Hello all-

I am new to this board and new to my 1986 Suburban with the 6.2. I love this truck but it's got a bit of an issue. It uses what appears to be about a quart of oil every 500 miles or so and has some pretty nasty smelling exhaust fumes. I can see a bit of blue smoke coming out of the right side tailpipe when I rev it up. I have not checked out the CDR but I am a bit worried it's something bigger because it looks like it's just burning oil on the one bank of the engine. It has a couple of leaks, the front seal being the one I can see the best, not sure if this be the CDR thing.

Is there a good way to diagnose if it's rings? The truck does not seem to have a lot of miles, the odo reads 34k and I doubt it's 234k judging by the condition of the rest of the truck.

Anyhow, any suggestions will be helpful, thanks.

The CDR valve on your truck should be located just above the alternator and have a hose that connects it to the oil fill tube. Thats where you usually find them, but some where mounted on top of the valve cover.

OK. More info. I had a bit of a problem with a clogged fuel filter and a "Water in Fuel" light coming on. Changed the filter and drained the water out. Runs much better now.

It used to blow out blue smoke under hard acceleration and now its more black. Also there seems to be a lot less burnt oil smell coming out the tail pipes. Still a bit though.

Is it possible that the engine was burning sump oil because it was starving for diesel due to the clogged fuel filter?

Thanks again for your input.

Oh, by the way. The CDR tested fine and I cleaned it too.

I did the clear tubing test at the dipstick and it has a bit of vacuum in the crankcase at about 2k rpm. This is correct right?

Another thing you can do is remove the valve covers and make sure the drainback holes in the cylinder head casting aren't blocked or restricted as this will keep excess oil in the valve cover area and upon the valve stem seals and since the seals can only handle so much,too much oil upon them will cause excessive oil consumption to take place.It might also be a good time to install new umbrella type seals too.They work pretty good on the 6.2 engine.Definately better than the o-ring seals they are sometimes equipped with.