Oil Pressure
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wedgepilot
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Mine was like this when I bought it. It sat slightly above 5 all the time, and was cured by a new sender. It' s true that too much pressure can damage an engine, but unless somebody has recently topped up your oil level to way over the maximum, this is unlikely to be the case.
Guest
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It seemed to work itself out on the way home from work but was the same again this morning. Ill have to check what the oil level is. Mind u i have changed the oil recently and put some slick 50 if that make a difference, but its def not overfull, i made that mistake in my 924 and managed to smoke out 4 lanes of a dual carridgeway
wedgepilot
New member
If the problem is intermittent, it' s unlikely to be the oil level....never hurts to check though! More than likely it' s the sender on it' s way out, or possibly a loose connection.
sawood12
New member
When cold the pressure will read high at idle and will drop at idle when warm (3 - 4 bar). Under power it should be up around the 4.5 - 5 bar level again.
This oil pressure thing seems to be a very common debating point but I can't recall ever reading a thread where it is an actual problem. The oil pump on 944's appears to be 100% reliable as far as I can tell. Is it just a case of the fact there is a gauge then people take notice of it and ask questions about it? I've never had a car before with an oil pressure gauge and i've never spared a second thought about oil pressure and I still don't in my Focus, but even I find myself mesmerised by the dancing needle in a obsessive way. Sometimes ignorance is bliss.
This oil pressure thing seems to be a very common debating point but I can't recall ever reading a thread where it is an actual problem. The oil pump on 944's appears to be 100% reliable as far as I can tell. Is it just a case of the fact there is a gauge then people take notice of it and ask questions about it? I've never had a car before with an oil pressure gauge and i've never spared a second thought about oil pressure and I still don't in my Focus, but even I find myself mesmerised by the dancing needle in a obsessive way. Sometimes ignorance is bliss.
Guest
New member
I had an old Cavalier SRi which I fitted VDO oil pressure/temperature guages to and I was watching them constantly... and forever asking the dealer about what pressures/temperatures I should expect... .. I had the guys tortured ! I still have them and have resisted the temptation to fit them to anything.... As sawood12 says "Ignorance is bliss"
I think it is less important to worry about absolute values, and more important to watch for trends.
If you oil pressure is usually around 4, and one day it drops to 2.5, that is something to be investigated.
If, on the other hand, it is usually around 3, don't worry about it.
(I quite associate with the story about adding a gauge to cars which didn't have them. Similar experience here.)
Oli.
If you oil pressure is usually around 4, and one day it drops to 2.5, that is something to be investigated.
If, on the other hand, it is usually around 3, don't worry about it.
(I quite associate with the story about adding a gauge to cars which didn't have them. Similar experience here.)
Oli.
Hilux
New member
You will be quite surprised to learn how little oil pressure is required at the bottom end. With modern engines coming out of the factory almost blueprinted the tight tolerances require little pressure as it is volume that is key as oil`s main feature (apart from lubrication) is to remove heat.
I would guess that oil pressure warning lights come on at about 5psi ish and crank pressure can be even lower before the oil film breaks down. The main indicated psi is the head pressure required to circulate a viscous liquid around the engine in quantity so as to remove heat and not `burn` the oil. Low pressure means that the gaps in the engine are larger therefore the head pressure is reduced BUT if enough oil flows its not an issue. Its when the pump cannot maintain a head of pressure that the oil light illuminates but there is still oil flowing albeit at a critical volume.
However when an engine is revved hard with low oil pressure the increase in heat is then a cause of oil failure as it is not flowing quickly enough to dissipate the heat or to create a protective film.
Thats as I understand it. I would also suggest that the OEM gauge is wildly innacurate when put up against a properly calibrated specialist gauge but is probably better than most mass produced cars. Ironically the more gauges you have the more there is to worry about. How ever did we manage with just a little yellow light [
]
I would guess that oil pressure warning lights come on at about 5psi ish and crank pressure can be even lower before the oil film breaks down. The main indicated psi is the head pressure required to circulate a viscous liquid around the engine in quantity so as to remove heat and not `burn` the oil. Low pressure means that the gaps in the engine are larger therefore the head pressure is reduced BUT if enough oil flows its not an issue. Its when the pump cannot maintain a head of pressure that the oil light illuminates but there is still oil flowing albeit at a critical volume.
However when an engine is revved hard with low oil pressure the increase in heat is then a cause of oil failure as it is not flowing quickly enough to dissipate the heat or to create a protective film.
Thats as I understand it. I would also suggest that the OEM gauge is wildly innacurate when put up against a properly calibrated specialist gauge but is probably better than most mass produced cars. Ironically the more gauges you have the more there is to worry about. How ever did we manage with just a little yellow light [
]When I was a young, newly-licensed nipper, my folks had a Pug 205 with two gauges - speed and fuel. And a few warning lights. (Damned good thing it didn't give any more detail really, given the way I drove that car ... beaten like an illegitimate ginger stepson would not be over-stating it ... !)ORIGINAL: Hilux
How ever did we manage with just a little yellow light [
Oli.
Guest
New member
The sensor itself is a 2 pole VDO variety.... Mounted down the right hand side of the engine near the filter. You are better to get at it from below. One side of the sensor is printed 'G' which is your oil warning light which goes to ground putting on the light. This is fed by a Blue/White wire. The other side is printed 'WK' which is the guage side. This is like a variable resistor to ground. The more ground you have the less pressure. This side is fed by a Blue/Black wire. If you disconnect the wire and switch on the ignition the guage should read full scale. I dont know if your car is the same but its like that on my '87 Turbo. I think that German cars of that era like VW, Merc BMW etc with OE guages are all the same but I am open for correction on that one[]
]Clarks garage says:
"The oil pumps on these cars are generally bullet proof. When they go bad, it's generally the result of losing prime to the oil pump which can destroy not only the pump but, the main and rod bearings as well. Again, this is one of those things that you can't really test for. All you can really do is remove the pump, disassemble it, and inspect the pump gears."
Could the belt coming off the bottom crank shaft pulley to the oil pump cause a loss of prime?
"The oil pumps on these cars are generally bullet proof. When they go bad, it's generally the result of losing prime to the oil pump which can destroy not only the pump but, the main and rod bearings as well. Again, this is one of those things that you can't really test for. All you can really do is remove the pump, disassemble it, and inspect the pump gears."
Could the belt coming off the bottom crank shaft pulley to the oil pump cause a loss of prime?
The bottom pulley bolt needs to be tight for theoil pump to drive and generate pressure, if you lost pressure with the engine running it might have destroyed the main and big end beaings. Is the bottom puley properly tight now? It needs to be as the p7oil pump rie is taken from a sleeve over the crank, held by the bottom pulley.
Tony
Tony
Thanks Tony, an update..
Botton crank pulley torqued to 155 lbs ft and belt tensioned 5mm deflection as per manual. We have 3 bar pressure at 3000RPM but drops off in and out of the red light. No bottom end rattles only noisy tappets which suggests the oil is still not getting to the top. Any suggestions for a reduced pressure?
If i have a look at the oil filter and find foreign objects this would suggest engine damage , If no foreign objects then a damaged oil pump could be the problem. does this sound feasible?
Botton crank pulley torqued to 155 lbs ft and belt tensioned 5mm deflection as per manual. We have 3 bar pressure at 3000RPM but drops off in and out of the red light. No bottom end rattles only noisy tappets which suggests the oil is still not getting to the top. Any suggestions for a reduced pressure?
If i have a look at the oil filter and find foreign objects this would suggest engine damage , If no foreign objects then a damaged oil pump could be the problem. does this sound feasible?
Of course. Basically it's only different in the ancillaries. The Devil is in the detail though and things like the ECU is different and not all 250 ECUs will even plug straight in. The 220 bottom end might actually be better if its one with forged rods in any case.
As Tony states the front pulley is the key and presumably yours came off. You don't have to prime the oil pump in any special way and it should quiet the top end quickly if all is well so I assume something else is still awry if the pulley is back as it should be and you still have a problem.
Even so the idea of swapping an engine is drastic as it may be something relatively minor and you won't get a good 250 engine for £200 like you might with one for something like an Escort.
As Tony states the front pulley is the key and presumably yours came off. You don't have to prime the oil pump in any special way and it should quiet the top end quickly if all is well so I assume something else is still awry if the pulley is back as it should be and you still have a problem.
Even so the idea of swapping an engine is drastic as it may be something relatively minor and you won't get a good 250 engine for £200 like you might with one for something like an Escort.
Thanks Fen, I have the car back in my garage now and something is still awry. There is no debris in the oil filter. The only solution i can come up with is the pulley and spacer have worn and the bolt has bottomed out, no amount of tightning will solve. Or the oil pump is goosed.
Worst case scenario is a rebuild and I've been suitably scared off from an independant for rebuild costs (£2000-£4000 not a realistic price!). I can source a new engine for £1200 with history. How long to fit @£60 p/h.
Never had to get my hands that dirty with any of my cars engine wise and only carried out basic maintenance. Looks like i'm going to be learning pretty fast. How muxh of the engine can you take apart with it in situ?
Worst case scenario is a rebuild and I've been suitably scared off from an independant for rebuild costs (£2000-£4000 not a realistic price!). I can source a new engine for £1200 with history. How long to fit @£60 p/h.
Never had to get my hands that dirty with any of my cars engine wise and only carried out basic maintenance. Looks like i'm going to be learning pretty fast. How muxh of the engine can you take apart with it in situ?
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