Oil Level/Comsumption

[GOLDCYLON]

Originally Posted by sammy

i find that the same happens with me on the top QT.what is also interesting is when i tried changing dipsticks between my 90 and 92 the oil level didnt read the same . the 90 stk in the 92 read full when the 92 read add. are they different ?????

No they should not be

[sammy]

.i then just cant figure out what is going on . i havent done anything to either dipstk or tube .

[Mahogaraunch]

Originally Posted by Hib Halverson

I go 15,000 miles or every two years on oil changes, but....

1) I use Red Line 10W30, not Mobil 1. That allows extended drain interval
2) I change the filter every 5000 miles.

I've been doing this since I got the car.

The 3000 mile oil change was a valid choice 50 years ago, but not today. It's wasteful, inefficient and environmentally irresponsible.

As for oil use, the 90s were the only LT5s with no exhaust valve stem seals. GM found that, in practice, stem seals were needed on the exhausts and began using them in 1991 engines.

It was said earlier that the OE design of the LT5 with open deck cylinder case was prone to oil consumption problems.

I'm not sure that's true of stock or near stock engines and, given proper cylinder wall thickness, proper cylinder wall finishing and proper liner installation, I don't think it's true of modified engines.

I'd sure be interested to see any documentation and testing Paul Workman has to support his statement.

To revive and old thread, after 5 months of not running at all, I started my '90 today, and let it idle for about 30 min. I noticed only when reversing back into the garage, a bit of blue oil smoke was coming from the exhaust. The garage had a burnt oil smell to it. I cant remember if the same thing happened last year or not. In any event, the car has 13,000km on it, and i probably put on around 900km last season. I checked the oil, looked clean, with a tiny bit of soot on the dip.

Not sure if the exhaust valve stem seal is the cause of the blue smoke or what?

What are your thoughts?

[GOLDCYLON]

Originally Posted by Mahogaraunch

To revive and old thread, after 5 months of not running at all, I started my '90 today, and let it idle for about 30 min. I noticed only when reversing back into the garage, a bit of blue oil smoke was coming from the exhaust. The garage had a burnt oil smell to it. I cant remember if the same thing happened last year or not. In any event, the car has 13,000km on it, and i probably put on around 900km last season. I checked the oil, looked clean, with a tiny bit of soot on the dip.

Not sure if the exhaust valve stem seal is the cause of the blue smoke or what?

What are your thoughts?

Idle fuel Injectors. GC

[GOLDCYLON]

Originally Posted by scottfab

Yup, I see the soot. If I make the mistake of starting before opening the garage door I get two big black spots. Not exactly fun to clean.
Otherwise I get the two spots on the driveway just outside the door.

Yep I can relate to that happened. Pre engine exchange that was a daily occurance

[Mahogaraunch]

Originally Posted by GOLDCYLON

Idle fuel Injectors. GC

I'm not mechanically inclined so could you explain that to me? I did have all 16 injectors replaced 2 years ago.

[GOLDCYLON]

Originally Posted by Mahogaraunch

I'm not mechanically inclined so could you explain that to me? I did have all 16 injectors replaced 2 years ago.

Sure. You stated you haven't driven much. I am suggesting the blue smoke could be a combination of no valve seals and/or your fuel injectors may have built up deposits that need to burn off with a little spirited driving

[Mahogaraunch]

Got it now. Thanks. I'll give it a shot once the rain washes the salt remnants off the road.

[Hib Halverson]

90s don't have valve stem seals on the exhaust, consequently, 90s tend to use oil and start to smoke much sooner in age than do 91-95.

While that blue smoke thing could be injectors–and you can determine if it is by running the fuel pressure tests in the FSM–it's possible that it may be time to pull the heads and have the intake valve seals replaced and have them installed on the exhausts.