burning oil after oil change

98 Regal LS

I changed the oil (and filter) in my Regal for the first time, using 10w30 Castrol Syntec Blend. I don't know what type oil was being used previously. After changing the oil, when I start the car, I get a big puff of smoke. I don't see any smoke after the first couple of seconds but apparently its still burning oil because I am down a quart after a couple of weeks. When I changed the oil, I put in 5 quarts (per AutoZone). I have since read that the correct capacity is 4.5 quarts. I wouldn't think that half a quart could cause it to start burning oil, could it? Could it be that the engine doesn't handle this particular oil well, Should I go back to a non-synthetic or regular oil?
Any ideas?

Thanks

How many miles do you have?

The correct capacity is 4.5 qts with oil filter change. Best not to exceed the top most line on the dipstick.

If you didn't have the issue before the oil change then you might consider switching back before it is too late. Caution should be used when using syn blends and full syn motor oils especially if your engine has high mileage. Your seals may leak to include valve cover gaskets, oil pan and it may affect the valve guide seals.

10W-30 Castrol GTX dino oil works fine.

~111,000 miles.

I'll switch back this weekend.

Thanks for the quick answer.

it could be because of what you drained out... you say first time u did & dont no what was used before.did u just buy it??hopefully the oil was'nt doctored up!!!!

inafogg,

I don't even want to think about that, (anymore).:uhoh:

When you say for the first time, how long have you had this car?

111K miles is nothing on SII 3800 engine. It is not an oil burning engine. Our '99 LS barely uses any between oil changes and it has well over 130K miles now.

After changing the oil, when I start the car, I get a big puff of smoke. You have valve stem seal leaks. The engine is draining oil past the valve guides into the combustion chamber. When you start the engine, it burns off quickly and blows out the exhaust. Try one more test; let the engine idle for ten minutes, then rapidly accelerate the engine (in park or neutral) to see if you have smoke coming out the exhaust.

It is also possible the top end is sludged up trapping some oil and exascerbating this possibility.

You are absolutely right Shep, even when the upper head area is clean, oil drain-back is a problem. This is one design flaw I have noticed with this engine; oil accumulates in the lower portion of the head/valve cover area, therefore creating the increased probability of valve cover gasket leaks. This is especially manifested while braking hard! GM has offered a weak solution to this problem; :runaround: replace the valve cover gaskets on a regular basis and don’t forget to remove the plastic ignition wire retainers that trap oil gunk underneath and are subject to ignite & burn when oil drips on the exhaust headers! :devil:

Well, I changed the oil this past weekend, back to a non-synthetic, Castrol GTX 10W-30. As of this morning (Friday), I am still seeing the problem.

Bo, I let the engine run for ~10 minutes and then gave it some gas. I did see some smoke. It only smoked for a couple of seconds. Not as much as when starting the engine. Does this confirm a valve stem leak?

Regarding the smoke when starting, I don't see smoke on every start. I see it in the morning when going to work and when leaving work. My commute is about 20 minutes. So, the smoke appears when the engine is started, after cooling, after a goodish drive. I think this fits with what you guys are saying regarding the valve stem leak.

My next question is why did the problem appear after changing the oil. Did the Castrol Syntec Blend create or loosen sludge or was there something in the old oil that prevented or masked the problem? Will the problem go away if I can get the sludge cleared out?

Thanks guys

What is the history of this Regal? How long have you had it? Is the mileage correct from reviewing past maintenance history/records or titling records?

Sure sounds like the valve guide/stem seals. With someone driving behind you any other smoking conditions? Just to be safe you might consider running a compression test. Of course, this test won't help if just the stem seals are bad but it won't hurt. Also, have you checked all spark plugs and performed a read on them. Look for wet oil or excessive carbon buildup.

Also, just to be sure check your PCV valve.

More than likely the “synthetic blend” did cause the valve stem O-ring seals to expand; (O-rings shown in first pic) When they expand, oil can drain down between the valve stem and the guide into the combustion chamber. This is common on high mileage engines equipped with the simple O-ring seal. The solution is to install seals that fit tightly over the guide as shown in the second pic. You can find several versions of this type seal and they are often referred to as “umbrella seals”. They are much better at controlling oil than the O-Ring seals!

http://img393.imageshack.us/img393/3861/vssealsng1.jpg

http://img393.imageshack.us/img393/417/vsseals1kx4.jpg

What is the history of this Regal? How long have you had it? Is the mileage correct from reviewing past maintenance history/records or titling records?

Sure sounds like the valve guide/stem seals. With someone driving behind you any other smoking conditions? Just to be safe you might consider running a compression test. Of course, this test won't help if just the stem seals are bad but it won't hurt. Also, have you checked all spark plugs and performed a read on them. Look for wet oil or excessive carbon buildup.

Also, just to be sure check your PCV valve.

Bob,

I have had the car just over a month. I bought it from a new car dealer that had taken it on a trade in. I have put a little over 1000 miles on it.

Regarding the PCV valve, I did install a new one the same day I changed the oil. I didn't see any smoke until three or four days later.

More than likely the “synthetic blend” did cause the valve stem O-ring seals to expand; (O-rings shown in first pic) When they expand, oil can drain down between the valve stem and the guide into the combustion chamber. This is common on high mileage engines equipped with the simple O-ring seal. The solution is to install seals that fit tightly over the guide as shown in the second pic. You can find several versions of this type seal and they are often referred to as “umbrella seals”. They are much better at controlling oil than the O-Ring seals!



Bo,
Do you think that there is any chance of O-ring seals to shrink with an oil treatment such as Lucas' or the like?

wtijr,you replaced the pcv but did u check for vacuum??i'm not sure of your question about lucas treatment are u thinking of using it as a fix??if so there are additives for this.your local parts house should carry these.

Bo, Do you think that there is any chance of O-ring seals to shrink with an oil treatment such as Lucas' or the like?OK, let’s assume that you have good compression & vacuum and the only problem you have is a puff of smoke after the car has been sitting (or idling) for an extended period of time. None of the “oil treatments” will fix the valve seal problem; :shakehead all they will do is increase the viscosity of the oil. Replacing the seals is not that difficult, or expensive. It is about a 2 ½ - 3 hr labor job and the better design seals cost less than 25 bucks. In addition to a normal set of hand tools and a valve spring compressor, you will need an air compressor with a connector hose that will screw into the spark plug hole. You can only do one cylinder at a time. If you don’t have the tools, shop around and get some estimates from several trusted shops. A fair estimate would range from 250-300 bucks. Good Luck!

OK, let’s assume that you have good compression & vacuum and the only problem you have is a puff of smoke after the car has been sitting (or idling) for an extended period of time. None of the “oil treatments” will fix the valve seal problem; :shakehead all they will do is increase the viscosity of the oil. Replacing the seals is not that difficult, or expensive. It is about a 2 ½ - 3 hr labor job and the better design seals cost less than 25 bucks. In addition to a normal set of hand tools and a valve spring compressor, you will need an air compressor with a connector hose that will screw into the spark plug hole. You can only do one cylinder at a time. If you don’t have the tools, shop around and get some estimates from several trusted shops. A fair estimate would range from 250-300 bucks. Good Luck!

I'm sure you're right. I was hoping to buy a little time. This job would certainly be pushing the envelope for me. Do you know of any detailed instructions on doing this job?

Thanks

This problem is not something that will damage the engine; in fact, what little oil drains down into the combustion chamber will quickly burn off when you start the engine. I have seen people drive a car like this for years. You will probably never notice any side effects other than the slight increase in oil consumption and a puff of smoke after you first start the engine. I would not worry about it unless you just can’t stand to see smoke!

Problem Solved

My smoking at startup problem has been fixed. I want post the solution for the record.

Inafogg, HotZ28 and BNaylor, you guys pointed me in the right direction. The problem was with the PCV valve. The first time I changed the oil, I also changed the PCV valve. I managed to lose one of the O-rings. That was the problem. I had a pro look at it. He immediately picked up on a vacuum problem and traced it back to the PCV valve. It ended up only costing me about $50 (not counting multiple oil changes and time :frown: )

Thanks guys