Oil pressure problems

[wayno]

The oil pressure light illuminated whilst i was driving home last night in my 1990 range rover 3.9.

I stopped as soon as i could, checked oil level all seemed ok. Restarted engine sounds fine no loud rattles etc. I then removed the filler cap and there doesnt seem to be a great deal of oil around the valvetrain, not dry but not as much as i would expect to see.

Are there any common faults that i should check first or is the pump kippered.

[sidecar]

The oil pressure light illuminated whilst i was driving home last night in my 1990 range rover 3.9.

I stopped as soon as i could, checked oil level all seemed ok. Restarted engine sounds fine no loud rattles etc. I then removed the filler cap and there doesnt seem to be a great deal of oil around the valvetrain, not dry but not as much as i would expect to see.

Are there any common faults that i should check first or is the pump kippered.

There never is much oil visible round the valve train, you can see puddles of it when the rocker covers are removed.

It could be that the pressure relief valve in the pump has stuck open, if your pump is like mine then its easy to get to and check.

I certainly would not use the car until the problem is sorted out.

I only really know about the pre-serp 3.5 SD1 lumps, Im not sure what varriation of RV8 you will have under your bonnet.

Pete

[wayno]

Mines definatly not a serpentine engine. The oil does look fairly black so im going to change that tommorow.

I think ill change the pressure switch and the pressure relief valve too and see what happens.

Surely if there was no oil pressure at all the lifters would be very noisy ?

[jrv8]

Hi,
If the lifters are quiet, then you should have pressure, I would try an oil pressure switch first.

Jim

[sidecar]

Mines definatly not a serpentine engine. The oil does look fairly black so im going to change that tommorow.

I think ill change the pressure switch and the pressure relief valve too and see what happens.

Surely if there was no oil pressure at all the lifters would be very noisy ?

I guess they would be very noisy if there was no pressure at all. I'm not sure if the pressure will drop to zero if the relief valve is stuck open, it would certainly go very low at low RPM.

The really safe way to check what's going on would be to remove the dizzy and spin the pump with a priming tool whilst one of the rocker covers is removed, if you spin the pump for quite a while you should see oil starting to run down the pushrod holes back into the valley. If you removed one of the rocker shafts and its supports oil should come shooting up one of the holes that the removed support has now exposed.
It only four extra bolts to take the rocker assembly off.

Taking the dizzy off will allow you to check the drive gear!

An oil pressure gauge would also be useful!

I guess the you might still get some oil flow when spinning the pump even if the pressure relief is stuck open so I'd check that first along with the switch.

The problem with removing the dizzy is resetting the timing but at least you can spin the pump without fear of wrecking the engine.

good luck,

Pete

[wayno]

Thanks for the advice chaps ill look into it tommorow.

Hopefully it wont be too serious, fresh oil, pressure switch and a new relief valve. Fingers crossed this should get it sorted. Ill post up how i get on.

At what pressure would the switch illuminate the light then ?

Just a little worried that i may have starved the engine of oil which may cause future issues ?

[sidecar]

Thanks for the advice chaps ill look into it tommorow.

Hopefully it wont be too serious, fresh oil, pressure switch and a new relief valve. Fingers crossed this should get it sorted. Ill post up how i get on.

At what pressure would the switch illuminate the light then ?

Just a little worried that i may have starved the engine of oil which may cause future issues ?

I think they go off at about 10 psi. (That is why on some "lose" engines the light can flicker on at tickover). You maybe able to rig up a foot pump and some hose to pressurise the thing whilst measuring across the contacts.

They are pretty tolerant these lumps, hopefully you be OK. Just make sure you fix the issue if it isn't the switch before you fire the lump up!


Pete

[RoverP6B]

The oil pressure warning light will come on when the pressure on the outflow side of the oil pump falls to a maximum of 10psi or to a minimum of 8psi, then stays on till the pressure increases.

The pressure relief valve will typically only open when the oil pressure reaches 60psi or so. Unless you were using high revs, ie more than 3000 with a stone cold engine it is unlikely that sufficient oil pressure would have been reached in order to open the valve, and then of course it would have to remain open.

At idle, with the pressure relief valve open, oil pressure will be next to zero, and unless the engine is shut down pretty well straight away, expensive damage, especially to the bearings will result.

My Rover P6B has an oil pressure gauge, and warning light, and on two occassions in the last 22 years the oil light has come on, but the gauge showed more than 30psi pressure. On replacing the oil pressure warning switch, the problem was solved.

Start with replacing the switch, and progress from there if need be.

Ron.

[Pocket rocket]

If it helps, this is what my engine looks like with no rocker cover and very good (indicated oil pressure)
[/URL][/img]

Very little oil visible at the top end

[wayno]

Just like to say chaps a new pressure switch and fresh duckhams today and shes sweet as a nut.

Examined the oil that was drained was very black, well past its sell by date but no metal swarfing so im guessing it never lost pressure.

Again thanks for the advice

[sidecar]

Just like to say chaps a new pressure switch and fresh duckhams today and shes sweet as a nut.

Examined the oil that was drained was very black, well past its sell by date but no metal swarfing so im guessing it never lost pressure.

Again thanks for the advice

Glad that it's sorted out!

I must admit that I do tend to jump the the worst conclusion possible, I think it stems from my racing days, if something went wrong, it was always bad news and it always cost a bomb to sort out!

It was probably just the switch! (An oil change never does any harm though!)

Pete

[sidecar]

[quote="Pocket rocket"]If it helps, this is what my engine looks like with no rocker cover and very good (indicated oil pressure)
[/URL][/img]

Very little oil visible at the top end[/quote

Just ran your vid, I'm not sure if its something to do with the way that its recorded but the valve action looks really odd to me! (Please don't take this the wrong way, I'm sure that its me just being a dimwit!)

The valves seem be opening and then partically closing again for each lift cycle, did it look like that when you are watching the rockers?

Pete

[Pocket rocket]

You're right - it does look weird.

Vid was taken some time ago but engine has run fine.

Anyone got any ideas?

PS Just checked - vid was taken March 2006. Engine has done many miles since then and doesn't appear to have any problems but the vid does seem to show the rocker arms doing a double tap.


Opinions as to whether this is something I should worry about

[katanaman]

It will just be the video, half the frames will be chopped out to compress the size of it so your not seeing all the video which causes a kinda strobe effect. Watch a movie with cars in it and odds on you will see the wheels go backwards, obviously in reality they aren't.

[sidecar]

It will just be the video, half the frames will be chopped out to compress the size of it so your not seeing all the video which causes a kinda strobe effect. Watch a movie with cars in it and odds on you will see the wheels go backwards, obviously in reality they aren't.

I'm sure your right. If the valves were really doing what they look like there doing (i.e opening and closing about 4 times per cycle) then the engine would not be running!