I have a 2011 Infiniti G37x. For 2 days, it was making a thumping noise (not very loud - had to turn off radio to really hear it) when I started driving it in the morning. The thumping noise seemed to stop when the car shifted to a higher gear (out of the neighborhood over 25 mph). On the 3rd day, the thumping noise was much, much louder, and after driving about 1/2 mile, the car shut off. Car will turn over, but it won't catch. Diagnostics indicated a problem with the cam position detector. The dealer removed the detector and found sludge had accumulated on it. When you open the oil fill and look down the pipe, you can also see sludge. The car has had an oil change about every 10,000 miles and has approximately 36,000 miles on it. Dealer says cleaning the sludge and replacing the sensors is not a viable option, as they believe there is a good chance the car has "jumped time" as well and would need additional repairs. They are recommending an engine replacement at $9,600 for a used engine or $13,000 for a new engine. Do I need a new engine? If so, is the cost exurbanant compared to what an independent auto repair shop would charge me?

 

Dude. 10K oil changes? I get nervous changing it 7500 miles with full synthetic.

I think 9K is a lot for a engine. You may want to look into totaled rear end cars and see if you can salvage a motor from a yard. I think you may get away with a new block for 5-7 maybe? I'm not sure.

Definitely recommend changing your oil way more often than 10,000 miles.

 

Have a trusted independent shop look at your car and give an opinion. Someone that's not a dealership.

 

2011 with 36k...no warranty?

 

Warranty is not being honored since I did not follow the manufacturer's recommendation for oil change frequency

 

I'm confused as to how you thought changing the oil at 10k miles was okay. Anyways, I have been told by the dealer that the long block is $9k in case I blew the motor if I decided to go FI.
Also, sometimes its best to try and not cut corners when it comes to motors. If you let someone rebuild the motor and it breaks again then you will potentially be out of more money. Try buying a salvaged motor, or just get a new one.

 

For the oil changes that were being done, what oil did you use?

I do my own oil changes 2x a year. Usually ~3700-4K miles.. Pennzoil ultra. There better not be any sludge!

 

If you would have kept up a decent interval like every 5k, you would be fine.
Infiniti replaced my entire long block assembly & covered it under warranty.
Hate to say this, I never side with the dealer. In this case you caused the engine failure die to lack of maintinence.
If I were you, I'd look at other motor options than oem.
Unless you have 10k burning a hole in your pocket, look at SAMs rb30.
His set up was not cheap, just an example.
Then at least you could build & boost your ride for that much $.
Or have the motor sent out & re machined.
With only 36k, I would imagine your block is ok.
Sounds like your internals are done though.
Good luck with the repair.
It's going to be expensive.

 

Here is a photo of my 06 G35 shortly before I traded it in at 171796 miles



Engine still ran like new, however it had 53 oil changes never going over 4k miles between changes.
Where did you ever get the idea that you could go 10k miles without changing oil?
Change oil at 3.5k miles yourself to see what comes out of the crankcase & you'll understand why.
I've seen the damaged engines at the dealer as you are not the only one that thinks you can save money by infrequent oil changes.

Good luck

Telcoman

 

Good luck... a sludged VQ cannot be cleaned... you need a new longblock, I've seen it way too much.

 

Why does Mobil 1 offer extended interval oil that can go 15K miles?

 

Some cars can... not these.

 

It's funny when people come and think they're smarter than the entire engineering team at Nissan and start coming up with their own oil change intervals. If they say change every 5,000 km's then you better do it. 10,000 if most of what you do is highway driving and your conditions permit. But 10,000 miles on a VQ?

 

Your next best bet is to look on CL for scrapyard ads that parts out totaled cars. I've seen engines for $3k - $4k

 

I have been running 10,000 miles between oil changes with zero issues .. So it can be done and I have beaten the crap out if my car . I consume about a quart and a half within 10,000 miles . I have also sent my oil to black stone and it still was good .. Changing oil around 3,000 miles is a waste of money . But , what ever floats your boat ...