No oil pressure

[GO LEO]

Hi there,

Search not working so I need to ask this (presumably) simple question...

Started my 4.2 1997 Cerbera on Sunday for the first time after 3 months.
Let the engine run for a couple of minutes to wait for fans to cut in.
I then headed off for a careful 20km drive to see whether everything's running smoothly.

Only after 5miles I spotted that the needle of the oil pressure gauge hadn't actuall moved. Gauge showed zero!
Since I was on a dual carriage way and there was no warning light on I continued but extremely careful.
I returned home with engine still sounding fine. I never revved it above 2500rpm though.

Question: if warning light doesn't go on, is it possible that there was really no oil pressure? Or is it just the gauge or the sender that failed? Any ideas where to start searching?

I never had oil pressure issues. Oil pressure switch has been replaced last year and 3000miles ago. Symtoms last year were exactly the opposite btw... Gauge showing oil pressure but warning light on...

Thanks for your advice... And I hope I will not be in the market for a new engine this year :-)

Leo

[bionicjim]

The oil warning light only shows that there is no oil
The gauge works off a pipe with oil in it
I had the same prob last year and I had a blocked
Oil way that coursed the crank bearing no1 to spin

[Jhonno]

Sounds more like a faulty gauge setup to me.. If the engine sounded fine that is.

[Dave 500]

Yep would't panic, probably just the sensor fubar.

If both the gauge and light come on stop

[gabbro]

Might be worth checking the oil pressure relief spring- I had somethign very similar. It suddenly dropped to zero yet sounded fine then occasionally showed up depending on how the bits of spring aligned themselves. Either way, its a common problem and worth getting it replaced at service time whether it needs it or not

[APMAUTO]

is the light on when just the ing is on? oil light comes on around 7 psi(which is a bit too late)so you may have just enough to turn it out but not enough to save the engine, put a remote gauge on the line to check oil pressure rather than assume a faulty gauge

[jamieduff1981]

Without meaning to sound offensive, assuming the instrumentation is faulty is an approach that gets people killed in some occupations. You should always assume it's a mechanical failure until you can prove it's the instrument.

[ukkid35]

APMAUTO said:

oil light comes on around 7 psi(which is a bit too late)

I didn't realise it was so low, just 0.5 bar!

[bionicjim]

You could try bleeding the pipe to the gauge
Remove the pipe from the back of the gauge
Put it in a cup and turn the engine over with
Out it starting until nice clean oil comes out
Then reconnect
And see if that helps

[Jhonno]

jamieduff1981 said:

Without meaning to sound offensive, assuming the instrumentation is faulty is an approach that gets people killed in some occupations. You should always assume it's a mechanical failure until you can prove it's the instrument.

Ok my bad.. I didn't really write a full reply. I thought the warning light came on earlier than it apparently does, plus he stated the engine was running fine. I personally would have turned the engine off instantly I noticed no oil pressure on the gauge.

[GO LEO]

Hi all,

Thanks for the many answers so far.
I did some further investigation. Firstly, the warning lights are all OK, so when ignition is turned on, they are all on.
When I start the engine they go all off. The needle of the oil pressure gauge doesn’t move at all, so it doesn’t actually show anything, not zero as I said before.
I am a mechanical numpty so will not be able to try the work arounds myself…

Drive to garage 20miles away or not?
Potentially big question…

Cheers for final advice.

Leo

[RUSSELLM]

Don't think I'd risk it.

As improbable as it is, if anything did go wrong with the actual oil pressure on route, you'd have no early warning.

I'd be ringing the AA & explaining the situation. That's a breakdown in my book

[jamieduff1981]

Personally I would not start the engine again until it's proven that the relief spring is intact, the sump isn't full of metal and the pump turns with the engine. Next it would be a case of proving the calipary to the pressure gauge is bled properly as above, then it's a suspect gauge.

If it turns out to be the gauge then arguably the cost of a recovery to the garage from your house was wasted. I'd rather waste a recovery than an engine though.

I have no experience inside the AJP yet, but I've stripped and rebuilt a fair few light aero engines and have first hand experience of the carnage that oil starvation causes. It's your engine, but there's no way I'd fire it up again with an indicated 0psi if it were mine. The last engine I had apart was a Subaru flat 4 which had been dry sump converted and run by the owner's friend with an indicated 0 psi for just under 10 minutes. It was assumed that the instrument was at fault, but infact it was a non-return valve on the suction side of the supply pump from the header tank which had jammed and it really was a complete lack of oil pressure. I got a ring and was asked to take a look. I removed the sump pan before anything else and it was full of metal. Bores ruined, big end and main journal bearings disintegrated and crankshaft deeply scored - it was scrap.

Your choice - but there's a safe way and a risky way to deal with this.

[Tanguero]

jamieduff1981 said:

Personally I would not start the engine again until it's proven that the relief spring is intact, the sump isn't full of metal and the pump turns with the engine. Next it would be a case of proving the calipary to the pressure gauge is bled properly as above, then it's a suspect gauge.

If it turns out to be the gauge then arguably the cost of a recovery to the garage from your house was wasted. I'd rather waste a recovery than an engine though.

...

Your choice - but there's a safe way and a risky way to deal with this.

Absolutely!!! Recovery is cheap, engine rebuilds are not!

[Jhonno]

Tanguero said:

jamieduff1981 said:

Personally I would not start the engine again until it's proven that the relief spring is intact, the sump isn't full of metal and the pump turns with the engine. Next it would be a case of proving the calipary to the pressure gauge is bled properly as above, then it's a suspect gauge.

If it turns out to be the gauge then arguably the cost of a recovery to the garage from your house was wasted. I'd rather waste a recovery than an engine though.

...

Your choice - but there's a safe way and a risky way to deal with this.

Absolutely!!! Recovery is cheap, engine rebuilds are not!

100%..

[DAVEY DEE]

£50 vs £8,000 ? Play the safe route.

[GO LEO]

OK, I'll call AA then :-(
Even though I still believe (applying logic, I know I shouldn't on a TVR) that the gauge would at least show 0 (or any value) if it would be OK. It would not just show nothing at all. So many cars out there have no oil pressure gauge... how do these people ever get to know when oil pressure is down? They also only have the light that I have (and that doesn't tell me sth's wrong).

Anyway, will let you know...

Leo

[tur8o]

take out aa warrenty £99 for 12 months, wait the two week starting period, call them, get recovered and get them to pay to fix it. should easily recoup the £99 in this visit alone.

[Nickccc]

tur8o said:

take out aa warrenty £99 for 12 months, wait the two week starting period, call them, get recovered and get them to pay to fix it. should easily recoup the £99 in this visit alone.

Just a few problems with that master plan
1 it'll cost about £130.00 for a years membership
2 £99.00 for your warranty
3 they only contribute £500 towards the repair
4 less £50.00
So for £450 you will need to spend £229
So £ 221.00. Towards your repair,
Oh nearly forgot, this thread , as I can assure you the AA will be checking on here as they did with me, not that I was trying a scam but they probably won't take to kindly to someone trying to rip them off.
6 they will cancel your policy and warranty, so that will be £ 229.00 you'll be out of pocket.
7 back to the drawing board.

[tur8o]

i never knew they would go to such lengths, i had it the whole time i had my cerb and claimed five or six times without any problems, usually for close to the full £500.