GM 5.3 owners ??

[Davis]

I have a 2004 Suburban that has a 5.3 engine with 90,000 miles on it. it has just started using oil between changes I am adding a quart at 2,000 miles and I have also noticed at different times a puff of blue smoke at start up. The engine runs excellent with no knocks but has just started this oil consumption.I change the oil every 4,000 miles since it is a daily driver for the wife. Anybody got any ideas on what could be going on ? Thanks

[bobfowler]

Originally Posted by Davis

I have a 2004 Suburban that has a 5.3 engine with 90,000 miles on it. it has just started using oil between changes I am adding a quart at 2,000 miles and I have also noticed at different times a puff of blue smoke at start up. The engine runs excellent with no knocks but has just started this oil consumption.I change the oil every 4,000 miles since it is a daily driver for the wife. Anybody got any ideas on what could be going on ? Thanks

My first instinct is to think valve guides and/or seals, but I could be very wrong. It's really impossible to tell without doing some diagnostic checks...

[bobfowler]

I should add that the 5.7L in my '99 'Burb is starting to use oil as well, but it's the rear seal that's starting to go.

[TomW]

Originally Posted by bobfowler

My first instinct is to think valve guides and/or seals, but I could be very wrong. ...

Me too. But I think bobfowler is closer to right than wrong.

Tom

[Davis]

I have not seen any oil leaks on the engine exterior so i guess the problem would be internal unless if there is some type of sensor that could cause this.

[TomW]

Originally Posted by Davis

I have not seen any oil leaks on the engine exterior so i guess the problem would be internal unless if there is some type of sensor that could cause this.

Nope - It is a mechanical issue.

Tom

[ROBERTSUNRUS]

Originally Posted by Davis

I have a 2004 Suburban that has a 5.3 engine with 90,000 miles on it. it has just started using oil between changes I am adding a quart at 2,000 miles and I have also noticed at different times a puff of blue smoke at start up. The engine runs excellent with no knocks but has just started this oil consumption.I change the oil every 4,000 miles since it is a daily driver for the wife. Anybody got any ideas on what could be going on ? Thanks

Hi, with bad valve seals you will notice smoke at start up, smoke when coasting down hill, and oil fouled spark plugs. If your valve guides are worn out, new seals won't help. Need to repair or replace the heads. On the other hand, oil is cheap compared to engine repair. [keep it full]

[howco]

Bfowler is right Davis, it's the valve guides. When they wear out, after you turn the engine off and it sits over night a bit of oil slides past the guides and drips into the combustion chamber. When you start the engine, poof, the oil burns off. Yes you could rebuild the heads, I have a 1989 Burban that has 130,000 on it, it started doing the same thing about a year ago. It uses about one qt of oil between 3000 oil change. To me, this is not bad.
I change the plugs about once a year. Runs fine.....
Or, spend the money.......Good old Chevys, run forever....

[Davis]

Thanks for the replies. I agree 1 qt of oil between oil changes is cheaper than rebuilding the heads and risking something else to be torn up during the repair since it still runs excellent.

I have always faithfully change the oil at 4,000 miles and I don`t understand why this has happened. Are the 5.3`s prone to this ?

I do know that some of the early 5.3`s had a piston slap problem but mine does not have it thank goodness. Thanks Davis

[richinny]

heat and time stiffen the seals. i know that on older chevy engines, if the guides are good, just the seals can be changed without removing the heads from the engine. i don't know if it still applies.

[tpi]

I suspect valve guides/seals. You can try one of the "high mileage" oils. They're a little higher viscosity in the grade, and have more seal conditioners in it. Probably won't change it much but could help a little. I'd let it go until it worsens, fails a smog test, or you notice a misfire after long downhill compression braking. It may go a long time just as it is.