Oil pressure problem 3200 - auto box

[Bart3200GT]

Hi guys,

After taking the Mas in for a works carfest (beautiful hot and sunny day and LOADs of lovely vehicles) and then a rapid drive home, the oil light popped up on the dash and I noticed that the oil pressure gauge had dropped down to 2 bar (with that round red warning light) on as well - throughout the drive home this would bounce up and down the gauge.

The engine sounded ok, no lack of performance.

I did some investigation on the forum and it appeared that it could have been the oil pressure sender.

So with not a lot of time available I had her booked into a local independent jaguar and Ferrari garage to have a new one fitted.

Had a phone call from him yesterday saying it was fitted but there was no difference. I asked what it could be and he was unsure - possible major engine problems!!!!

On picking it up this morning and driving her back - I was trying to see if what would happen under different loads.

In all gears under load it would go up to 5 bars - off load drop to 2.5 bars and lower. Third gear it would stay around the 2.5 bar

Then (there is a rcy issue) after taking her up the rev range the rcy light came on (3rd gear) - instantly on the oil pressure gauge it hit 5 bar, oil light went out.

The rcy light went out, the oil pressure light came back on and the pressure dropped to 2.5 bars and slowly dropped.

The question is -

Are the gear box / oil and engine oil related in any way i.e. connected electrically? Was it just the fact the revs were high and dropping into 3rd allowed the pressure to build up?

It’s recently been in for a major service where the gearbox oil and filter was changed - could it be a low gear box oil level?

I’ve also read it could be the oil switch or wiring around the turbo and engine bay.

I look forward to hearing what you all have to say

Regards

Bart

 

[Contigo]

It could be a few things namely oil pressure sensor which you have changed or the actual gauge itself. Manual cars suffered from endfloat problems (Autos too but to a lesser extent) and a check for this is if the oil pressure drops when you press the clutch.

 

[safrane]

What oil did the service centre use? Was it the correct grade?

 

[davy83]

engine oil and gearbox oil are not connected, physically or electronically. So if you have a gearbox problem and an oil pressure problem they are separate. Grade of oil is worth a look as the correct oil is specifically designed to maintain viscosity at high temperatures and with the oil lubricating the turbo bearings the oil gets very hot. So wrong oil will make it loose pressure when hot. oil pumps are not known for failure but its possible, and as mentioned it could be end float or internal engine problems. i would also check the wiring and the connector around the oil pressure sensor, as the wiring can be prone to bad contacts.

 

[Bart3200GT]

I believe that the grade of oil used looking at the receipt was fully synthetic 10w 60 motor oil.

This latest garage said they checked the wire which joined to the sensor (approx 3 inches and it seemed ok)...but they dont know what its like around the turbo without taking the turbo out...

Took it out for a bit of a drive - and the gauge is up and down...sitting mainly at about the 2bar position, but then all warning oil lights clear - up to 5 bar..then down to 2.5 bar and so on..also noticed this turning right

The outside temp was 29 degrees.....and not alot of air.

Thanks for your expertise so far - cheers

 

[Bart3200GT]

It could be a few things namely oil pressure sensor which you have changed or the actual gauge itself. Manual cars suffered from endfloat problems (Autos too but to a lesser extent) and a check for this is if the oil pressure drops when you press the clutch.

In neutral - handbrake on - the pressure shows 2 bar - lit oil pressure lights

 

[hodroyd]

It would make me think Oil Pressure Sensor by the sound of it..!! What type did they fit, they are a sod to get in and replace, are you certain it has been done..??
We had a similar problem on our AC and it was the sender, as said, it is a sod to get at, right at the back of the engine and special tools are needed to get it replaced..!! If you put your head under the bonnet, right at the rear of the engine in the middle, you should be able to see it, make sure it's a new one and connected correctly..!!

 

[Bart3200GT]

I have to say that I did forget to ask him for the part...but he said that it has been replaced.

 

[highlander]

I'm no expert in these by any means but since you noticed it after the service but before the new sensor was fitted (providing one has been fitted which seems likely at a specialist) then the problem lies elsewhere imo. phil suggested the gauge so might be worth exploring that once you completely rule out the new sensor failing also.

 

[conaero]

The main concern is endfload.

To check this, get someone to pump the clutch (I assume its a manual) and watch the front lower pulley on the end of the crank for movement.

Also, with the car running press the clutch and see if this is consistent with the drop in oil pressure.

If either of the above are a yes, you need to take it to a garage to have the enfloat measured, a simple procedure.

Once you know the end float is ok and the you have replaced the sender, you can start inspecting the wiring (as it goes cripsy from the heat) and the gauge and bridge cann unit.

I would personally take it to Emblem in Poole for them to take a look at it.

 

[highlander]

I'm assuming it is an auto matt given thread title.............have you started the bottle early?

 

[Contigo]

In neutral - handbrake on - the pressure shows 2 bar - lit oil pressure lights

Then it is wrong, they should be 4 bar or 5 bar on idle in neutral or with the clutch depressed.

I would check wiring to the actual sensor/sender first as said then check the gauge as they are notoriously bad.

 

[BennyD]

I would get them to put a mechanical pressure gauge on the engine in place of the electrical one. Fire it up, let it get hot and watch what the pressure does. That's what Marios did with mine when I was having problems a couple of years ago. It showed 7 bar when cold and dropped to 3-3.5 bar when hot whereas the one on the car was showing 3 bar when cold and 0 when hot. It was, apparently, a problem with an engine earth.

 

[hodroyd]

They only idle at 5 bar'ish when cold, when hot it's normal to idle at about halfway, or thereabouts..!!

 

[conaero]

I'm assuming it is an auto matt given thread title.............have you started the bottle early?

Ah, I think that Auto Box but has been added since I replied.

As for starting early I bought 8 Fosters Radlers as they where on offer only to find they are 2%! Taste nice though, basically cloudy lemonade shandy.

 

[Bart3200GT]

The main concern is endfload.

To check this, get someone to pump the clutch (I assume its a manual) and watch the front lower pulley on the end of the crank for movement.

Also, with the car running press the clutch and see if this is consistent with the drop in oil pressure.

If either of the above are a yes, you need to take it to a garage to have the enfloat measured, a simple procedure.

Once you know the end float is ok and the you have replaced the sender, you can start inspecting the wiring (as it goes cripsy from the heat) and the gauge and bridge cann unit.

I would personally take it to Emblem in Poole for them to take a look at it.

Thanks for the info - its an auto box

 

[Bart3200GT]

Thanks for your answers guys -

I'll get her booked in.

 

[Contigo]

Mine had a funny minute doing exactly this today which was spooky! Turned engine off and was fine after that, just put it down to the usual quirkiness! Hopefully!

 

[Bart3200GT]

Im looking out for a oil pressure gauge first to see if that is the problem - as it started behaving herself last night, but still bouncing around. Ive also seen it can be down to a bad earth - if thats right or wrong.

 

[tom27]

Firstly : - Measur oil pressur with an external gauge .=> it its different, check the wire and gauge .
Secondly : - Check in old oil or in the OIL SUCTION ROSE Grill if you find alu deposit (sign of wear Thrust bearing) + Check the Hight Pressur valve on oil pump ( may cause low pressur if it always open)
Thirdly : - Measur with a DTC the endfloat of crank. => if it is too hight , replace all thrust bearing or/and rebuild the crank ( If crank weared : rebuild it by a specialist and take the good size of Thrust bearing grade A, B or C)

Many people say if endfloat is bad, you must replace engine. but is wrong . You can repair the crank ;-)