Blue smoke, help / advice needed.

[artificer]

I would not be too worried, looks pretty normal.
Your little smoke puffs indicte fairly good vacuum & slightly worn valve guides.
I think you can now sleep well on both ears, as Gindi often says. JG.

[MBJeep]

Hi John,

thanks for your evaluation, so looks like no immediate mechanical problem.
Can the valve guides be replaced by a non mechanic, is special tooling needed?
What about the excessive oil consumption? Is it caused by the worn valve guides?
Or do I loose it somewhere else, say when driving, because there's no oil puddle under the jeep when parked, just some drips?

thanks,

Mat

[artificer]

I went back to the start to re-check how this thread began. That is a lot of/too much oil & external loss should be evident, so you should investigate further. When you remove the oil filler cap with the engine running do you hear puffing or view smoke?
Rings tested OK on the wet test but a cylinder leak test might be on the agenda [google search]. You can make from an old spark plug with the centre removed & an air adapter brazed in place of the porcelain. Wear safety glasses when removing the old centre. JG.

[Joe Gopan]

How many miles on the engine. They can start showing wear by 30,000 Highway miles, less if used off road.

[Rick O]

When you remove the oil filler cap with the engine running do you hear puffing or view smoke?

What does smoke from the filler tube indicate? I get smoke after the engine is off and I remove the
dipstick,

[Joe Gopan]

What is the oil Consumption, how often do you add a quart of oil?

[MBJeep]

@Ben Dover: like I said it is 1 quart per 74,43 miles.

@John: I checked for a leak down tester, seems not that easy to get one affordable over here in Germany, but will keep researching.
"When you remove the oil filler cap with the engine running do you hear puffing or view smoke?"
This I will check as soon as I am back from business travel.

Also you guys think I might have a problem with the PCV?
I found this thread: viewtopic.php?f=4&t=253778#wrap

Mat

[Joe Gopan]

That is a bit more than normal, It's probably beginning to show some wear.

[artificer]

That is a bit more than normal, You must be joking. It's more than 10 times what's normal. It's probably beginning to show some wear. I don't think so. Nothing so far indicates overhaul time, yet.

@John: I checked for a leak down tester, seems not that easy to get one affordable over here in Germany, Where in Germany? Put it in your user profile. I'm around this regional area, tomorrow is Munchen, till mid October. I suggested how one could make this tool in no time, for peanuts, did I not? Old spark plug with air quick connect braze/welded in the plug's centre & away one goes testing leak down.
Also you guys think I might have a problem with the PCV? I found this thread: viewtopic.php?f=4&t=253778#wrap That is a very good possibility that has been overlooked, especially since compressions appear pretty good. That engine, on compression readings alone, is NOT old, tired &/or worn out. Plus the solution is most likely quite simple so go for it.

[Joe Gopan]

That is a bit more than normal, You must be joking. It's more than 10 times what's normal. It's probably beginning to show some wear. I don't think so. Nothing so far indicates overhaul time, yet.

@John: I checked for a leak down tester, seems not that easy to get one affordable over here in Germany, Where in Germany? Put it in your user profile. I'm around this regional area, tomorrow is Munchen, till mid October. I suggested how one could make this tool in no time, for peanuts, did I not? Old spark plug with air quick connect braze/welded in the plug's centre & away one goes testing leak down.
Also you guys think I might have a problem with the PCV? I found this thread: viewtopic.php?f=4&t=253778#wrap That is a very good possibility that has been overlooked, especially since compressions appear pretty good. That engine, on compression readings alone, is NOT old, tired &/or worn out. Plus the solution is most likely quite simple so go for it.

____________________________________
Not joking, just trying to be nice.

Oil consumption varies, low mileage Jeeps, 20,000 miles or less can vary from a quart in 700 miles to zero consumption. If a Jeep is driven over 45 MPH, some consumption is to be expected. I have always been content with a quart in 1200 miles.
My MB is doing a quart in around 1800 miles which is now several years of driving and my M-38A1 is doing about a Quart in 400 miles with nearly 5000 miles on rebuild, most driving is in town, it would be a lot less if I were to take long trips.

Without out knowing the condition of the subject Jeep, one can only offer a friendly guess.

[artificer]

one can only offer a friendly guess.

When did mechanics start guessing? Asking questions is what most should be doing. Guessing costs unnecessary money when one should be diagnosing to establish exactly what to be looking to solve & fixing that problem. Jeep engine's, even in fair condition don't use oil like has been described.

[Joe Gopan]

Not being there and not knowing the history of this Jeep, we can only guess the reason for it's oil consumption. It does not take much for a Jeep to burn oil as the engines wear more quickly than today's short stroke engines.

[artificer]

What did the wet test tell us?
We haven't heard about the PCV valve, leak down or a vacuum gauge reading.
These will tell us what to do & possibly what additional questions need asking.
Much more mechanic like & more sensible/reliable than guessing.

[JIMN]

You know, if I had a jeep that used quart of oil every 100 miles, and it wasn't leaking, and it had one cylinder down to 80, I certainly would not be afraid to drive it anywhere I wanted to go. Heck, lots of jeeps would burn that quart. 100 miles is a fair amount of driving for those engines. You can't compare them to a modern car. However I would be thinking that someday when I have the time I should pull the motor and go through it. And probably more because of the 80 psi. As long as your carb is good, it will run better when you are done.

[Joe Gopan]

When I drove my CJ-5's and later M-38A1's for use on highway survey and construction there were weeks when I averaged 700 miles to and from work including miles driven off road on the project with no addition of oil. This was before Scouts and Broncos.