high oil pressure ld28

Discuss (and cuss) the Nissan LD-series OHC Six diesel engine, popularly available in the US in 1981-83 Datsun/Nissan Maxima Sedans & Wagons.

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72fj40
Posts: 6
Joined: 11 years ago
Location: christchurch New Zealand

high oil pressure ld28

#1

Post by 72fj40 »

on start up my oil pressure goes real high like 100 top of the gauge so high that it blew the seam on the oil filter. at idle it sits around 40-50 but if you give it any revs it jumps back up

any ideas what the prob is? im running 15w 40 oil
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asavage
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#2

Post by asavage »

Sounds like a classic stuck pressure relief or regulator valve, built in to the aluminum base that the oil filter screws on to. There are three.

The lubrication circuit schematic is here.

I'd be looking hard at the regulator valve first. It's in the oil pump housing cover at the front bottom of the engine.

Image
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
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asavage
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#3

Post by asavage »

I once borrowed a car for a 250 mile trip, and when I arrived, I had no oil pressure. When I disassembled the oil pump pressure regulator, I found a chunk of blue silicone stuck in it, holding open the shuttle valve. Some bit of debris left over from somebody being sloppy in resealing the valve cover.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
72fj40
Posts: 6
Joined: 11 years ago
Location: christchurch New Zealand

#4

Post by 72fj40 »

how hard should the bearing be to push in? i checked the ones ont the cooling circuit and the filter housing and both move easily but the one at pumps a bit stiffer im assuming this is the prob
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asavage
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#5

Post by asavage »

I have no experience with the one on the LD engine, so I can't advise.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Duaneclark
Posts: 107
Joined: 11 years ago
Location: Peyton Colorado

just a comment

#6

Post by Duaneclark »

I've been using 10w30 as the owners manual suggests, on cold days, it could be that 15w40 is too thick, however the pressure relief valve should moderate this. On a Ford diesel, I only had the block heater plugged in for 3 hours one morning, no pan heater, and 15w40 blew out the oil cooler seals.
Duane
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