Oil Pressure Warnings

[JamieR07]

Hi guys!

i have an MGZT 1.8T and its developed a weird issue

if the engine has been running for 20-30mins the oil pressure light comes on, no noises no running problems or anything

if you rev it above 1k it turns off

leave it running for 10 more minutes and you have to rev it above 1.1k to have the light turn off

another 10minutes and 1.2k to turn off etc etc

anyone had anything similar?

plenty of oil and definitely the right grade used, no running issues when the light is on

many thanks
J

[SD1too]

Hello Jamie,

I would begin by activating the digital coolant temperature display to make sure that the engine isn't running too hot. Doing the "demist test" to check the engine fan would be a good idea too.

What grade of engine oil are you using?

Simon

[trikey]

I would suspect a failing oil pump, do an oil pressure test when cold using an analogue gauge then run it up to temp and see what reading you are getting.

If it is a failing pump, its only a couple of hours to fit a replacement.

[TourerSteve]

Originally Posted by trikey

I would suspect a failing oil pump, do an oil pressure test when cold using an analogue gauge then run it up to temp and see what reading you are getting.

If it is a failing pump, its only a couple of hours to fit a replacement.

To add to Trikey's post , Remove the sump pan and check the pick up strainer as it was only a couple of months ago that a members car seized with a blocked strainer

[JamieR07]

Hi!

I had no idea they had a digital coolant display!

What is the demist tests?

I'm using 10/40 fully synthetic



Thanks for all the replies guys, I'm going to test oil pressure this morning, what readings should i be getting from cold and then when it's at temp?


I'll also remove the sump and check out the pickup to make sure it's not blocked

[SD1too]

Originally Posted by JamieR07

Hi!
I had no idea they had a digital coolant display!
What is the demist tests?
I'm using 10/40 fully synthetic

Hi Jamie,

The digital coolant temperature display is part of the instrument pack diagnostics. It's test number 7.0. Quick reactions are needed when setting it up so don't worry if it takes you a few attempts.

Expect the temperature to be in the low nineties when driving, rising no higher than 104˚ when the car is stationary.

The "demist test" is as follows:

1. Start the engine from cold.
2. On the air con./heater control panel press the windscreen demist button. The blower will start at full speed.
3. Get out of the car and walk to the radiator grille. Is the fan running continuously? It should be.

These are simple tests to rule out common problems before you dive in with spanners flying everywhere.

For your 1.8T engine, RAVE gives the oil pressure as 4.0 - 4.2 bar (58 - 61 psi) at 1,000 rpm. There's also a low oil pressure switch which could be on your list.

Simon

[JamieR07]

Originally Posted by SD1too

Hi Jamie,

The digital coolant temperature display is part of the instrument pack diagnostics. It's test number 7.0. Quick reactions are needed when setting it up so don't worry if it takes you a few attempts.

Expect the temperature to be in the low nineties when driving, rising no higher than 104˚ when the car is stationary.

The "demist test" is as follows:

1. Start the engine from cold.
2. On the air con./heater control panel press the windscreen demist button. The blower will start at full speed.
3. Get out of the car and walk to the radiator grille. Is the fan running continuously? It should be.

These are simple tests to rule out common problems before you dive in with spanners flying everywhere.

For your 1.8T engine, RAVE gives the oil pressure as 4.0 - 4.2 bar (58 - 61 psi) at 1,000 rpm. There's also a low oil pressure switch which could be on your list.

Simon

Thank you so much!

I'll rip the sunp off and check that first since there's no harm in cleaning the pickup and resealing the sump!

then run these tests and post back with what I've found

Many thanks

[JamieR07]

So I've pulled the oil pressure sensor plug off and it's covered in oil, woth a small leak of oil from sensor

I haven't taken the sensor off, I've just unplugged it

Hopefully its just a sensor!

Checked the oil pressure while i was there, it started at 60 from cold, it dropped to about 50ish PSI as the engine is heating up

Should it stick around 50ish or will it change as it gets warmer?

Now its warmed up its sitting at 30PSI

i imagine that's too low?

[stocktake]

My understanding is that low oil pressure switches operate below 10 psi in general ( 0.68bar). Usually by the time the light comes on the damage is done. As you are saying you have 30psi then I would suggest the sensor is the problem. Haynes says low oil pressure light comes on 0.2 to 0.6bar yours appears to be on at 30psi which is a little over 2bar

[JamieR07]

Originally Posted by stocktake

My understanding is that low oil pressure switches operate below 10 psi in general ( 0.68bar). Usually by the time the light comes on the damage is done. As you are saying you have 30psi then I would suggest the sensor is the problem. Haynes says low oil pressure light comes on 0.2 to 0.6bar yours appears to be on at 30psi which is a little over 2bar

Ahh interesting!

Thank you so much for this information, you've been a great help!

Should i be concerned that the pressure was steadily dropping or is there somewhere i can get the recommended readings?

Many thanks!