Engine/Transmission (1994 - 1998) A couple quesrtions

[Cummins12V98]

My new to me 98 12V quad cab 5 speed 2wd 313K on odo.

It was a couple quarts low when I bought it. I sent a oil sample to Blackstone. They said I got a good one and the Chromium was 2, Iron 11, Copper 1, silicon 6, fuel less than 0.5%, Antifreeze 0.0%.

I have 2K on the oil since it was changed and I just added 1 qt. What would cause that kind of use? Don't have big puddles under it in the morning.

Also it idles a bit rough but smoothes out after 1,000 rpm and runs strong. I was thinking about removing the injectors and installing a set of 215's I took out of my last 98.

I really don't have any history on the truck.

The guy I bought it from was selling it for his Grandparents that moved to Hawaii to retire. He said Dynomite Diesel installed an "economy fuel plate" what ever that is. I would guess they installed a 3K governor spring kit also since it revs to 3K easily. When accelerating it feels like it runs out of fuel at about 2,200rpm but if you push down on the pedal it will take off. No idea if the vac/ps pump was rebuilt or not.

 

[jgillott]

Do you see any shaft play or oil residue in the turbo?

 

[HCannon]

2k miles and one qt. of oil doesn't sound bad to me on a 313k motor. I have a couple that has nearly that many miles that will use a qt. about like that. They start good and pull good so I add one and Keep going. They have no blow-by and start without any smoke on start up. They are both 98 12v.

 

[Cummins12V98]

No oil residue or play in turbo.

I am comparing this to my 98 12V I sold my Son with 380K that used about 1qt in 5K from 50K to when I sold it, it used the same.

 

[JR]

Check your breather, is it really oily around that area? If the seals on the engine are good and dry and you don't have any oil residue in the intake piping it's likely from blow by, but you would know it because the truck should have a pretty good undercoat by now.

 

[fest3er]

Take the 710 cap off and zip-tie a sturdy rag over the opening. Or just generally limit boost to 10 PSI. If oil consumption decreases, it's blow-by. Crankcase pressure increases, and oil finds other places to go when it can't drain back to the pan.

 

[MLee]

Are you using the same oil that was in it originally? Or a new brand. When I started to use the Premium blue by Valvoline, in my 95, I used oil for no apparent reason. I called them and they told me to do a couple changes and see what would happen, and that it would stop using oil. It did. so when Premium Blue went away, I started to use Delo 400 And have been happy ever since.

 

[Cummins12V98]

Are you using the same oil that was in it originally? Or a new brand. When I started to use the Premium blue by Valvoline, in my 95, I used oil for no apparent reason. I called them and they told me to do a couple changes and see what would happen, and that it would stop using oil. It did. so when Premium Blue went away, I started to use Delo 400 And have been happy ever since.

He said it was due for an oil change and was 2 quarts low when I bought it and he said his Grandfather used Schafers Synthetic. I Changed the oil to AMZ/OIL 15-40 non LE. So I don't think it is the change of oil. Does not have a big spot under the breather in the morning. Looks like the rear seal leaks but I don't think that much.

 

[SnoKing]

Cummins, did you buy this new 98 just to use up the dump of oil you have in the garage? Ha! Ha! Chris

 

[Cummins12V98]

Yes I did but at one quart every 2K it won't last long!

It's been kinda fun rowing gears again. Gets the coordination dialed in again with the coffee/breakfast sandwich/cell phone and shifting all at the same time.

 

[JMcCoy]

With that many miles and if the oil was changed regularly, you can probably still see the original cross hatching on the cylinder walls. My money would be the valve seals. That would be easy maintenance, especially if you already plan on doing injectors.

 

[SnoKing]

I have a baring tool you can borrow! I assume you want a cylinder at TDC when you remove the valve spring? SNOKING

 

[Cummins12V98]

Thanks! My Dad has one. I would assume TDC also. With injectors out easy rotation.

I will have to look into the valve seal replacement. No Idea what is involved. 350 Chevy yes Cummins no!

My Son had the head replaced on my 98 12V I sold him with over 380K and the cylinder walls still looked new.