hello i am new to the g35 forum and fairly new to my g35 it is a 2005 at coupe with about 100000 miles on it but i just recently noticed a knocking noise coming from my engine that doesn't go away and when i rev the engine it goes even louder i feel like this is fairly common but i would like to know how much i can expect to pay if i take it into the shop because im out of warranty or at least a ball park thanks.

 

Is this car an automatic or manual? Have you checked the Oil level? Any "knocking" is a very bad sign, if its a manual transmission that means it has the Rev-up engine which was notorious for oil consumption. If this is the case its likely the oil level got low and spun a bearing.

The only other thing I can think of (optimistically) is that its injector noise, our injectors tend to be very noisy and maybe you just aren't accustomed to that sound.

I recommend taking it to a proffesional shop (G/Z Specialists if possible) and let them diagnose it, then report back to us what they say.

Goodluck,
-Rob

 

I get that knocking when im low on oil. Like the above person mention that might be the problem if you have a Rev-Up engine. But so far I have not had a spun bearing due to that issue. (fingers crossed)


Keep us posted if that wasnt the problem.
Good Luck.

 

When your oil pressure drops (in this case due to low oil) the VTCs get extremely noisy, thats more than likely what your referring to. But I wouldn't really call that a "Knock" noise.

If you are frequently hearing that sound you should check oil more frequently and possibly invest in an oil pan spacer so you can run 6qts, also try raising your oil weight to a 40 or 50 which should slow down the oil consumption slightly.

-Rob

 

so i took it into the shop and immediately they said it wasnt the engine which i was very thankful for but they said it was coming from the exhaust and when i got that checked out they said both my cat converters are shot they quoted me 2200 feel like i could do this myself any ideas thanks again for the help

 

WOW, even OE cats are only ~$600 each, thats a crazy quote. We now offer High Flow Cats, which will be a cheaper alternative to replacing with OE cats and also a performance upgrade.

More information can be found HERE

Goodluck! Let me know if I can help you with anything!
-Rob

 

those look exactly like test cats which are illegal why are those not illegal not to be rude jw and what would installation run on it?

 

I hate to thread jack but I'm going crazy over here about this car I just bought a month ago with a knock already. It's a 2006 g35 coupe 6mt. It has 74,000 miles on it, When I got it,it wasn't knocking. I checked the oil everyday. I noticed it was losing some but it wasn't that bad. About 1qt in 1800 miles.

I cranked it up one morning and it knocked on start-up but it went away. I filled the oil back up to the top of the full mark. It was still knocking every once in a while. It would do it on start-up and go away. Plus it would do it after a short 8 mile drive. Very quietly but it was still there. I changed the oil today to 10w 30 valvoline high mileage oil and the filter. Also,I took the oil pan off and looked for metal. There were a few 1mm pieces of metal in the oil. I put everything back together and it was filled to the upper level on the dipstick.

The knock is worse now. It's louder and it stays through the rpm range. I tried searching but I can't find if I need to use 5w 30 and that's it or what. I figured to help the consumption problem I would go to a thicker weight. Was I wrong in doing this? What is a good oil brand that no one has had worse consumption problems with?

 

This happened to me at 77K miles. In my 04 AT. Plz check ur Cats. U can replace them with HighFlow Cats or Test Pipes if price is an issue. Both of mines cats got crushed by compacted snow after a blizzard. Caused.heat to build up in my engine & burn oil fast as ****. By the time I realized it, that "knocking" that you guys are hearing destroyed my engine with the engine beating itself up internally. If ur hearing the noise when ur full on oil the damage may have already been done. Its easiest to tell if ur car turns over (starts) hard or it seems like it doesn't want to. Either way, take it to a specialists for our motors!!

 

Our HFCs are not test pipes, they do contain a Catalyst, however they are *intended for race/offroad use only*

PM Sent about install

-Rob

 

Your issue sounds more like normal transmission noise. Its pretty common among G/Zs to make a *knocking type sound* from transmission during cold start/low idle/ or after being driven hard.

Without hearing it in person of course i can't say for sure but that's my best guess. A lot of people mistake it for engine noise.

-Rob

 

ight i got the 04 g35 auto injen cold air and greddy exhaust. i got the same problem of course. i been thinkin the cats were bout to be done in mine cause u can smell it and the knock noise would come around on occasions since i bought it in june well it didnt become more noticable until i got it sideways comin out of walmart one night playin and i had it in manual mode wit traction off and i shifted 2nd way late tryin to keep the drift and went straight to cash wash to wash it wen i got ready to leave is wen i became a more constant thing after engine start note that i got all the same symptomss yall have had ok this happen like i think couples days ago less than week i believe ight well since then i ve been reading forum after forum gettin idea where to start first on car cause i know cats can cause problems wit motor but i didnt know if they could make that knockin so that was my confusion wit that ive noticed a slight power diff as u would if cats were cloggin last night on way home slowin dow to redlight noticed a hesitation in car more of astudder maybe so wen i pulled off thats wen i noticed it was straining to hard to pull off luckyly i lived right by light so got home cut off ad engine was cool as h** cats were poppin so i was like u know but after reading these latest threads from u all got me hopin that new cats will kill the knock wat yall think need some opinions thanks yall


wen tryin to diagnose it couple days ago started by changn oil and plugs u already know lil bit of metalic to the oil and oplugs were shot

 

That is all the same symptoms. Cat starts to tick & it can only b heard in the car, you can feel the heat from the cat if your window is down, then you start getting loss of power hear & there & it becomes more frequent. My car starting literally cutting off if I accelerated over 80MPH after I broke and dropped under 60MPH. Happened twice, then it did it at 60 then 1 day at 30... find a reputable shop & have them switch it out to High flow cats or Testpipes. Check your states emission laws. I just had an inspection here in MD while my testpipes are on & I passed bcuz for our cars (depending on state) they just check our ECUs to make sure the car is throwing a code. My mechanic told me of this from the jump. So if you have the right mecganic you shld b fine. Good luck brothers... hopefully you get that fix b4 your engine dies like mines did... $4K.

 

*To make sure the car is NOT throwing a code*
No CHECK ENGINE light is on!!

 

Probably a bad bearing. Typical problem with the VQ's.

Are you running Premium or Regular fuel?