Help - new FI HFC leaking at gaskets on exhaust side

InnerDragon10 · 03-21-2015, 05:59 PM

Installed Fast Intentions HFC, and have been fighting with the SES light for over a week now. I spoke with Tony @ Fast Intentions and he helped narrow it down. I went under the hood and tightened alot of fasteners on my Stillen CAI system (surprised to find so many!), but now I have a different issue.

The gaskets are leaking between the stock Nismo CBE and the back of the cats. I found out by observing condensate dripping from them after starting the car. I've tightened the bolts a lot. These are new gaskets and new bolts. I'll post a video once it's done uploading.

Assuming my flanges are all straight, why can't I get the gaskets to seal? They're symmetrical (as far as I know) and shouldn't have a specific orientation, so what gives? Anyone else come across this issue?

InnerDragon10 · 03-21-2015, 06:58 PM

Video:

JARblue · 03-21-2015, 07:20 PM

Quote:

Originally Posted by InnerDragon10

Assuming my flanges are all straight, why can't I get the gaskets to seal?

This would be a nice assumption, but have you actually checked the flanges? Other than that, not sure man. If the gaskets are new, it's unlikely they are the culprit.

37zeroZ · 03-22-2015, 11:35 AM

I had the same problem when I installed my AAM exhaust. After firing it up, I had leaks on all fours seals after the cats. One being worse than the others. I wound up redoing those flanges by applying cooper seal to the four gaskets. All turned out great.....no leaks.

Chuck33079 · 03-22-2015, 11:52 AM

RTV the hell out of it and go on about your day.

TechnicZ · 03-22-2015, 12:43 PM

I would take a wire brush bit attached to a drill to clean the mating surfaces. A gasket won't work if both surfaces werent somewhat clean.

InnerDragon10 · 03-22-2015, 01:15 PM

Yea i put a straight edge on them to check. I ended up using permatex, so we'll see if I solved it.

Trips · 03-22-2015, 02:08 PM

Quote:

Originally Posted by Chuck33079

RTV the hell out of it and go on about your day.

InnerDragon10 · 03-23-2015, 02:35 PM

Got the SES light again. However, I admit that I didn't let the copper permatex set for 24 hrs before returning to service (more like one hour, I just didn't have the time to let it sit), and I only re-did the y-pipe to HFC flanges. Looks like I'll have to pull it all down this weekend (have four new gaskets on order), and will apply sealant to all four flanges. Sigh.

37zeroZ · 03-23-2015, 06:45 PM

Quote:

Originally Posted by InnerDragon10

Got the SES light again. However, I admit that I didn't let the copper permatex set for 24 hrs before returning to service (more like one hour, I just didn't have the time to let it sit), and I only re-did the y-pipe to HFC flanges. Looks like I'll have to pull it all down this weekend (have four new gaskets on order), and will apply sealant to all four flanges. Sigh.

I let mine sit for nearly two days. Overkill, however, I applied a fair amount to each side of the gasket.

Merv · 03-23-2015, 07:27 PM

What I did was just snug up all 3 nuts,than do another round of tightening on all 3,THEN I torqued the sh:t out of them! Kind of like how you do the lugs on the wheel.

37zeroZ · 03-23-2015, 08:21 PM

Quote:

Originally Posted by Merv

What I did was just snug up all 3 nuts,than do another round of tightening on all 3,THEN I torqued the sh:t out of them! Kind of like how you do the lugs on the wheel.

Won't work if the flanges are off. I even purchased higher strength hardware thinking I can muscle stainless steel. I was wrong.......even afraid I would crack the weld joints. The Ultra Cooper solved my problem......simple and solved my problems.

Merv · 03-24-2015, 09:22 AM

Quote:

Originally Posted by 37zeroZ

Won't work if the flanges are off. I even purchased higher strength hardware thinking I can muscle stainless steel. I was wrong.......even afraid I would crack the weld joints. The Ultra Cooper solved my problem......simple and solved my problems.

I just re read the post and seen he's using high flows in conjunction with nismo exhaust. I could see how they might not match up.

InnerDragon10 · 03-24-2015, 06:45 PM

Quote:

Originally Posted by 37zeroZ

Won't work if the flanges are off. I even purchased higher strength hardware thinking I can muscle stainless steel. I was wrong.......even afraid I would crack the weld joints. The Ultra Cooper solved my problem......simple and solved my problems.

So you had some exhaust leaks and resolved them with permatex? I hope that's the case for me, I'm gonna be pissed if that SES light still comes up..

37zeroZ · 03-24-2015, 10:55 PM

Quote:

Originally Posted by InnerDragon10

So you had some exhaust leaks and resolved them with permatex? I hope that's the case for me, I'm gonna be pissed if that SES light still comes up..

Yes, as stated, I had four flange leaks and used Permatex Ultra Copper to stop the leaks. I waited longer than the recommended 24-hours to fully dry before I fired up the Z and drove off.

The SES can be or not be related to a problem with your exhaust. I suggest after you correctly Permatex your seals is to reset your ECU.

Here's a good link to do so:

RESET ECU alternative method

03-21-2015, 05:59 PM	#1 (permalink)
InnerDragon10 Base Member Join Date: Mar 2014 Location: USA Posts: 90 Drives: '14 Black 370Z Nismo Rep Power: 11	Help - new FI HFC leaking at gaskets on exhaust side Installed Fast Intentions HFC, and have been fighting with the SES light for over a week now. I spoke with Tony @ Fast Intentions and he helped narrow it down. I went under the hood and tightened alot of fasteners on my Stillen CAI system (surprised to find so many!), but now I have a different issue. The gaskets are leaking between the stock Nismo CBE and the back of the cats. I found out by observing condensate dripping from them after starting the car. I've tightened the bolts a lot. These are new gaskets and new bolts. I'll post a video once it's done uploading. Assuming my flanges are all straight, why can't I get the gaskets to seal? They're symmetrical (as far as I know) and shouldn't have a specific orientation, so what gives? Anyone else come across this issue?

03-22-2015, 11:52 AM	#5 (permalink)
Chuck33079 A True Z Fanatic Join Date: Nov 2011 Location: Houston Posts: 12,265 Drives: 2011 370ztt Rep Power: 29539	RTV the hell out of it and go on about your day. Trips, JARblue and Zoren 370 like this. __________________ 2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

03-23-2015, 07:27 PM	#11 (permalink)
Merv Track Member Join Date: Dec 2013 Location: Vancouver B.C Posts: 518 Drives: 11 GM grey sport tou Rep Power: 14	What I did was just snug up all 3 nuts,than do another round of tightening on all 3,THEN I torqued the sh:t out of them! Kind of like how you do the lugs on the wheel. InnerDragon10 likes this. __________________ Swift springs \| upgraded headlights \| stillen gen3 cai \| FI HFC's and FI CBE \| ecutek tune in the mail!

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03-21-2015, 06:58 PM	#2 (permalink)
InnerDragon10 Base Member Join Date: Mar 2014 Location: USA Posts: 90 Drives: '14 Black 370Z Nismo Rep Power: 11	Video:

03-22-2015, 11:35 AM	#4 (permalink)
37zeroZ Enthusiast Member Join Date: Feb 2010 Location: Dallas Posts: 346 Drives: Truck Rep Power: 14168	I had the same problem when I installed my AAM exhaust. After firing it up, I had leaks on all fours seals after the cats. One being worse than the others. I wound up redoing those flanges by applying cooper seal to the four gaskets. All turned out great.....no leaks.

03-22-2015, 12:43 PM	#6 (permalink)
TechnicZ Base Member Join Date: Oct 2009 Location: NJ Posts: 106 Drives: 2009 370z Base Sport Rep Power: 16	I would take a wire brush bit attached to a drill to clean the mating surfaces. A gasket won't work if both surfaces werent somewhat clean.

03-22-2015, 01:15 PM	#7 (permalink)
InnerDragon10 Base Member Join Date: Mar 2014 Location: USA Posts: 90 Drives: '14 Black 370Z Nismo Rep Power: 11	Yea i put a straight edge on them to check. I ended up using permatex, so we'll see if I solved it.

03-23-2015, 02:35 PM	#9 (permalink)
InnerDragon10 Base Member Join Date: Mar 2014 Location: USA Posts: 90 Drives: '14 Black 370Z Nismo Rep Power: 11	Got the SES light again. However, I admit that I didn't let the copper permatex set for 24 hrs before returning to service (more like one hour, I just didn't have the time to let it sit), and I only re-did the y-pipe to HFC flanges. Looks like I'll have to pull it all down this weekend (have four new gaskets on order), and will apply sealant to all four flanges. Sigh.