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Diagnosing oil burning + advice needed?

My car is a 2001 Buick Regal LS (3800 V6) with 33,600 miles on it.

This car was purchased new by my grandfather. Between 2001 and 2005, it was driven only by him and I’m sure it was never driven over 45 mph. I cannot account for any maintenance during this period.

Between 2005 and 2007 it was driven very sporadically by my grandmother, and the oil was changed about once a year (~ 750 miles).

I purchased the car in Oct 2007 and it had 14,000 miles on it. I changed the oil at 15,000 miles and then adapted a 5,000 mile oil change interval.

In Aug of 2008 at 19,000 miles my “Low Oil” light came on (this is not the same as the oil pressure light). I shut it down and added a qt, noting with some alarm that the oil was significantly below the “Add 1 Qt” level. I had not been checking the oil because of my father’s assurance that “the car burns no oil at all… it’s perfect!”

Now I’m over 33,000 miles and the oil consumption is accelerating. I am adding a 1/2 qt every week (~ 250 miles) and I have also recently noticed that I can smell burning oil from the engine bay when it is hot, and also if I smell the oil filler opening (don’t know why I smelled that originally, but there you go).

My questions are:

Any ideas what might be causing the burning? I see no leaks and have no drops on cardboard after a week.

Does it seem likely that this oil burning is going to continue to accelerate, or will it level off eventually?

These relate to me trying to decide between keeping the car and buying something else. What would you do?

Thanks for any insights!

This rings of an engine that wasn’t broken in properly, and now oil is getting past the rings.


This is pretty much what I was thinking too. I guess I will pull a few spark plugs this weekend and think about making an appt for a leakdown test (although all that will tell me is that I need an expensive repair… lol)

Since the vehicle saw very little use you might consider the possibility of a clogged up PCV valve. This is easy to inspect and cheap to replace if necessary.
Simply remove the PCV and shake it. If it rattles like a rock in a can then it’s fine. If it does not rattle or the rattle is very erratic then it needs to be replaced. (Probably about 2-3 dollars)

After that any oil consumption could come down to valve seals or piston rings.
Odds are the valve seals are fine but what can happen is this and I’m assuming that you’re not mechanically astute here.
Each piston has 3 piston rings on it; 2 compression rings and one oil wiper ring.
The wiper ring is just what it’s name signifies; it wipes the oil from the cylinder walls on the piston downstroke.
Sometimes these rings can sludge up due to light use or seize due to overheating.
When this occurs the wiper ring does not expand and contract as it should and does not wipe the oil from the cylinder walls. This leads to oil consumption problems.

You can try adding a can of SeaFoam to the engine oil. This may free up the wiper rings and give it a thousand miles to see what happens as to oil useage.
I would add there is no test as to determining whether the wiper rings are stuck or not; it’s simply an educated guess and a prayer the SeaFoam will work. SeaFoam can be gotten at most parts houses or even Wal Mart.

Hope that explains it and hope it helps you out.

I suspect the PCV system is the culprit, not the rings or valve seals…Check inside the air filter housing for any oil residue and clean out the PCV system. What type of oil are you using?

Make sure vacuum is reaching the PCV valve. I saw one case where the port to the intake manifold was clogged.

OK, I will check out the PCV valve this weekend.

My oil is currently Formula Shell 10W-30, but I’m not really partial to a brand. I was thinking about trying a high-mileage oil next, like maybe Castrol.

I will check this also. Thanks!

Thanks for the clarification! I sort of understood that but not in that much detail… I will update this on Saturday when I get a chance to check out the PCV situation.

sounds like a problem with pressurization in the oil reservoir/pan system that can be caused by the failure of vaccuum devices like Pcv VALves can force this to happen. I would make sure the simple things are checked first and a compression test is a wise choice as well.

If all the above doesn’t work, and it should but just in case it doesn’t, remove the valve cover and check for sludge or gunk build up. If you see a lot, remove as much as you can with scraping and brushing. If you need to use any solvents, then change the oil when finished before starting the vehicle.

While the valve cover is off, check the oil drainback holes at the back of the head to make sure they are clear. When an engine sludges up, these often get clogged up. When that happens, oil fills up the top of the head and seeps into the valve guides.

Another thing to look for is a leaking oil pressure sending unit. It will spray out a fine mist so you may not see oil dripping with the engine off.

If all that doesn’t help, then try one more thing. Find a little used road and do about 10 hard accelerations at low RPM. Basically get up to speed where the car shifts into the highest gear, then let it slow down to the lowest speed that it will stay in high gear, then accelerate as fast as possible while not downshifting. You only need to add about 30 mph each time, ie 30-60. The idea is to put as much pressure on the rings as possible to get then to reseat.

Just an update… I pulled the PCV and it is fine, at least as far as I can tell (it rattles and it did not have crud or sludge all over it).

Not sure what I will do now. I will probably wait until it’s warmer to do anything more since everything that needs to be done now will take a while.

Thanks for all the advice!

In the meantime I would dump a can of SeaFoam into the engine oil and hope that if there is a sludge problem on the wiper rings and that the SF clears it up.

I am leery of any oil additive… I will have to do some research on this seafoam stuff (I have heard of it, but only through forums…)

Does the PCV valve suck a little air when the engine is running?

Well, go straight to the ten 30-60 runs in high gear while waiting for warmer weather.