Helpful advice needed for my 550, won't start.

[Bruce Brodie]

Help my V9X won't start, died whilst driving, had to get it towed to my mechanic, he said the valve on the fuel pump had to be replaced and also the fuel filter, it was full of red rusty muddy crap but the tanks clean, not getting any errors coming up, he has bled and primed it, even tried Aero Start but the engine just speeds up, my mechanic has not come across this before, any helpful advice would be appreciated, maybe old Tony knows.

 

[Old.Tony]

It could have been a bad batch of fuel - red rusty crap sounds like it came from a service station tank. Your tank is plastic, the fuel lines are rubber, there's nowhere for crap like that to be created except for a couple of joiners and the fuel filter itself, and you'd need water in there to get the rust started. This is something that we have seen quite a few times from service stations.

 

[Bruce Brodie]

It could have been a bad batch of fuel - red rusty crap sounds like it came from a service station tank. Your tank is plastic, the fuel lines are rubber, there's nowhere for crap like that to be created except for a couple of joiners and the fuel filter itself, and you'd need water in there to get the rust started. This is something that we have seen quite a few times from service stations.

Thanks old Tony but it looks like the timing chain may have jumped a few teeth now, the fuel filter and one way valve were both changed, the compression is running from 150-180, should be over 220 from what the mechanic said, hopefully it's not too serious but will still be up for a bit.

 

[Tajine]

Hi Bruce,
I'm curious as my V6 refused to start next morning after I had returned from Mid North Coast to Central Coast. Battery terminal loose so I fixed connections but engine finally started after I used a bit of Startyabastard. Drove 400m up the road where it conked out again & then no start. Taken it to 2 mechanics who said compression was low (140-150) & I need a new engine. It's been a couple of months now & have taken it to Challenger for a rebuild ($14K!) Sam there told me these engines have a flaw in the crankshaft & he went to Europe to source good quality replacements. I'm still not 100% convinced & your description sounds more like what is the likely case for mine. I had no indication of anything suspect. No sounds or overheating but an engine that turns over as if there is no compression but not a sound from anything. Despite being at the guys yard for 2 weeks he hasn't given me banking details for required deposit so I'm still open to a cheaper resolution. I have found another wreckers who says they will rebuild for $10K but won't guarantee new parts unless required as they say parts are hard to track down. I've seen rebuild kits for less than $3K on ebay though. Have you any news or an update on your engine? Mine has done 187K km & was going like a dream until that day.

 

[Old.Tony]

Sam there told me these engines have a flaw in the crankshaft & he went to Europe to source good quality replacements.

Ok just on this one point: Sam might actually be correct, but he's not going ot be able to fix it with good quality parts.

The story that I heard - and this is absolutely hearsay, I have no proof except that it sounds feasible - goes along the lines of Nissan asking for a V6 diesel that could outpower the competition, but still fit in the vehicle without much modification. A V6 is longer (thanks to a necessarily longer crankshaft), and a longer engine means sacrificing something elsewhere - cabin space or tub space, and both were a premium Nissan didn't want to surrender.

So in order to make the engine shorter, they made the major bearings narrower (not thinner, but a smaller distance across the face of the bearing). The cumulative result of this was to shorten the engine sufficiently to allow them to shoe-horn it into the engine bay.

The penalty (that Nissan doesn't have to pay, it's the owners of the vehicles who wear this one) is that the stresses one would normally see on a bearing surface of X are now pushing on (say) 0.75*X. This means that the life of the bearing is also reduced.

Now I really have to stress that it's hearsay - I can't prove it - but from an engineering + marketing perspective, it's so easy to believe.

And if it's true, it means that the engines will need their main bearings replaced more often than one might hope, but that doesn't mean it's going to affect compression, which is usually subject to the condition of the bore, piston rings, piston, valves and head gasket.

 

[Tajine]

Thanks Tony. What you have said here really does tie in with what Sam appeared to be trying to convey to me. He mentioned a weakness at the harmonic balancer end but didn't actually mention the bearings. Rather he banged on about hairline cracks that appeared on some crankshafts & when he travelled to Europe to hunt down replacements he insisted on thoroughly checking a sample with a certain dye & microscopic visuals. Finding the supply true he told me he then bought around 60 which he brought back to Australia.

I too have heard reports that the bearings seem too narrow for the job but still in a quandary as to how my engine just failed without any real (dramatic) indication of crankshaft failure. It seems that these engines should have recommended oil changes of 5000-7500km intervals.

The only fault in your story seems to be the reality that the engine is a Renault engine designed for their van series but perhaps a van is more "fitting" since engine space is certainly at a premium in that as opposed to a 4WD.

 

[bernjong]

How would narrower bearings reduce the length of the engine block?

 

[brent.harvey]

Hi Bruce,
I'm curious as my V6 refused to start next morning after I had returned from Mid North Coast to Central Coast. Battery terminal loose so I fixed connections but engine finally started after I used a bit of Startyabastard. Drove 400m up the road where it conked out again & then no start. Taken it to 2 mechanics who said compression was low (140-150) & I need a new engine. It's been a couple of months now & have taken it to Challenger for a rebuild ($14K!) Sam there told me these engines have a flaw in the crankshaft & he went to Europe to source good quality replacements. I'm still not 100% convinced & your description sounds more like what is the likely case for mine. I had no indication of anything suspect. No sounds or overheating but an engine that turns over as if there is no compression but not a sound from anything. Despite being at the guys yard for 2 weeks he hasn't given me banking details for required deposit so I'm still open to a cheaper resolution. I have found another wreckers who says they will rebuild for $10K but won't guarantee new parts unless required as they say parts are hard to track down. I've seen rebuild kits for less than $3K on ebay though. Have you any news or an update on your engine? Mine has done 187K km & was going like a dream until that day.

Please check the fault codes and fuel pressure on cranking and at rest, before spending big money

 

[Bruce Brodie]

Please check the fault codes and fuel pressure on cranking and at rest, before spending big money

Hi Tajine, they took it apart and borescope the pistons and cylinders, do damage or scoring also tested the injectors without a problem, the computer says the pump is delivering 3900+ psi but they will also bench test the pump, they have managed to get her to kick on Aerostart but won't run, they think it might be to blow off valve to the common rail being stuck open or partially open, so it's not letting the fuel get to the engine. Problem is it's up near the turbo at the back of the motor, tight spot to get to, they are seeing if they can modify a spanner to crack it open to see what's happ. If they can't it's engine out to do that, but it could be something as simple as that. West End Diesel in Wetherill Park NSW are the ones doing the work.

 

[Bruce Brodie]

Hi Tajine, also my 550 has only done 213k which is bugger all for a diesel, and West End Diesel are now called Cornell, in case you want to chat with them.

 

[Tajine]

Please check the fault codes and fuel pressure on cranking and at rest, before spending big money

Hi Brent & thanks for your input. First mechanic said he checked the codes but got nothing remarkable. 2nd mechanic, SBO in Gosford did a fuel rail test & said all was fine but suspects low compression because motor turns over like an engine with no compression. (I agree but don't know why it suddenly did this). He couldn't do a proper compression test because he said the manual indicates 37hrs just to get to removing glow plugs fo tester. !st mechanic had a special tool suited to injector point entry I'm told but he could only test one bank as the left bank requires huge effort. He at least didn't even charge me for what he did do.

 

[Tajine]

Hi Tajine, they took it apart and borescope the pistons and cylinders, do damage or scoring also tested the injectors without a problem, the computer says the pump is delivering 3900+ psi but they will also bench test the pump, they have managed to get her to kick on Aerostart but won't run, they think it might be to blow off valve to the common rail being stuck open or partially open, so it's not letting the fuel get to the engine. Problem is it's up near the turbo at the back of the motor, tight spot to get to, they are seeing if they can modify a spanner to crack it open to see what's happ. If they can't it's engine out to do that, but it could be something as simple as that. West End Diesel in Wetherill Park NSW are the ones doing the work.

Hi Bruce & thanks for your reply. The borescope is exactly what I wanted the 2nd guy to do but he said none of his cameras could fit down the injector holes. Showed me them & looked true so I didn't get a check on that. Did test the fuel pump & said all was fine; fuel getting delivered okay. Thanks for the "Cornell " tip. I might give them a call tomorrow. I rang ARA engineeringandconditioning.com.au to get a rebuild quote today. They said they can do the full job of removal & complete rebuild & install for $16500 which is even higher than I suspected but at least will know the full job has been done if I go ahead.

How would narrower bearings reduce the length of the engine block?

Apparently the bearings might be only 75% as wide as normal so with 4-6 that might add up to 30-50mm shorter overall length of engine. Sounds ridiculous I know but then the motor is apparently ridiculously difficult to source parts for (& work on?) which is strange in itself given that the motor is widely used or was used in many European Renault Vans.

 

[Tajine]

Hi Tajine, also my 550 has only done 213k which is bugger all for a diesel, and West End Diesel are now called Cornell, in case you want to chat with them.

Hey Bruce did they say the timing chain had jumped a cog or two? That would result in out of sync valves & low compression but then I'm told there would likely be head damage & nasty noise effects at some stage (which I haven't heard in my case) Replacing timing chains & gears would certainly be a cheaper option if nothing else is damaged.

 

[Bruce Brodie]

Hey Bruce did they say the timing chain had jumped a cog or two? That would result in out of sync valves & low compression but then I'm told there would likely be head damage & nasty noise effects at some stage (which I haven't heard in my case) Replacing timing chains & gears would certainly be a cheaper option if nothing else is damaged.

They said that's highly unlikely, would have damage to pistons valves etc if it had. I will keep posting on what they find.

 

[landmannnn]

Ok just on this one point: Sam might actually be correct, but he's not going ot be able to fix it with good quality parts.

The story that I heard - and this is absolutely hearsay, I have no proof except that it sounds feasible - goes along the lines of Nissan asking for a V6 diesel that could outpower the competition, but still fit in the vehicle without much modification. A V6 is longer (thanks to a necessarily longer crankshaft), and a longer engine means sacrificing something elsewhere - cabin space or tub space, and both were a premium Nissan didn't want to surrender.

So in order to make the engine shorter, they made the major bearings narrower (not thinner, but a smaller distance across the face of the bearing). The cumulative result of this was to shorten the engine sufficiently to allow them to shoe-horn it into the engine bay.

The penalty (that Nissan doesn't have to pay, it's the owners of the vehicles who wear this one) is that the stresses one would normally see on a bearing surface of X are now pushing on (say) 0.75*X. This means that the life of the bearing is also reduced.

Now I really have to stress that it's hearsay - I can't prove it - but from an engineering + marketing perspective, it's so easy to believe.

And if it's true, it means that the engines will need their main bearings replaced more often than one might hope, but that doesn't mean it's going to affect compression, which is usually subject to the condition of the bore, piston rings, piston, valves and head gasket.

The problem has been linked to poor manufacturing of the crankshaft. Very much the same issue with the Discovery (another French engine, also known as Lion and in the new Wildtrack too)

I hear the same company made both crankshafts.