2007 GX 470 220k miles smoke at startup

[rtpatter]

My GX recently started smoking at startup. Vehicle has been well maintained and hasn't used any oil. Just had the power steering pump replaced mechanic says PCV on pump lines are dry so he doesn't think the PCV on power steering pump is bad. I find it hard to believe the valve seal started leaking this badly in such a short period of time. See attached video and let me know what you think.

 

[Rednexus]

I'd pull the vacuum lines off the PS pump, loop them together with a vacuum hose connector, then cap the nipples on the pump and see if it still smokes at startup.

 

[rtpatter]

I'd pull the vacuum lines off the PS pump, loop them together with a vacuum hose connector, then cap the nipples on the pump and see if it still smokes at startup.

It typically only does it after the vehicle has been sitting a while which would seem more inline with valve seals. However, all of this didn't start until right before power steering pump began to fail or at least mechanic said it was about to fail. After pump was replace they then said rack and pinion needed to replaced which was causing difficulty in steering so we replaced that. Now Ive got 3k worth of repairs in car that still blows smoke out the rear and mechanic that doesn't seem to have any answers.

 

[Rednexus]

It typically only does it after the vehicle has been sitting a while which would seem more inline with valve seals. However, all of this didn't start until right before power steering pump began to fail or at least mechanic said it was about to fail. After pump was replace they then said rack and pinion needed to replaced which was causing difficulty in steering so we replaced that. Now Ive got 3k worth of repairs in car that still blows smoke out the rear and mechanic that doesn't seem to have any answers.

Capping the vacuum lines running to the PS pump would eliminate the PS pump as a variable in the smoking equation. If it still smokes with the PS lines looped together, the oil/fluid it is burning must be coming from somewhere else. At that happens I would suggest pull a few of the spark plugs after it's been sitting for days, drop a borescope in those cylinders, and see if there is a pool of oil sitting on top of the pistons (which would indicate valve seals). Outside of that, I'm not sure where it could be pulling oil from.

Valve seals would be an expensive job as the cams, shims, and valve springs all have to come out (plus VVTi actuators if you have an 2005 or newer). My GX has about 204K on it and valve stem seals definitely do not leak.

FWIW, your steering rack was probably shot with 220K on it. Mine was with fewer miles on it. But the PS pumps on these don't seem to fail often (I haven't seen a failure mentioned on this forum), so I'm not sure why it was replaced. However it's possible that a failing PS rack could have sent a lot of metal though your old PS pump, and the mechanic may have proactively replaced it.

 

[rexington14]

Blown head gasket?

 

[aztoytec]

Seen this numerous times..
When the power steering valve allows fluid to bypass into the vacuum hoses it will FILL the intake/platum full of p/s fluid. After by passing the valve it will continue to smoke until intake is cleaned, replaced or burns all the fluid. Confirm it’s the valve, remove and clean intake or replaced it. Will that much fluid in the motor, it will take awhile to burn off. New spark plugs maybe needed too!!

 

[rtpatter]

Seen this numerous times..
When the power steering valve allows fluid to bypass into the vacuum hoses it will FILL the intake/platum full of p/s fluid. After by passing the valve it will continue to smoke until intake is cleaned, replaced or burns all the fluid. Confirm it’s the valve, remove and clean intake or replaced it. Will that much fluid in the motor, it will take awhile to burn off. New spark plugs maybe needed too!!

He said the vacuum lines were dry to the pcv for the power steering pump. If the PCV was allowing fluid by wouldn’t it have some fluid in the lines?

 

[aztoytec]

Yes. There would definitely a fluid in them…
Interesting. Is the coolant low?

 

[rtpatter]

Yes. There would definitely a fluid in them…
Interesting. Is the coolant low?

Not that I can tell. My son drives this one away at college so its hard to keep an eye on it day to day but the coolant didn't seem to be abnormally low when I checked but I topped it of nonetheless. I guess we could always drive it and see. Something is clearly burning at some point either oil, coolant or PS fluid is going to start showing low. I just hate to risk breaking something else until the problem openly present itself.

 

[aztoytec]

Something is definitely burning. Check all the fluids, Be careful driving it. If it’s coolant it would most likely over heat fast. Also that smoke would have a strong sweet smell.

 

[aztoytec]

Check your gas cap and see if it smells like diesel fuel…
Just an idea. Diesel will smoke like that too

 

[rtpatter]

Confirmed head gasket is not leaking. They are going to run a scope on cylinders tomorrow. I feel like they are grasping at straws but clearly something burning hopefully issue will present itself soon.