Car with low oil pressure dash light on

[hunt123]

Hey

There's a car for on ebay, a lancer evo 7, looks good apart from the seller saying this :

"...only bad point i can think about is oil pressure switch need to change i might do it when i got time..."

and via messages he said this about it :

"...so the oil pressure switch won’t effect the car anything at all only when the oil up to certain temperature the dash will show the light

This to me is not good however my mechanical knowledge/skills are low so I would like your opinion on it please. A dash warning light for low oil pressure might be a faulty switch but it could also be a worn engine or bad oil pump, am i right in thinking this? You can't trust a seller when they claim it's something simple so it's best to assume the worst imo.

Would this put you off buying such a car? I think it has me.

[Register1]

So when the engine internals expand, there isn't sufficient volume of oil to maintain a pressure.
Also to remember, the oil could be carp, ant turning to viscosity of water when warm/hot.
Strikes of worn crank, big end bearings, mains etc.

[TwinKam]

...their poor grasp of spelling and grammar is enough to put me off!

[hunt123]

^^^ thanks for the replies. You've confirmed what I thought, it's not worth the risk. If it was so simple as he's suggesting then why not get it fixed as it would be worth more money surely. Think i'll be avoiding this car, thanks again.

[ARHarh]

Its always a cheap £10 fix. That's why they spent £10 and 10 minutes fixing it. Or the engine may have no bearings left. I put my money on the second option.

[SturdyHSV]

As above, engine internals expand when hot (especially if an ally block but steel crank etc.) so clearances open up.

In addition to that, the oil naturally thins out with temperature (that's what the oil 'weight' figures dictate) and so pressure will drop as well.

This is what engines do.

If that behaviour triggers an oil pressure warning light, then yeah, it's fked mate

If the light was on permanently, and you could see via a mechanical gauge that it did in fact have pressure, then maybe it's the sensor, but it sounds like the sensor works, and is doing its job of highlighting that the oil pressure is too low once it's warmed up.

Unless you just want the shell / drivetrain and are chucking a different engine in, personally I'd run far away. If you want to be really optimistic, maybe the seller was told this by a mechanic / someone they trust, so you could possibly suggest they put a mechanical gauge on it and verify the actual oil pressure, but I'd sadly assume the seller knows its one decent pull away from lunching itself and is hence getting rid.

[GreenV8S]

SturdyHSV said:

In addition to that, the oil naturally thins out with temperature (that's what the oil 'weight' figures dictate) and so pressure will drop as well.

It really isn't "in addition". This is what causes the variations in oil pressure. .

[SturdyHSV]

GreenV8S said:

SturdyHSV said:

In addition to that, the oil naturally thins out with temperature (that's what the oil 'weight' figures dictate) and so pressure will drop as well.

It really isn't "in addition". This is what causes the variations in oil pressure. .

Yep fair enough, I ordered those the wrong way around, the oil viscosity change with temperature is clearly the biggest factor.

But in addition, the bearing clearances do grow with temperature, as I said especially if it's an aluminium block and steel crank, those larger mains clearances will drop the pressure.

Hopefully OP is still running away from the car either way

[sean ie3]

No mention of the price of the car, might be worth a look for someone who knows what they are looking at, probably the mentioned oil pressure switch is a hope in vain though.

[Tom8]

Any ad that says something is minor but they don't have time means Barry has ragged the car and not maintained it. There is no bigger signal to walk away and find a good car.

[hunt123]

The price is at 10k with 3 days to go on the auction, similar cars are fetching 20+k. maybe it will rise alot as the auction ends, i've seen that happen before.
i have had quite a bit of contact with the seller, he is adamant it's a faulty switch, says he had the oil pressure checked by the garage he uses. he's sent me a pic of an invoice for a new switch and a pic of the new switch itself.

says it'll be fixed tomorrow. i mean, if whoever wins the auction checks for the warning light not coming on after a decent test drive then i suppose the seller is right? though it could be possible to remove the bulb though for the warning light? the seller has perfect feedback, he'd be risking losing that if it blew up. but i suppose he wouldn't care then.

[ARHarh]

But why didn't he fix it before listing, or not mention it if it was going to be fixed before it sold? If it quacks etc.

[TwinKam]

You have to ask why he didn't change the switch before listing it, he 'knows' the problem and he's bought the part to cure it, fitting it would've meant he didn't even have to mention the light, none of this debate would've happened, and he'd attain the true auction value for the car.
So why hasn't he?
Ebay is littered with these types of ads; 'just', 'only', 'easy', 'simple'. Go on then, you do it.

[SturdyHSV]

Also if the switch is faulty, it's quite odd that it coincidentally behaves in the way it would if it was in fact working and detecting low oil pressure, given it's signalling low pressure at times when the oil pressure would naturally be lower.

[hunt123]

Hey guys i agree with you, i'm not going to buy it, with the information at hand it's too risky when spending this sort of money, i'm just relaying what the seller is telling me.