Engine/Transmission (1994 - 1998) Vacuum Pump Oil Consumption?

[JHastings]

Alright, I have ben trying to figure out my oil consumption and I think it has either come down to my head or the vacuum pump. I have resealed my vacuum pump about a year ago with the double lipped seal. There is still some oil residue in that area of the engine, but not near what I am losing.



How can I trouble shoot the vacuum pump to see if it is causing my oil consumption?



Thanks, Jamie

 

[BigPapa]

The vacuum pump cannot "consume" oil, it can leak it. If you are losing oil, it has to be going out the exhaust, into the coolant, or on the ground.



Scott

 

[hsmith]

Make sure the oil is not diluted with fuel also. That will increase the rate of consumption.

 

[Vaughn MacKenzie]

Also make sure you don't have a vacuum leak somewhere, either the line to the pump or the pump itself. A leak causes the pump to vent lots of air into the crankcase which carries away a lot of oil vapor and causes a considerable increase in oil consumption. A quick visual check is when near operating temp look at the draft tube with it idling, if it's a lazy stream of vapor you're OK, if it's gushing out fast you have a vacuum leak (and hopefully not a lot of blowby).

 

[JHastings]

Ok, I guess I was thinking more along the lines of what Vaughn is talking about. I'll check it out. Also, would oil consumption increase when I added a second breather tube? Can increased crankcase breathing be poor for carrying out more oil vapor?

Jamie

 

[hsmith]

Don't think there is such a thing as too much crankcase ventilation. No way it could increase oil consumption.

 

[BigPapa]

Don't think there is such a thing as too much crankcase ventilation. No way it could increase oil consumption.

That right.



Scott

 

[GAmes]

That right.



Scott

Hey Scott. Haven't bought another 12 valve yet?

 

[BigPapa]

Hello G,



Was my truck wrecked when you were at the shop? It got wrecked back in February.



I bought a nice '98 24V auto, quad cab, short bed, RWD out of Florida that had a messed up motor. I'm in the process of putting my 12V motor in it. It is a wiring nightmare!



Sorry for the derail!



Scott

 

[GAmes]

I was there in Feb, shortly after you had wrecked it. Hey, at least you aren't bored:-laf



Back to the OP. If all your vacuum operated items are working the VP is putting very little air, if any, into your crankcase. If you seriously think it is the cause of your consumption you can easily troubleshoot it by capping the inlet of the pump. You won't have cruise, vents or 4 wd, but you won't have a pump blowing air into the crankcase either.



How much oil are you consuming anyway? There are a dozen or more sources for oil leaks on these engines, and I have experienced every one of them at least once.

 

[BigPapa]

I was there in Feb, shortly after you had wrecked it.

Easy there G! You're making it sound like it was my fault. Remember, I was in the bed when all this went down.



Good to hear from you again. Been away from TDR too long.



Scott

 

[GAmes]

OOPS, CRS attacked again Hope the project gets smoother.

 

[JHastings]

Ok, sounds like it probably isn't the pump. I guess I'm really left with the head or the rings. Doesn't seem to be any blowby to speak of. It hardly hazes or pushes any vapor out the tubes even under higher rpm. I guess there is a chance it could be my turbo eating it? No external leaks to speak of. No drips on the ground.

As for consumption, its about 1 gallon per 1500 miles

 

[Vaughn MacKenzie]

Yeah that is high consumption. The turbo is a good thought, a failing seal will cause it to consume oil. More likely goes out the exhaust side. The easiest way to rule it out is to find a known good turbo and trade it out, but you can disconnect the discharge tube and see if it's oily, and also disconnect the exhaust at the elbow and see if it the soot is pasty like it has oil mixed with it.

 

[hsmith]

Wow, that is definitely high consumption. I agree with Vaughn. Since you have little blowby, give the turbo a thorough exam.

 

[JHastings]

Haven't gotten to the turbo yet, but got a vacuum tester today and it seems OK. Makes 26 Hg-in off the tee that is near the main vacuum line and it leaks down about one inch per 45 seconds. Does this seem acceptable? If this is OK, the turbo is next and then maybe valve stem seals?

 

[JHastings]

Well, I took off my aux breather and found that the motor does have a fair amount of blowby. Also with the other breather off, it drips a good amount of oil overnight. With both breathers, the blowby was distributed and it masked any blowby problems.

So where does a guy go from here? Wait for $$$ to rebuild it i guess? Is it worth trying Lucas oil for the next year or so until I get the time and $$ to rebuild?

Thanks,

Jamie

 

[JHastings]

Took the pickup on a bit of a road trip this weekend. 1000 miles it burned almost 2 quarts. Does anybody use a thicker oil once the motor starts getting a bit of blowby? Would this even help?

 

[hsmith]

160K, wow, low mileage for that kind of oil consumption. Doubt viscosity is the problem. Good luck, hope you have some extra cash laying around.

 

[JHastings]

Its had a rough life. 175K now. PO had a set of twins on it making somewhere around 80-90 psi then I had my twins on it for 50K and I towed heavy a LOT.