Rebuilt engine low oil pressure

Technical questions and answers concerning all models of VW diesel vehicles.

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sgnimj96
Turbo Charger
Posts: 226
Joined: Thu Feb 20, 2014 2:08 pm

Re: Rebuilt engine low oil pressure

Post by sgnimj96 »

It came with an alh intake too.

Just found a post where andrew gives the part number for the oil pump bushing,
https://www.jimellisvwparts.com/product ... 03541.html
better pic
https://www.brickwerks.co.uk/oil-pump-b ... w-use.html

One of the few discussions that includes mentions of that bushing
https://www.vwvortex.com/threads/interm ... c.5721990/
81' Scirocco 1.6D (conversion)
86 Golf 1.6D
85' 300TD
sgnimj96
Turbo Charger
Posts: 226
Joined: Thu Feb 20, 2014 2:08 pm

Re: Rebuilt engine low oil pressure

Post by sgnimj96 »

That oil pump shaft bushing is really soft. I knocked it out with a 3/8 extension and it dented the metal where it
won't go back on the shaft unless you hit it with a die grinder. Gotta use an exact size socket for knocking that bushing
in (or out) to avoid having to do it over. Btw, the oil feed hole in the bushing goes to the left side, towards the oil filter.
I tried it the other way to see if I'd get better oil pressure, and I did, but then you get NO vacuum for the brakes LOL.
My old oil pump shaft bushing actually had some gunk in the oil passage, looks like the red paint inside the crankcase
Image
This crud was probably helping the oil pressure, if anything, but not helping the vacuum pump pressure.

I did try the 30mm oil pump after changing the vac pump seal and the oil pump shaft bushing and there was
little difference in oil pressure. The old black vac seals looked really stretched out compared to the new green ones
but the black seals were actually still working good.
Image

I made sure the vacuum pump feed hole was clear. This vac pump I pulled the screen out, like someone did in a vortex thread.
I don't recommend removing the little oil screen, PIA, it came out in pieces and some stay stuck in the edges.
Wish there was documentation to fully disassemble a vane pump.
Play in this vac pump was minimal and with the 36mm oil pump it does pull better vacuum.

Been driving it for a while now,
Oil pressure with the chinese 36mm pump is not great, but better.
Cold startup pressure seems better.
Fully warm gets around 40psi cruising at 65 and 15 at idle.
Never goes above 80psi cold, losing a lot of pressure somewhere (probably IM shaft)
but the lower end pressures are better and that makes me feel better.
The 36mm oil pump seems like a good patch for now.
Last edited by sgnimj96 on Sat Jun 11, 2022 11:31 pm, edited 2 times in total.
81' Scirocco 1.6D (conversion)
86 Golf 1.6D
85' 300TD
Fatmobile
Global Moderator
Posts: 7526
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: Rebuilt engine low oil pressure

Post by Fatmobile »

Glad to hear you could find a 36mm pump and that it helped increase oil pressure.
It didn't help much when I upgraded to one.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
sgnimj96
Turbo Charger
Posts: 226
Joined: Thu Feb 20, 2014 2:08 pm

Re: Rebuilt engine low oil pressure

Post by sgnimj96 »

Just took it on a long trip, crossing mountains. Seems to be running well. Those rings are seated now :P
I put in a stronger mix of coolant to raise the boiling point. I could tell that was going to be an issue when I got into some real steep runs
so I did that before crossing the border.
Still really liking the (relayed) manual fan switch with the fan indicator light for keeping the temp normal on hard runs. Going up a steep grade just really
shows the mk1 design flaw in the thermo-electric cooling system. Add the boiling coolant factor and it's no wonder the cooling fan fuse melts
and engines overheat.
81' Scirocco 1.6D (conversion)
86 Golf 1.6D
85' 300TD
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