17 qx70 smokes on start up

1

17qx70

Member
Car
2017 qx70
Name
marc
Hi,
New member here. We bought a used 17 qx70 with 38k on odo. It smokes on startup and has fouled #1 plug twice. It also had a leaking valve cover which we replaced gaskets and fixed. The motor was sludged up worse than I've ever seen in a motor. I'm currently trying synthetic oil with a chaser of Marvel and Prestone seal fix(supposed to soften stiff seals. I think I'll do a compression test on #1 next, but my tester won't work for these little plugs, so, I'll have to get an adapter , or another comp tester.
Where is the best place to get a service manual?
any one else experienced anything like this?
tia
marc
 
My G37S (3.7 the same motor as yours) started smoking and burning oil. I had the valve cover gaskets replaced at Infiniti and the tech noted the sludge, but failed to check the Post crankshaft ventilation valves (PCV valves) while he was right there. I fouled the same plug repeatedly until I replaced both pcv's and it stopped smoking immediately. They're inexpensive and you can easily do it yourself. You don't have to do anything major to get to them. I burned a quart of oil every 2 weeks before I replaced them and it plagued me for 2 years. They're plastic. The sludge clogs them. Remove the airbox on each side, remove the 2 coil-packs closest to front of the car, and replace the valves. The smoke was worst on startup, embarrassing and stressful. Ask questions if you need help doing it.
 
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Thanks, That was a good idea. I tried to get new pcv's , but they didn't stock them at auto parts store, so I pulled them, blew them out with brake cleaner and compressed air. they seem to be flowing air ok, but the car still smokes. I'm thinking stuck ring, or valve stem seals. I don't want to have to do either one.
Can the head be pulled with motor in car?
 
I forgot to mention I initially replaced all of the plugs, but one plug in particular (closest to the front of the motor/closest to the PCV valve) kept fouling and turning black. So, I then replaced a coil pack with a new one, but there was no improvement. For years, the car would blow giant plumes of smoke on cold start or after sitting for 30 minutes or more. I thought it was a clogged drain-back hole at that point. It has not smoked or burned any oil since I replaced the PVC valves. To the original poster, I'd recommend ordering 2 new ones and having them mailed to your house if its too far to the dealership. I understand you cleaned them, but Id spend $40 dollars before rebuilding a motor. Best of luck. I hope this helps someone experiencing smoke on start-up and oil consumption. Let us know if you find a solution or need links for the PCV valves. Cheers
 
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