Brief "rattle" noise immediately after cold start

M

Mike005

Member
Location
Dallas, TX
Car
2004 Infiniti FX35 AWD
I've owned my 2004 FX35 for 4 years now and can't figure this out to save my life. I just picked it up from the Infiniti dealership for what was the 10-12th time attempting to diagnose/fix this noise, with no luck. This time cost me $3,200 and although I have a new timing chain, guides, tensioners, water pump etc…, I still have the noise. And again, like all other times, they told me the noise is “normal”. I simply don’t believe that, but maybe I’m wrong. Does anyone else hear this noise? It only does it after a cold start and last’s for less than 2 seconds. The best way to describe it is a rattle or knocking noise. The explanation from Infiniti is the oil is not pumping into the area with the timing chain guides/tensioners fast enough on a start, hence the brief noise on a cold start and not any other time. We replaced everything you might want to replace while in there, even the sprockets. Has anyone experience this? Any ideas?
sugarsync.com/pf/D635395_60657675_6052886
 
Fire0nic3FX said:
You know that sound was a common problem on G35's. sounds similar to a timing chain issue but its not and could be the main bearing:



Aaron,
Thanks for the reply. I can't believe I haven't seen that thread after all the searching I have done on this issue. I really appreciate you sending that.

---------- Post added at 10:12 PM ---------- Previous post was at 10:10 PM ----------
soonster said:
might be good idea to ref this old thread:

good luck in finding a resolution.
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Thanks...that was actually my post from a few years ago :smile (2):
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Even though it could be that issue lets just hope bro that it isn't. Because that guy had to replace his engine which could end up being costly :bad:
 
I can honestly say that I too have heard this noise on my FX35 on startup and the noise I hear IS the timing chains. I have done the timing chains/guides on these motors before and what you likely hear is the lack of oil pressure as was stated by the dealer upon startup. You have gravity working against you as well as thicker oil and small oil passages. If you have ever looked at the hydraulic chain tensioner on these cars (or any car) the oil port is very small. I dont know that it is a huge cause for concern especially without hearing it myself, but I will say that 3200 dollars should net you peace of mind. Thats an insane repair bill for the timing chains. I know they are not easy by no stretch of imagination I wouldnt just say everyone should attempt them, but they are not THAT hard and parts 100% oem replacement are in the neighborhood of 800-900 from the dealer if memory serves me right.
 
I agree that it's oil pressure causing the problem. What I would like to know is how to fix it. Surely this was not happening when the car was new, so something has changed. I like the car but can't stand the noise. Even more frustrating is the inability to fix it.
 
macuto69 said:
I have a 2004 FX and it does the same noise on a cold start up. Make sure the oil levels are good because these engine consume a lot of oil.
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Unfortunately, oil levels don't affect his particular issue. I've literally spent thousands of dollars trying to fix the problem and it turns out it's a problem that can't be fixed without replacing the entire engine. It's common with most 2003-04 FX35's. Infiniti is aware of the problem but can't/won't do anything about it.
 
Mine makes a slight/sudden "clunk" noise on cold starts. It Idles / Run / Drives perfectly fine though and aside from the 1 second clunk there isn't any other issue. If this is what you are experiencing then i have to ask.. What is the big deal? My advice would be to stop throwing money at something that isn't really a problem.
 
Stealth said:
Mine makes a slight/sudden "clunk" noise on cold starts. It Idles / Run / Drives perfectly fine though and aside from the 1 second clunk there isn't any other issue. If this is what you are experiencing then i have to ask.. What is the big deal? My advice would be to stop throwing money at something that isn't really a problem.
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It's more of a loud rattling noise, like the timing chain rattling against metal. Might not be a big deal for you, but it bothers me that my car sounds like a cheap 1971 Ford Pinto every time it starts. Don't get me wrong, I love the FX35. Unfortunately I made the mistake of buying the first year model (2004 but made in Sept 2003, so still considered first year in my opinion) and like all first year models, it has bugs.
 
I heard a good explanation on this on the G35 forums.

I heard the reason it does this on cold starts or startup only is because the motor oil is laying in the pan and hasn't got a chance to circulate and lube the chains and what not. My G35 makes this start up clunk it rattle sometimes. I also noticed it more pronounced after I just did a motor oil change and start it up for the first time because the new motor oil hasn't lubed the chains and stuff yet. Too me it sounds normal. I really don't care what if it sounds like a pinto or whatever because it only happens for a brief 1 second. And that is only SOMETIMES. Its not like I have someone standing outside my G35 on a startup trying to listen for things. So it doesn't bother me.

It also doesn't effect how my G35 drives. My car runs great and the motor is quiet as hell.
 
Yeah, I read that same post. But it doesn't make sense because the car certainly wasn't doing it when it was new. Seems to start after 30k+ miles. I've given up on trying to figure it out. Hopefully this post will save others from wasting their time and money on this problem.

Sent from my SCH-I545
 
I am assuming the rattling is coming only from your engine bay, but did you check your exhaust? I have a 2004 FX 35 and the counter weights and steal tension wire for the exhaust rusted off, the heat shields were rattling till I wired them and the exhaust pipe finally broke at the muffler flange. My fix was a new gemini invidia exhaust system, I'll tell you if the rattling goes away when I finally get to install it.
 
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Thanks for the note. It's definitely coming from the engine bay. Please do let me know. I'm actually dropping it off at the dealer for a transmission flush this coming Monday, so it would be great to know by then!

Sent from my SCH-I545
 
Mike005 said:
Thanks for the note. It's definitely coming from the engine bay. Please do let me know. I'm actually dropping it off at the dealer for a transmission flush this coming Monday, so it would be great to know by then!

Sent from my SCH-I545
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I know this a couple years later but what ever ended up happening?? My 2003 g35 has this same issue
 
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