Disco 96 V8 oil pressure

[gkm24]

I have a 96 Discovery with the 3.9 V8 serpentine engine. When running it is smooth, powerful and very quiet. When I initially start it in the morning, the oil pressure light stays on for up to 6-7 seconds and the tappets are really rattley and then it all goes ultra quiet and is fine for the rest of the day. I have not checked to see what the actual oil pressure is yet but I'm wondering if there is an oil non return valve fitted which has failed which lets the oil escape back into the sump. Although I am a BMW technician, I have little experience with Rover V8's and there fore ask for any info on this subject. Many Thanks.

[landi41]

I have a 96 Discovery with the 3.9 V8 serpentine engine. When running it is smooth, powerful and very quiet. When I initially start it in the morning, the oil pressure light stays on for up to 6-7 seconds and the tappets are really rattley and then it all goes ultra quiet and is fine for the rest of the day. I have not checked to see what the actual oil pressure is yet but I'm wondering if there is an oil non return valve fitted which has failed which lets the oil escape back into the sump. Although I am a BMW technician, I have little experience with Rover V8's and there fore ask for any info on this subject. Many Thanks.

I've been around a lot of 4.0.... V-8's ( basically the same as a 3.9 ) anyway i've seen these engines abused to the point of pain.......

I don't know where you live or what your ambient temperatures are.... but i would consider changing the filter and going over to a single weight oil, SAE 30 for starters and the see what happens next.....If you are in a really warm climate, then go to SAE 40

As a retired pilot, i have had many hours on air cooled engines where at times (many times actually) where we ran on Aero Shell 100.. that is a 50 weight oil........

I know this didn't answer your initial question..but yes, all Land Rover engines have some sort of oil pressure relief mechanism, usually a ball and spring arrangement (check your manual) but in my experience over the years, with many different types of LR engines, this has never been a source of low oil pressure..........

Worst case scenario, if you have a decent running engine.... but the oil pressure thing bothers you...order up a set of new standard crank and con-rod bearings and change what you can in situ.... actually if it were me, .... i'd just change the con-rod shells.........

Good Luck with it..........

My BMW connection? I have owned and raced the bikes for over 40 years

[discojmz]

interestingly enough, on a 4x4 is born they get the same low pressure light on due to that self same valve sticking. could certainly be worth a look.

this is me assuming you have actually checked your oil level in the sump already

[teabag]

You have two things to look at and may and maynot be related 1. Rattley tappets and 2. Oil pressure light.

1. Oil should remain within the hydraulic tappets overnight, it will remain for months. I suggest u change the oil and fill up with the correct grade or maybe use a higher/thicker grade depending on the mileage of the engine.

2. If the engine has done a high mileage then the pressure relief valve assembly may be excessive worn check the valve for fit ie no side movement or any scoring also check the spring for wear on the sides, the valve and spring are located behind the hex bolt on the side of the oil pump.

Also may be worth changing the oil pressure switch also when u change the oil and filter.

regards