2005 CTS with the 3.6 using oil?

[Rat407]

My next door neighbors grand daughter has a 2005 CTS with the 3.6. It seems this thing likes to drink oil. She goes through a qt every 1,500 miles. She got it used and it has 115,000 miles on it. I drove it and it seems to run great. No codes or anything. I've changed the oil on it twice and both times I used synthetic 5w30. By the way I love how easy it is to change the oil filter on this thing.

We have basically resorted to changing the oil out every 3k miles and just running regular Pennzoil Conventional in it. Seems to be a waste to run anything else for any longer interval since you have to add so much oil.

Just thought I would post here to see if anyone else has this issue with so much oil consumption. Thanks.

 

[SatinSilver]

I'd change the pcv valve and start topping off with some High Mileage oil like Valvoline MaxLife 5w30. Seems silly to do a short oci when your topping off all the time. Or hopefully someone is topping it off. Then use the High Mileage oil for the normal oci's.

 

[bigblumer]

I don't think that engine has a PCV valve, just a tube that runs from the crank case to the air intake. It seem silly to me, as I always end up cleaning out a bunch of oil from the tube.

I was having some consumption issues as well, but not as severe. I never noticed any spots on the ground, but I didn't notice any of the other signs of burning oil either. It turned out to be a leaking gasket on the timing chain cover, which isn't an uncommon thing on any of the GM 3.6s. Luckily I was still under warranty, so it didn't cost me a dime. I've heard the main seals can also go out early on these guys.

Good luck trying to find the source of the leaks/consumption.

 

[dparm]

If the PCV valve doesn't fix anything, do a compression and/or leakdown test.

 

[Rat407]

More than likely it is the rings, the engine is nice and clean and dry, even underneath. So from what I can tell it is burning it. No knowledge at to the previous owner. They don't mind the early oil changes and if I just use good old Super Tech oil, then 3k oil changes would not be that expensive since I don't really charge them. They are great neighbors and put up with me. LOL

 

[951Indy]

Are you saying a high mileage oil isn't in its future?

 

[Anduril]

You could try running a few OCIs of HDEO to see if consumption slows or stops. Either from the thicker oil or from the cleaning effect it has on the engine.