Oil Pressure

[Mike Walker 0]

My oil pressure has been reading progresively lower as times gone on. The oil has been going down but i've been topping it up to max whenever it needs it and I check the level about twice a week. At 4500rpm in fifth the needle used to point directly upwards but it now sometimes sits just above the second white line. The strange thing is that when you decrease revs in fifth and cruise at about 3000rpm or so the pressure often rises back up to the usual place ????

 

At idle the pressure reads more or less on the first white line (just above the red) which seems alright to me.

 

Any ideas as to why the pressures decreasing over time and why it would increase with less revs?

[Dino 3]

Sounds like your oil pressure switch is faulty.

 

I had a similar issue with mine and a new switch cured it. If you buy new then I would recommend you go to a Citroen dealers to buy one as they will supply you with the same part as Pug but MUCH cheaper.

 

Alternatively you can get one 2nd hand for peanuts. I'm sure someone on here will have one.

[Mike Walker 0]

Sounds like your oil pressure switch is faulty.

 

I had a similar issue with mine and a new switch cured it. If you buy new then I would recommend you go to a Citroen dealers to buy one as they will supply you with the same part as Pug but MUCH cheaper.

 

Alternatively you can get one 2nd hand for peanuts. I'm sure someone on here will have one.

 

It would be ace if it is just that as i've been getting increasingly concerned about big end bearings etc. etc. etc. (you know how your mind runs away with itself in these situations!)

[PumaRacing 1]

There is a known mechanical reason why oil pressure can actually fall at higher rpms contrary to all normal operation. A blocked pick up pipe in the sump. Strings of silicon or other debris blocking the strainer can allow enough flow at low rpm but cause oil starvation to the pump at high rpm. It certainly isn't a common occurence on most engines although some VW's are known to suffer from it quite often.

 

If a known good oil pressure gauge shows the same symptoms as the existing gauge then it could well be rebuild time, or at least sump-off time.

[dd_156ar 0]

Are the oil pressure guages in our cars very accurate? I assume, as they have no markings, that they are there to give a general indication but cannot replace a 'proper' oil pressure gauge?

Edited October 31, 2006 by dd_156ar

[dd_156ar 0]

Are the oil pressure guages in our cars very accurate? I assume, as they have no markings, that they are there to give a general indication but cannot replace a 'proper' oil pressure gauge?

 

Pumaracing - I think you have just answered my question for me. Posted this before I saw your reply!

[ada205 2]

If your gonna try a new sender, always worth giving the connetors a clean before buying a new one. I use to have a similar problem where my pressure would fall when accelerating, then rise when i backed off. Cause was simply oil and grime on the connecting tag that attached to the sender. This problem use to come back when things got grimey again, but a wipe of the spade on the sender and a squirt of wd40 and all was good again Worth a try before spending any money.

[Mike Walker 0]

There is a known mechanical reason why oil pressure can actually fall at higher rpms contrary to all normal operation. A blocked pick up pipe in the sump. Strings of silicon or other debris blocking the strainer can allow enough flow at low rpm but cause oil starvation to the pump at high rpm. It certainly isn't a common occurence on most engines although some VW's are known to suffer from it quite often.

 

If a known good oil pressure gauge shows the same symptoms as the existing gauge then it could well be rebuild time, or at least sump-off time.

 

Nasty man putting nasty thoughts in my head!

 

I'll start by changing the sender, then i'll try a new gauge (Mocal, Racetech or similar) then i'll s*it my pants and buy an Mi16 block when I realise my engine might be screwed

[Beastie 1]

My experience with various vehicles over the years has lead me to suspect the PumaRacing explaination as a likely cause of this problem in most cases. However the 205GTI is the nearest to being an exception to this rule The guage is very susceptible to doing this: It was really obviously a guage fault when it happened to my car because the gauge reading seemed to be related to throttle position rather than engine revs. The car lost oil pressure at anything over 3000 rpm on the motorway but as soon as I maintained a trailing throttle the oil pressure returned on the gauge. In other words there was no indicated oil pressure at 3000rpm with any significant throttle opening but at 4000rpm on a trailing throttle indicated pressure was normal. A new sender cured it.

 

The other frequent culprit for dodgy guage readings is a poor connection on the brown multiplug above the gearbox area.

 

I keep a callibrated bourdon tube guage and loads of fittings in the workshop. Usual practise is to tee it in alongside the guage of any car with low oil pressure readings to verify the instrument in the fascia before investigating any mechanical causes.

[Mike Walker 0]

My experience with various vehicles over the years has lead me to suspect the PumaRacing explaination as a likely cause of this problem in most cases. However the 205GTI is the nearest to being an exception to this rule The guage is very susceptible to doing this: It was really obviously a guage fault when it happened to my car because the gauge reading seemed to be related to throttle position rather than engine revs. The car lost oil pressure at anything over 3000 rpm on the motorway but as soon as I maintained a trailing throttle the oil pressure returned on the gauge. In other words there was no indicated oil pressure at 3000rpm with any significant throttle opening but at 4000rpm on a trailing throttle indicated pressure was normal. A new sender cured it.

 

The other frequent culprit for dodgy guage readings is a poor connection on the brown multiplug above the gearbox area.

 

I keep a callibrated bourdon tube guage and loads of fittings in the workshop. Usual practise is to tee it in alongside the guage of any car with low oil pressure readings to verify the instrument in the fascia before investigating any mechanical causes.

 

This description sounds suspiciously familiar. Euro Car Parts do the sender for £1.77 so i'll pop down there on Saturday to pick one up, hopefully this will solve the problem

[vince 0]

hi!

 

did you trace your oil leak?

I'm just wondering if your oil leak and pressure problem could be related... are you loosing oil internaly (valve seals) or externaly?

it may sound stupid, as I guess that if the leaks is coming from the pressure transmitter then you would notice it, but...

 

vince

[Mike Walker 0]

hi!

 

did you trace your oil leak?

I'm just wondering if your oil leak and pressure problem could be related... are you loosing oil internaly (valve seals) or externaly?

it may sound stupid, as I guess that if the leaks is coming from the pressure transmitter then you would notice it, but...

 

vince

 

I don't think they're related as when you top it up to max it doesn't change the pressure readings. There is a very slow leak from somewhere externally, just havn't investigated yet and am not that bothered about it to be honest.

 

I think it might well be the sender as the pressure on the way to work yesterday (motorway) was really bad and on the way back was really good with no logical reasoning for this to be the case.....

[vince 0]

it make sense... but it's better be the sender because I don't know if your engine will last long with such low pressure...

for comparison, on my 1.6, from 1986 and with 350000km, at idle I've slightly more than 2 bars (second line on the gage), and a steady 4 bars (3rd line) at and above 2000rpm.

 

vince

[Grim.Badger 15]

This description sounds suspiciously familiar. Euro Car Parts do the sender for £1.77 so i'll pop down there on Saturday to pick one up, hopefully this will solve the problem

 

I'm fairly certain that's the wrong part, it's the one that activates the big red STOP sign on your dash (sender), rather than the larger mushroom shaped one that runs the guage (sensor). iirc the sensor is about £27 from my local factors.

[Mike Walker 0]

it make sense... but it's better be the sender because I don't know if your engine will last long with such low pressure...

for comparison, on my 1.6, from 1986 and with 350000km, at idle I've slightly more than 2 bars (second line on the gage), and a steady 4 bars (3rd line) at and above 2000rpm.

 

vince

 

Is this a normal pressure reading for everyone else??

[Mike Walker 0]

I'm fairly certain that's the wrong part, it's the one that activates the big red STOP sign on your dash (sender), rather than the larger mushroom shaped one that runs the guage (sensor). iirc the sensor is about £27 from my local factors.

 

This is becoming a complete nightmare

 

On the way to work today I had some other issues with a horrible grinding noise that suddenly came and went away a few times and made the car shudder a bit and felt like it made it slow down a bit as well. I've decided to go all out and replace both front driveshafts and hubs (which I assume come complete with bearings) as well as both rear wheel bearing sets and the sensor so all in all very expensive and time consuming but I need the car to be fully reliable and safe for my 85 mile round trip to work and back every day

[vince 0]

did the grinding noise came only while driving, or did you also heard it at stop with the engine running?

at the first stage of wear the driveshaft should only be heard during turn (usually). to check them go to a parking turn the wheels to max steering angle and start driving forward and then backward, if you hear anything, then you can replace them...

for the wheel bearings, the noise is constant increasing with speed and stopping at rest.

and, the bearings can be extracted and replaced without having to replace the hubs...

 

if it helps...

 

vince

[Revla 2]

This is becoming a complete nightmare

 

On the way to work today I had some other issues with a horrible grinding noise that suddenly came and went away a few times and made the car shudder a bit and felt like it made it slow down a bit as well. I've decided to go all out and replace both front driveshafts and hubs (which I assume come complete with bearings) as well as both rear wheel bearing sets and the sensor so all in all very expensive and time consuming but I need the car to be fully reliable and safe for my 85 mile round trip to work and back every day

 

Wheel bearings don't come with driveshafts............

[Mike Walker 0]

did the grinding noise came only while driving, or did you also heard it at stop with the engine running?

at the first stage of wear the driveshaft should only be heard during turn (usually). to check them go to a parking turn the wheels to max steering angle and start driving forward and then backward, if you hear anything, then you can replace them...

for the wheel bearings, the noise is constant increasing with speed and stopping at rest.

and, the bearings can be extracted and replaced without having to replace the hubs...

 

if it helps...

 

vince

 

The driveshafts are definately gone quite badly, they make a loud knocking noise round corners.

 

The grinding was heard on the motorway at eighty going in a straight line, I had heard a slight amount of normal wheel bearing noise at times in the past but only very quietly, the kind of 'humming' sound. I've read a few threads using the search on here where people have heard this grinding noise and it has turned out to be a sudden and potentially dangerous failure of wheel bearings.

 

I was going to replace the hubs because I need to do the driveshafts anyway so thought I may as well fit 1.9 driveshafts and therefore I need to fit 1.9 hubs.

[Mike Walker 0]

Wheel bearings don't come with driveshafts............

 

I thought the wheelbearings might come with the hubs but have now found out that they don't with the particular hubs I was going to buy so have ordered a set of wheelbearings and am going to source second hand hubs.

[Owain1602 0]

I can vouch for blocked pick-up strainers causing low oil pressure at some engine speeds and normal pressure at other. Again it is quite common on VAG engines, we have had quite a few engines with this problem, most of them being the 20V turbo engines with unbelievable ammount of crap caught in the strainer in the sump.