Club 80-90 Forums

Hi all.
I'm after the correct procedure for checking oil pressure on a 2.1 wbx engine. Which switch to check from and what readings to expect.(Just rebuilt the engine and oil pressure light and buzzer kicks in once warm)

And inwould like to fit a permanent gauge to the dash.what gauge kits are people using and where to get them from?

Cheers

You need to measure pressure at the oil pressure switch between pushrod tubes.

I have a wet gauge that can be connected there they are around 30 quid on ebay but beware some are not accurate so you need to check it against another gauge. these can't be used on the road.

The oil temp neds to be 80 degrees to check the only VW measurement given which is 2 bar min at 2000 pm 80 deg oil temp.

They don't say where to measure the oil temp but it seems to me this must be sump oil as thats the only easy place to measure.

You will need a K type thermocouple and a multimeter that supports it.

P1060864 by Paul_Barr, on Flickr


What happens with a worn engine ( perhaps worn tappet bores) or badly fitting oil pump if the oil pressure at 100+ drops off massinvely, the VW spec does not help you here and 100+ is where a DJ is going to be most of the time.

this is a guide to whats normal
https://club8090.co.uk/wiki/Pe ... ure_survey" onclick="window.open(this.href);return false;



Mine is disappointing low after a rebuild, I improved it a bit with a 30mm pump but it does not sound the buzzer and above VW spec so I'm living with it.


Either a permanent wet or electric gauge needs a remote T piece ( £30 quid of ebay) as it won't fit between pushrods, the T piece can be routed on to p of the engine and you then fit the original switch and the gauge sender or pipe to dash in the other hole.

Electric gauges ( around £25 quid on ebay) have a sender which again may not be accurate and so again it needs checking against something else.
Wet gauge at front is probably more accurate as the manufacturers of these generally are better quality and you have no sender to give extra inaccuracy, you do need to run a oil pipe to the dash but you have to run a wire to the dah with an electric gauge anyway.

this is my electric gauge .
https://www.ebay.co.uk/itm/12v-Oil-Pres ... XQVT9SqDNL" onclick="window.open(this.href);return false;

remote T piece
https://www.ebay.co.uk/itm/LMA-Oil-Pres ... 6kntHMbNJA" onclick="window.open(this.href);return false;

P1090968 by Paul_Barr, on Flickr

P1100012 by Paul_Barr, on Flickr


and being compared to wet gauge by connecting both to the T piece at the same time and leaving the switch out.


P1100004 by Paul_Barr, on Flickr

P1100002 by Paul_Barr, on Flickr

P1100007 by Paul_Barr, on Flickr

I fitted a very accurate mechanical gauge.
It has been in place for several years.

Simple to fit and simple to understand

Another option is to get a diagnostic tester like this one https://www.ebay.co.uk/itm/UK-Wave-Box- ... Sw5IJWcWhA

Less than £14 for the kit delivered.

There are two sender units on your van. The one between the pushrod tubes is the "normal" one. It activates the warning light when the pressure is below 0.3 bar. It should have a blue wire running to it from the left hand side of the engine bay.

The second one is at the rear of the engine, near the fan pulley and water pump. This is only operative when revs are above 2000 rpm. If the oil pressure is less than ~0.9 bar the oil light will flash and the buzzer sounds. It should have a yellow wire from the left hand side of the engine.

You can use the water temperature as a surrogate for oil temperature for initial testing. Itchy has done a lot of work in this area, but you can just do initial testing by simply ensuring the water is up to normal temperature. The hotter the oil, the lower the pressure.

Here's an article that I used to understand how the system works http://www.gowesty.com/tech-article-details.php?id=42

and some diagnostics and a link to a photo from me in this thread https://club8090.co.uk/forum/viewtopic.php?f=39&t=163521, start at post 13

http://syncrosport.com/info/wiring/VW_T ... _SP_DG.pdf

Page 5 of the above pdf has the relevant current flow diagram

Cheers boys I'm gonna get looking at it tomorrow. Drove it to MOT this morning and it drove fine. Passed!! just a few niggles to sort out . Wasn't on the road for 5 years.

937carrera wrote:Another option is to get a diagnostic tester like this one https://www.ebay.co.uk/itm/UK-Wave-Box- ... Sw5IJWcWhA

Less than £14 for the kit delivered.

not the right scale really, you measure up to 5 bar max

Did you fix the engine and oil pressure light on and and buzzer thing then?

I have shied away from having a dash mounted oil pressure gauge on my vehicles as I tended to become obsessed with the drop while waiting to move of in traffic etc.

Kiw707 wrote: boys.

itchyfeet wrote:not the right scale really, you measure up to 5 bar max

Fair point, the one I bought was the lower range scale, probably equivalent to the 10 bar one here https://www.ebay.co.uk/itm/0-140-PSI-Ve ... SwGllaZQ6L Should give sufficient granularity.

I'll double check the range on mine in the morning.

Checked mine this morning. Unfortunately it's the 35 bar version. A bit strange as I remember searching through the listings for one that had a smaller range. I should have checked the oil pressure on the engine I bought it for 5 months ago. Oh well, I suppose I'll try it out and then decide if I need to buy another.

10 bar test gauges are much harder to find and alot of ebay listings don't say but it's what you need to get any sort of accuracy.
For a permanent gauge a 0-5 bar is best, the WBX oil pressure relief valve won't alow it to go above 5 bar.

Some people love PSI but VW's were made in metric