Best oil for a smoking vehicle?

[hl2nine]

I have a 1994 gmc sierra 1500 with the 5.7 350 v8. It has a leaking valve seal (at least im almost posative, smokes a lot when its been sitting for a few hours then clears right up) and im prety sure its a fairly harmless problem, however, i am worried about oil burn off. Is there a kind of oil or an additive that would slow the leak? Or if not what would the harm be in running the cheap-o oil? the oil burns off prety quick, and i cant afford to continue putting the good stuff in it. Thanks!

[MagicRat]

The only thing that will slow down the oil burning is to use a thicker oil. However, such an oil will not pump or flow well in cold weather causing increased wear on start - up.

Cheaper oils are fine for ordinary, higher mileage engines. So long as the viscosity grade (ie: 10W30) is suitable (per the owners manual) and it is rated 'SM, SL or SJ' then it's okay.

[LeSabre97mint]

Originally Posted by hl2nine

I have a 1994 gmc sierra 1500 with the 5.7 350 v8. It has a leaking valve seal (at least im almost posative, smokes a lot when its been sitting for a few hours then clears right up) and im prety sure its a fairly harmless problem, however, i am worried about oil burn off. Is there a kind of oil or an additive that would slow the leak? Or if not what would the harm be in running the cheap-o oil? the oil burns off prety quick, and i cant afford to continue putting the good stuff in it. Thanks!

So... what you're concerned about is the fact that you are using oil. The smoke isn't an issue for you. Right?

How much oil are you going through?

Do you live in a cold area?

BTW... Welcome to AFs!

Regards

Dan

[j cAT]

Originally Posted by hl2nine

I have a 1994 gmc sierra 1500 with the 5.7 350 v8. It has a leaking valve seal (at least im almost posative, smokes a lot when its been sitting for a few hours then clears right up) and im prety sure its a fairly harmless problem, however, i am worried about oil burn off. Is there a kind of oil or an additive that would slow the leak? Or if not what would the harm be in running the cheap-o oil? the oil burns off prety quick, and i cant afford to continue putting the good stuff in it. Thanks!

if it smokes on start up after sitting it could be a sludged head drain back holes....oil does not drain quickly and leaks into the valve guides and valve seals to the combustion chamber..

another condition would be crank bearings worn causing high oil vapor being generated....

all this is usually avoided if the engine was properly maintained..

[bobss396]

More than likely the valve stem seals are dried out and oil pooling in the back of the heads runs down the guide when you shut it off. The fix is relatively inexpensive and should be done if it fouls out a spark plug.

A heavier oil will fix it somewhat. My old Caprice was doing the same thing, only the plugs were fine and it passed the emissions test all the time. I was going through a quart in 1200-1500 miles, more in the summer heat.

[curtis73]

This is a VERY common issue on TBI trucks. My 1988 truck smoked a pretty good puff at startup for 10 years and 125k. My main concern was spark plug life (didn't seem to be affected) and the catalyst getting clogged, but it never gave me any trouble.

I don't think its enough oil to really harm much. If it were constant, it would affect things, but I honestly wouldn't worry a single minute about it. Running a different oil has more drawbacks than just letting it smoke that puff it seems.

One thing you can do is switch to 10w30. Most GM vehicles of the era spec'd 5w30 to get that tiny edge in fuel economy, but 10w30 is a better match for most of their engines. My GMs spec'd 5w30, and I ran 5w in the winter and 10w in the summer for years. Now I just run 10w all the time because its easier and its a fine match.

[bobss396]

In warm weather I have run straight 30, 40 and even 50 weight oil in my "mosquito trucks". Of course the straight grade makes it harder to start in cold climates, but it does cut down on the smoke dramatically. I had one that was so bad, I'd use Valvoline 60 weight blower oil to keep it down.

Bob