Mk3 1997 High Oil Pressure

[xReapeRx]

Hey guys, first post here so most important order of business is to introduce myself.  Name's Joel, mechanic from Sheffield.

Right, down to business... I've got a 1997 mk3 Golf in the garage, had it in since before Christmas and been having a play with it on and off over the hol's.

It's got the Oil Pressure Light blinking, and the buzzer beeping (From about 5 seconds after turning the car on, even on tick over)

Worth mentioning that the car won't idle whilst cold, idles when warm but a bit lumpy... might be related but I suspect different problem, possibly throttle body.

Things I've done:

• Checked Oil Level - Fine
• Changed Oil Pressure Switch (The one ontop of the filter housing)
• Oil Pressure Test showed 5 bar on tick over! (around 80PSi, very high)
• Changed the Oil pump, Oil and Oil Filter (That includes the oil strainer and pressure relief valve)

I've since read that the car has 2 Oil Pressure Sensors, one for below 2000RPM on the side of the head(?)

I don't know what the problem could be, My first reaction would be a fault with that other sensor that I haven't changed, or even a wiring fault... but with the Oil pressure physically reading so high, I think there's gotta be a real problem?

I don't know what else could be causing such a problem, there's obviously loads of cases of low Oil Pressure, but I can't find any similar problems to mine.

Cheers for any help folks.

Joel

Edit: Forgot to mention, Also flushed the system with an Oil Treatment.

[itavaltalainen]

There is 10+ different engines in the mk3, my crystal ball is broken so which engine code is it?

[xReapeRx]

There is 10+ different engines in the mk3, my crystal ball is broken so which engine code is it?

Hi mate, thanks for the reply! With this forum being GTi specific I didn't think of adding further vehicle details, my bad!

it's the 2.0 petrol GTi.

According to Autodata the code SHOULD be ABF.

Again, according to Autodata, there are only 3 engine variants in a 1997 mk3 2 litre... and only 1 engine code for a 16v 2.0... which I'm assuming the GTi is.

So I'd say it's engine code is ABF.

Joel

[Len]

The abf has 16 valves and is 2.0 litre there is also the 2.0 litre 8v.

Sounds to me like you have blocked oil ways.

[xReapeRx]

Dropped the oil again and ran it up with 1:3 10w40/Kerosene mixture and had the gauge on it at the same time, over the course of 15 minutes it dropped down from about 3 bar (thin fluid of course) right down to about .5 of a bar, changed the oila nd filter again and have put 5w30 in it now too, and once the oil was warm it was sat steady at about 1.8 - 2.0 bar, which is exactly what it should be!...

HOWEVER! The bloody Oil light and buzzer are still going! I was checking the pressure at the top sensor at the head, and while I had that sensor out and unplugged, there was no warning light/buzzer... as soon as it was back in it was there... so I'm forced to conclude that it's that sensor that's faulty (I've replaced the bottom one on the oil filter housing already).

The sensor on the head is Brown, but I'm sure I read somewhere that it could be either Blue or Brown?  My parts factors can only get the Blue one, my question now is "Will this matter?" I assume they'll have a different resistance and therefore throw the warning flags up at different pressures...

Anyone got an idea?

Joel

[Santiago]

Yep, should be fine.

Brown switch is nominal 0.3 bar, blue is 0.25 bar.  There is no resistance as such, it's just a switch that shorts the wire to earth (or not) depending on the pressure that its inner end sees.

On Mk2s, the white switch on the filter housing is normally open (wire not shorted to ground), and shorts the wire to ground when the pressure is above its nominal value (1.8 bar on a Mk2). The other (brown or blue) switch works the other way round; shorted when pressure is below nominal, open when it's above.  (So disconnecting this one will indicate  'good pressure' to the clocks.)

On Mk2s though, only the white switch triggers the audible warning, and only above 2000rpm I think.  Maybe the Mk3 is different in this, and can get the audible warning triggered by either.

One sure way of telling that a switch is buggered, is if there is oil oozing out around the electrical connection pin. This means the diaphragm inside it is leaking, soaking the electrical switch within; and making it unable to respond to pressure changes.