MK5 Golf GTi low oil pressure warning

Marcus Burden

Marcus Burden

Marcus Burden

Associate
Joined
24 Apr 2020
Posts
12
Hi all.
Been scratching my head over and over again with this issue.
Low oil pressure warning (red flashing light)
I've recently had over £2000 of repairs done to my Mk5 GTi.
Along with the repairs that were needed I've also had the oil pick up pipe replaced, sump cleaned out, oil pressure switch replaced.
Whilst it was stripped the technician also inspected the oil pump and balance shaft and my main end bearings and everything was perfectly ok with them.
After I had the pick up pipe replaced sump cleaned and pressure switch replaced I'm still getting the low pressure warning after the car has warmed up.
I'm at a loss now I've spent a small fortune on this car and I can't seem to fix the low pressure issue.
Any advise? Maybe use a thicker oil it's currently got 5w30 in, would you recommend using 5w40 or even 10w40?
Also I have had 3 oil pressure tests carried out and my engine if producing the right amount of pressure.
Many thanks in advance
 
If the oil pressure is correct, and the switch has been replaced, then personally I'd be chasing the wiring back to see if there's any damage to the loom for it.
 
How old is it and how many miles has it done?

The Oil pressure warning light at idle on a (very) high mileage engine isn’t necessary the end of the world, although I’d be surprised to see it on something with average miles which I’m assuming your has.

If it’s coming on during normal driving and your engine hasn’t trashed itself - it sounds and performs normally - I’d suspect an electrical fault somewhere.
 
Thanks for you reassuring reply @Scania my engine runs very smooth it's quiet, no knocks and clanging noises.

The year is a 2006 and has 136,200 miles on it now but it does drive superbly.

I am hoping it is an electrical fault as I said I had the oil pressure sensor replaced 3 days ago now.

The warning only seems to come up and beep when the engine reached 90 degrees though and yes always normal driving under normal acceleration I never over rev my car.

Either way I'm still baffled by this.
 
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It sounds like you've had the oil pressure tested using a mechanical gauge. If it's within spec, when hot, then the fault lies elsewhere.

If that hasn't been done, however, it should be your first port of call (although, as mentioned, it sounds like that's been done already).

Your engine isn't that high mileage, by any stretch, and otherwise sounds in fine health. Is the oil level correct and the dipstick okay?
 
check the oil filter iv seen crap mechanics before that just bung on a new filter and dont check to see if the old filters gasket game off with the old filter. so it double gaskets and iv seen the gasket get stuck in the filter housing causing low pressure light to come on.
 
@Lashout_UK.
Dipstick and oil are all perfectly fine.

I do agree with you that this issue lies elsewhere. I'm just wondering where! Could it be something as simple as the electrical connection that plugs into the sensor itself?

Or maybe a long time outstanding software update that hasn't been done?

@Cyber-Mav has the filter housing checked and no double gasket everything is where and how it could be.
 
There is a known issue with this, it's mainly caused by the oil pickup/strainer in the sump of the car getting clogged - some think because of long life service intervals..

You need to have the sump removed and get the strainer cleaned/changed for new, and get the car engine flushed while you are at it.
 
hominid said:
There is a known issue with this, it's mainly caused by the oil pickup/strainer in the sump of the car getting clogged - some think because of long life service intervals..

You need to have the sump removed and get the strainer cleaned/changed for new, and get the car engine flushed while you are at it.
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OP has already done all of this and more.

OP, maybe temp fit and oil pressure guage then you can be 100% the pressure is ok when the warning light goes off, considering all you've have done this doesn;t sound like presssure is an issue
 
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g60dubster said:
OP has already done all of this and more.

OP, maybe temp fit and oil pressure guage then you can be 100% the pressure is ok when the warning light goes off, considering all you've have done this doesn;t sound like presssure is an issue
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I don't know how I missed it, I thought I read all in this thread.. :(

Anyway.. It'll be odd if it was electrical as you said it only happens when ~90deg C, if it was electrical then it would most likely happen at random times/temps. Also ~90Deg C is when the, already thin 5/30W, oil is getting to it's thinnest with temperature, ie at it's working temp. As it's happening then I would say you have wear, somewhere, out of spec.

If I was you I would have put a set of big and main bearings, or at the very least taken the end caps off to inspect them(I know you said he inspected the mains), when you had the sump off anyway.

What was the other work you had done? was it camshaft/fuel pump? Did you get the oil pressure/revs logged with vagcom? That way you could see if it's a blip or it slowly loses oil pressure as temp rises.

Good luck!
 
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hominid said:
Anyway.. It'll be odd if it was electrical as you said it only happens when ~90deg C, if it was electrical then it would most likely happen at random times/temps.
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Not necessarily, the horn on my Focus works fine when the cars cold, once it's up to temperature, it won't work, and I have no idea why despite two garages looking at it (typically, it worked on both visits...) Give me a mechanical issue (although not a major one, please!) over an electrical gremlin any day! :o :D
 
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The 90C thing is a bit of a red herring, the ecu will only look at the oil pressure once certain conditions have been met e.g. engine up to temperature and a certain rpm.

I would try running an earth wire to the sensor body if it is a simple 1-wire switch. You could even do this with a jumper cable as the clamp would be ideal. A typical sensor is open circuit until the set pressure is reached and then closed once the target pressure is reached but it relies on having an electrical return path through the body of the sensor and via the engine block.

Edit: as others have said, this is assuming the oil pressure has been measured with a mechanical gauage and is known to be good when hot and across the rpm range.
 
BUDFORCE said:
I'd ignore it and carry on driving it as normal.
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Don't do this..

Looking at the videos that Dave linked it looks like a hardware issue, you can try putting heavier oil in but eventually it'll probably need a new/second hand engine.

The reason you get knocks is because the bearing tolerances are out, ie the gaps in the planar bearings is too wide because of wear. Therefor, with the oil pump pumping is normal amount of oil, too much of that oil is leaking through the gaps in the bearings/lubrication system it's cannot maintain oil pressure - the oil pump cannot flow the amount of oil needed to stop metal-metal contact.

I would say don't throw any more large amounts at trying to save this engine, start saving for either another car or a new engine/engine repair for this one.

It sounds cooked - sorry..
 
Thanks all for your replies.

I've had the engine knocks sorted it was a variable valve timing issue on the exhaust cam I believe the car is now running smooth and quiet and no knocking whatsoever.

Drives smoother feels like a completely different car.

I just want to get this oil pressure warning sorted now and it's driving me nuts doesn't happen all the time but when it does happen it drives me crazy!
 
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