Definitely using/losing more oil

[xxch4osxx]

Originally Posted By: RacerE7773
GM W bodies are notorious for Lower Intake Manifold gaskets being bad (no wonder GM almost went under. They still won't fix these but they will worry about profits rather than getting repeat customers. I'm done with GM) on the 3.4 (my '03 Impala) and the 3.8.

We had a oil light go on once, but we had not checked the oil in 2 1/2 months, so it leaked 2 qts from that area. It doesn't do it when it's parked; mainly when the system is under pressure it loses the oil. I'll keep up on the changes and when I can get enough money saved will get the gasket replaced. But I told my wife if she smells smoke and then see fire, let him burn. Makes you wonder where these "design engineers" get their degrees. Maybe cracker jack since they only have paper type of "prizes" now.

The Series III 3.8 engines have a dry intake manifold, no coolant flows through it, so it won't have the typical leaking intake manifold leaking problem.

 

[Steve S]

Try a 10w30 dino oil you don't really benefit in La. from a 5w oil.

 

[Benzadmiral]

I guess I'll:

1) take the 5W-30 Mobil Clean 5K back to PepBoys and exchange for 10W-30

2) if I have to add another quart to the Edge before oil change time, I'll pop in a quart of Castrol HM 10W-30

2a) add a pint of MMO about 500 miles before the change (maybe?? good idea??)

3) when I change (which I might do earlier than Nov., weather permitting), I'll use the 10W-30 Mobil Clean 5000 for 5K, see how the consumption goes, and if I need a quart, try the Mobil 1 HM

4) next spring, if the consumption hasn't slowed, go with Valvoline MaxLife 10W-30 for 6K or so, and see what happens

Comments? More MMO, less, none needed?

 

[sciphi]

Look up at the oil pan gasket. My 99 LeSabre's 3800 with 84k miles on it is leaking a quart every 4-5k miles through the pan gasket. I see the little drips on the pan bolts, and the pan is covered in oil. It's been going on for the past 20-30k miles or so, I'd guess. A new pan gasket is about $45.

If it's a pan gasket leak, nothing will stop it except a new pan gasket, or so people with more experience with 3800's tell me.

 

[Gene K]

We used a HDEO - 10W30 Rotella T CI4+/SL for annual 9,000 mile changes in our 3800. If we still had it we would likely be using Rotella T5 10W30 Synthetic Blend now.

 

[The_Eric]

I for one would be checking the upper and lower intake gaskets.

 

[lucerne06]

I own a 06 lucerne with only 21,000 miles. I just had an authorized buick repair shop near me, get the ok to do some warranty work on the car, which the reason is due to oil usage. it started using a qt every 1200-1500 miles, and I found out about a silent recall for lack of a better word. bulletin 05060135A. The tech bulletin is to replace the VALVE STEM SEALS on the exhaust valves, which is supposed to take care of the oil burning/ussage condition.

We shall see, i was told that they have done two of these repairs on two different 3.8l engines that had the problem and that the oil burning condition was solved.

 

[lucerne06]

bulletin on this for oil consumpution.#2034062 Some customers may comment of excessive oil consumption on the 3800 Series III engines. An engine that has excessive oil consumption uses 0.9L (1 qt) of oil or more within 3,200 km (2,000 mi).
This condition may be caused by the retaining ring on the exhaust valve stem seal not securely holding the seal on the cylinder head guide boss. If this occurs, the exhaust valve stem seal(s) may move off the cylinder head guide boss and no longer provide a sealing function between the exhaust valve stem and the valve guide.this bulletin covers 06-08 lucerne with 3.8 vin code 2 and 4.

 

[lucerne06]

Oh I also forgot to tell , that the dealer said to use 10w-30 instead of 5w-30, and they put in wolfs head 10w-30, I posted a UOA of it, during that time the car used about 12oz between oil changes, over the winter mainly short trip city driving, since then I switched to 10w-30 QS full Syn, and have been doing mainly highway miles, it so far has used about 8oz in 800 miles.

So either high speed highway miles in the mountains of PA, or full Synthetic oil or a combo of both is not a good match for this engine...just my observations. I think I will end up going back to a thicker dino oil from now on. I also just think that the car just might be a bit too heavy for this engine, and even though it will probaly run for 200,000 care free miles(knock on wood)they are just going to use oil no matter what and you need to monitor it.

 

[Benzadmiral]

Update, all,

The Buick is now at 79,200 miles. In 1700 miles on MobilClean 5000 10W-30, I've used a quart -- a pint at about 800 miles, another yesterday at 900 after that, both at the prompting of the low oil level message. I had checked the oil on Sunday, and it looked a little low but not bad. Then I started the car, which was parked on a level surface, Monday afternoon, and got the message.

So a quart in 1700 is better than 1200, but not much. Maybe I should change this time to MaxLife and then run 5K intervals if the consumption improves?

 

[Hounds]

Well, Admiral, it's time to invest in two relatively inexpensive diagnostic tests: compression and leak down. A compression test will tell (in psi) how well each cylinder is sealing in relation to the others. If the readings you get are low in any particular cylinder or overall, at least you'll have some idea where your oil is going. A leak-down test will tell you whether the loss of compression is due to worn cylinders and/or piston rings, or cylinder head and valve problems. (Your oil loss could be something relatively simple and inexpensive to repair such as worn valve guides.) Once you know the source of the problem, you can then decide whether you want to repair your motor or simply continue to buy oil to replace that being consumed. In any case, nothing you can pour from a plastic container will fix a mechanical problem.

 

[Benzadmiral]

Is it normal for a mechanical issue like this to come on so suddenly? I'd have thought it would be more gradual. The abrupt change from about 1 quart in 5K miles to 1 in 1200 (and now 1 in 1700) happened very sharply, within the first 1200 miles after my change in April. The car still drives beautifully and gets decent gas mileage for a beast its size.

In any case, I suspect I'll need to have it checked out. Thanksgiving is coming, so it'll probably have to wait until early December.

 

[Benzadmiral]

Update, all,

At the last change at 82K miles, I had a full 5 quarts of MobilClean 10W-30 put in -- the engine takes 4.5 -- which brought the oil up to the full line on the dipstick. Yesterday, at 1K miles (the usual mix of 70% city driving in cool to nasty-warm temps), I found it down to halfway between add and full. So it looks now as if the Buick has consumed a pint in 1K, which would mean a quart in 2K -- definitely improved over 1200 and 1700 miles/quart.

When the little dash robot tells me the oil level's low, I'll add a mix of MobilClean and MMO and see if that changes anything.

 

[addyguy]

Coming into the summer in Louisiana, topping it off with 10W-40 or 15W-40 wouldn't hurt.

 

[Benzadmiral]

Another update to the continuing saga of "The Buick that Swallowed a Mobil Refinery":

The "low oil" message showed up yesterday while the car was parked at an angle, at 1600 miles. It didn't show when the car was on the level, but from past experience I knew it would soon. Oil was barely a hair above the ADD mark.

So, in went a pint of Formula Shell 10W-30 (whaddaya want from me, it was on clearance at Target) and a pint of MMO. The level is now back up to the FULL mark, and the engine runs as smoothly as ever. We'll see if the MMO contributes to cleaning, as it's reputed to do.

 

[Bladecutter]

Why not just have your mechanic pop one or both of the valve covers and see if the loos exhaust valve guide seals are out of position? If they are bad, then take it to the dealer for the fix.

That sounds like the best explanation.

BC.

 

[Benzadmiral]

Update, all,

Cautious optimism --

In late June I had the oil changed to more Mobil Super 5000 10W-30, the third OCI with that stuff, I think. Five qts. brought the oil on the dipstick to Full.

Yesterday, at 2080 miles, I checked the stick. Right between Add and Full, which I think means I've lost only about a pint!

Even if I'm wrong about the level because of where the car was parked or other factors, and even if the Low Oil message (denoting 1 qt. low) comes on today, that makes a distinct improvement over 1 qt. lost in ~1600 miles and a whopper of an improvement over 1 qt./1200!!

Again, I'm cautiously optimistic, here. But it might be that not switching oils for more than a year, plus judicious adds of MMO, has done something good.

 

[addyguy]

Glad to hear you are having sucess in reducing oil consumption. Sticking with one brand of oil usually helps.

That said, I would still try a 10W-30 HM oil in your Buick - Mobil HM, maybe?

 

[Benzadmiral]

Originally Posted By: addyguy
Glad to hear you are having sucess in reducing oil consumption. Sticking with one brand of oil usually helps.

That said, I would still try a 10W-30 HM oil in your Buick - Mobil HM, maybe?

I've never seen the conventional HM, the Mobil Super High Mileage, anywhere.

I drive about 10K miles a year. What kind of OCI could I extend to, if I went to the HM synthetic?

 

[addyguy]

You could definetly do 1 year on the HM syn. No problem.