Low oil pressure

[lidvii]

The oil pressure low light is coming on when the engine is warm and at idle.

The oil pressure low light stays lit when the engine starts from cold. It takes about 20 seconds to go out. The motor runs a lot quieter once the oil light goes out.

Could this be as simple as the pressure relief valve being stuck open? Or is it most likely the oil pump gears?

Or something else?

V8 3.5 rover motor 1988 stock.

[Homestar]

How many KM has the engine done?

Mine did the same after it clocked up 350KKM. Oil pump clearances would have been very bad, as was the rest of the engine, so I stuck a new one (engine) in it.

[Meccles]

These engines are known for low oil pressure, and associated issues.
How many km's on engine? Could be wear/age. Easy enough to fit new oil pump gears/and relief valve which is one way to go. Paul at Rover V8 Engines, Parts and Services from V8 Tuner (http://www.v8tuner.co.uk) sells gears etc and higher pressure relief valve springs, about 30 quid for gears. They have been good to deal with

[lidvii]

The motor has travelled a lot of miles. However the oil pump is a bit of an unknown. I fitted a second hand timing cover and oil pump. The gears looked okay but I guess not.

Does not look expensive for the new parts. I'd better order them up and get them fitted.

[Homestar]

In the meantime, use some thicker oil - it works well as a stop gap - I did this with mine,

[DoubleChevron]

check the oil pressure switch ... Is it weepy ? You oil pressure maybe ok, but the switch is on it's way out.

seeya,
Shane L.

[Pedro_The_Swift]

doesnt explain the noise change,,

[350RRC]

The motor has travelled a lot of miles. However the oil pump is a bit of an unknown. I fitted a second hand timing cover and oil pump. The gears looked okay but I guess not.................



You did pack the gears in the pump with vaseline to prime it, and used a drill with the dizzy out to see if it would make pressure before starting?

Could be all that's wrong, plenty of info if you search.

Chevs don't have these strange issues. TF

cheers, DL

[lidvii]

I primed the pump with petroleum jelly when I installed the (2nd hand) timing cover. I dont think the initial prime is the cause of the current problem.

I'm wondering if the pressure relief valve is stuck open.

I'll take it all to pieces and have a look.

[lidvii]

I fitted the 'old' oil pump gears, housing and pressure relief valve at the weekend. These were the ones that were on the engine before I replaced the timing cover and before this 'low oil pressure' problem started.

I'd say making this change has made little to no difference. The engine still rattles when cold and quietens down after the oil pressure light goes out. After about 20 seconds of running.

Once warm the oil light comes on at idle and goes out once the revs build.

Given the high miles that the engine has covered 335,000KM I know it is worn but this problem started only after I ran an engine flush and changed the oil. (Penrite HBR Gas 30 (20W-60))

Is it possible that the flush has somehow contributed to this issue?

Could the oil filter be defective? Does it have a non return valve?
Could the oil strainer in the sump be blocked? perhaps with debris from the flush)

Paul

[alien]

I did an oil change on my 3.9(280'km) and used a top end all sing you butte Penrite oil, bad move.
Same as yours I had the oil light on longer at start up and rattling in the lifters.
I swapped back to a basic Castrol oil, oil light out straight away and after a few days all went quite(only2X 6min runs a day to work).


Your flush may have freed up the lifters but my experience as above is it could take a little time to settle.

[PhilipA]

Could the oil filter be defective? Does it have a non return valve?


This is the most common cause of rattles at start up, and can happen with OEM filters or any of the common brands.
The non return valve can be faulty.
However I find usually the humble Ryco is as good as any.
Just change the filter and see if it helps.
Regards Philip A

[Bundy]

Just reread post the pickup could be blocked up a bit. How dirty was the inside of the engine?

Try some Castrol Edge 25W50 it works great in mine with 390K. I too was having the light come on at slow idle.

Paul

[Meccles]

Pretty hard to go past Castrol/Ryco combination. Just put a high quality Penrite in sons Subaru, it made strange noises, dumped oil and put Magnatec in, all noises gone. Have tried many brands over years but keep coming back to Castrol.

[lidvii]

I changed the oil and filter at the weekend. A new ryco filter and Valvoline 15w 40 oil.

The oil light goes out much quicker at start up. Now maybe 10 seconds.

It does still come on at idle but, if this makes sense, it is flickering and trying to go out. So I assume the oil pressure is closer to the minimum than it was with the Penrite 20w 60 oil.

[PhilipA]

With an engine with 335K, it is probable that the low oil pressure is caused by worn bearings.
However , I have rebuilt 2 engines with low oil pressure only to find it was a faulty sender. Yes I am a slow learner.
I suggest that you replace the sender before deciding to rebuild the engine as you should do that anyway. They are only cheap AFAIR.
It beats rebuilding the engine and starting up, only for the light to come on. ARRRGH!
Regards Philip A

[Bundy]

Valvoline 15w 40 oil is way to thin if you suspect your engine is worn!

[Homestar]

Valvoline 15w 40 oil is way to thin if you suspect your engine is worn!

Agreed, When my old Rangie engine was doing a similar thing - at similar KM, I stuck in some 20w 50 (I think - or 60) designed for old engines. Made a big difference and the oil light would then only flicker on the hottest days. I got 6 months more out of it before dropping in a new donk.