GM 3800 III Valve Seal cost

[LeakySeals]

Its pretty clear now why the 2008 Pontiac in my signature was such a good deal. It has a serious oil consumption problem. 1qt every 2k. Been like that since purchase @70k. I was hoping that it would be something simple like a cleanup or a PCV valve, but after a 10k cleanup there's been no change. To consume so much with such low miles there must be something mechanical going wrong. Googling I found a TSB that fits. The short of it..

TSB 05-06-01-035A
Condition - Some customers may comment on excessive oil consumption on 3800 Series II and Series III engines. An engine that has excessive oil consumption uses 0.9L (1 qt) of oil or more within 3200 km (2,000 mi).

Cause - This condition may be caused by the retaining ring on the exhaust valve stem seal not securely holding the seal on the cylinder head boss. If this occurs, the exhaust valve stem seal(s) may move off the cylinder head boss and no longer provide a sealing function between the exhaust valve stem and the valve guide.

This is my third headache with this car in a year. I'm going to farm the job off. Have a quote of $500 to replace intake and exhaust valve seals, replace VC gaskets. Is that price reasonable?

 

[Burt]

Hmmm...$500 to save about $100 of oil over the next 100k miles?

2 quarts of make-up per 6,000 mile OCI.

How about trying high mileage or thicker oil?

 

[Chris142]

I do not consider a qt in 2k a serious problem. Id drive it knowing that it is getting some new oil every 2k

 

[PhillyJoe]

Maybe just one valve seal leaking?
I would do a compression test and try to narrow down the suspect.
If one cylinder is giving you a low reading, replace the seals on that bank. I doubt all the seals are leaking.

 

[Merkava_4]

Originally Posted By: LeakySeals

Cause - This condition may be caused by the retaining ring on the exhaust valve stem seal not securely holding the seal on the cylinder head boss. If this occurs, the exhaust valve stem seal(s) may move off the cylinder head boss and no longer provide a sealing function between the exhaust valve stem and the valve guide.


I think I see the retaining rings in this picture:

 

[Tzu]

If you can be sure that will fix the oil consumption, $500 does not seem too bad to me. It probally isn't the cost of putting a few quarts in between OCI's, just the fact you have to do it at all would make it worth it for me. Getting to the firewall side plugs and valve cover would be money well spend to have it done. I replaced our 3800 Impala intakes/ valve cover gaskets 2 years ago, so I know how it is to work back there.

 

[dishdude]

Originally Posted By: Chris142
I do not consider a qt in 2k a serious problem. Id drive it knowing that it is getting some new oil every 2k


I agree totally. You're keeping an eye on it, so why tear it apart and risk either not fixing the consumption or causing another issue in the process? You can buy 100 quarts of oil for $500.

 

[Cardenio327]

Get two more quotes from two other reputable shops to get an idea if it is a fair price or not.

A compression test will not show which valve seal is leaking.

Regardless of the cost of top up oil, the oil is going straight to the catalytic converter. It will foul it prematurely and generate more problems and more elevated repair costs.

 

[Trav]

+1

 

[KB2008X]

Jeez Louise, you need to properly diagnose the problem that you're experiencing first. Just because you've found a TSB that could possibly, maybe, kinda-sorta, if you squint just right, looks like it might fix a problem that you're guessing applies to your situation, doesn't mean it does.

There are dozens of other possible causes for needing to add oil between oil changes in that engine, and many of them can be a simple, low-cost fix. Find a competent, honest mechanic and let them diagnose this issue for you.

 

[Trav]

Leaky did you change the PCV and check the VC gaskets? These engines are not known to be oil users.

 

[DC44]

I have a Series II 3800 and it burns around 1qt per 2k miles also. I think it burns less that my father drives it now but I haven't checked on the consumption rate in awhile.

I change by valve stem seals and valve cover gaskets a few years ago. It only cut the consumption rate by 300 miles per qt. I don't think changing the valve seals will do much. It also has a main seal leak and I think the oil pan leaks, or a combination of both.

It drove me crazy and I couldn't break the 2k barrier. So I just decided to deal with it and added 2qts between my 5k oil changes which added up to 6qts a year or around $15-18 worth of extra oil. If oil cost $3qt and you added it every 2k you would only spend $150 over 100k but it's a mind thing.

My Toyota burns 1qt per 4k-4.5k miles. I just don't have one of those 1 drop per 1,000,000 mile cars.1qt per 1k would concern me though, but I don't lose sleep over oil burning any more.

 

[LeakySeals]

Originally Posted By: Trav
Leaky did you change the PCV and check the VC gaskets? These engines are not known to be oil users.

Yeah. No leaks, replaced the PCV. Its been running PU and PP for 10k so its had time to clean up. The reason I'm leaning toward the TSB...

The description seems to align with how the engine is consuming. Observed it closely for 10k. I get no blue startup smoke, putting around town the consumption is not noticeable. But when I'm out on the highway, higher revs, the oil literally disappears! I consumed just under 1/2 qt going to Hampton Beach and back. 80mph both ways. Approx 100 miles round trip. But I can go 1500 miles putting around town and the level doesn't move.

Compare that to the TSB...

"This condition may be caused by the retaining ring on the exhaust valve stem seal not securely holding the seal on the cylinder head boss. If this occurs, the exhaust valve stem seal(s) may move off the cylinder head boss and no longer provide a sealing function between the exhaust valve stem and the valve guide."

The VIN matches the TSB. 2005-2008 Pontiac Grand Prix 3800 Series III V6 Engine (VINs 2, 4, K, 1 - RPOs L26, L32, L36, L67)

Also add the fact that its been like this since purchase at 69,800 miles. Too new to be doing this.

What do you think?

 

[LeakySeals]

Originally Posted By: Cardenio327
Regardless of the cost of top up oil, the oil is going straight to the catalytic converter. It will foul it prematurely and generate more problems and more elevated repair costs.

Agree with you. I put on 30k+ a year and change used cars every 3-4 years. The oil burners I've driven foul, clog cats, misfire, eventually leave me hanging somewhere. I can be 300 miles out on business all week so I need cars that can go long distances and periods of time without TLC. Right now thats the Camry but its getting old so I bought the Pontiac to back it up/replace it. I'd rather take the Pontiac on a 4hr trip tomorrow. More comfortable. But I won't.

 

[Merkava_4]

Originally Posted By: DC44

I change my valve stem seals and valve cover gaskets a few years ago.


Did you have to use a valve spring compressor? If so, which kind?

 

[Ross]

I have a buick lucerne with the 3.8 Series-3 with the same tsb.
Mine does just the opposite of yours. Around town, with many starts, it uses 1 qt per 1500-2000 miles. But on the highway, the level doesn't move. I chose to just leave things as is. With mine I had greater useage with gc0w30. and less useage with pp 5w30.

 

[Trav]

Originally Posted By: LeakySeals
Originally Posted By: Trav
Leaky did you change the PCV and check the VC gaskets? These engines are not known to be oil users.

Yeah. No leaks, replaced the PCV. Its been running PU and PP for 10k so its had time to clean up. The reason I'm leaning toward the TSB...

The description seems to align with how the engine is consuming. Observed it closely for 10k. I get no blue startup smoke, putting around town the consumption is not noticeable. But when I'm out on the highway, higher revs, the oil literally disappears! I consumed just under 1/2 qt going to Hampton Beach and back. 80mph both ways. Approx 100 miles round trip. But I can go 1500 miles putting around town and the level doesn't move.

Compare that to the TSB...

"This condition may be caused by the retaining ring on the exhaust valve stem seal not securely holding the seal on the cylinder head boss. If this occurs, the exhaust valve stem seal(s) may move off the cylinder head boss and no longer provide a sealing function between the exhaust valve stem and the valve guide."

The VIN matches the TSB. 2005-2008 Pontiac Grand Prix 3800 Series III V6 Engine (VINs 2, 4, K, 1 - RPOs L26, L32, L36, L67)

Also add the fact that its been like this since purchase at 69,800 miles. Too new to be doing this.

What do you think?


It sounds like you may have the stem seal problem. Not a big deal on this old school 2V engine.
Some nylon rope down the plug hole when the piston is down then bring it back up to trap the valves will work fine using the crank bolt and a socket.
Figure on spending a Saturday doing it.

One of these types of compressor will do the job.

http://www.sears.com/shc/s/p_10153_12605...=30-173971513-2

http://www.carid.com/comp-cams/item-3073...CFUyY4AodjDsA9Q

 

[artificialist]

Sometimes the valve guides in the cylinder head wear out, and in those cases valve guide replacement does little or nothing to solve the problem. If you have valve guide wear, you need to have your cylinder heads rebuilt.

 

[DC44]

I bought a $15 dollar valve spring compressor from AutoZone. The trickiest part is inserting the keepers back around the valve spring when you put them on. They're very small and there's not a lot of margin of error to put them on, or you will repeat over and over.