Suburban Question

[REELMAN]

One of my buddies and I just returned from a family outing that we both drove our sub's about 400 miles. His used about a quart of oil, which he says is normal inbetween changes. It is a 1998 3/4 ton with about 45K miles on it. Does this seem normal. Is there anything that he should check. He is using Val 5W30 oil.
Is there any forums on the web that could help?

[AquaMan]

Negative on the normal. If he is burning (and I say burning since he obviously does not see any puddles) through a quart after 400 miles, there is a serious problem. I have a 1994 that does not use a drop. Does yours?

Possible bad ring or main bearing. I assume that because he sees no puddles, that he feels that there is no problem. The oil is burning if not leaking and equally as bad. Fouled plugs and worse, poor performance, result.

Either way, it is not normal to add a quart every 3000 miles, let alone after 400.

Have him take it in and do a compression check on all cylinders.


AquaMan~~~~~~~~~~~~~

.·´¯° --- "It all begins and ends at the water's edge"

Eric@crowncomputerinc.com

[RANGER]

REELMAN,

I can't speak for sub's but what I can say is that no 8 cylinder engine should consume a quart of oil on a 2000, 4000 or a 6000 mile trip, much less a 400 mile trip!! That's EXCESSIVE for modern vehicles, really. I think there is something wrong there. I have a '98 5.2L (318 cu. in.) and I use NO oil between changes, 3,500 to 4000 miles and I have 42,000 on 'er, now! And that's with pulling a glass boat around, too! Over the last 25+ years I have never used oil between changes, never.


RANGER


"KEEP YOUR LINES WET, YOUR POWDER DRY and THE BEER COLD"!

[RANGER]

Another possibility is a bad head gasket. Check to see if there is oil in the antifreeze reservoir and the radiator. If there is, the head gasket is blown. Head gaskets don't always fail INTO the cylinders, causing huge amounts of water vapor in the exhaust, they also fail into the water jacket. When the tremendous pressures of ingnition are forced against the walls of the cylinder the lubricating oil is forced into the water jacket and not vice versa.


RANGER


"KEEP YOUR LINES WET, YOUR POWDER DRY and THE BEER COLD"!

[Dave in Mpls]

I agree with the above - a quart every 400 miles on a 454 with 45K is excessive. That being said, my '94 1500 350 Suburban goes through a quart between oil changes. I should qualify that statement with a few things: 1) I run Mobil 5W30, so I go 5000 miles between changes on a oil which is more viscous than conventional oil, and 2) my motor leaks oil out of the front seal (the seal just behind the harmonic balancer). It doesn't leak enough to creat a puddle, but I can see oil "sludge" on the lower radiator hose. Someday I'll replace that seal (which can be done from the top of the motor), but so far it hasn't bothered me enough to deal with it. much easier to just keep an eye on the oil level.

It is not unusual for an engine to use a quart of oil between changes, depending upon age and miles. It's obviously gonna use some, because the top ring doesn't wipe the entire layer of film away as it moves down in the intake and power strokes, although that may be splitting hairs!

Regards

[Dave in Mpls]

That should say "Mobil 1 5W30"