5.3 Tailpipe Smoke - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**truckster** · 01-08-2022, 08:53 PM

I have a 2002 Yukon with a 5.3 engine and roughly 200,000 miles. It had a P0420 code, so I replaced the O2 sensor behind the cat on the driver's side this morning. I didn't do anything else. My son drove it today, and it's blowing oil smoke out the exhaust. It seems to be heaviest when it's been idling a while. I haven't done much with LS engines, so I'd appreciate any advice.

crazy longhorn · 01-11-2022, 05:58 PM

Quote:

Originally Posted by truckster

I have a 2002 Yukon with a 5.3 engine and roughly 200,000 miles. It had a P0420 code, so I replaced the O2 sensor behind the cat on the driver's side this morning. I didn't do anything else. My son drove it today, and it's blowing oil smoke out the exhaust. It seems to be heaviest when it's been idling a while. I haven't done much with LS engines, so I'd appreciate any advice.

Well, these LS engines do run a long time! That said, from the idle & take off, I would bet valve guides/ seals. Still, to put the money into the top of a 200,000 mile engine, its a gamble. IMHO, you can go for a lower mileage used Engine, & do the swap. Best of fun,Longhorn

**truckster** · 01-11-2022, 11:52 PM

Thanks. I'm trying a complete tuneup first - plugs, wires, filters, PCV, etc. I'll see what that does for me.

It's also possible that my son was just beating on it and it may not be a constant problem. I almost never drive it, so I'll take a look this weekend.

crazy longhorn · 01-19-2022, 05:30 PM

I do not know how you came out on the (fun)? But i will add, if all cyls came in pretty much equal (comp presser)l think..... you might get by with valve guide seals. If you do this, IMHO, I would replace the valve springs

I went with the blue springs on my 5.3. Heads were surfaced/valves ground.....but I had it down to the shortblock. if the guides are not to loose, A fresh seal/ springs may take care of the issues

Longhorn

**truckster** · 01-20-2022, 12:00 AM

I replaced the PCV valve with the updated model. I also needed to tune it, so it got new plugs, wires, and filters. I'm not seeing any smoke now. I suspect my son was on it hard before it started smoking.

01-08-2022, 08:53 PM	#1
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,829	5.3 Tailpipe Smoke I have a 2002 Yukon with a 5.3 engine and roughly 200,000 miles. It had a P0420 code, so I replaced the O2 sensor behind the cat on the driver's side this morning. I didn't do anything else. My son drove it today, and it's blowing oil smoke out the exhaust. It seems to be heaviest when it's been idling a while. I haven't done much with LS engines, so I'd appreciate any advice. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

01-11-2022, 11:52 PM	#3
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,829	Re: 5.3 Tailpipe Smoke Thanks. I'm trying a complete tuneup first - plugs, wires, filters, PCV, etc. I'll see what that does for me. It's also possible that my son was just beating on it and it may not be a constant problem. I almost never drive it, so I'll take a look this weekend. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

01-19-2022, 05:30 PM	#4
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Re: 5.3 Tailpipe Smoke I do not know how you came out on the (fun)? But i will add, if all cyls came in pretty much equal (comp presser)l think..... you might get by with valve guide seals. If you do this, IMHO, I would replace the valve springs I went with the blue springs on my 5.3. Heads were surfaced/valves ground.....but I had it down to the shortblock. if the guides are not to loose, A fresh seal/ springs may take care of the issuesLonghorn __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

01-20-2022, 12:00 AM	#5
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,829	Re: 5.3 Tailpipe Smoke I replaced the PCV valve with the updated model. I also needed to tune it, so it got new plugs, wires, and filters. I'm not seeing any smoke now. I suspect my son was on it hard before it started smoking. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson



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