not white smoke. That kinda threw me...in spite of the other glaring symptoms. And maybe I shouldn't try to diagnose so late at night...lol. Good thing we aren't depending just on me for answers. Everybody have a good Sunday.
Could be a combination of a leaking head gasket and stuck rings in #7. Has this engine been sitting all this time with antifreeze in the cooling system? Bad antifreeze could have rotted out the gasket allowing a leak.
Pumping air into 7 might tell you something, bubbles in radiator, air coming out somewhere..sounds like it's gotta come apart but an easy test that might clue you in a bit.
I would think that if the intake gasket is leaking that much it would show up in how the motor runs. Is it pulling a vacuum on the crankcase with the PVC plugged? Poor manifold vacuum reading? If not, I'd be more inclined to think head gasket or an issue with the block or head. I'd run a compression test on the offending cylinder with the intake off.
Could the engine have frozen up with weak coolant or just water in it? Sitting from '94 is a long time. I would pull it apart, agree on looking at the head gaskets and also the intake gaskets. But first, if it has a radiator on it, pressurize it and see if there are any traces of leaks around the intake and heads.
If it's coolant or water getting into a cylinder that's still firing, it should be easy to spot if you pull the head. Everything in that one cylinder will look like it was just freshly steam cleaned... because it was.
On the old Vega, we would pull 1 spark plug at a time and start it up. The offending cylinder(s) would have steam coming out it.
I like to diagnose things before ripping it apart. I use a leak down tester. The two gauge one I have is a MATCO unit I have had for years. Connected to the plug hole, motor on TDC set the pressure in to 100 psi and then into the cylinder. The second gauge should be close to line pressure and it will show the amount of leakage. This is helpful because if it’s a head gasket it will bubble back into the radiator, works better than 15 lbs with a cooling system pressure tester. Cliff Ramsdell
Also remember to loosen the radiator cap before pressurizing the cylinder, especially on a hot engine. Leave the cap in loose and maybe throw a fender cover over the top of the radiator. If you do in fact have a blown head gasket, 100 psi will empty the cooling system in a hurry. If the radiator cap is sealed it will blow out a heater or radiator hose.
Correct, with the cap off you could see bubbles coming as you apply pressure to the cylinder. This method has helped me find a bad head gasket over the years long before they started smoking as it was usually a small, consistent coolant loss and sometimes a cold start miss fire because of a coolant washed spark plug. Cliff Ramsdell
The Jalopy Journal
