Motorhome drinking oil

[Janss]

We keep having to add engine oil to our Chevy 8.1L motorhome in signature...like 16 oz. every 500 miles. It had a leak a couple months ago and we had an oil line changed. No visible leak now. No smoke coming out of exhaust pipe. Oil pressure on dash gauge is just like it's always been, about 55 when driving...with 40 being the middle and 80 the highest. Does that sound good? We don't even know what those numbers mean.

We are over 3,000 miles from home, so can't go back to the mechanic right now.

Just wondered if anyone has any ideas about our older motorhome, with 90,000 miles, that uses alot of oil. Should we be concerned? What can be done?

The engine still sounds and runs great!

[Chum_lee]

As long as it passes emissions, (if required) starts easily, it's not smoking, leaking, missing, fouling plugs, lighting the Check Engine Light, and generating rated power, . . . . . . keep driving it. Add oil when it gets below the "ADD" line on the dipstick. Don't worry about it. Enjoy life and have a good trip.

You can tear the engine down and replace the seals, rings, bearings, etc. spending thousands to save $3.00 every 1,000 miles, if you prefer, but it will take the life of the motorhome to recoup your investment in a rebuilt engine. (that is otherwise operating fine except that it uses a little oil) IMO, some things are best left alone and tolerated.

Chum lee

[twodownzero]

I would just keep adding oil. I bet you'll get another 5 years or more out of that engine. If you absolutely can't stand the oil consumption, I bet a new set of valve seals alone will reduce the consumption by 50% or more. If it has good power and no smoke, I highly doubt it needs a set of rings.

[rgatijnet1]

I should add that the 2 quart AC Delco oil filter is readily available and only costs a few bucks extra. It also makes changing the filter a breeze since it hangs down and clears the things that made the 1/2 quart filter harder to remove. The additional oil capacity from that filter is one thing but the 4 times increase in filter area is also a very good thing as is the added cooling from the additional oil. I traveled a lot in the Western mountains always towing and after almost 100,000 miles I do not have any oil issues.

[Janss]

We'll keep watching the dipstick over the next few thousand miles as we continue our trip. And someday when my body feels nimble, I might crawl under the motorhome to have a look at the undercarriage.

Thanks for the additional comments. All very helpful.

[Rick_Jay]

I, too, will add that I don't think that oil consumption is out of line for that engine at that age. While I never gave it any thought, there might be something to the statements that the "FULL" mark on the dip stick might be too high. I seem to have experienced situations where the first 1/2 quart or so seems to be used up fairly quickly, but then the level stabilizes for the rest of the oil change interval. Hmmmm....interesting.

~Rick

[rgatijnet1]

90,000 miles is not much for the GM 8.1L engine. On my 8.1L engine, I used the 2 quart oil filter instead of the 1/2 quart standard filter. This increased my oil capacity by 1 1/2 quarts. I then started filling the crankcase to the BOTTOM line of the normal range on the dipstick.
The point is I was not running the engine low on oil but I noticed that the amount of oil used dropped dramatically. I believe that the marks on the factory dipstick are too high.
Naturally there are many places where oil can leak. I would get under the coach and look closely for any oil traces on the undercarriage that would indicate a leak. The rear main seal could be leaking, rocker cover gaskets, etc. It could also be something as simple as your valve seals hardening.
A simple compression check will give you a basic health report on your engine but I am sure that you will find that your engine does not need to be rebuilt.

[Bruce_Brown]

K Charles wrote:
1/2 qt in 500 miles but how much in 1000 miles? Many engines will use a half at and stay there for many miles. You don't need to add until it gets to "add" our almost.

I agree with this. Many times an engine will seek it's own level and stay there for many, many miles.

[enblethen]

PCV could such some oil as Chris said.
Quart every thousand miles is not that bad for Chev big block.90,000 miles should not need engine rebuild.
You may even put Seafoam in crankcase and run it to clean system. Run for 1000 miles before next oil chaange.
We have nearly 200,000 on 7.4 miles and uses a quart very 12-1500 miles. This depends on how hard the engine is working.

[Janss]

Thanks for the great input from all you knowledgeable people! Puts us at ease for the rest of our trip.

[Chris_Bryant]

I’d be tempted to slap a pcv valve in it- cheap and cannot hurt.

[time2roll]

Next oil change make sure you check the level immediately after to verify the full mark. Slight overfill can burn more oil.
Fill by capacity specification not the stick.

[olfarmer]

K Charles wrote:
1/2 qt in 500 miles but how much in 1000 miles? Many engines will use a half at and stay there for many miles. You don't need to add until it gets to "add" our almost.

I agree, a qt to 1000 miles is no big deal. I don't think the manufacturer would fix that even if it was still under warranty.

[K_Charles]

1/2 qt in 500 miles but how much in 1000 miles? Many engines will use a half at and stay there for many miles. You don't need to add until it gets to "add" our almost.

[SidecarFlip]

Keep an eye on the oil level and when you get home, take it to a shop and have the motor rebuilt.

90K in a Mo Ho, it's time.

[boogie_4wheel]

I had a '97 SBC with a bad valve stem seal suck approx 1qt per 600mi when I was on a trip from UT to CO. I did have a cold misfire at idle. The problem cylinder had heavy ash deposits on the spark plug. I could not see any smoke from the pipe.

A 'quick' test would be to pull the spark plugs and inspect for abnormal, this would tell you which cylinder(s) are having an issue. Leak, rings, or valve stems.