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Matt, Mechanical Engineer
Category: Nissan
Satisfied Customers: 22736
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a Nissan terrano 2 2.7td, I've recently had to replace

Customer Question

I have a Nissan terrano 2 2.7td, I've recently had to replace engine but I'm having trouble with back pressure filling air box and making it leak oil, the engine replacement didn't have the pipe that runs behind the head between manifolds. It ran fine but started to lack power till switch off and on and power kicked back in, so I swaped both manifolds for the original ones and turbo so I could fit the original pipes (2 rubber, 1 to intake and 1 to back of intake on pipe between manifolds only now I'm having problem with back pressure? When switch off you can hear a hissing that sounds like its escaping from airfilter box! What am I doing wrong? Please help
Submitted: 2 years ago.
Category: Nissan
Expert:  Matt replied 2 years ago.
Hellothis sounds like the crankcase pressure system is either faulty or not plumbed correctly 1st check the crankcase pressure relief valve (PCV) these are sprung loaded and are only meant to 'burp' excess pressure every now and then. The exiting gas is piped back to the inlet, however should the valve stick open then the engine tends to suck the air out of the crankcase all the time and this carries oil over with it.If you remove the air intake pipe and look inside where the crankcase breather is plumbed in you may find evidence of oil.
Customer: replied 2 years ago.

where is the pressure relief valve and what does it look like? Is there a way to test it?

Expert:  Matt replied 2 years ago.
hello if you look on the main air intake pipe, there should be a pipe of about 1/2" diameter that runs back to the engine cam coverwhere this pipe attaches back to the cam cover should be where the PCV is
Customer: replied 2 years ago.

the pipe coming from the intake pipe goes to what I'm led to believe to be an oil separator it has a pipe connected to bottom which comes from the oil sump at bottom of engine. The other pipe that goes to cam cover as nothing along it and just connects to the cam cover? I've had the cam cover off and where the pipe connects to the cover it doesn't look like air can get through there? All you can see inside the cover is 3 small bolt heads that keeps the housing the pipe goes connected to the cam cover?

Expert:  Matt replied 2 years ago.
Hello the valve should be screwed into the cover and look like this
Customer: replied 2 years ago.

There isn't anything on the cam cover? ould it be anywhere else?

Expert:  Matt replied 2 years ago.
Hello sometimes the valve is fitted inside the hose, feel along it to see if there are any solid sections otherwise the valve will be built into the cam cover
Customer: replied 2 years ago.

There is nothing in any pipes and where pipe goes into cam cover there is no valve it just free flows air? I think the hissing I here when switch engine off comes from fuel filter

Expert:  Matt replied 2 years ago.
Hello your engine should look like this?and its part 11810
Expert:  Matt replied 2 years ago.
and the hissing from the filter also needs dealing with as if its drawing air then this will make for poor starting so I'd suggest fitting a new filter and ensure that the selaing rings are sat into their grooves
Customer: replied 2 years ago.

my engine doesn't look anything like that? It hasn't been that long since fuel filter was changed and it starts almost immediately but as soon as you touch accelerator it starts spewing oil out the top of turbo where the intercooler goes, without the intercooler on the oil hits the bonnet

Expert:  Matt replied 2 years ago.
Hello Ok for that much oil to be coming out I think that you're somehow pressurizing the crankcase with boost pressure from the turbo? If you remove the oil filler cap does the flood of oil into the airbox then stop? If so then check the pipework after the turbo, the main inlet pipe should run through the intercooler and only have 1 spur off it that runs into another large flat valve the other side of that valve will be plumbed to the cam cover if this isn't the case block off the spur for now
Customer: replied 2 years ago.

I haven't tried it with filler cap off . There is no pipes that run through the intercooler? It just basically sits on top of the turbo at 1 side and the inlet manifold on other. I thought the crankcase might be pressurizing cos of stuff I've read online that's why I was looking for pcv valve. There isn't any pipe work after turbo it bolts straight onto outtake manifold with intake on front of turbo and exhaust down pipe at back. The only pipes on turbo are oil pipes, 1 to the bottom which I think feeds oil in and 1 on top that goes to oil filter , there's 1 rubber hose that comes from intake before the turbo and joins what I think is an oil separator which sits ontop of crankcase breather? Then another hose comes from the oil separator to the cam cover. There's some kind of spring loaded valve on oil filter housing that's bolted to engine block but I've noticed it has the same kind of thing on the other side above starter motor where oil sensor/switch is and it looks like 2 spring loaded valves on there? I'm on phone at moment but I'll take some pictures and try to send them

i tt

Expert:  Matt replied 2 years ago.
I look forward to the pictures