car is stuck with oil pressure problem? no oil at vacuum pump, have pressure

[damac]

I was just going to start daily driving my 79 rabbit tomorrow and have come face to face with a problem I have never experienced before.

I have manual gages in place that I watch like a hawk while getting it road worthy.  The other day I went to get the car aligned and the timing belt made a nasty noise so I stopped and found the rotary vacuum pump siezed, not a hint of oil up there.  I thought it was odd but slapped another pump in and got the car to/from without the oil pressure dropping?  My sensor is on the side of the head.

At the time I thought maybe the pump just went but I also didn't have assist on the brakes so wanted to tinker some more.  That other vacuum pump also showed signs of no oil and of course no vacuum assist that I tested with a gage.

I should have known something was up but while running the car in the garage getting timing, etc. right and testing things I never had a hint of that binding so never even thought of checking the vacuum pump, I didn't notice any noises from it.  Also I remember last timing I could still easily turn the car over with the wrench.

But now as I get ready to pack up to leave in the am there is no way I can drive it like this.  I dumped the oil in the pan just to double check and that is good.  Put it back in and took a drill to the oil pump tang and it took seconds before it started to drag yet I see no hint of oil?

Also I put another rotary pump in and bolted it down and had somebody crank it while I watched.  I held the lid without bolts off to the side a bit and pushed down so it would be driven by the oil pump, which it is, and don't see a hint of oil coming up through middle.  It is also clear I blew it out.

Now my readings at the head with oil pressure didn't alarm me, if the car sits outside its pegging 100 pounds on gage.  Inside the garage it restarted after a half an hour or so after running for a bit at 60+.  When I drove it seemed healthy to me, almost spec oil pressure at head just idling, and increased relatively when on the throttle.

And I have slapped 2 vacuum pumps that were doing the deed on a seperate jetta which the seals at the bottom of the pump are fine.

Would love to have input on this.  I thought pressure ends at the head so wouldn't it bleed off pressure before getting up there.

This has a 36mm pump I got from a forum member, looked fine and is tight to block.  I have another and some other smaller pumps that were doing the job in other cars as well.   I am tempted to blindly swap in another pump.

[damac]

ok i have to leave in 3 hours and am going to sleep.

long story short i found a thread where somebody mentioned top oil pump bushing spinning choking oil flow so i broke things down.

everything was tight, bushing was orientated correctly, i popped it out even and compared to another turbo block.

put bushing from other turbo block in for the hell of it, put another 36mm oil pump that i got from a member here in after cleaning all passages/mating surfaces.

spun with a drill to prime, within a few seconds drag and cavity filled with oil, oil trying to shoot up from center.

put best rotary pump on and held lid on loose and within a few seconds of cranking engine the whole middle pooled over with oil.

im very confused as to what happened.  but now that i think back inbtween tinkering and having that vacuum pump lid off there has probably been no oil this whole time with that other pump install in the engine.  too many times i had it off and not a hint of oil pooled up.

i put that out of my mind, blindly looking at my manual oil gage at the head?  things seem pretty healthy to me, pegs 100 cold, warms up and is almost spec at idle warm.  blip throttle and it goes up relatively and is easily meeting bently spec.

but i killed a couple rotary pumps in short order, not on the driveway where most of the work was timing, etc. but on the road in 1st gear.  had to pull over right away and swap.

also the brakes have sucked since i replaced parts and bled the system.  they work and the pedal isn't going to the floor but they are not like the 85 jetta.  which its brakes also suck when the booster goes out.  harder to stop, harder pedal.     we'll see tomorrow

[TylerDurden]

Sounds like the oil pump shaft was plugged.

[fatmobile]

A '79 can have a shaft without a hole.
 They are fed oil through a little curlyQ tube coming from the oil filter mount.
 If you just swapped a vane pump on and plugged the curlyQ,.. then you were running an oil pump with no hole.

 There is also a seal in the bottom of the vacuum pump gear that can get brittle and let oil past the shaft.

[R.O.R-2.0]

A '79 can have a shaft without a hole.
 They are fed oil through a little curlyQ tube coming from the oil filter mount.
 If you just swapped a vane pump on and plugged the curlyQ,.. then you were running an oil pump with no hole.

 There is also a seal in the bottom of the vacuum pump gear that can get brittle and let oil past the shaft.

yup, the OLD 1.5D engines had a coiled oil supply line feeding the vac pump..

the shaft lengths were different tho.. the solid shaft pump had a shorter shaft than the pump with a hollow shaft..

so, the 2 pumps are not even interchangable.. if you have a solid shaft oil pump, the vac pump that requires a hollow shaft, then it wont even engage the drive tang on the pump..

[fatmobile]

 You are right on that.
 I once was stranded in new Mexico with a bad vacuum pump/oil pump and NAPA ordered/got the wrong one,
 it was too short.

 Soo that couldn't be it or he would have had no pressure.

[damac]

Sorry I was tired and stressed that night, I had no idea I needed to do major work to get on the road

I should have mentioned my motor is a vw rebuild 1.6 td from 1985 so mechanical.

I have driven it a few hundred miles since the incident and me forgetting to bolt down the vacuum pump lid   damn that emptied the sump fast but i saw pressure drop and pulled over.  oil was all over the engine.

What I was hoping for is for some confirmation on what I saw happen?

Not even a drop was coming through the oil pump tab or that cavity you see when you look through vacuum pump hole.  The oil pump bushing was aligned properly.

I took the oil pump apart again and as well as the vacuum pump(that was working on jetta) and cleaned them out with braker cleaner on some shop towels.  I did not find any chunks inside any screens, etc.

So oil pressure at the head that was more than bently spec taken by the oil filter sensor?

The pump was mated to the block just fine when I had the pan off, etc. 

Do I just assume there was a blockage in the oil pump tab?  I sure as heck didn't find anything but I could have missed something I guess.

I'm going to try that pump in another engine for fun, but the experience freaks me out, if that happened at speed I wonder if the timing belt would have held?

[libbydiesel]

So is it working correctly now? 

[damac]

So is it working correctly now? 

I have driven 225 miles since I put it back together that night.  Vacuum pump is still being oiled, still getting good oil pressure readings at head.

I have never seen anything like it, if the old vacuum pumps won't lockup if that tab is starved for oil I want to use them from now on and just carry an extra/rebuild kit in the emergency kit with the car.

[fatmobile]

The diaphram style still needs oil pushed through the shaft to lubricate it.