1.6 NA Diesel Oil Pressure

[airsweden]

Hello, I recently got my hands on an '82 Vanagon Westy Diesel and could use a little advice. I've never owned a vw diesel before this one but do have a basic understanding of engines in general.

One frightfull thing that I noticed right away was that the oil pressure light on the dash stays on for what seems to be an eternity at start up... hot or cold. The warning light will stay on for at least 1 min, usually longer and only goes out as as I start to putt down the street.

I finally got a hold of a brand new VDO electric oil pressure gauge the other day and hooked it up for a look see.

At cold start up it was the same as usual, dash light stayed on but now I could also see the gauge didn't even wiggle either. After about 1 min of slow driving 10-20 mph, the light went out and gauge spontaneously read 20 psi.

As I proceeded to increase speed, the pressure rose to a lofty 70 psi at around 60 mph on a flat road. Later after slowing down, the gauge was back down around 20-40 psi cruising my neighborhood. When I returned home and let it idle in the driveway oil pressure dropped down around a scary 5-10 psi on the gauge with the dash light flickering.

So It seems the harder this engine works, the higher the oil pressure and that seems good to me. I'm wondering though why it takes so long for the pressure to materialize in the first place. Does this sound like a symtom of a dying oil pump? I should say that I believe the PO used 30 weight oil... I found a couple bottles in one of the handy bins near the engine bay.

Many thanks!

Josh

[82vdub]

Welcome to the forum.

I think that the previous owner knew about the low oil pressure problem, from the 30w bottles of evidence that he left around for you. These things, when in good condition and when cold, will typically peg a 100PSI gauge upon startup. I would investigate the front intermediate shaft bearing for wear. These bearings have a lot of thrust on them from the timing belt and if not taken care of will wear and show low oil pressure as a symptom. The bearing surface may also flake away and you may find pieces in the oil pan or a cut open oil filter.

You could also have a timing belt that's not completely turning the intermedate shaft. The intermediate shaft spins the oil pump and vacuum pump and is turned by the backside of the timing belt. If this slips, then the oil pump will not be turning as it should.

If you do not own a Bentley repair manual, now's the time to purchase one. It IS the repair manual that you need for these engines.

[airsweden]

Hey thanks for the reply/info.

Ever hear of such a scenario being limited to the oil pump? I might be trying too hard to remain in denial here but was thinking that since my oil pressure does eventually seem reasonable and considering it probably has straight 30 in it now, maybe I would be lucky enough to avoid a teardown and rebuild at this point.

I'm going to at least get some 15/40 rotella in it with a Mann filter and put the guage on it again just to see if that makes any difference at all. After that, if I still have the lack of pressure at start up... would it make sense to try a new oil pump or do you think its bearing replacement time?

Thanks,

Josh

[Quantum-man]

I think you should take your sump off and check the pump.
1) for blocked gauze
2) A simple strip down and check with a feeler gauge for wear.
End on wear can be removed by abrading the casing under the cover.
3) Make sure the pressure relief plunger is not sticking.

[82vdub]

Using 15/40 in it won't improve the oil pressure. If anything, it will be lower. Pull the pan off and check as quantum-man suggested. That doesn't require a tear down, only partial disassembly.

[Quantum-man]

My main reason for checking the pump, is because it allows you to have a true base line, and not get distracted [possibly] by cosmetically tarnished bearings, that are not the source of your pressure delay