Low oil pressure

[Marian]

My car is burning a fair bit of oil and showing signs of low oil pressure, at hot idle the gauge reads 20psi although on acceleration the gauge jumps up to 60psi
Would this mean I need a rebuild? Car is a 96 4.2.

[Gazzab]

I am the worst person to give advice as I tend to get engines rebuilt if they are anything but perfect. But my view is that if you leave it then it might get worse and the rebuild might cost more.

[jbvipercerb]

When I first got mine the oil pressure was about the same as yours, a new oil pressure relief valve spring later and its about 40/45 at idle and 70/75 running both when hot.
As for oil consumption, when I used Mobil 1 it used loads, so the last service I changed to Valvoline 5/40 synthetic and it hasn't used a drop in a thousand miles.
Here's hoping!

[marcus1970]

Marian said:

My car is burning a fair bit of oil and showing signs of low oil pressure, at hot idle the gauge reads 20psi although on acceleration the gauge jumps up to 60psi
Would this mean I need a rebuild? Car is a 96 4.2.

Too low an idle can also cause low oil pressure.

If its idling around 1000 and the engine is fully warm, then first port of call would be oil pressure relief spring as above.

MB

[RUSSELLM]

jbvipercerb said:

When I first got mine the oil pressure was about the same as yours, a new oil pressure relief valve spring later and its about 40/45 at idle and 70/75 running both when hot.
As for oil consumption, when I used Mobil 1 it used loads, so the last service I changed to Valvoline 5/40 synthetic and it hasn't used a drop in a thousand miles.
Here's hoping!

On my 4.2, the dipstick is at the back, and I've noticed that when it comes back from service, the oil mark is a fair way above (max) on the dipstick.

Consequently, when the oil goes anywhere the middle mark of the dipstick, I tend to get zero oil pressure when turning left etc. Therefore I tend to use the "max" mark, as my minimum mark. I'm pretty certain the dipstick "over reads".

I agree, low oil pressure will be the spring.

My 4.2 has gone over the "1 litre every 1000 miles" point... In fact, with a bit of spirited driving & hot weather, it's more like 1 litre every 500 miles. I tend to find the oil goes Black as well.

The 4.5 hasn't used a drop in 2000 miles, and remains "honey" coloured.

I've been told the valve guides are most likely the cause of my oil usage, and to expect about £3k for a top end rebuild. That said, I'm most likely to wait for the next 12k service now, and see if I can try & combine the two.

[trooperiziz]

Marian said:

My car is burning a fair bit of oil and showing signs of low oil pressure, at hot idle the gauge reads 20psi although on acceleration the gauge jumps up to 60psi
Would this mean I need a rebuild? Car is a 96 4.2.

That's exactly the symptoms I had before I had mine rebuilt.

It's up to you if you think that is a good or bad thing