Oil pressure rising when accelerating!

[IanLWarrington]

Hello all,

Not sure if I've just not noticed this before but, yesterday, when I accelerated to around 5,500 revs, I noticed the oil pressure gauge rose to around 5. At idle or 'normal' revs, it returns to a healthy 3.

Is this a sign of a problem to come?

If I blip the throttle I notice an associated slight small rise in the pressure.

Be gentle with me if it's not good news,

Best regards

Ian

[Woody VT]

IanLWarrington said:

Hello all,

Not sure if I've just not noticed this before but, yesterday, when I accelerated to around 5,500 revs, I noticed the oil pressure gauge rose to around 5. At idle or 'normal' revs, it returns to a healthy 3.

Is this a sign of a problem to come?

If I blip the throttle I notice an associated slight small rise in the pressure.

Be gentle with me if it's not good news,

Best regards

Ian

How warm was the engine? How hard was the acceleration?

[_AJ_]

From memory <sob>, and when warm, oil pressure was about 2.75 at idle, and got to maybe 3.25 ish with revs. Never seen it up the top there.

[IanLWarrington]

Thank you for the rapid responses

Engine was hot yesterday (showing normal temperature after a long run) when I noticed it go right up - engine was cold this morning when I 'blipped' the throttle and it just edged 3.25.

I did do a bit of 'Googling' and forum's responses range between "this is normal" (which would be great wouldn't it) to "this could be a sign that the pump is on the way out" or a "problem with the pressure release valve".

Ian

[Woody VT]

I would say the pump is fine, after all its generating pressure!
The relief valve is where I would look, personally.
How old is the oil and filter? How regularly is the car used?

The relief should operate at 52PSI (So about 3.5 BAR). The only reason, pressure should climb much beyond that is:

A) Oil temp is low and therefore it's thicker and harder to move (even when the relief operates) which is why we should be taking it easy on a cold engine until oil temp is at operating temp.

B) There is a flow restriction so a blocked galley/clogged filter/sludgey oil

C) The relief valve isn't operating correctly

My first point of action would be an engine flush followed by an oil and filter change as this is cheaper than getting into mechanics.
Use a mechanical gauge on the pressure side of the pump, after the relief to rule out the dash gauge. It's unlikely to be faulty but better to rule it out.
Look at the relief valve next. Change it and see what happens.
If that doesn't work, sadly things get expensive.

Edited by Woody VT on Wednesday 6th April 10:09

[IanLWarrington]

Woody VT said:

I would say the pump is fine, after all its generating pressure!
The relief valve is where I would look, personally.
How old is the oil and filter? How regularly is the car used?

The relief should operate at 52PSI (So about 3.5 BAR). The only reason, pressure should climb much beyond that is:

A) Oil temp is low and therefore it's thicker and harder to move (even when the relief operates) which is why we should be taking it easy on a cold engine until oil temp is at operating temp.

B) There is a flow restriction so a blocked galley/clogged filter/sludgey oil

C) The relief valve isn't operating correctly

My first point of action would be an engine flush followed by an oil and filter change as this is cheaper than getting into mechanics.
Use a mechanical gauge on the pressure side of the pump, after the relief to rule out the dash gauge. It's unlikely to be faulty but better to rule it out.
Look at the relief valve next. Change it and see what happens.
If that doesn't work, sadly things get expensive.

Edited by Woody VT on Wednesday 6th April 10:09

Had the oil changed in February at Monkfish (along with a 10k service + all other oils changed (5 year recommendation)) so oil should be OK.

Car is used regularly and, in fact, I've been on holiday for the last week and a half so did about 1,000 miles in the last 10 days or so.

Re running temp, I am very careful to ensure car is warm before increasing revs - and I'm pretty gentle with it in general.

So, discounting the pump (I agree with your assumption that this is unlikely to be the cause) looks like a check on the relief valve.

A trip to chums in MW Performance (Chester) looks to be in order (Milton Keynes is just a bit too far - only for 'special occassions').

Fingers crossed it's nothing too serious or expensive - I'll also take her out for a run tonight to doubly check the corellation between revs and pressure reading and I'll post the actual figures - the more I think about it and on reflection, I'm pretty convinced that this only started happening yesterday - I noticed it straight away and can't believe that I would have missed it.

Best regards

Ian

[monkfish1]

Dont forget its oil temp that is important. This lags considerably behind coolant temp. Sadly Monaro does not have a gauge for oil temp. Its perfectly possible for coolant temp to be up, but oil still to be quite cold. In which case as suggested above pressure will rise beyond the relief valve setting.

If the oil is hot, then really, cant be much else than a sticking relief valve.

[Woody VT]

IanLWarrington said:

Woody VT said:

I would say the pump is fine, after all its generating pressure!
The relief valve is where I would look, personally.
How old is the oil and filter? How regularly is the car used?

The relief should operate at 52PSI (So about 3.5 BAR). The only reason, pressure should climb much beyond that is:

A) Oil temp is low and therefore it's thicker and harder to move (even when the relief operates) which is why we should be taking it easy on a cold engine until oil temp is at operating temp.

B) There is a flow restriction so a blocked galley/clogged filter/sludgey oil

C) The relief valve isn't operating correctly

My first point of action would be an engine flush followed by an oil and filter change as this is cheaper than getting into mechanics.
Use a mechanical gauge on the pressure side of the pump, after the relief to rule out the dash gauge. It's unlikely to be faulty but better to rule it out.
Look at the relief valve next. Change it and see what happens.
If that doesn't work, sadly things get expensive.

Edited by Woody VT on Wednesday 6th April 10:09

Had the oil changed in February at Monkfish (along with a 10k service + all other oils changed (5 year recommendation)) so oil should be OK.

Car is used regularly and, in fact, I've been on holiday for the last week and a half so did about 1,000 miles in the last 10 days or so.

Re running temp, I am very careful to ensure car is warm before increasing revs - and I'm pretty gentle with it in general.

So, discounting the pump (I agree with your assumption that this is unlikely to be the cause) looks like a check on the relief valve.

A trip to chums in MW Performance (Chester) looks to be in order (Milton Keynes is just a bit too far - only for 'special occassions').

Fingers crossed it's nothing too serious or expensive - I'll also take her out for a run tonight to doubly check the corellation between revs and pressure reading and I'll post the actual figures - the more I think about it and on reflection, I'm pretty convinced that this only started happening yesterday - I noticed it straight away and can't believe that I would have missed it.

Best regards

Ian

Good luck. I hope it's a simple (and cheap) fix

[IanLWarrington]

Many thanks Woody,

And, apologies to you Roger for not dropping you guys a line thanking you for the excellent service and advice you provided in February when I was down there.

When you say 'sticking', is it possible that it could be 'unstuck'?

I'll certainly make sure it's hot tonight before carrying out my test - not too severe though - don't want anything to pop!

Ian

[monkfish1]

IanLWarrington said:

Many thanks Woody,

And, apologies to you Roger for not dropping you guys a line thanking you for the excellent service and advice you provided in February when I was down there.

When you say 'sticking', is it possible that it could be 'unstuck'?

I'll certainly make sure it's hot tonight before carrying out my test - not too severe though - don't want anything to pop!

Ian

It may unstick, but sticking relief valves are not good. When they stick open, you have NO oil pressure at low rpm!

I suspect that there is nothing wrong with it. just wants the oil hot.

[Woody VT]

IanLWarrington said:

Engine was hot yesterday (showing normal temperature after a long run) when I noticed it go right up - engine was cold this morning when I 'blipped' the throttle and it just edged 3.25.

Ian

The oil must have been up to temp after a long run. Not wanting to scaremonger but I think it's more than oil temp having read the post.

[IanLWarrington]

Thank you Roger - as Woody says, I think it was pretty hot.

I'll PM you if that's OK to check the price for a replacement valve.

Remember to let me down gently though.

:-)

Regards

Ian

[monkfish1]

IanLWarrington said:

Thank you Roger - as Woody says, I think it was pretty hot.

I'll PM you if that's OK to check the price for a replacement valve.

Remember to let me down gently though.

:-)

Regards

Ian

OK, sadly comes with an oil pump attached though. It is strippable though, so maybe can just be lapped in.

Cost will be in getting to it, not the parts.

[IanLWarrington]

monkfish1 said:

OK, sadly comes with an oil pump attached though. It is strippable though, so maybe can just be lapped in.

Cost will be in getting to it, not the parts.

Bump!

:-(

[ARAF]

That sounds similar to how our VXR8 gauge is. I don't pay much attention to is, as it's always been like that, so it could just be that the gauge is reading high. How many miles have your Monaro done?

Could the gauge have always been like this and you've only just noticed it? If so, I'm not sure I'd worry too much.

[IanLWarrington]

Hi Araf,
Thank you for the response - car's only done 31k. I'd like to think that this is 'normal' but it seemed so noticeable when I noticed it (if that makes sense) I can't help thinking it's not been happening before.
I noticed on the way home from work tonight that the needle was 'wavering' a bit between just under 3 and over 3. Again, haven't noticed this before but you could be right that i'm now over sensitive.

I'll see how it goes for the next day or so - looks like it's gong to cost me though if I do need to have it done - apparently "a few hours work".

:-(

Again, thank you for the supporting words,

Best

Ian

[slippery]

I'll check mine today after reading this!

[slippery]

Don't know what to think now! At 105 degrees, I'm ticking over at 2.3 and swing straight round to 5 at 5,500 rpm? It would appear you're not alone, although everything sounds and feels fine and like the op, I had a Monkfish service not too long ago.

[liam1986]

drove my to work this morning.

cold idle 3bar

hot idle 2bar

didn;t do any cold 6,000 rpm

hot (after 10-12miles) either normal crusing or taking it to red line, never went much over 3 bar

could it just be that your oil pressure senser is on it way out?

Edited by liam1986 on Thursday 7th April 11:15

[eztiger]

And presumably this is all for vxr and vxr8 owners who have the luxury of a pressure gauge?

If you were in a cv8 you wouldn't have this info to worry about. Can't say I pay much attention to it, I had enough 'must check oil pressure gauge every 2 seconds' issues with my last car.