Piston #3 burning out?
- Thread starter Aussie Frontier
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Got talking to the service manager at my local dealership late yesterday (warranty issues with worn out front seat, rear door speaker and rear door handle) and quite by chance he mentioned this very problem with YD25's. I 'jumped' on the issue and quizzed him over it. I also suggested that it was a ZD30 issue, but no.
Make no mistake YD25s are burning out the 3 piston. The issue appears to related to crook injectors leaning out the fuel delivery. My dealership has seen three examples.
He humerously added that it was unlikely that there would be any issues with my D40 given the wild tune I am running with my chip.
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D
Dave
Guest
Go Nissan.
You have tainted the name of another diesel engine.
Well lets face it, the YD25 hasn't had a good name in Europe for years.
After they use to throw rods through the side of the block.
You have tainted the name of another diesel engine.
Well lets face it, the YD25 hasn't had a good name in Europe for years.
After they use to throw rods through the side of the block.
i doubt it leaning out the fuel, its far more likely injectors are sticking giving it to much fuel and burning out a piston. fairly common with dirty fuel.
would be odd that its always number 3 tho. i wonder if theres an egr fouling the intake issue.
would be odd that its always number 3 tho. i wonder if theres an egr fouling the intake issue.
Whatever the cause, it is happening to the odd engine.
but it may not be a YD25 problem. if its just fuel contamination stuffing up injectors it can (and does) happen to every make/model of engines. so its hard to tell if its a design problem or just a maintenance issue.
Good point!
There's nothing overly different about the intake manifold - it's a straight tube with 4 openings, the high-pressure air entering from the front, with EGR fed in from the side of the same section. If it were a case of the high pressure air entering the manifold in front of cylinder 3 I could understand it perhaps being a little leaner than the other cylinders, but it's not.
There doesn't appear to be anything odd about it.
However there might be something about the exhaust manifold (for those of you who studied Fluid Dynamics as part of your Mech Eng degrees you'll understand this, and why). Cylinder 3 is the second last cylinder before the turbocharger which hangs off the back end of the manifold. Exhaust temps around the #3 port ought to be quite high.
What if the flow from Cyls 1 and 2 is being caught up at #3 and overheating #3, or at least making it run a few degrees hotter - and when pushed hard, for long periods, #3 cooks?
The intake/exhaust valve patterns, injector placement etc don't seem to be different between the cylinders. There's no extra (or reduced) water flow in the jacket around #3. I think flow of the hot exhaust and its combination around #3 might be the only thing that could affect it.
Another point - when #1 is venting exhaust, there's only one place for the exhaust to go - that's to turn towards the rear of the motor. When #2 is open, the hot gas can go in both directions, but most of it will head towards the rear because #1's exhaust valves should be closed and the pressure won't increase too high in that direction. So, for #1 and #2, the exhaust pretty much heads in the right direction. #3 should do mostly the same, but may increase the pressure & temps upstream (outside #1 and #2) a fraction.
#4's venting would add to the damage, because it should be capable of compressing the gas volume outside #1, #2 & #3 a small degree so the hot exhaust is able to move towards #3 and increase the temps there before being evacuated in the direction it is supposed to go.
Tweake, what do you say? Could the temps around #3 exhaust port be higher?
There doesn't appear to be anything odd about it.
However there might be something about the exhaust manifold (for those of you who studied Fluid Dynamics as part of your Mech Eng degrees you'll understand this, and why). Cylinder 3 is the second last cylinder before the turbocharger which hangs off the back end of the manifold. Exhaust temps around the #3 port ought to be quite high.
What if the flow from Cyls 1 and 2 is being caught up at #3 and overheating #3, or at least making it run a few degrees hotter - and when pushed hard, for long periods, #3 cooks?
The intake/exhaust valve patterns, injector placement etc don't seem to be different between the cylinders. There's no extra (or reduced) water flow in the jacket around #3. I think flow of the hot exhaust and its combination around #3 might be the only thing that could affect it.
Another point - when #1 is venting exhaust, there's only one place for the exhaust to go - that's to turn towards the rear of the motor. When #2 is open, the hot gas can go in both directions, but most of it will head towards the rear because #1's exhaust valves should be closed and the pressure won't increase too high in that direction. So, for #1 and #2, the exhaust pretty much heads in the right direction. #3 should do mostly the same, but may increase the pressure & temps upstream (outside #1 and #2) a fraction.
#4's venting would add to the damage, because it should be capable of compressing the gas volume outside #1, #2 & #3 a small degree so the hot exhaust is able to move towards #3 and increase the temps there before being evacuated in the direction it is supposed to go.
Tweake, what do you say? Could the temps around #3 exhaust port be higher?
K
Krankin
Guest
Personally, re the YD 25's in the D22 melting No 3 in quantities,
I'd like to see undeniable proof.
I'd like to see undeniable proof.
^ +1.
I think the thing would have to be flogged to within an inch of its life on a regular basis for it to happen. Even if the exhaust port temp theory is right, it'd have to be extreme.
I did think of another issue that could cause it. Rumour was back in the late 80s you could always outrun the police if you could maintain a high enough speed. The Fords just couldn't handle any sustained speed above 190km/h and they'd boil. The Commodores had super-efficient oil pumps and above 160km/h they'd pump all their oil to the top of the heads and leave the sump fairly dry - boom. It was rumour only - but where there's smoke ...
So what if the YD25 is pumping too much oil up and not getting enough through to the squirter under piston 3? Same deal - hot piston crown, melted piston. I wonder if it's caused by too low an engine oil level.
Excessive blow-by (through heavy use) could consume extra oil and if the owner doesn't check levels regularly it could cause the sump to have less oil than needed. We know our cars are fairly temperamental about oil levels anyway.
Still, one dealer with 3 cases isn't really evidence, it's possibly coincidence.
Would Nissan say anything, give us the cause and tell us how to avoid it? I would hope so.
I think the thing would have to be flogged to within an inch of its life on a regular basis for it to happen. Even if the exhaust port temp theory is right, it'd have to be extreme.
I did think of another issue that could cause it. Rumour was back in the late 80s you could always outrun the police if you could maintain a high enough speed. The Fords just couldn't handle any sustained speed above 190km/h and they'd boil. The Commodores had super-efficient oil pumps and above 160km/h they'd pump all their oil to the top of the heads and leave the sump fairly dry - boom. It was rumour only - but where there's smoke ...
So what if the YD25 is pumping too much oil up and not getting enough through to the squirter under piston 3? Same deal - hot piston crown, melted piston. I wonder if it's caused by too low an engine oil level.
Excessive blow-by (through heavy use) could consume extra oil and if the owner doesn't check levels regularly it could cause the sump to have less oil than needed. We know our cars are fairly temperamental about oil levels anyway.
Still, one dealer with 3 cases isn't really evidence, it's possibly coincidence.
Would Nissan say anything, give us the cause and tell us how to avoid it? I would hope so.
+1
of course it could be like the ZD30's where the rear pistons do run slightly hotter and thats the pistons that normally fail. however often the other pistons/head has cracks in it to.
the whole lot have been running way to hot and its just the slightly hotter ones that have let go first.
so the issue is not no3 piston failing but rather the overall EGT's are running way to hot.
Not in D22s only D40s
K
Krankin
Guest
my mistake...dunno why i put that in
K
Krankin
Guest
Tony, if there's not enough sump oil there will be a drop in pressure and your guage and or idiot light will show....
the yd25 oil/gauge/ecu systems are right onto oil pressure checking and sump volume, even before engine firing.
Bluenavara
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Absolutely correct.
You can even adjust the startup display to show your oil level, in 5 level increments from full to low.
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