Z starting to smoke

[Bob94]

So my 04 de has started smoking (bluish) this morning, I was driving it harder than usual this morning down the county roads but when reversing into my space at work I noticed a little puff of smoke. I got out and gave it a few blips to about 3000/4000 rpms and each time bluish smoke came out. I can't seem to see any when driving it hard......yet

 

I know for a fact one of my spark plug tubes has a little oil in it from when I checked all my coil packs 2 weeks ago but that's been like 6 months  and not had any smoke in all that time. I've been reading people's most common faults i.e. Oil in spark plug tube, stem oil seals, piston rings. Last time I tried to measure oil consumption it was roughly 1L/1000 miles which most people seem to agree is within nissan spec. But I'm going to keep an even closer eye on it from now on.

 

So I'm going to stay back tomorrow after work and sort the leaky tube out (hopefully like I did with the other one that is now still dry) and do a compression  test and keep my fingers crossed it's not down on any cylinders. 

[Bob94]

So I did my compression test tonight and the results were

cylinder

5 195 psi       6 195 psi

3 195 psi       4 200 psi

1 195 psi       2 195 psi

 

which according to information I could find is above manufactures recommendation. For 108,000 miles I think is quite good. The tops of most of the pistons looked a little bit damp with oil.

 

So im thinking (hoping) rings are ok and the problem could be the valve stem oil seals and or the valve guides.

 

What have people come across as the most common culprit? Is there anything else I can check aswell?

[cs2000]

Mine has recently started doing this too, but at under 90,000 miles. I actually park up next to a fence and noticed the fence was splattered with oil!

 

I have (as a troubleshooting step) replaced the seals on all the spark plug tubes using the Torqen replacement kit, which didn't seem to have any effect, i too was getting oil pooling in bank 1 and 6 (the two closest to the rear of the engine bay).

 

I then cleaned and tested the PCV which had no effect. What MOSTLY cured it for me was actually replacing the PCV. The car does still smoke, but not to the point where oil is spitting out of the exhaust.

 

I also ran Seafoam (like cataclean) through the fuel injection and air intake system to remove any residual oil/deposits in these systems. LOTS of smoke came out, so there was a hell of a lot of carbon build up, but didnt stop the issue.

 

I also got a bit lapse on my servicing due to time and money pressures (wedding and a new house) and ive read a couple of instances where others did all of these things to no avail, gave it a good service and it magically disappeared. My thinking is that if the engine is a little worn, like ours are, and the oil is full of particles, that they are causing the oil to weep past the stem seals or valve guides so a good service with an engine flush may help.

 

Failing all of this, it likely will be the Valve stem seals, then the valve guides.

 

 

[Bob94]

That gives me a few things to to try next before diving into to rebuild territory. 

 

I did notice with the bore scope there is a lot of build up on the valves.

 

I'm running 10w-40 she'll helix as I have for for the last 3 oil changes, my 6 monthly oil change is due next month but may do it sooner to see if it helps with reducing the smoke.

 

i have got berk test pipes which have been on about 2 months now, dare say the amount it smokes now would not be noticeable if I still had cats fitted.

 

If none of those help I'm probably going to start planning on replacing stem seals and guides

[Bob94]

Tested the pcv yesterday and tried to blow through it, some air did come through but not sure if it was enough or normal amount but I've order a brand new one seen as though it's probably still the original one on 108,000 miles.

 

stripped the plenum down to see if the was much if any oil in or around the manifold. There was a large pool of oil in the bottom of the lower plenum.

before and after clean pics below.

 

there was also some oil on the inside of the upper plenum and throttle body which was quite thick but cleaned it all off.

 

the thing that concerned me most was when I looked down the inlet I saw that the back of the valves looked quite wet with oil, I'm not sure weather this is from the pool of oil in the plenum or if it confirms that the guides and or stem seals are leaking :/

 

ive ordered an oil catch can that I'm going to install to see if the smokeyness gets any better combined with a new pcv, I've seen 2 ways to install a catch can

1. Just pcv side 

2. Pcv and n/s rocker cover pipe both into the can then vent to atmosphere.

think I'm going to go for option 2 as there was more oil than I expected in and around throttle body.

 

[cs2000]

Cant say i looked at my valves to be honest, but your upper plenum looked much the same as mine, perhaps a touch worse

 

I ran some Seafoam through the engine oil this last week (so have now had it though the fuel system and air intake system) and had a service at the weekend from Sly at Kaizer Motors, cant say i noticed any smoke at all on the way home so i think a combination of these things helped fix the issue.

 

The only smoke i did see is when i was in the dartford tunnel and engaged 2 step launch control, but that expected as you get a load of un burnt fuel in the exhaust and im running full decat too so it wouldnt have burnt off properly.

 

The PCV is dead, i too could blow a small amount of air through, you're not supposed to be able to do this at all.

[Bob94]

6 hours ago, cs2000 said:

Cant say i looked at my valves to be honest, but your upper plenum looked much the same as mine, perhaps a touch worse

 

I ran some Seafoam through the engine oil this last week (so have now had it though the fuel system and air intake system) and had a service at the weekend from Sly at Kaizer Motors, cant say i noticed any smoke at all on the way home so i think a combination of these things helped fix the issue.

 

The only smoke i did see is when i was in the dartford tunnel and engaged 2 step launch control, but that expected as you get a load of un burnt fuel in the exhaust and im running full decat too so it wouldnt have burnt off properly.

 

The PCV is dead, i too could blow a small amount of air through, you're not supposed to be able to do this at all.

Can I ask where you got the seafoam from? 

Did you notice any issues running it through the fuel system? Always a sceptic with things like this but willing to try this if my new pcv, oil catch can and clean the plenum and throttle body doesn't help 

[cs2000]

13 hours ago, Bob94 said:

Can I ask where you got the seafoam from? 

Did you notice any issues running it through the fuel system? Always a sceptic with things like this but willing to try this if my new pcv, oil catch can and clean the plenum and throttle body doesn't help 

Of course, the usual place I get things from is eBay

https://www.ebay.co.uk/itm/SEA-FOAM-Diesel-Petrol-engine-injector-carb-cleaner-SF16-14-00-Free-postage/152729863408?epid=16008808657&hash=item238f68c4f0:g:MUgAAOSwEYBaU3fs

 

Ive used it in all my cars, the Z had probably had 3 or 4 treatments over the years. Its very simple to use. 1/3rd of a can in a full tank of fuel, another 1/3rd you suck into the plenum via the brake booster line and the other 1/3rd put into engine oil 100 ish miles before an oil change. Theirs more detailed guides around on the net of course, but has never done me any harm and the deposits and smoke that come out the back are insane if you have a really gummed up engine.

[Bob94]

On 17/07/2018 at 12:29, cs2000 said:

Of course, the usual place I get things from is eBay

https://www.ebay.co.uk/itm/SEA-FOAM-Diesel-Petrol-engine-injector-carb-cleaner-SF16-14-00-Free-postage/152729863408?epid=16008808657&hash=item238f68c4f0:g:MUgAAOSwEYBaU3fs

 

Ive used it in all my cars, the Z had probably had 3 or 4 treatments over the years. Its very simple to use. 1/3rd of a can in a full tank of fuel, another 1/3rd you suck into the plenum via the brake booster line and the other 1/3rd put into engine oil 100 ish miles before an oil change. Theirs more detailed guides around on the net of course, but has never done me any harm and the deposits and smoke that come out the back are insane if you have a really gummed up engine.

Thanks I will check it out