Truck using oil

Oil is disappearing from my 2001 GMC Sierra 1500 4.8 V8 auto trans. I must admit I don't check it much. I still view the truck as new and figure it shouldn't be using any. Up until early 2010 it was a second vehicle and not driven much. At that time it only had 24000 miles on it. I then lost my car and started driving it full time. It was shortly after that that the low oil level light came one once on an incline. I pulled into a parking lot and checked the level and there was no oil on the stick. As the oil pressure was ok I drove to the nearest store and bought a quart of oil. Put it in and the stick read top of full. I blamed that on the tire shop that I'd allowed to change the oil after putting on new tires. I figured they dumped 5 instead of the required 6 quarts in it. But since then it's happened again.

Today at 38,500 miles I checked the oil level and mileage since last change and I'm at the bottom of full on the stick and it's been 3,500 miles since last changed. It's parked on pavement and there are no leaks. The underside of the truck is clean. I don't see any hint of burning oil either.

Only other oddities of it's running are in the last couple years when it's like 20 deg or less when started it has a light knock for the first 30 seconds to a minute as I pull out the driveway. It also has a slight ping at times under load. I don't remember either problem in the early years but then I didn't drive it much then and might not have driven it in the very cold. And the ping might be due to the new gas formulas. I've read that other owners are being told by dealers that the knock is "normal" as a result of low friction piston rings and the cold.

Is it normal for the truck to be using that much oil? Are there simple things that might be wrong to cause this that I can check?

Back in the days of the diaphragm fuel pump, the fuel was on one side and the crankcase on the other. If it failed, oil would/could be sucked up and into the fuel flow hence consuming oil.

If you are still using one, you might check a spark plug or two and monitor the exhaust for oil residue.

HTH,

Mark

3500 miles?

Doggone it, I'd sure be happy with that. I want 'em to use at least a quart in 3.000 miles to make sure we are gettin' lube to the upper combustion chamber area.

That noise you are hearing is piston slap. More pronounced on your truck because of the short piston skirt used on that engine. Totally normal with colder temps.

Allan

3500 miles?

Doggone it, I'd sure be happy with that. I want 'em to use at least a quart in 3.000 miles to make sure we are gettin' lube to the upper combustion chamber area.

That noise you are hearing is piston slap. More pronounced on your truck because of the short piston skirt used on that engine. Totally normal with colder temps.

Allan

Thanks, yes seems I did read that about the knock too. I wish it didn't but as long as it only when real cold and it's considered normal I'm ok with it. If figure the ping is pretty normal too. It's only when it's pulling hard enough it's thinking of downshifting and it pings for a few seconds then they disappear.

So I'll add you to the column of the oil usage is normal. Most vehicles I've owned never used any until they were nearing 100,000 miles.

Thanks.

(quoted from post at 08:46:49 12/08/11) Thanks, yes seems I did read that about the knock too. I wish it didn't but as long as it only when real cold and it's considered normal I'm ok with it. If figure the ping is pretty normal too. It's only when it's pulling hard enough it's thinking of downshifting and it pings for a few seconds then they disappear.

So I'll add you to the column of the oil usage is normal. Most vehicles I've owned never used any until they were nearing 100,000 miles.

Thanks.

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When it drops to around 1000 miles per qt. start thinking about a rebuild, but you are good to go at 3500 miles per qt.

Just a "For what it's worth",

You might want to check that initial ignition timing just to make darned sure someone hasn't "yanked it around" a bit to give 'er a little more "umph". :>)

That pinging can really cause some greif on those pistons.

Allan

put a set of new spark plugs in it.and take a good look at the old ones you might see where the oil is going.
RICK

It's all electronic ignition with little individual coil packs at each plug so other than some electronic change that might have happened without my permission while in the shop for routine maintenance nothing should have been changed and it might not even be able to be changed.

I wondered about carbon buildup in the combustion chamber. I've run quite a bit of fuel system, injector cleaner you pour in the gas tank through it and I can't really say if it's worked or not other than draining my wallet.

Your warm-up knocking is piston slap, as someone said below. Change your engine oil and filter. Use Mobil One 5W30 or 10W30 as you prefer. This WILL STOP the poston slapping you are hearing, and stop its long term bad effects. Seen it work time after time. Try it and post back.

I sold my 1990 GMC S15 Jimmy with the 4.3 V6 to my neighbor, it had about 70k on at the time. About a month later he complained about knocking at warm up. I ask if he continued to use the Mobil One 5W30 as I had advised, he had not but had changed oil and filter, using a "big name" synthetic blend. He changed back to Mobil One and cured the knocking. Tom

there is a tsb about this concern. GM says it is a "normal condition"

make sure you don't have the orignal PCV valve in the driver valve cover. GM came out with a updated PCV with out a valve in it, just an orifice. Suppose to help with the oil eatin. If that don't work, Go to the GM dealer and buy there TOP ENGINE CLEANER to clean the rings.

Get Engine warm, pull spart plugs and use a rubber hose and fill the cylinders with the cleaner and let sit a few hours. DISABLE coils by unpluggin them and spin motor over to spit out cleaner. use rags to catch the gunk. install plugs and drive the snot out of it. Will smoke a ton.

You can also run the engine and "pour" small amounts of cleaner into the pcv inlet on the intake to clean your valves.

Here at the dealer we have been putting in a set of pistons almost weekly due to stuck rings on 08 09 5.3 v8s.

GM has us do the top engine cleaner first and replace the driver side valve cover (PCV side) but it doesn't work.

They always come back and we slam pistons in em.

Here in Nebraska 4.8 5.3 v8s are cheap at the junk yards cause they don't sell alot of them.
I have bought engines for less then 500 bucks with under 80k. Easy to drop in.

On gas engines the only combustion chamber cleaner
that I have faith in is to use a mustard bottle full of water slowly dribbled into the open carburetor or throttle body of an engine at normal operating temperature while you hold rpm in the
2,000 to 2,500 range. Really cleans carbon deposits out of a motor.

Mustard bottle--that's a good idea. I have tried it on small engines, however it's hard to get the pouring steady enough. I might just have to try that on the pickup. I hear it does work. I dumped 3/4 a quart I had around here in it and am going to let it go awhile--it tells me when it needs the oil changed and I bet that will pop up soon.

I've got that motor in my 3/4 ton van, with 525,000 miles on it. It seems to hold a lot of oil up in the engine more than any other car I've had. Checking warm will always bring a low reading. That said, Lucas will cure your oil useage. One full bottle with 6 quarts oil every change.

According to GM a quart of oil every 1000 miles is "normal" even on their new engines.

Seriously? That's amazing to me.