Oil consumption?

[Grit dog]

My 1989 big block has variable oil consumption too - sometimes a little, sometimes none, sometimes more than I expected. I just check the fluids every time I fill up and tell people it identifies as British....

Good description. Lol

 

[JBswth]

Does anyone know what the average/acceptable oil consumption might be for a 5.0L "H" series engine with 65k miles? When I started work on this original and stock truck (52.4K), a compression check showed #1 @ 175 and the remaining cylinders @ 180-190 psi. A small amount of soot accumulates in the tail pipe but there is never any visible smoke on startup or while driving, even when I open the secondaries. Early on, I replaced all sixteen valve guide seals. It currently uses about a quart between oil changes every 3-3.5k miles.The truck runs and shifts GREAT! However, there is quite a bit of wear on the right side of the brake pedal.

Until the 90s, a quart consumed every 1,000 miles was considered acceptable. Anything less than that was considered outstanding oil economy.

J. B.

 

[JBswth]

Looks like more brake pedal wear than expected for 50,000mi.

Whether it’s 50k or 150k, your compression looks high. I’d think it’d be closer to 125-135 psi.

180psi is L88 type numbers (12.5:1 CR).

Burning a quart between 3000mi OCIs isn’t terrible, but it’s not great either.

Before the 90s, a quart consumed every 1,000 miles was considered acceptable. Every 3,000 miles was considered outstanding.

J. B.

 

[staco]

If it’s a quart low when you go to change oil is fine but if you added a quart and then it is a quart low again when you’re changing that’s excessive

 

[idahovette]

It all depends on how much is on the ground???

 

[Trucksareforwork]

I have an H motor in my 85. It has probably 90k on it and zero leaks, and I changed the valve seals a couple years ago. It probably burns a quart every 3k.

I consider this good performance.

 

[Ricko1966]

If it’s a quart low when you go to change oil is fine but if you added a quart and then it is a quart low again when you’re changing that’s excessive

Not according to GM .