NAXJA Forums -::- North American XJ Association  

Go Back   NAXJA Forums -::- North American XJ Association > NAXJA Unibody Jeep Technical Forums > Jeep Cherokee XJ (1984 - 2001) > OEM Tech Discussion
HOME Member FAQ Sponsor Info Rules Bylaws E-Mail

OEM Tech Discussion Forum for OEM (Original Equipment) or stock XJs and MJs.

Reply
 
Thread Tools Display Modes
  #1  
Old October 4th, 2017, 08:30
4x4JeePmaNthINg's Avatar
4x4JeePmaNthINg 4x4JeePmaNthINg is offline
NAXJA Forum User
 
Join Date: Nov 2008
Location: colorado, Foco
Posts: 430
99 xj, can exhaust feed into the cab via HVAC?

Is there anyway that something on the 4.0 can fail sending exhaust fumes through the heater into the cab?

where does the hvac system pull air from, air box, intake. vacuum....?

thanks
Reply With Quote
  #2  
Old October 4th, 2017, 14:48
Rob Mayercik's Avatar
Rob Mayercik Rob Mayercik is offline
NAXJA Member #920
 
Join Date: Jun 2002
Location: NJ, U.S.A.
Posts: 1,947
Re: 99 xj, can exhaust feed into the cab via HVAC?

As far as I know:

Primary intake is under cowl on passenger side.

Secondary intake is wherever in the passenger front footwell it sucks from for recirc (MAX) in A/C mode.
__________________
1992 Cherokee Laredo: "A wonderful balance of grace and rust"
1984 Dodge Omni
2002 Volkswagen Jetta GLS TDI
Reply With Quote
  #3  
Old October 4th, 2017, 15:59
Ewenm's Avatar
Ewenm Ewenm is offline
NAXJA Forum User
 
Join Date: Jun 2003
Location: Gold Coast Australia
Posts: 205
Re: 99 xj, can exhaust feed into the cab via HVAC?

the cabin air is picked up at the base of the windscreen, where the wiper motor is, so no exhaust gas should not be able to get in, unless you have the back of the hood jacked up and a serious exhaust manifold leak.

if you are getting exhaust in the cabin and the exhaust system has no leaks, check your tailgate seals , as you drive along you can suck fumes back in via a leaking tailgate.
Reply With Quote
  #4  
Old October 4th, 2017, 17:10
Ivan's Avatar
Ivan Ivan is offline
I Jeep, therefore, I am..
 
Join Date: May 2002
Location: Eureka, CA
Posts: 1,457
Re: 99 xj, can exhaust feed into the cab via HVAC?

There is a foam seal that fits between the HVAC coil box and the firewall. It falls apart over time. This is also a common water leak point for water into your passenger side cabin through the engine bay, so exhaust from a leaky manifold is possible where the foam seal once was.

If you need to replace either your AC or heater coils anyway in order to replace the foam seal, there's a long process for removing the dash for access. Search other posts for that procedure.

However, you can stilll seal it from under the hood, by applying silicon sealant where the blower motor pokes out into the engine bay. Just move aside some emissions line, and apply sealer all the way around firewall and blower motor area....
__________________
Member #133

Kleptomaniacs help themselves, because they can't help themselves......
Reply With Quote
  #5  
Old October 4th, 2017, 22:45
Ewenm's Avatar
Ewenm Ewenm is offline
NAXJA Forum User
 
Join Date: Jun 2003
Location: Gold Coast Australia
Posts: 205
Re: 99 xj, can exhaust feed into the cab via HVAC?

yep that is correct, i had forgotten about that.

one of the first things i had to fix 18 years ago, when the factory converted the XJ to right hand drive, the lower part of the cutout for the blower was Below the inner guard, water would pool and run into the cabin, grrrrr that was hard to find.
Reply With Quote
  #6  
Old October 4th, 2017, 23:28
4x4JeePmaNthINg's Avatar
4x4JeePmaNthINg 4x4JeePmaNthINg is offline
NAXJA Forum User
 
Join Date: Nov 2008
Location: colorado, Foco
Posts: 430
Re: 99 xj, can exhaust feed into the cab via HVAC?

if you are getting exhaust in the cabin and the exhaust system has no leaks, check your tailgate seals , as you drive along you can suck fumes back in via a leaking tailgate.[/QUOTE]

Tail gate does rattle some, but I know the manifold is cracked near the front of the engine. Windows up I didn't think I should smell anything , but my way down the canyon I had the heater on and I swore I smelled exhaust.
Reply With Quote
  #7  
Old October 5th, 2017, 05:30
Ewenm's Avatar
Ewenm Ewenm is offline
NAXJA Forum User
 
Join Date: Jun 2003
Location: Gold Coast Australia
Posts: 205
Re: 99 xj, can exhaust feed into the cab via HVAC?

i would be checking the blower seal as mentioned by Ivan
Reply With Quote
  #8  
Old October 6th, 2017, 00:16
md21722 md21722 is offline
NAXJA Member
 
Join Date: Feb 2014
Location: Colorado Springs
Posts: 2,286
Re: 99 xj, can exhaust feed into the cab via HVAC?

The exhaust manifold isn't that far from the throttle cable where it passes through the firewall. If that grommet is shot, that's another entry point.
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Please I need some feed back 98_XJ_Classic Modified Tech Discussion 11 January 20th, 2009 13:54
Feed Me Seymour.... bburge SoCal Fest 2007 7 April 24th, 2007 19:40
RSS Feed makmadison User Support, Questions and Suggestions 1 September 7th, 2006 15:39
rss feed gregclimbs User Support, Questions and Suggestions 0 March 23rd, 2005 09:40


All times are GMT -7. The time now is 14:50.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
NAXJA and NAXJA logo's Copyright NAXJA. All content/images Copyright NAXJA 1999-2014