Hi all,
Over the last couple of days I’ve noticed the oil pressure guage (real guage - 1992 mk1) has been a bit shakey - it won’t settle on a position like it used to, and will fluctuate very slightly, then settle. Has anyone else experienced this? Or know what it would be? Bad oil? Oil pressure sensor dodgy?
I changed the oil about a month ago (Halfords 10w40 - though not a great oil I now realise), and it has only just started with the shakes…
Any advice appreciated!
Thanks,
Sam
First of all lets get the quality of the oil nonsence out of the way. At the moment Halfords oil is supplied by Comma. Search Companies House and you will see that Comma is owned by Exxon Mobil.
So are we saying here that Mobil is a poor quality brand. I think not! It could still be a bad batch of oil but Comma is widely used by the motor trade.
I have only had that problem re oil pressure many years ago on an oil pump that had debris from a broken bearing in it. So lets hope that’s not the problem.
Can you possibly manage to get a indpendent guage on the car to confirm the uneven readings, maybe the guage or sensor is on the way out.
I wonder if maybe some peice of solid deposit has been detached from the engine internals and is semi blocking a main oil way.
Cheers Eddie.
The shakes have now stopped - I wonder if it was a bit of desposit that was dislodged and blocking an oil way as you suggested? A bit worrying incase it’s anything serious… but I imagine I’d be seeing other signs if this was the case.
RE: Halfords oil - I read somewhere once that you can tell a good oil by how quickly the oil pressure changes and gets to where it wants to be… ie a good oil will immediately rise to a set value and stop there. Since putting in the Halfords oil, the needle movement has slowed. Of course this could be made up, or my imagination, or even due to the fact a different grade of oil was in there before affecting the pressure change!
Good news that the problem is no longer there
The only way to check if the oil is within spec for your car is to send a sample away and get a used oil analysis. Just had that done on my Impreza cost about £25.
Anything else is probably an old wifes tale as there are too many variables in the observation and the assumptions could well be wrong to begin with.
Just a thought, but both symptoms could also be caused by a sticky oil pressure gauge needle. It’s damped with grease, which gets thicker in the cold…and traps dirt over time.
That’s true - it did stop doing it when the weather started getting a little nicer…
Is there some sort of voltage controller on the dials? I wonder if this may be on the blink as recently I’ve noticed the tachometer sitting at 200rpm when the engine is idling nicely so it can’t actually be at 200rpm. Rev the engine and falls back down to 200rpm. After a bit of driving the idle will then sit at around 800.
Also the speedo needle can be a little wavey around 30/40mph - but this could be the cable I believe.
Thanks,
Sam
Sounds more like a dodgy ground from the instrument panel PCB. Would be worth checking and cleaning the connectors.
sounds like a dashboard/electrical thing. my “fuel empty lamp” doens’t come on anymore - well at least that’s what I assume the blank square is above the fuel gauage - meh.
No, there is no fuel light. Not unless you get yourself a binarypunk fuel light kit from Autolink… 
wow all this time I assumed it was a fuel lamp, just looked it up - it’s a lamp for the rear window heater thingy on the hard top :o
Yeah - interestingly this light of mine comes on when I attempt to start the car without disabling the remote immobiliser. Odd.
Ah, could well be - I assume this connector is somewhere behind the instrument panel? Or is it easy to get to under the dash?
Thanks,
Sam
Very easy. 4 screws and pop off the top of the steering column cowl, 2 more screws and pull the instrument panel cowl towards you firmly. Connectors will then be accessible at the back.
Thats heated rear window on light. I thought it was a failed low fuel warning light untile my new hood went on with its heated glass. 
Easy indeed! It didn’t fix the problem with the tach, but has definitely brightened up the instrument lights - the green indicator arrows are blinding!
Could the issue be with the tachometer sensor? I believe it comes off the cam position sensor, so will check the connectors when it stops raining…
This time I gave it a thorough clean and haven’t seen the problem since.
I’ve been regretting posting this as these kind of electrical problems always return after calling them ‘fixed’… but I think it’s been long enough now…
Had similar with my Mk 1. Changed the sender to cure it.