# 1999 GMC Sonoma Uses Oil **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** oil\ **Created:** [June 10, 2014, 2:58am UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371 "2014-06-10T02:58:24Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![blacksmith](https://avatars.discourse-cdn.com/v4/letter/b/e99b99/32.png) [@blacksmith](https://community.cartalk.com/u/blacksmith)\ **Post date:** [June 11, 2014, 7:39pm UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/21 "2014-06-11T19:39:08Z")
Some of the innards had come loose, producing a lot of rattling when sitting at idle. ---
**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\ **Post date:** [June 11, 2014, 11:43pm UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/22 "2014-06-11T23:43:30Z")
It is a 15 year old car, no repair would be cheaper than adding oil. In Seattle I would have no problem with 20-50 and it would probably slow the oil burning by half. As far as valve seals go, if your valve seals were bad you would get a big puff of smoke on startup in the morning. ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [June 12, 2014, 12:19am UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/23 "2014-06-12T00:19:00Z")
Yes @oldtimer and severely leaking valve seals will show up on the spark plugs also. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [June 12, 2014, 12:48am UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/24 "2014-06-12T00:48:03Z")
Valve seals generally make smoke at start up. In general compression runs 160-200 psi; and cylinders within 10 psi of each other. ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [June 12, 2014, 3:33am UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/25 "2014-06-12T03:33:57Z")
Thanks for that information ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [June 12, 2014, 3:46am UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/26 "2014-06-12T03:46:16Z")
It’s also quite possible to have 195 PSI compression on every cylinder and still have an engine burn oil rapidly past the rings if the wiper rings are stuck, the cylinder walls glazed, etc. ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [June 12, 2014, 3:59am UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/27 "2014-06-12T03:59:53Z")
That was actually the case with one of my previous cars ---
**Author:** ![Triedaq](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@Triedaq](https://community.cartalk.com/u/Triedaq)\ **Post date:** [June 12, 2014, 5:19am UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/28 "2014-06-12T05:19:46Z")
I had a 1971 Maverick that took a quart of oil about every 300 miles. I had the valve stem seals replaced and that reduced the oil consumption to a quart every 1200 miles. The job can be done without removing the head. The spark plug is replaced with an adapter that allows air from a compressor to be blown into the cylinder with the piston at its highest position. The allows the valve to be held in place with the compressed air while the keeper, spring and seal are removed, a new seal installed, then the spring a keeper replaced. I think the cost was under $50 back in 1974. I have no idea what this would cost today. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [June 12, 2014, 7:21am UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/29 "2014-06-12T07:21:34Z")
I wouldn’t replace the valve guide seals unless I was pretty certain that was the problem. I’d want to eliminate some of the other common possibilities first I mean. Wet/dry compression, leak down, etc. One common symptom of a valve guide seal leak is a puff of blue or dark smoke out the tail pipe immediately on starting the engine, after the car has sit parked for several hours. Then the smoke goes away completely, within a minute or two. It’s not a definite thing as the cat can mask the smoke, but if you see smoke out the tailpipe first thing in the AM, then it quickly goes away, that’s pointing to valve guide seals. ---
**Author:** ![blacksmith](https://avatars.discourse-cdn.com/v4/letter/b/e99b99/32.png) [@blacksmith](https://community.cartalk.com/u/blacksmith)\ **Post date:** [June 12, 2014, 7:32pm UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/30 "2014-06-12T19:32:21Z")
Will check compression over the weekend and try 10W-40 or 20W-50, since I’m due for an oil filter change anyway. I’ve had no smoke on starting. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [June 12, 2014, 8:18pm UTC](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371/31 "2014-06-12T20:18:53Z")
Using 20W-50 oil will just accelerate engine wear at cold start-up. It takes longer for that heavy of oil to reach critical engine components when the engine is started. So if the rings/cylinders are worn, that weight of oil will just make them wear out faster due to the lack of lubrication. Tester [Previous page](https://community.cartalk.com/t/1999-gmc-sonoma-uses-oil/85371.md?page=1)