AuthorTopic: Low oil pressure in 3.5 EFi  (Read 817 times)

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Offline paulmmc

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Low oil pressure in 3.5 EFi
« on: November 11, 2010, 16:11:08 »
After stripping the top end of my 1987 3.5 V8 Efi I can't manage to get the oil pressure back up, both the oil pressure warning light and my electric gauge are showing low pressure so I'm fairly happy it's not as simple as a dodgy pressure switch.

I have tried priming the oil pump with vaseline by removing the oil filter housing, taking out the two cogs and packing with vaseline, then putting the cogs back in so that there really is an much vaseline in there as i can manage then turned the engine over but still no pressure.

I also put a new pressure relief valve and spring in just in case it was that sticking open, although i don't think it was. However, i did notice that when the spring is at full extension the valve cylinder itself seems to stick in the closed position, though if this is a problem it should be causing high pressure if anything.

I've ran the engine fine and tried to get some warmth into the oil but it isn't working and obviously i don't want to run it for long with no oil. I'm using a 10w-40 so it is fairly thin stuff

I would greatly appreciate any tips or tricks for getting pressure back up, or any reason why i might be having problems?

Thanks, Paul
1981 Series III, Petrol SWB
1987 Rangie 3.5V8 Auto
(Both of the above soon to become one hybrid!)

Offline Range Rover Blues

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Re: Low oil pressure in 3.5 EFi
« Reply #1 on: November 12, 2010, 00:48:44 »
You can take out the dizzy and use an old screwdriver in a leccy drill to spin the pump over and prime the oilways.  What work did you do on the top end? there should only be one drilled hole going onto the head on each side, this feeds the rocker.  On the head gasket there is a steel washer with a tiny hole to provide resistance to this supply, if it is missing it could effect the oil pressure.
Can you see oil getting into the heads? you should see oil seeping out of the rocker shaft under the filler.
Blue,  1988  Range Rover 3.5 EFi with plenty of toys bolted on
Chuggaboom, 1995 Range Rover Classic
1995 Range Rover Classic Vogue LSE with 5 big sticks of Blackpool rock under the bonnet.