6.0 vortex burning/consuming oil issue

[df_puffer]

Hello all, Looking for some help trying to find out what may be causing my oil consumption issues. any direction would be appreciated.

My 2003 Yukon Denali 6.0 (209,000mi) had the rear main seal replaced about 10,000 miles ago because of leakage. I ran it awhile prior to the new seal. keeping an eye the oil level. I ran it down pretty low a couple times to the point where it barely read on the dipstick.. didn't use any specific oil brand as long as I kept it on the dipstick. Prior to seal change I had no oil usage issues. since the change I have been going thru a quart every 1300 mi on highway and 700 in town.

I have no coolant in my oil or oil in coolant. The only oil I see is my cover gasket seeps minor oil...nothing even close to what I am using. no smoke out the exhaust on startup, hammering it down cold or hot. my oil pressure is 35-50psi depending on temp and rpms and I get 12-18 mpg. it runs great just a slight rough idle if you feel for it.

Since seal change 5 months ago I have done the following on order

-cleaned the PVC valve (light oil in it...no spring type) been there since I bought truck at 60,000mi

-Compression test- all cylinders dry 180-190 w/oil 182-200. seems high...but consistent. first timer with new cheap gauge and 8 cranks.

-new plugs & wires. some oil fouling but not gross. gonna try to match up pics of plugs I took back then with cylinders today

-replaced original catalytic converter on left side only (p420 code)

-changed intake gasket. felt slight stumble when sprayed carb cleaner around area. (knock sensor clean area between gaskets not oily) cleaned throttle body-all vac lines to it, fuel injectors, intake and path down to valve as best as I could with carb cleaner. had some caked on carbon/oil outside injector spray path . looks lot better now.


going to look at plugs today after 9000mi. spray carb cleaner around new gasket area as well as injector oring area. maybe cover gasket change and see what it looks like in there. verify another compression test at same time. just don't know where to look next. could the main seal change gone wrong...that the timeframe it started....any ideas besides my engine on its way out.

 

[df_puffer]

got side tracked last week, too long of a "to do" list.

Got a chance to pull plugs this morning. oil of course...don't look good. anyone read plugs? I seen on a site before that a plug can be read like a doctor.

Was going to do some kind of oil flush and maybe try to do the valve seals. never done before. and cover gasket tonight-tomorrow.

 

[livingez_123]

Running low on oil can have a severe effect on the rings, by the looks of some of your spark plugs, you could have some bad oil rings.

Have you done a compression test?

 

[df_puffer]

probably the rings and it sounds like a sizeable project for someone who hasn't done them. I am trying to take care of the easier low hanging fruit first.

Compression test showed... dry 180-190 and w/oil 182-200. seems high...but consistent. first timer with new cheap gauge and 8 cranks. Im not sure what good compression and burning oil tells me to look at next besides what I did. rings, seals, guides? just don't have any experience with them but capable if need to do.

 

[df_puffer]

Been a couple weeks and finally got a chance to look at my truck. I decided to change the valve seals. Opened up the valve cover and it looked varnished up inside. Not sure what 210k miles buildup should look like.

Wasn't sure how much psi I should use to hold the valves up. I set the regulator to 40psi. I ran into a problem when I hooked up the air to the cylinder my little 3 gal compressor gave me about 7-8 min before it lost too much pressure to do the job. Good thing I tested to see how long the cylinder could hold pressure before I pulled the spring just to see the valve to fall. Decided to stop till morning before I even start. I heard the air escaping from the valve seals but more from the oil filler tube. Doesn't sound good. I had good numbers on previous compression test. I guess I could have good compression but bad rings. Not sure what to do at this point.

Do the seals quick at a lower pressure to give memore time... 30 lbs maybe and run an oil additive to try to clean rings not big on additives but I think that’s all I can do before a new motor as this one fails. Some pics of what I’m seeing so far. Any help would be greatly appreciated.

 

[livingez_123]

there is a much easier way to hold the valve closed. rotate the piston about half way down the cylinder you are doing. take some 3/8" nylon rope and stuff it into the cylinder. rotate the engine by hand until it stops. The rope will hold the valves in place while you change the seals. And if your a bit rough, the valves can't drop.

 

[df_puffer]

there is a much easier way to hold the valve closed. rotate the piston about half way down the cylinder you are doing. take some 3/8" nylon rope and stuff it into the cylinder. rotate the engine by hand until it stops. The rope will hold the valves in place while you change the seals. And if your a bit rough, the valves can't drop.

Thanks for the rope tip....worked great!!

Did the seals Monday and wanted to wait to get some miles on the truck before I report if consumption issues have changed. Old seals were wallowed looking. so far 300 miles and looks like a quarter qt so far. gonna do a good Seafoaming next to see if I could clean the rings and things inside. got a new problem all sudden with truck turning over but wont start. gonna post as new topic.

Thanks all