Accelerated Ring Wear
Accelerated Ring Wear
(OP)
A local Nissan dealer just told a lady friend that her 2005 V-6 w/96000 miles had suddenly begun to burn oil at a high rate because the catalytic converters were disintegrating. They claimed that when she went downhill and lifted her foot the pieces were being drawn up into the combustion chamber causing the sudden ring failure. They’d done all of her service work since purchase - so she believed them.
I need some replies to help her see the light.
I need some replies to help her see the light.





RE: Accelerated Ring Wear
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RE: Accelerated Ring Wear
Sounds like a lawsuit (if she got that in writing... doubtful).
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Accelerated Ring Wear
Time to produce the extended warranty contract if she has one...
Mike Halloran
Pembroke Pines, FL, USA
RE: Accelerated Ring Wear
"Schiefgehen will, was schiefgehen kann" - das Murphygesetz
RE: Accelerated Ring Wear
... but it's worth trying to make a claim anyway.
Mike Halloran
Pembroke Pines, FL, USA
RE: Accelerated Ring Wear
RE: Accelerated Ring Wear
Is there more info about testing done to arrive at the "worn rings" disgnosis?
If just based on oil consumption then I call criminal malpractice.
A compression and leak down test could provide some indication if ring condition.
What is the view under the oil fill cap?
Any external leaks? Be a real shame to overhaul an engine because the cam cover or oil pan gaskets are bad, or the fasteners just need tightening.
Adding a quart every week or 4 is way cheaper than engine repairs and just might get her to 200 kmiles.
Regardless I think I'd check that the various Crankcase ventilation breathers and whatnot are clear. PCV testers of various forms are available to clamp over the oil fill hole. Some would say a decent test is to set the unscrewed cap in place, and if it lifts or dances with the engine idling there is excess pressure. Others advocate observing whether a sheet of saran wrap elastic banded to the filler neck is concave (good) or convex (bad). While I'd vbe interested in those results a test at idle is not as tough as at highway loading.
Some cars maintenance schedules are pretty weak in that PCV system maintenance area. Excess crankcase pressure will force oil out somewhere, and make the seals wear even faster. The pressure can be excessive because worn rings are allowing lots of blowby, OR because even normal amounts of blowby in an engine in fine shape have no place to go due to a resticted or plugged PCV system.
RE: Accelerated Ring Wear
During a scheduled service they forgot to put the oil back in.
Now they are covering their ASSets.
They will not admit voluntarily that they may have negligently destroyed an engine.
Contact a factory rep and avoid that dealer. DO NOT confront the dealer. That will give them an opportunity to refine their story.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Accelerated Ring Wear
Mike Halloran
Pembroke Pines, FL, USA
RE: Accelerated Ring Wear
http://techinfo.subaru.com/proxy/71914/pdf/ownerMa...
His (newer) "roo has an oil level warning light, which he has set off a time or two.
I think his lack of periodic oil checking reflects badly on his parents and to a small extent even me.
I guess "Excessive" oil consumption is to some extent clearly in the eye of the beholder.
RE: Accelerated Ring Wear
As mentioned above, the cost of top-up oil is quite low. The real issues are the mess and potential embarassment, if one is finicky about that sort of thing.
"Schiefgehen will, was schiefgehen kann" - das Murphygesetz
RE: Accelerated Ring Wear
RE: Accelerated Ring Wear
RE: Accelerated Ring Wear
RE: Accelerated Ring Wear
-----------------------------------------------------------------------------------------------------------------------
Reference: Date: NTB03-070c November 17, 2006
VOLUNTARY RECALL CAMPAIGN ALTIMA AND SENTRA QR25DE ENGINE EXHAUST PIPE HANGER PIN AND PRE-CATALYST
CAMPAIGN I.D. # NHTSA #: R3007, R3014, R3015, R3016, & R3017 03V-084
APPLIED VEHICLES:
2002-03 Altima (L31), with QR25DE Engine 2002-04 Sentra (B15), with QR25DE Engine
APPLIED VINS:
Altima: 1N4AL11**2C100000 - 294952 1N4AL11**2C700001 - 719020 1N4AL11**3C100003 - 311983
Sentra: 3N1AB51**2L700019 - 730181 3N1AB51**3L716572 - 736783 3N1AB51**4L727627 - 730593 3N1AB51**4L736618 - 738436
INTRODUCTION
Nissan has determined that some 2002-2003 model year Altima and 2002-2004 model year Sentra vehicles equipped with the 2.5 liter engine have defects that relate to motor vehicle safety. For 2002-2003 model year Altimas, there is a possibility that the exhaust pipe hanger pin may catch debris from the road that could be ignited by contact with the catalytic converter and cause a fire. In addition, for 2002-2003 model year Altimas and 2002-2004 model year Sentras, there is a possibility that certain engine operating conditions may cause damage to the pre-catalyst. Material from inside a damaged pre-catalyst could enter the engine and result in increased oil consumption. If the engine oil level is not checked on a periodic basis and drops below the low level, and the driver continues to operate the vehicle ignoring noticeable engine noise, engine damage may occur which could result in a fire.
RE: Accelerated Ring Wear
RE: Accelerated Ring Wear
RE: Accelerated Ring Wear
There is overlap between intake valve opening and exhaust valve shutting, during which both intake and exhaust valves are open. Under high intake manifold vacuum conditions, reversion flow will occur during the valve overlap period.
Also during shut-throttle coastdown with no fuel supplied (and deceleration-fuel-cut is the norm!) the pressure in the cylinder at time of intake valve closure is well below atmospheric, and in those conditions, nothing happens to it between then and exhaust valve opening, so the cylinder pressure will still be well below atmospheric at the time of exhaust valve opening. What happens ... Reverse flow from the exhaust manifold to fill the cylinder, then forward flow (out of the cylinder) during the last part of the exhaust stroke, then reversion during valve overlap. The net flow when all of these are added up is indeed from intake to exhaust, but there is plenty of opportunity for instantaneous flow from the exhaust manifold into the cylinder at certain times.
RE: Accelerated Ring Wear
seems as though the gremlins in motor trade are the same world wide great replies as always from all.
Here in South Africa cats and the like are unheard of, only being introduced certainly perhaps in the last few years!! My point is that Vw SA in the hand book state that a litre of oil per 1000 kms is ok if that is the case what about pollution!? However I think I digress, from a personal experience re exhaust debris being drawn back into engine.......... Mazda rotary fitted to a Puma car {Brazilian VW] based sports car fabricated exhaust system remember noise on them things a few 1000 K,s down the road bang engine gone no evidence of ingress of foreign particles rebuilt fitted started bang no compression stripped found mechanical damage and bits and pieces from the baffles from the silencer. High exhaust pulse ??? no evidence of rust causing the breakage of the baffle silencing medium but it was sucked back into the engine . Hope not too far off the point hope the lady gets some form of recompense.
Cheers Golfpin
RE: Accelerated Ring Wear
RE: Accelerated Ring Wear
Turns out that they were.
I’m an old car guy, got my BME in ’61. Later on I was the lab instructor in an IC engine course while in grad school. Cats weren’t invented until decades later – and they went down under the car with the muffler. My (obsolete) common sense was that the Nissan dealer’s story was nonsense.
I knew nothing.
The pre-cats are practically inside the exhaust manifold, to get them hot ASAP. (Yes, there’s another down under the car too.) Numerous posters had it right – Nissan used a large valve overlap in their emission control in lieu of the usual EGR valve strategy. Periods of sustained high intake manifold vacuum results in exhaust gas being drawn back into the cylinder. When the cat begins to fail (as they all do eventually), bits of the media (and perhaps the baffling itself) enter the cylinder with disastrous results.
This unfortunate lady lives 35 miles away from her Santa Barbara dealer (who is at sea level). Her house is at ~500’ above sea level – but in between is a 3000 foot mountain. Each trip into town provided a steep, fast descent with her foot off the gas, and the car rolling up to 80 mph. It was likely years of making these descents that contributed to her trouble. Worse, the disintegrating cat still worked, so the oxygen sensor did not detect any problem. Her motor is now destroyed, yet she still doesn’t have a check engine light!
Nissan is apologetic, but otherwise unhelpful. She’s car shopping now, for other brands.
RE: Accelerated Ring Wear