Oil loss/ Tuneup

I have a 00 Siverado 1500 Z71, 4.8 Vortec, Automatic with 274,388 miles.
I had the oil changed at 272,000 and have had yo add oil twice since. I have had the Valve cover gaskets, Oil pan gasket and Rear main seal replaced recently. I cannot find any sign of leak under truck. Truck is not smoking at all. But every 1200 miles or so my check engine oil level light comes on.

Also I will be doing a Tune up soon and was wondering if any one as suggestions as to What are the best Spark plugs and Plug wires to use.

I have a 00 Siverado 1500 Z71, 4.8 Vortec, Automatic with 274,388 miles.
I had the oil changed at 272,000 and have had yo add oil twice since. I have had the Valve cover gaskets, Oil pan gasket and Rear main seal replaced recently. I cannot find any sign of leak under truck. Truck is not smoking at all. But every 1200 miles or so my check engine oil level light comes on.

Also I will be doing a Tune up soon and was wondering if any one as suggestions as to What are the best Spark plugs and Plug wires to use.

you said added oil 2 TIMES what does that mean ? like how much in 2K MILES ?

what oil do you use meaning viscosity and type meaning conventional or synthetic.

most times this can be simply the PCV needs replacing also check that the hoses of this crankcase venting are not damaged in any way.

I would also check that the fuel regulator vacuum line does NOT have fuel /vapors in it ..

the spark plugs I use are iridium ac delco. these plugs will last some say 200K miles. my plugs are at about 50K miles still look new.. reason is the metal can take the very high heat in these engines... older engines cast iron heads plats are good but NOT in these .. tips burn off..

plug wires maybe good.. if you used dielectric grease in the boot ends and they are not cracked. measure resistance should be around 600 OHMS ..

being short and not near heat these last forever.. on the old 350cu .. plug wires need replacing heat damage. I always measure and inspect the OHMS and wire condition .. use the proper tool to remove wires from plugs. that is how these do get broke !

Thanks for the info Jcat. I use 5W30 Amsoil full synthetic oil. Seems like I am having to put in 1 quart every 1200 miles.

Thanks for the info Jcat. I use 5W30 Amsoil full synthetic oil. Seems like I am having to put in 1 quart every 1200 miles.

closing in on 300K using 1 qt /1k miles is not really bad.. not great though.

I would replace the PCV and make sure those hoses are working properly .. how much blowby do you have ? remove the oil fill with engine running does it create lots of oil vapors ? what engine oil pressure do you have ?

just wondering how long you owned this , and how long this , has been using synthetic oil. what filters you use ?

my 2000 5.3L truck has almost 170K uses 1/3qt in 7500miles which is when I do my oil change with mobil 1 and pure one Purloator or wix oil filters..
original owner.......

I have had the truck for 10 years. It had 86,000 on it when I bought it. I've run only Amsoil 5w30 per Manufacturer spec. I use an Amsoil filter and change the oil every 5,000 miles. Oil pressure has always been 50-60. I got the truck through an auction and have no service info or any idea what it was used for. It came with a factory tow package but that's all I really know. The mechanic who does all my work for me suggested going to a Higher viscosity oil. He said he had a similar issue with his Expedition and it helped quite a bit. Having the oil changed in a couple days.

I have had the truck for 10 years. It had 86,000 on it when I bought it. I've run only Amsoil 5w30 per Manufacturer spec. I use an Amsoil filter and change the oil every 5,000 miles. Oil pressure has always been 50-60. I got the truck through an auction and have no service info or any idea what it was used for. It came with a factory tow package but that's all I really know. The mechanic who does all my work for me suggested going to a Higher viscosity oil. He said he had a similar issue with his Expedition and it helped quite a bit. Having the oil changed in a couple days.

you have to use 5-30 or 10-30wt... engine is made for use with that viscosity. my oil pressure @190 deg f is 45psi 650 rpm. that is the min psi.. max is 55 psi. at 1000 rpm ++ cold start psi can go to 70 PSI @10deg f on a cold overnight start. down your way your not gonna see that .. with high miles the PCV does cause mysterious oil loss. replace it. they wear out not so much get plugged up esp with high quality synthetic oil. the faster you drive on a worn engine the more blow-by ..

I wanted to add that many folks, even automotive experts, consider oil consumption which is equal to or less than 1 quart per thousand miles to be perfectly acceptable.
My '02 Silvy 6.0 has 242,000 and uses very little oil in city driving. But on high-speed highway drives, it uses about a quart every thousand miles. I have never seen oil smoke from it, but I think even at a quart per thou, it is not going to be burning enough oil to make any visible smoke.
My guess is the rings are going, so at higher RPM it is slinging a lot more oil up onto the cylinder walls, and the rings are no longer able to cope with it like they could when new. I use also use full Synthetic 5/30 oil.

I wanted to add that many folks, even automotive experts, consider oil consumption which is equal to or less than 1 quart per thousand miles to be perfectly acceptable.
My '02 Silvy 6.0 has 242,000 and uses very little oil in city driving. But on high-speed highway drives, it uses about a quart every thousand miles. I have never seen oil smoke from it, but I think even at a quart per thou, it is not going to be burning enough oil to make any visible smoke.
My guess is the rings are going, so at higher RPM it is slinging a lot more oil up onto the cylinder walls, and the rings are no longer able to cope with it like they could when new. I use also use full Synthetic 5/30 oil.

most times the compression rings get worn or stick. then the heat from the combustion chamber pushes into the crankcase creating blow by .. what I used with this is adding MMO to the fuel . this marvel oil helps clean and loosen up the compression rings . 3 OZ /tank full see if it runs better. It also lubes the injectors and reduced alcohol corrosion .. I use it in my small engines and the 170 HP boat engine .