oil pressure question

[Hillbillybuddha]

Just picked up an 84 Jetta 1.6L diesel NA. Fun little car. Had some shifter linkage problems (relay ball was half gone) but I got that figured out and it was simple.
Starts easy, lots of low end torque although top speed is a little slower then I'd hoped for, I'm still not at all disappointed. I did notice I was burning through and leaking oil. I found the leak, it's on top of the valve cover, where the hose goes to the air box. it was pretty easy to find as there was oil all around both sides of the hose (valve cover & air box sides). While I was looking around (and reading forums) I noticed a hose coming from the front of the crankcase that had been cut and a bolt had been put into the hose to block it off. Did some more research figured that the crankcase hose was suppose to connect to a Y fitting and connect to the valve cover and the air box but I couldn't find anything in the Bentley about this. Also, through my searches I hear a lot of people asking about oil spray through the dip stick, I checked and did not have this problem.
So being the smart guy that I am (lol) I decide to rebuild the hose system. I figure that the oil leak is caused my a pressure build up and that valve cover hose to air box is the weakest point. So I get a Y connecter and some oil resistant hose and connect all the parts. I even install a PCV in the hose between the Y and air box figuring that if oil did continue to come up that hose is would now drain to the crankcase and solve my leak problem. Hmmmmm. Or maybe not. It was late and I may know just enough to be dangerous.
So I get it all set up and turn on the car. The little oil light on the dash starts beeping at me. It had never done that before. This doesn't sound good. I get out to look at the motor, oil is now spraying out of the drip stick hole, it had never done that before. I turned it off, as I had just read about something called "run away" and I was losing light.
So now I'm going to pull that PCV to see what happens. If it's still acting up, I'll put it back the way I found it.

Any ideas? Is was running fine, and now I feel like an idiot.

[air-cooled or diesel]

that hose coming out of crankcase sometimes is coupled with a relief for vac pump and for ccv. take hose off valve cover and run her and if you have a lot of oil coming up out of that vent, im afraid new rings fix that, look in your air box @intake and look for oil there, more than a little moisture is basically too much. you can still run but your getting excessive ccpressure. no telling when it ll run on its own on oil coming in there. ive never heard of a pcv used on these engines, so get rid of that, and try again, check the hose you put on from crankcase that was closed and you opened, with running check pressure coming out of it. shouldnt be alot of pressure coming out. and some air goes back in as cc breathes.
hope you didnt blow that small dipsticktube o-ring, it was a prob to get an o-ring back in it and seat, mine didnt go back together right.

[Hillbillybuddha]

Hmm. So, It would seem that lots of oil is coming from the valve cover. So that means rings? I can do that in car, right? Either way, I have a cherry picker.

So back to today. I ran the car up to operating temperature. And the buzzing started again. I pulled the hose from the crankcase and lots of smoke came out. I put my thumb over the hose, didn't feel like a lot of pleasure (but I realize "a lot" is relative) but I left the hose vent to atmosphere and it smoked a lot. Ran a couple blocks and the buzzing started again. (This buzzing means high oil pressure, right? ) so I pulled over and pulled the pcv, and left one side of the Y connecter open (hoping to a: relieve some of the pressure and b: allow the oil to drain from the hose to the engine compartment so it wouldn't go into the airbox and cause run away) Got a few more blocks and the buzzing started again.

Got it home and checked the oil. I was wondering how much oil it had burned since yesterday. Turns out that the oil is over filled now. I think all the "topping it off" I was doing, ended up over filling it. Oops. Would that cause the buzzing?

Anyway, before I concede to replacing the rings, (I'm not sure it's the rings because it's so easy to start and it had a lot of power) I want to check compression. Is there a good write-up on checking compression on these engines? I've heard a lot of mixed advise. Some say to check through injectors, some say to check through glow plugs, some say you'll have to replace them (which could be expensive if I have to check through the injectors ) Is there consensus on how to check compression?

[air-cooled or diesel]

dont jump to the fact i mentioned rings, were not sure of that at this point, there are some other things go see how it goes 1st, as long as you get that overfill straightened out, pull pcv, delete, and run at idle for a while and check out the vents and how they are doing, then around the block at first and recheck then longer etc, some smoke comes out of these, if its blinding then yea thats going to be a problem,

[TylerDurden]

Checking compression via the injector ports is easy-peasy... GP holes, not so much.

When you pull the injectors, the heat shields will need to be replaced or re-formed (~$1/ea). They seal the injectors in the bores as well as protect the nozzles from heat.

NB when you remove/replace injectors, it's best to push the wrench handle toward the firewall, not pull toward the bumper, to avoid cracking the threaded boss. Putting a universal joint on the socket can help too.

[TylerDurden]

Overfilling can set-off the buzzer... oil can foam and screw with pressures.

[Hillbillybuddha]

Alright. So my plan for tomorrow is to change the oil (I got Rotella and a filter), once oil is changed, I'll go back to the old set up. Plugged crankcase hose, valve cover hose to air box (quick questions, did this hose have a restricter in it? Will I be in danger of run away without this restricter? )

I went to napa and got 4 injector heat shields and 4 injector O-rings (just in case) and then I went to harbor freight and picked up a cheap diesel compression tester. I figure I should have an idea what the compression is, regardless.

I'm hoping this doesn't take to long because I need to get the oil pan back on my 61 Thunderbird (and that's a surprisingly complicated procedure )

I'll let you know what's what tomorrow, I'm off to work for the night.

Thanks for chiming in everyone.

[Hillbillybuddha]

There was probably about a full quart of oil over filled. I drained out the oil and got it to just a mm below the full line. The buzzer kept going off every time if get above 2k RPM's. I decided I needed to know what the actual oil pressure was So I bought an oil pressure test guage. Pulled the sensor and hooked it up. At cold idle it was at 75 psi, once it warmed up, it is at 28 psi at hot idle. BUT At 3k rpm, I'm at about 95 psi. Does all this sound right? Why is the buzzer still coming on?

I'm no longer being getting leaks at the valve cover or the air box BUT I've got a pretty steady drip at the dip stick now. Didn't have that leak before I over filled it.

I also re-plugged the crankcase vent hose, it wasn't smoking as bad before I plugged it up but since the buzzer was still going crazy, I tried plugging it. Should I leave it plugged or let it vent?


I'm going do the compression test tomorrow, I think. Work was brutal last night.

[Hillbillybuddha]

I've been doing some research on this forum and Google. I'm wondering if this might be a problem with the oil pressure relief valve? If so, I'd that part of the oil pump or is it it's own thing? Looks like replacing the oil pump is pretty easy.

[Fatmobile]

According to the gauge; your oil pressure is good.
Probably a bad sensor.
Since it's only happening at over 2000 rpm, it's the sensor on the oil filter.
,.. or maybe it came unplugged?

Sooo did they put a vane style vacuum pump in it?
Because that block port is usually where the vacuum pump dumps air.

[Hillbillybuddha]

So the high psi (95+) at high RPM's is Ok? I've read that the psi goes down at high RPM's.... Maybe I misread that.

Vane pump? No, the crankcase had a hose that the PO plugged with a large bolt. I pulled the bolt out thinking it would relieve some of the oil pressure or at least, redirect the pressure so it stop blowing oil out the valve cover. Should it have a vane pump? What's a vane pump?

[TylerDurden]

Running a tube from the crankcase port to the airbox can relieve crankcase pressure, but a lot of oil mist can cause a runaway (stall or suffocate to shut down).

[Hillbillybuddha]

Ok. I'll change out the sensor today. I'll leave the oil pump alone for now.

I don't remember seeing anything looking like a vacuum pump in there but I'll look again. Honestly, the idea of a vacuum pump is messing with my head. I consider myself a bit of a gear head. I like building hot rods and rebuilding classics. The only time I have ever needed a vacuum pump in a gas car was to supplement the vacuum needed for the power brake booster on a car with a hot cam. I'm having trouble wrapping my head around why anyone would ever need a vacuum pump on such a small car? Doesn't the engine itself create enough vacuum for its minimal needs? Are diesel engines really that much different?

[air-cooled or diesel]

diesels dont make their own vacuum, so you need a vac pump for things like power brakes and for things like the vents. its right above your oil pump, its on the drivers side of motor right there with a big line to power brakes.

[Hillbillybuddha]

diesels dont make their own vacuum

Well that is interesting. Thanks for pointing that out, I've got to look into that more. I'd imagine that has something to do with the intake? Time to Google for some old fashioned learning.