sd25 oil pressure sending unit

SD diesels were widely available in the US in the 1981-86 Datsun/Nissan 720 pickups, and in Canada through '87 in the D21 pickup.

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ten10
Posts: 12
Joined: 16 years ago
Location: Central California

sd25 oil pressure sending unit

#1

Post by ten10 »

I am wanting to install a Frantz oil filter and want to know if there is any reason i can not install a 'T' to where the oil pressure sending unit is and hook one end to the Frantz (which is what the company recomends) and one to the oil pressure sending unit. Also i think i know where the unit is, but could someone verify that it is behind the existing oil filter, with the yellow wire attached.
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Thanks.

I also want to thank this site for existing. Having just read about Phillip's passing I just wanted to say that even though I am too knew to have spoken with Phillip, I have read many of his posts and wish to send my condolences to his friends and family. With the kind of attention he gave his vehicle and all of the forum, i am certain that those close to him miss him dearly.
83 Nissan 720 SD25
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asavage
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#2

Post by asavage »

Yes, the OP sending unit is in your picture, and you can tee there for your bypass filter fine.

You could also tee from the fitting at the vacuum pump's oil feed line, if that's more convenient.

Just curious: are you planning to plumb the return line to the valve cover, the oil fill cap, the timing cover, or the vacuum pump's return line?
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.
ten10
Posts: 12
Joined: 16 years ago
Location: Central California

#3

Post by ten10 »

well now that you mention it the company said i could tap into the oil pan or the oil fill cap; but the vacuum pump lines sound much more convenient for both tees. I'm not a mechanic, but i am learning- could you tell me where these vacuum pump lines can be located for T's.
Thanks.
83 Nissan 720 SD25
ten10
Posts: 12
Joined: 16 years ago
Location: Central California

#4

Post by ten10 »

After posting the previous i found a thread regarding both lines with a good diagram of each. I would put in a link to the post but do not know how to do it. Al, could you explain this process to me? thanks.
83 Nissan 720 SD25
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asavage
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#5

Post by asavage »

One thread with pics is the Vacuum Pump Oil Line thread.

One pic from the thread:
Image


On linking to other posts: follow the advice here. It's not as hard as it sounds.

Routing the return line up to the valve cover will work well too, on this engine, but if your vacuum pump's drain hose is hard as a rock (and has to be replaced anyway), now would be a good time to order the hose, and put a tee in it before installing it.

If you can find a good, oil-resistant aftermarket hose of the correct size, so much the better. Heater hose won't do.
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