4.2 Oil pressure question

[cerby_mike]

Hi guys,

The oil pressure on my dad's 1997 4.2 reads at a constant rate (about 40-45psi I think) regarless of revs or temperature. It has just been to the dealers and they (allegedly) replaced the sensor but it has made little difference. They said they tested it on a seperate gauge and got 42psi, checked with the factory they said that was OK.

My question is, surely the oil pressure should vary between hot/cold, idle/high rpm? If so, what could be the problem?

Thanks

Mike

[davidd]

cerby_mike said:

Hi guys, The oil pressure on my dad's 1997 4.2 reads at a constant rate (about 40-45psi I think) regarless of revs or temperature. It has just been to the dealers and they (allegedly) replaced the sensor but it has made little difference. They said they tested it on a seperate gauge and got 42psi, checked with the factory they said that was OK. My question is, surely the oil pressure should vary between hot/cold, idle/high rpm? If so, what could be the problem? Thanks Mike

for the record, when cold mine is on about 62psi, it then drops to around 50 and I have seen it stray towards the mid 40's when sitting in traffic on very warm days.

D

[cerby_mike]

Does it vary between hot idle and hot high rpms though? That's the bit that really has me confused.

Mike

[trooper1212]

cerby_mike said:

Does it vary between hot idle and hot high rpms though? That's the bit that really has me confused. Mike

It should. How new is the engine? A well run in early cerb should have a fair amount of movement I'd have thought. A newer engine with less miles would have less movement?

My 96 4.2 Cerb is very free revving and has a 50psi difference between high and low revs when warm.

[cerby_mike]

It's very low mileage (about 8500 I think). Even so, I would have expected a certain amount of variation (every other car I've experienced does!!).

Cheers mate. Might suggest we visit another dealer with it to get a second opinion.

Cheers

Mike

[gazzab]

I had the same symptomns on my cerb - thought oh good I have got ok oil pressure but wait what is that noise and why is running badly ?! Oh the previous owner replaced the oil pressure relief spring but broke it off and shoved a new one on top. But if they say they have replaced it (I assume that is the sensor they refer to) then I would check the gauge. If that is ok then I would get it to an indie who knows his onions. eg APM or Joolz (the APM of the North).

[cerby_mike]

Cheers mate. I did tell my dad to get them to replace the relief spring after a previous thread on here. He suggested it but they didn't do it - it was the oil pressure sensor they replaced. Think it's time to visit someone else.

Cheers
Mike

[simonsparrow]

Pretty much every day when I start my car I have to give the oil pressure gauge a gentle 'tap' to get it to read full pressure.

Might be worth a go..... ;-)

[tvrslag]

My rebuilt 96 4.2 reads 70-75 psi when cold then goes down to about 55-60 psi when warm and drops down between 40-50 psi when hot and at idle. But like I said its only been 4000 miles since the rebuild which included a fully rebuilt and reconditioned oil pump.