CHeVy 350 HELP?

Question

on my chevy 350 someone told me that my valve guide seals were bad and thats why i was burning oil, is this right what are other symptoms of this problem

Answer 1

It could be possible, here's how you tell. If you get a good puff of blue smoke on a cold start, and you trail smoke out of the exhaust on a long decel, then most likely the valve seals are shot. If you make smoke under accel, then its most likely time for rings. "mad_mav" is absolutely wrong.

Answer 2

Your problem is more than likely your valve seals. 90% of engine oil consumption is from bad valve seals, not from bad rings. I would replace the valve seals because the reason why you are burning the oil is because too much oil leaks down the valve into the cylinder, which the pistons and combustion of the engine then use that oil. The valve seals are made to meter the amount of oil going on the valves. Also everybody who is telling you about black smoke out of the tail pipe are correct but the problem with that is if you have a catalytic converter it will burn up all the extra oil in there and then you won't have any blue smoke come out of your tail pipe. If bad valve seals are ignored long enough the extra oil can wreck the catalytic converter. Also put your finger over where the pcv valve enters the valve cover and if you feel a suction when you do this that means you have a leaky intake gasket which could also cause you to use oil. Well i hope this will help you diagnose your problem.

Answer 3

Your Chevy does not have valve seals from the factory. It has oil umbrella shields beneath the spring retainers covering a third of the valve spring. Since your 350 has no seals do this test. Have someone follow you while you drive. If the car smokes all the time the piston ring clearance, or pistons may be out of spec. If the smoke comes out the exhaust on deceleration only the valve guides have too much clearance. The guides will need to be drilled oversize and new bronze wall or crosshatched steel guides need to be pressed in your heads. Guide seals will not correct warn guides.

Answer 4

All these Answers have a lot of truths to them, blue smoke on a cold start or on hard acceleration are a very good sign of bad valve stem seals and/or worn valve guides. blue smoke all the time would mean piston rings are worn or damaged. and it is possible that your transmission modulator is bad and the engine is sucking up and burning the transmission fluid into the intake to be burnt. But it is also possible that high mileage engines that has not had the oil changed regularly may have plugged oil returns in the heads which will let the oil sit in them and leak past even a good stem seal and guide. pull the valve /rocker covers off and look to make sure the oil return holes in the front and rear of the heads are clear of sludge and crusty carbon like deposits, so the oil can flow freely back down to the oil pan. and make sure the PCV valve is working properly and breather in other head is clear so crank case pressure is not building up and pushing oil past the valve stem seals.

If this is a high mileage engine 80-100,000 miles and the valve stem seals were found to be bad it would be better to just have the cylinder heads rebuilt .... pressure checked,milled flat,valve grind, guides checked and repaired if needed and springs locks and retainers inspected and replaced if needed.That way you are sure to have a good clean running Chevy engine.

Answer 5

If you have a vacuum gauge, hook it up to the intake manifold vacuum. at idle if the gauge is fluctuating rapidly, the guides and or seals are worn, If when you first start the vehicle there is a momentary puff of blueish smoke, that's oil and it has leaked down into the cylinders through the guide seals. Changing valve seals is not too bad a job most reputable mechanics could get the job done in a few hours. If you only use half a quart of oil between changes, I wouldn't worry too much about changing them.

Answer 6

ive had valve seals rot off and plug the return holes in the heads causing the oil to back up and flood the valve stems and leak into combustion chamber.Remove valve covers and run a coat hanger down the holes in the corners of the heads and see if thats the problem, old chevys never die they just go faster

Answer 7

that's true, blue smoke is a dead give away. You could probably get away with just the valve seals, but you may want to just rebuild it now while your inside. That way it will last you another 200,000 miles. Chevy the longest lasting, most reliable motors on the road.

Answer 8

If it smokes when you start it up or when you sit at a light then start it is valve guides, a common problem with the Chevy small blocks. Bad rings will smoke when going down a hill then stop when going up a hill. Good luck.

Answer 9

he's right it is also caused by bad rings it is a common problem among the GM 350 engine they are a good engine if you don't mind that they tend to use oil after about 100,000 miles

Answer 10

Not knowing how old your engine is. Are you sure it's engine oil its burning or is it ATF?
An older vehicle's transmission relied on a vacuum shift modulator. When it fails the ATF is sucked into the engine via the vacuum line.