50fils

Hey, whats up guys, ok so i have issue with my g37. i did some research and it sounds like i have a spun rod bearing. Car runs smooth and drives great. Here the problem with the car parked on idle it runs great no ticking nor knocking sound no rough idle either everything seems to be normal. But when you gas the car little and reach about 1500-2500 rpms it make a wired engine noise (clunk clunk clunk) and it goes away in the higher rpms. when driving the car in the first gear you can hear it the same rpm range and it goes away as the rpms gets higher and when in the second you don't hear it at all. . I did some research and i came across it might be a spun rod bearing FML. but can you guys check your car and see if they makes the same kind of noise. Here what you have to do with the engine warm just rev the engine between 1500-2500 rpms and hold it and see if you hear the knocking noise. I will really appreciate it i trying to find another g37 local to hear but thought forum is the best help i can get.
Fyi no codes on scan tools
but if I remove the VVT solenoid and replace it with faulty one then the noise gone any explanation?.

jfridge92

When you quick rev the car in park or neutral, when the RPMs come down around that same range, do you hear the noise? Try to get under the car while someone holds the RPM's at that range and see if you can hear the noise in the catalytic converters. The CATS on these cars tend to fail, causing the internal honeycomb material to break loose and rattle around. It can sound a lot like knocking, and they tend to vibrate the most around the RPM range you mentioned. I'd try to rule that out before deciding your engine is knocking.Generally if you have rod knock, it's going to be audible at all RPM ranges and not just a certain RPM.


Also, it'd be a good idea to drain the oil into an open drain pan and look for any sparkles or metal material in the oil, indicating a bearing failure. You can also pull the dipstick and look at the oil with a flashlight to see if you see any sparkles of metal on it as well. I'm not sure why swapping the VVT Solenoid would cause it to stop, as I haven't experienced anything similar with the solenoid.


TLDR: Check your catalytic converters first for loose material that rattles and sounds like a knock at the 1500-2500 RPM range.
Check the oil to see if there is any metal sparkles and material in it, indicating a bearing failure.

slartibartfast

iTrader: (7)

Rod knock sound doesn't go away. It's heard from idle to redline, just changing volume.

50fils

when it on P or N no knocking even when the RPMs come down around that same range, i dont hear any noise
I went to agent and kept the 3 days there and the report says everything is ok, they reprogramming the car only . And I ask them to check the cats but as per their report no issues with the cats.
I think it's something related to the timing that's why if I swap the vvt solenoid the problem gone
my concern is if I keep my car running with faulty vvt solenoid ( code p0021) is it s safe to drive the car or not
during the last year the only way to remove the knocking is to swap the VVT solenoid with faulty one
please I need help I went to agent and 100 mechanic but unfortunately nothing happened

jfridge92

So are you actually throwing code P0021 in the car? That code combined with a knocking noise could indicate low oil pressure, and a potential failure of the oil gallery gaskets in the rear timing cover. If you are throwing that code, have the oil pressure verified with a mechanical gauge.

50fils

my car have no codes but to stop the knocking I swap the vvt solenoid with faulty one then I got poo21 code and knocking stop
when vvt system work in my car I get the knocking that's why I have to stop it with faulty vvt solenoid
now I want to know is it safe to drive the car with code p0021 or not ???????

JonR

Did you find out what the issue was?

juster

I had something like this. Car would have a mild diesel like sound at 2800 to 3k range only under load. I always assumed it was VVEL and was going to replace it. Anyway I got a tune and after I ran the pop tune for a bit I haven't hear the noise since. Guessing the timing settings for that pop tune unstuck or straightened out whatever was going on. I don't know for sure but that was my experience with a noise like this.

JonR

TL : DR - Use full synthetic oil. I used a blend and was getting a knock when the engine was cold and cruising at 1,800 rpms. Never while parked.

I had a vvt solenoid fail on me. The car went into limp mode and threw a Code P0021.
While trying to diagnose the issue, I did an oil change as I read sometimes that could be the issue. It was about due for one anyways. By mistake I grabbed a synthetic blend, never thought twice about it.
Well the oil change didn't fix the issue, so I get a replacement vvt solenoid and that did fix the limp mode issue.
However, a new issue accrued. When the car was cold, and cruising at 1,800 rpms. (never sitting in park, the engine had to be under light load) There would be tapping. Giving it some gas would make the tapping go away. Normally all it took was a light goosing and the tapping would stop, till the next time I started the car while the engine was cold.
Now, I was very concerned at first, but after a week of driving like that. There wasn't a rough idle or any codes being thrown. So I figured it was the cheap vvt solenoid I bought. Told myself I'd replace it with an OEM one soon... Well about a year later and it's time for an oil change. I use the recommended full synthetic and guess what? No more cold engine knock. Luckily I didn't start throwing parts at it.