crankcase emission control system

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

crankcase emission control system

#1

Post by ten10 »

I have oil leaking at the inlet to the vapor separator and at the valve cover fill cap. I have read some threads that talk about excessive crankcase loss and after closing off the air control valve i put the palm of my hand over the fill cap with the engine at idle. There is a considerable amounts of pressure after only a few seconds. Did i do this this right? What could be the problem. thanks
83 Nissan 720 SD25
Nissan_Ranger
Posts: 270
Joined: 17 years ago
Location: Canada

#2

Post by Nissan_Ranger »

If I am understanding you correctly, you blocked the draught tube and then put your hand over the oil filler opening in the rocker cover... ? I am assuming that your crankcase draught tube is NOT already plugged or blocked by some means not known to you.

You also need to make sure that your vacuum system doesn't have a leak which would cause your vacuum pump to dump excessive air into the crankcase.

If all the above is correct, then you may be looking at a ring and/or valve guide job as the symptom you're describing points to excessive blow-by gases which can come from both of those sources, more likely the rings.

HTH,

N_R
The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.
ten10
Posts: 12
Joined: 16 years ago
Location: Central California

#3

Post by ten10 »

alright ill check for vacuum leaks first, any suggestions as to where i should start. thanks
83 Nissan 720 SD25
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