Oil Consumption, burning oil 06 V6

28790 Views 23 Replies 20 Participants Last post by KRDCAD, Jun 24, 2016

chkline

Discussion Starter · Apr 1, 2009

I have an 06 STS with the V6. The car now has 44k miles on it, and I noticed that it seems to be using oil. I just changed the oil 3k miles ago using the proper Mobil 1, and the dipstick now shows that I'm getting close to the bottom of the usable range (hash marks / holes). Has anyone experienced this on their V6, and what was the fix? I'm still in base warranty as well as having the extended coverage. I would think that the engine should be able to complete a normal drain without adding much oil. We have the same engine in my Wife's SRX and it doesn't seem to use much oil if any, and it has 78k miles on it now. Any help would be appreciated!

1 - 20 of 24 Posts

C&C

· #2 · Apr 1, 2009

If you change your oil yourself (and you know you put in six quarts at the oil change) then it appears it is burning one quart per approximately 3,000 miles. Although not desirable, this is going to be considered normal, so unless it gets worse, you'll not get any relief from the factory.

Now, just asking here; do you check your oil regularly, do you check it the same way all the time (ie similar oil temperature, same approximate time after engine shut-off, etc.), do you have a flat surface that the car sets when checking?

It seems as the simple oil check has gotten more complicated in the last couple years (as opposed to the olden days); see the CTS forum thread if you haven't already done so, pages of comments on checking the oil. It just shouldn't be that hard.

pgw85706

· #3 · Apr 1, 2009

Between oil changes, I usually add about 2 qts. I was originally worried about the apparent excess oil consumption but have come to consider it normal and just make a concious effort to check oil level often especially in anticipation of road trips.

Pat
'05 STS w/ V6

Aurora5000

· #4 · Apr 1, 2009 (Edited)

There have been reported problems with carbon buildup with the Northstar. A top end cleaner would be a good place to start. You can do it or have the dealer do it. Also drive car up to 60 or 70 in 2nd gear, then let it drop to 40,still in 2nd repeat process 10 times. WOT will help . It helps free up your rings. You cannot baby these cars. Read my post on Seafoam...Others chime in...

ECha3

· #5 · Apr 1, 2009

My wife's '98 STS N* burnt some oil. I'd add a quart at about 2,000 miles after an oil change. Our current N*'s do not lose much. Chkline is asking about his '06 V6.

Anyone else with a V6 that has to add oil once or twice between changes?

cadillacroadside

· #6 · Apr 1, 2009

the oil consumtion spec for your vehicle is "one qt in 2000 miles". that is posted by gm under oil cunsumption guidlines. this particular vehicle has a new tsb released to replace the piston rings and valve guide seals if you exceed the recommended oil usage. prior to the bulletin we had done the decarb procedure but it really didnt work. we have done many ring seal replacements with great results

mike sts

· #7 · Apr 24, 2009

the previous generation norhtstars were flawed, mid engine oild leaks and cracked heads. This post wories me I thought they fixed these issues with the new northstar? I went thru 2 engines in 150000 miles in my 94. When I junked it it was fouling plugs burning leaking oil wouldnt pass emissions the throtle body was always filthy. Buring oil will create many problems. so far my 05 is not using any

cnotesonly

· #8 · Apr 24, 2009

It depends on what kind of miles you put on it. City will burn more than freeway by about 4 to 1 ratio. Approx. 1/4 to 1/2 Qt every 1000 miles.

chkline

Discussion Starter · #9 · May 27, 2009

I'm heading to the dealer on Monday to get the oil changed and start the oil consumption check. The dealer says they need to change the oil themselves to start the test, but they will allow me to bring my own oil and filter, to save on cost.

Currently I have burned 4 quarts of oil for this oil change and I have driven just over 7300 miles. All of my driving is interstate and highway driving averaging 25 to 27 actual MPG (not computer). The oil change monitor still shows the oil at over 50% life.

pgw85706

· #10 · May 28, 2009

cadillacroadside said:
the oil consumtion spec for your vehicle is "one qt in 2000 miles". that is posted by gm under oil cunsumption guidlines. this particular vehicle has a new tsb released to replace the piston rings and valve guide seals if you exceed the recommended oil usage. prior to the bulletin we had done the decarb procedure but it really didnt work. we have done many ring seal replacements with great results

Can someone share the TSB mentioned here? Thanks.

c5 rv

· #11 · May 28, 2009

I'm seeing the same level of oil consumption in my V6 SRX with 44K miles. Someone has wondered if the level of oil consumption is contributing to the number of catalytic converter failures.

On the lighter side, I've scoured the owner's manual but can't find what 2-cycle oil GM recommends for pre-mix. We've got engines that want to grow up to be outboards.

next2pool

· #12 · May 28, 2009

c5 rv said:
I'm seeing the same level of oil consumption in my V6 SRX with 44K miles. Someone has wondered if the level of oil consumption is contributing to the number of catalytic converter failures.
QUOTE]

There has been a connection between catalytic converter failure and oil, but it is being blamed on ZDDP content (zinc and phosporus). ZDDP was added to oil as a high pressure lubricant. Modern engines need less of it because of roller lifters instead of flat tappet cams. The oil companies have steadily reduced the ZDDP content over the last few years, but even as late as 2005 and 2006, there was enough in there to poison the convertors.

mkammeier

· #13 · Nov 15, 2009

I’ve also seen what I consider extreme excessive oil consumption in my STS 05 v6 with 65K miles. With 36% left before an oil change I started hearing rattling noises when I started up in the morning. So after several mornings of hearing this I raised the rpm’s to 2.5K and held it there to listen. After about 10 seconds the engine actually cut off and the Check Oil Level message came on the display. The ratting noise was lack of oil! I had to add over 2 quarts of oil just to get a dip stick reading then another quart or so to bring it to the recommended level.

In my opinion this is a GM design flaw. I’ve always used the factory recommended Mobile 1 5w-30 weight oil but now I’m going to try the Mobile 15w-50 to see if slows down the consumption. We should not have to be adding oil to these engines between the recommended normal oil changes.

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pjbizjak

· #14 · Nov 15, 2009

As mentioned by Auora5000, take the car out and 'red-line' (hold the accerator to the floor)the engine in first gear and then let off the accelerator. Do this several times, 3 or 4, this will help loosen sticky rings and should reduce oil consumption. I have had Cadillac mechanics tell me this also.

ryannel2003

· #15 · Nov 15, 2009

I believe the 3.6's are known for using a little oil between changes. We've had a couple in my shop with work being done related to oil consumption. However, I don't think this problem is as widespread as the consumption on earlier Northstar's. My '00 STS uses a quart of oil every 2k miles or so... not bad at all for my model.

devilledb

· #16 · Dec 16, 2009

i also experence some oil consumption on my 04 CTS 3.6... 60 000 miles. What is this tsb released that your talking of? i'm thinking of ripping my engine down and doing the rings. I use about 3 litres in 4000 miles (burns as much as my 75 deville)... are there any upgraded replacement rings and seals??..

devilledb

· #17 · Dec 16, 2009

And i drive her hard, so i kno i dont need to do those rpm revs... she wont have any carbon build up, its gotta be worn rings? still runs like a top tho, and no blue smoke. im kinda lost, what should the compression be on a 3.6?

wileyf

· #18 · Mar 27, 2011

Sounds like the 3.6 is just an oil guzzler. I went throught 2 quarts of oil in just under 3000 miles after the 60,000 mile check up. I thought the dealer screwed me & just didn't do the oil change. They told me this is an issue with these motors. The rattling noise you are hearing is the timing chain slapping back & forth throwing the intake & exhaust cams out of whack. I did try the 2nd gear & redline the sucker & my oil consumption is not an issue any more. Worked like a charm. You pay dearly for these cars and come to find out they are just not worth the bullcrap. I will run this one into the ground and never buy another one.

ECha3

· #19 · Mar 27, 2011

Many members do not have this issue with the 3.6 but it's become obvious that many do have borderline to excessive oil consuption. Check the oil level frequently.

jaymevb

· #20 · Mar 29, 2011

i have the same problem, seems to be worse with long trips in cold weather and normal driving. it was 3 quarts down after only 2000 miles since the last change when i discovered it

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