Major Problem

[Chantz]

Alright I definitely need some opinions here. I've got a 1989 4X4 Chevy Suburban with a 350 TBI coupled with a 700R4 and the engine is burning oil. It was ran about 250km with very little oil. When in the city, I saw the oil pressure drop to 0. After a rev, it came back. At the time, I thought it was the oil pump, but when I checked the dipstick the next day, it was virtually dry.

Now I'm pretty sure the engine is damaged, even though it does not smell like it's burning oil, which confuses the hell out of me. Because the exhaust does not smell like oil at all. What, if anything, is going on? I just did an oil change so it's a bit too early for me to tell if it's burning oil, but only a day later and about 15km the oil was black.

Could someone give me some direction with this? We've just spent a lot of money on getting this thing fixed up, and I really don't want it to crater. Thanks

[J-Ri]

Originally Posted by Chantz

Alright I definitely need some opinions here. I've got a 1989 4X4 Chevy Suburban with a 350 TBI coupled with a 700R4 and the engine is burning oil. It was ran about 250km with very little oil. When in the city, I saw the oil pressure drop to 0. After a rev, it came back. At the time, I thought it was the oil pump, but when I checked the dipstick the next day, it was virtually dry.

What is virtually dry? If you had to add 3 or more quarts to bring it up to full (assuming you have the standard 5 qt capacity) there's a good chance you were starving the pump at times.

Originally Posted by Chantz

Now I'm pretty sure the engine is damaged, even though it does not smell like it's burning oil, which confuses the hell out of me. Because the exhaust does not smell like oil at all. What, if anything, is going on? I just did an oil change so it's a bit too early for me to tell if it's burning oil, but only a day later and about 15km the oil was black.

Why do you think the engine is damaged? Is it making a clunking sound? Is there a big hole in the side of the oil pan?

The oil is definately going somewhere. If there are no leaks, it is probably burning it. Pull the hose off the PCV valve. If oil drips out, replace the PCV valve. Otherwise it's probably the piston rings. These engines are known for the valve seals failing (usually a puff of smoke when you start it), but I wouldn't think you'd loose that much oil inside a regular oil change interval.

I would drain and fill the oil and then add Sea Foam according to the directions on the can. After running the engine as specified, change the oil and filter again. The carbon in the oil usually doesn't get burnt off when the oil does (assuming it's the rings), so when you burn off 5 qts you still have enough carbon to make 5 qts of oil dirty. Even if you let it drain until nothing drips out of the drain hole, there is oil trapped in the engine (BG says up to 1.5 qts). When you put the new oil in, it is instantly black. Oh, and stop using a Fram filter.