G35 exhaust leak

[gwoods]

On full throttle acceleration I hear louder exhaust sound from drivers side front of the car and it sounds almost like a miss fire at 7,000 RPM + I am 99% sure its an exhaust leak.

Looked around under the hood with a flashlight tonight and didn't see anything super obvious.

Where would you start....

I am hoping its not the manifold gasket cause the AC is on that side

[RED_DET]

Yeah, I'm thinking manifold my self. Hopefully it's no cracked...

[gwoods]

I just bought a junk yard exhaust manifold for $45.

Then I checked ebay and found this?

http://cgi.ebay.com/ebaymotors/350Z-G35 ... 230bbd752d

[RED_DET]

Junk, probably crack in 6 months or less. Ebay "stuff" should never be used for any kind of performance upgrade unless it is brand specific.

[gwoods]

Ya I was curious what kind of metal could offer such volume for so little cost LOL

[tollboothwilley]

That manifold isn't a fun one to get out...but you shouldn't have to worry about the AC lines. The passenger side is more of a pain because of the coolant piping. Drivers side you have the steering column that gets in the way.

I don't think I've heard of any stock manifold problems. The stock manifold are very thick and would be hard to crack.

[gwoods]

I'm doing brakes on Sunday so I'll have the wheel off and the car up and I will get a good look.

Its kind of intermitant not constant seems to go away once the car gets hot..... makes me think gasket leak? I'll have a spare manifold just incase.

[tollboothwilley]

the stock manifold gaskets are metal, so they shouldn't deteriorate.

You could test for smoke leak??

[gwoods]

So.... I bought a gently used G35 driver side exhaust manifold from a recycler, new studs, new gaskets from Infiniti.

Sunday the 12th I sat down in my garage and started trying to take it apart. After about an hour I decided that my hands were not going to fit between the fender wall and the motor to get the exhaust manifold off.

On 12/14 I dropped the car off at Infiniti of Scottsdale with the instructions that I am not willing to spend over $500 on this. I can buy a junk yard motor with 16000 miles on it in California for $1700. I have a guy here in Phoenix that imports Japanese motors with less then 40,000 miles on them and I can get one for $900.

The exhaust leak noise goes away when the car warms up so IOS spend a couple days starting the car cold and listening. On Friday they heard the exhaust leak. Car started coming apart on the 18th. On the 20th the service manager called to say they had broken 3 studs trying to disassemble the car.

The gasket was leaking the manifold was warped and cracked, 3 studs were replaced.

My service manager brought me the car at my house on Christmas Eve. I probably should not say what I paid but I will say I am incredibly satisfied. I could not have fixed this my self in the 10 days the dealership took at twice what I paid. Infiniti of Scottsdale took care of me and my car again. If you are even thinking of a new Infiniti and you are anywhere near Infiniti of Scottsdale take a look. The ownership experience is amazing!!

My Y pipe still leaks and now is much louder since the exhaust manifold leak is fixed. I am looking at Y pipes and will probably one this month or next.

I really enjoyed the 2010 G37 Sedan loaner I drove for 10 days and put just over 1300 miles on. The 7spd grew on me and this G37 did feel faster then my G35. I enjoyed the back up camera but missed my sunroof.

[tollboothwilley]

those manifolds are a pain to get off...but I'm sure you could have done it yourself if you really wanted to.

Glad you got it all fixed and taken care of though. Sounds like they have been incredibly generous and done a lot for you.

[gwoods]

If I had broke the 3 studs off in the head it would have cost me at least double what Infiniti charged me

[tollboothwilley]

True...but you might not have broken them either

Did they drop the motor to change it out after they broke the studs?

[gwoods]

I have no idea how they got to the studs to tap them. If it were me I would have pulled the head that's easy and then you have room to do the exhaust manifold. You can install the head with the manifold and head shield bolted to it.

[tollboothwilley]

easier to drop the motor than removing the heads.

just remove all the electrical connections, unbolts the AC condenser, remove the coolant lines and drop the subframe. If you have the dealers equipment it seems like it would only take 3 hours or so.