Oil Pressure Light

So...When my car gets to normal running temperature. The oil pressure light comes on. It only comes on when idiling...Just changed the oil, been checking it regularly and it is full. I read that sometimes the o-ring on the oil-pressure switch goes out, so I ordered a new one that I'll be installing this weekend. Does this sound about right, or should I look into the oil-pump?

i have seen oil pressure relief valves get stuck open before, the other thing to look at is the big end and main bearings, also make sure the pressure is down and its not just the switch playing up

Where is the oil pressure relief valve exactly? Its on a 4.0

all in the same place lol, its part of the pump housing on the from of the timing cover, my cousins bobtail disco used to stick open if you gave it a clout with a lump of wood and it would sort its self out

Thanks G-Man...While I've got ya here...Have you ever done a head gasket job on a rover before? mine's blown. Just ordered the top-end rebuild kit today. Looks like it won't be too incredibly difficult(only time will tell) just looking for pointers/tips...Thanks

Hi,

You might want to read www.landyzone.co.uk/lz/f10/v8-engine-problem-58167.html

I am going through this one and its a night mare. I have had no choice but fit a new lump in mine. (AGAIN) as I have replaced ever component on the engine and rebuilt the entire thing again and am still getting low oil pressure at tick over.

If you think your switch is okay then as a tip, listen to the engine and when the oil light comes on the top end should start to tap slightly as the followers start to close up.

Hope this helps

Bryan

Was the oil light coming on when cold as well? Don't know if it makes a difference, but mine only comes on when fully warmed up at idle?

Yep,

same as mine. only comes on when engine is warm.

great...I was hoping it would be a quick fix...Still might be. Who knows. What would you recommend checking 1st to see if this is the same problem you had...I'm really hoping its not

bboulan said:

So...When my car gets to normal running temperature. The oil pressure light comes on. It only comes on when idiling...Just changed the oil, been checking it regularly and it is full. I read that sometimes the o-ring on the oil-pressure switch goes out, so I ordered a new one that I'll be installing this weekend. Does this sound about right, or should I look into the oil-pump?

Click to expand...

Try new switch first. But odds on it's main bearings.

Main bearings eh? What would I be looking at to fix that?

yeah mate it ur oil pressure switch change that if not that change oil filter then go for ur oil cooler pipes they may be kinked my bets are the pressure switch common fault

bboulan said:

Main bearings eh? What would I be looking at to fix that?

Click to expand...

If the crank is nitrided, new shells B/end and Main and an oil pump may give you a result for a while. If the crank is damaged a regrind.

The handbook says that the oil pressure light coming on at idle when hot is normal but should go out when engine speed increases. Bear in mind that it is a long crank on the V8 and more oil spillage past the bearings occurs which drops the pressure. If the engine is stripped for a rebuild, oversize thrusts should be fitted to give minimum end float of the crankshaft and thus less spillage. Although my P38, 4.6 does not have the light on, a previous 3.5 Disco and Rover P6,V8, 3.5 did and they both ran sweet

Yeah. It doesn't tick or sound like anythings wrong. I'm just gonna change out the oil-pressure switch, check out the relief valve and also examine the oil pick-up..I don't have an oil-pressure gauge, so I don't know what psi its running at idle? What should it be at idle? anyone know?

According to rave, the oil pump should be able to give 25psi of pressure at idle and at hight revs 55psi of pressure. this is the point that the relief valve opens in the front cover. To take the releif valve out is a real nightmare with the front cover attached to the car. There are 2 fitted one is above the oil filter and if you were to slip the oil filter off and look up into the front cover you will see the spring. This valve opens should the oil filter become blocked. allowing oil to bypass the filter and go streight into the oil coller. the other one is on the right hand side of the front cover. thats the one which sticks normally.