Going conventional

[kschachn]

There is a 5W-50 which will be pumpable down to about -30 or so.

 

[Wingo]

There is a 5W-50 which will be pumpable down to about -30 or so.

I'll think on it. It does get colder than that often during winter here. Can just run a winter oil and summer oil though.

 

[PontiacHO]

I have decided to go backwards. My 2002 8.1L keeps eating oil even after putting in updated intake gaskets, and I am going to try conventional Valvoline. After talking to my father, older and wiser than me, he had a few examples of a few of his vehicles that consumed synthetic/semi-synthetic oil, but eventually took none when he switched to conventional. Only thing I can think of is it is dirtier and maybe accumulates at the top of the pistons reducing blowby.

I'm down, this engine was developed before synthetic oils were common and I am sick of adding oil. The intake gasket reduced it some, but I figured it won't hurt anything. I change oil at 3k. Anyone else ever have this result with old fashioned conventional?

It’s a poor design that has plagued owners since the inception. The crankcase gases being pushed into the bottom of the intake created a direct path to oil consumption from day one. There are modifications discussed on the Silverado forums that eliminate that oil access port to include adding a conventional top of the valve cover PCV system. Supposedly that greatly reduces oil consumption. It’s a shame you had the intake off already. Read up. The discussions are endless. Heck, I’d try creating just an open breather before doing anything else. Allowing the crankcase to vent easily would most like eliminate the pressure enough that it no longer pushes oil into the tube in the intake plenum.

 

[Wingo]

It’s a poor design that has plagued owners since the inception. The crankcase gases being pushed into the bottom of the intake created a direct path to oil consumption from day one. There are modifications discussed on the Silverado forums that eliminate that oil access port to include adding a conventional top of the valve cover PCV system. Supposedly that greatly reduces oil consumption. It’s a shame you had the intake off already. Read up. The discussions are endless. Heck, I’d try creating just an open breather before doing anything else. Allowing the crankcase to vent easily would most like eliminate the pressure enough that it no longer pushes oil into the tube in the intake plenum.

I thought about modifying the intake when it was off. Probably should have. Not a lot of room on the valve cover to add a breather. I saw on the smaller vortecs there are upgraded valve covers, but these big blocks aren't that common. Good idea though, thank you.

 

[Dudemanmaximus]

Oofda! I am in Michigan. I ran 15w40 all winter had no issues but it only occasionally gets below 0F here. I would try a 5w40 HDEO up there maybe rotella T6 or similar. I have a lot of family from the Fairbault area.

 

[Dudemanmaximus]

My 8.1 ran better with spark plugs with a .045 gap instead of the OEM .060 gap. There is some online scuttle about this on various forums as well. I changed plugs every 25-30K miles. Also this engine burns up plug wires fast and I always traveled with a few spare, especially after installing headers. I did eventually buy a set of high temp plug wires which were holding up well when I sold it. The 8.1 with the Allison tranny is a great combo and pulls almost as well as the diesels of the same era.

 

[2013ecof150]

I have success slowing down oil consumption using BG EPR and MOA in a few vehicles.

If that truck was mine I would use the EPR and change the oil to Castrol Gtx 20w50 high mileage and add a can of the MOA

I would be very surprised if the consumption didn’t decrease or stop all together on a 3k OCI

 

[ProbeGT]

If you were in central Texas I'd give you a good deal on some true conventional Pennzoil from my stash that I may never use. Have you tried High Mileage oil? I've had some success with it in the past.

 

[4WD]

If you are running 10W30 now - you can look at some 10W40’s like Quaker State High Mileage 10W40 - that’s the same winter rating …

 

[Wingo]

If you were in central Texas I'd give you a good deal on some true conventional Pennzoil from my stash that I may never use. Have you tried High Mileage oil? I've had some success with it in the past.

I use high mileage now. Max life 10w30

 

[Merek]

Yeah those 8.1's were not around for very long, they pull like a freight train but were gas guzzlers and serious oil burners. If you can get past those two issues the engine itself is fairly reliable. I'd be running a HDEO something dual rated 10w30 or 5w40 or you could look into the euro oils like M1 0w40 or PP Euro L 5w30.

I think the problem was so well known that GM dropped it, they were very common in the large UHaul trucks.

 

[travis8352]

I'll think on it. It does get colder than that often during winter here. Can just run a winter oil and summer oil though.

Could try an oil like delvac 1 5w40 year round

 

[Wingo]

Yeah those 8.1's were not around for very long, they pull like a freight train but were gas guzzlers and serious oil burners. If you can get past those two issues the engine itself is fairly reliable. I'd be running a HDEO something dual rated 10w30 or 5w40 or you could look into the euro oils like M1 0w40 or PP Euro L 5w30.

I think the problem was so well known that GM dropped it, they were very common in the large UHaul trucks.

For a big block my mileage isn't too bad. I am usually in the 12-13 mpg range. If pulling, 10. Good engine, just a few issues the engineers could have probably fixed easily by a traditional PCV valve system. Mine is in an Avalanche, only bad thing about that is they didn't come with the Allison transmission like the trucks did

 

[Plawan]

I have decided to go backwards. My 2002 8.1L keeps eating oil even after putting in updated intake gaskets, and I am going to try conventional Valvoline. After talking to my father, older and wiser than me, he had a few examples of a few of his vehicles that consumed synthetic/semi-synthetic oil, but eventually took none when he switched to conventional. Only thing I can think of is it is dirtier and maybe accumulates at the top of the pistons reducing blowby.

I'm down, this engine was developed before synthetic oils were common and I am sick of adding oil. The intake gasket reduced it some, but I figured it won't hurt anything. I change oil at 3k. Anyone else ever have this result with old fashioned conventional?

Chevron supreme 10w30 might still be real full conventional. Not 4 sure if it still is but it was not long ago I know.

 

[4WD]

It’s a poor design that has plagued owners since the inception. The crankcase gases being pushed into the bottom of the intake created a direct path to oil consumption from day one. There are modifications discussed on the Silverado forums that eliminate that oil access port to include adding a conventional top of the valve cover PCV system. Supposedly that greatly reduces oil consumption. It’s a shame you had the intake off already. Read up. The discussions are endless. Heck, I’d try creating just an open breather before doing anything else. Allowing the crankcase to vent easily would most like eliminate the pressure enough that it no longer pushes oil into the tube in the intake plenum.

There are some BBC valve covers on eBay (breathers) …

 

[mdocod]

The walmarts around here started carrying a quaker state 5qt 5W40 A3/B4 for $23.... Something like that in winter, and then the cheap supertech 15W40 HDEO in summer... I think those would be fairly easy/cheap options to step up to a 40 weight and keep other characteristics "rich."

 

[GMBoy]

Autozone sells STP conventional if you are looking to still go that route.

 

[andyd]

I follow Guy who lives in Lynn Lake Manitoba. He uses 15w40 yr round. If he want to start something, he plugs in the block heater a few hrs ahead of time. Don't you use them where you live.?

 

[SR5]

Nothing wrong with running a mineral oil with a modern approval like SN/SN+/SP, especially with a OCI of 3k miles. I’ve been switching between conventional and semi-synthetic and full-synthetic for years.

10W30 is a good grade, but if you can still cold start OK, then you could consider a 15W40, otherwise 10W40 will have the same cold start ability.

 

[facility1]

if you are looking for a conventual old school engine oil ,check at your local farm type store,Citgo supergard 10w-40, maybe what you want low priced and can get the job done.