obirer

After ignoring the unusual fogging on the windshield and the holly
smoke rising from the defroster duct for the last couple days, my 91
wrangler finally turned into a sauna...Vapor all over the place....

I suspect there is a coolant leak at the heater core and I found a
tiny pool of coolant on the engine side, (platform over the front
wheel on passenger side) I will attempt to remove the housing for the
heater but I wanted to ask if there are any particular points I should
be careful about. In Haynes manual it talks about removing the nuts
from the studs on the engine side of the firewall but does not specify
the number and positions. I appreciate if anyone has suggestions and
thanks to previous posts I know removing the passanger seat will save
me a lot of frustration....

Thanks

Oz.

Roy J

You didn't give a year, they are different. The later CJ and YJ
are similar, the key things to know:

-Drain some coolant then detach the heater hoses inside the
engine compartment.
-Remove the passenger seat. (This is optional, but you will
understand why after you do the removal LOL!!)
-Remove the obvious control cables and unplug the resister pack
plug at the passenger knees.
-Unplug the heater motor electrical connector in the engine
compartment.
-Find the ***FOUR*** nuts holding the heater box in place. Two
are up on top between the engine and the battery. The third is
way down below, under the starter solenoid. The 4th is behind the
valve cover, on the driver's side.
-Pull out the heater box.

You can get the core repaired at any good radiator shop, about
$30 and 4 hours around here. Make sure where ever you bring it
has piles of radiators, a test tank, etc laying around. Any place
else will just subcontract it to the REAL shop and charge you a
service fee to drop it off. As in doubling the price.

Might as well think about drain, flush, and new coolant while you
are at it. Bew thermostat is not a bad idea either. If you need
to drive it while you find or repair your heater core, you can
just use a piece of 1/2" copper tube from Home Depot to splice
the two hose ends together. No heat but no sauna effect either.

Cheers.

obirer wrote:

> After ignoring the unusual fogging on the windshield and the holly
> smoke rising from the defroster duct for the last couple days, my 91
> wrangler finally turned into a sauna...Vapor all over the place....
>
> I suspect there is a coolant leak at the heater core and I found a
> tiny pool of coolant on the engine side, (platform over the front
> wheel on passenger side) I will attempt to remove the housing for the
> heater but I wanted to ask if there are any particular points I should
> be careful about. In Haynes manual it talks about removing the nuts
> from the studs on the engine side of the firewall but does not specify
> the number and positions. I appreciate if anyone has suggestions and
> thanks to previous posts I know removing the passanger seat will save
> me a lot of frustration....
>
> Thanks
>
> Oz.

Roy J

You didn't give a year, they are different. The later CJ and YJ
are similar, the key things to know:

-Drain some coolant then detach the heater hoses inside the
engine compartment.
-Remove the passenger seat. (This is optional, but you will
understand why after you do the removal LOL!!)
-Remove the obvious control cables and unplug the resister pack
plug at the passenger knees.
-Unplug the heater motor electrical connector in the engine
compartment.
-Find the ***FOUR*** nuts holding the heater box in place. Two
are up on top between the engine and the battery. The third is
way down below, under the starter solenoid. The 4th is behind the
valve cover, on the driver's side.
-Pull out the heater box.

You can get the core repaired at any good radiator shop, about
$30 and 4 hours around here. Make sure where ever you bring it
has piles of radiators, a test tank, etc laying around. Any place
else will just subcontract it to the REAL shop and charge you a
service fee to drop it off. As in doubling the price.

Might as well think about drain, flush, and new coolant while you
are at it. Bew thermostat is not a bad idea either. If you need
to drive it while you find or repair your heater core, you can
just use a piece of 1/2" copper tube from Home Depot to splice
the two hose ends together. No heat but no sauna effect either.

Cheers.

obirer wrote:

> After ignoring the unusual fogging on the windshield and the holly
> smoke rising from the defroster duct for the last couple days, my 91
> wrangler finally turned into a sauna...Vapor all over the place....
>
> I suspect there is a coolant leak at the heater core and I found a
> tiny pool of coolant on the engine side, (platform over the front
> wheel on passenger side) I will attempt to remove the housing for the
> heater but I wanted to ask if there are any particular points I should
> be careful about. In Haynes manual it talks about removing the nuts
> from the studs on the engine side of the firewall but does not specify
> the number and positions. I appreciate if anyone has suggestions and
> thanks to previous posts I know removing the passanger seat will save
> me a lot of frustration....
>
> Thanks
>
> Oz.

Roy J

You didn't give a year, they are different. The later CJ and YJ
are similar, the key things to know:

-Drain some coolant then detach the heater hoses inside the
engine compartment.
-Remove the passenger seat. (This is optional, but you will
understand why after you do the removal LOL!!)
-Remove the obvious control cables and unplug the resister pack
plug at the passenger knees.
-Unplug the heater motor electrical connector in the engine
compartment.
-Find the ***FOUR*** nuts holding the heater box in place. Two
are up on top between the engine and the battery. The third is
way down below, under the starter solenoid. The 4th is behind the
valve cover, on the driver's side.
-Pull out the heater box.

You can get the core repaired at any good radiator shop, about
$30 and 4 hours around here. Make sure where ever you bring it
has piles of radiators, a test tank, etc laying around. Any place
else will just subcontract it to the REAL shop and charge you a
service fee to drop it off. As in doubling the price.

Might as well think about drain, flush, and new coolant while you
are at it. Bew thermostat is not a bad idea either. If you need
to drive it while you find or repair your heater core, you can
just use a piece of 1/2" copper tube from Home Depot to splice
the two hose ends together. No heat but no sauna effect either.

Cheers.

obirer wrote:

> After ignoring the unusual fogging on the windshield and the holly
> smoke rising from the defroster duct for the last couple days, my 91
> wrangler finally turned into a sauna...Vapor all over the place....
>
> I suspect there is a coolant leak at the heater core and I found a
> tiny pool of coolant on the engine side, (platform over the front
> wheel on passenger side) I will attempt to remove the housing for the
> heater but I wanted to ask if there are any particular points I should
> be careful about. In Haynes manual it talks about removing the nuts
> from the studs on the engine side of the firewall but does not specify
> the number and positions. I appreciate if anyone has suggestions and
> thanks to previous posts I know removing the passanger seat will save
> me a lot of frustration....
>
> Thanks
>
> Oz.

Mike Romain

To add to that, first check the hose very carefully at the firewall.
Maybe just a dead end on it or even just a turn needed on the clamp.
That can cause your symptoms.

If you have the 258 engine and have to open the heater, there is a
'radical' upgrade for the blower fan while it is open too.

http://www.off-road.com/jeep/tech/body/heater.html

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT'sv

Roy J wrote:
>
> You didn't give a year, they are different. The later CJ and YJ
> are similar, the key things to know:
>
> -Drain some coolant then detach the heater hoses inside the
> engine compartment.
> -Remove the passenger seat. (This is optional, but you will
> understand why after you do the removal LOL!!)
> -Remove the obvious control cables and unplug the resister pack
> plug at the passenger knees.
> -Unplug the heater motor electrical connector in the engine
> compartment.
> -Find the ***FOUR*** nuts holding the heater box in place. Two
> are up on top between the engine and the battery. The third is
> way down below, under the starter solenoid. The 4th is behind the
> valve cover, on the driver's side.
> -Pull out the heater box.
>
> You can get the core repaired at any good radiator shop, about
> $30 and 4 hours around here. Make sure where ever you bring it
> has piles of radiators, a test tank, etc laying around. Any place
> else will just subcontract it to the REAL shop and charge you a
> service fee to drop it off. As in doubling the price.
>
> Might as well think about drain, flush, and new coolant while you
> are at it. Bew thermostat is not a bad idea either. If you need
> to drive it while you find or repair your heater core, you can
> just use a piece of 1/2" copper tube from Home Depot to splice
> the two hose ends together. No heat but no sauna effect either.
>
> Cheers.
>
> obirer wrote:
>
> > After ignoring the unusual fogging on the windshield and the holly
> > smoke rising from the defroster duct for the last couple days, my 91
> > wrangler finally turned into a sauna...Vapor all over the place....
> >
> > I suspect there is a coolant leak at the heater core and I found a
> > tiny pool of coolant on the engine side, (platform over the front
> > wheel on passenger side) I will attempt to remove the housing for the
> > heater but I wanted to ask if there are any particular points I should
> > be careful about. In Haynes manual it talks about removing the nuts
> > from the studs on the engine side of the firewall but does not specify
> > the number and positions. I appreciate if anyone has suggestions and
> > thanks to previous posts I know removing the passanger seat will save
> > me a lot of frustration....
> >
> > Thanks
> >
> > Oz.

Mike Romain

To add to that, first check the hose very carefully at the firewall.
Maybe just a dead end on it or even just a turn needed on the clamp.
That can cause your symptoms.

If you have the 258 engine and have to open the heater, there is a
'radical' upgrade for the blower fan while it is open too.

http://www.off-road.com/jeep/tech/body/heater.html

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT'sv

Roy J wrote:
>
> You didn't give a year, they are different. The later CJ and YJ
> are similar, the key things to know:
>
> -Drain some coolant then detach the heater hoses inside the
> engine compartment.
> -Remove the passenger seat. (This is optional, but you will
> understand why after you do the removal LOL!!)
> -Remove the obvious control cables and unplug the resister pack
> plug at the passenger knees.
> -Unplug the heater motor electrical connector in the engine
> compartment.
> -Find the ***FOUR*** nuts holding the heater box in place. Two
> are up on top between the engine and the battery. The third is
> way down below, under the starter solenoid. The 4th is behind the
> valve cover, on the driver's side.
> -Pull out the heater box.
>
> You can get the core repaired at any good radiator shop, about
> $30 and 4 hours around here. Make sure where ever you bring it
> has piles of radiators, a test tank, etc laying around. Any place
> else will just subcontract it to the REAL shop and charge you a
> service fee to drop it off. As in doubling the price.
>
> Might as well think about drain, flush, and new coolant while you
> are at it. Bew thermostat is not a bad idea either. If you need
> to drive it while you find or repair your heater core, you can
> just use a piece of 1/2" copper tube from Home Depot to splice
> the two hose ends together. No heat but no sauna effect either.
>
> Cheers.
>
> obirer wrote:
>
> > After ignoring the unusual fogging on the windshield and the holly
> > smoke rising from the defroster duct for the last couple days, my 91
> > wrangler finally turned into a sauna...Vapor all over the place....
> >
> > I suspect there is a coolant leak at the heater core and I found a
> > tiny pool of coolant on the engine side, (platform over the front
> > wheel on passenger side) I will attempt to remove the housing for the
> > heater but I wanted to ask if there are any particular points I should
> > be careful about. In Haynes manual it talks about removing the nuts
> > from the studs on the engine side of the firewall but does not specify
> > the number and positions. I appreciate if anyone has suggestions and
> > thanks to previous posts I know removing the passanger seat will save
> > me a lot of frustration....
> >
> > Thanks
> >
> > Oz.

Mike Romain

To add to that, first check the hose very carefully at the firewall.
Maybe just a dead end on it or even just a turn needed on the clamp.
That can cause your symptoms.

If you have the 258 engine and have to open the heater, there is a
'radical' upgrade for the blower fan while it is open too.

http://www.off-road.com/jeep/tech/body/heater.html

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT'sv

Roy J wrote:
>
> You didn't give a year, they are different. The later CJ and YJ
> are similar, the key things to know:
>
> -Drain some coolant then detach the heater hoses inside the
> engine compartment.
> -Remove the passenger seat. (This is optional, but you will
> understand why after you do the removal LOL!!)
> -Remove the obvious control cables and unplug the resister pack
> plug at the passenger knees.
> -Unplug the heater motor electrical connector in the engine
> compartment.
> -Find the ***FOUR*** nuts holding the heater box in place. Two
> are up on top between the engine and the battery. The third is
> way down below, under the starter solenoid. The 4th is behind the
> valve cover, on the driver's side.
> -Pull out the heater box.
>
> You can get the core repaired at any good radiator shop, about
> $30 and 4 hours around here. Make sure where ever you bring it
> has piles of radiators, a test tank, etc laying around. Any place
> else will just subcontract it to the REAL shop and charge you a
> service fee to drop it off. As in doubling the price.
>
> Might as well think about drain, flush, and new coolant while you
> are at it. Bew thermostat is not a bad idea either. If you need
> to drive it while you find or repair your heater core, you can
> just use a piece of 1/2" copper tube from Home Depot to splice
> the two hose ends together. No heat but no sauna effect either.
>
> Cheers.
>
> obirer wrote:
>
> > After ignoring the unusual fogging on the windshield and the holly
> > smoke rising from the defroster duct for the last couple days, my 91
> > wrangler finally turned into a sauna...Vapor all over the place....
> >
> > I suspect there is a coolant leak at the heater core and I found a
> > tiny pool of coolant on the engine side, (platform over the front
> > wheel on passenger side) I will attempt to remove the housing for the
> > heater but I wanted to ask if there are any particular points I should
> > be careful about. In Haynes manual it talks about removing the nuts
> > from the studs on the engine side of the firewall but does not specify
> > the number and positions. I appreciate if anyone has suggestions and
> > thanks to previous posts I know removing the passanger seat will save
> > me a lot of frustration....
> >
> > Thanks
> >
> > Oz.

Tookie

While you have it apart, now is the time to do the blower motor
upgrade- use a blower motor out of a Blazer,I think.
Someone who has done this want to explain it?
I haven't done it yet, because I don't want to go thru all the trouble
of pulling it apart.
Tookie - Denham Springs, LA
88YJ,"Money Hungry"
4" lift, 33" TSLs, Lock-Rights
PosiLock, 4.10s

Tookie

While you have it apart, now is the time to do the blower motor
upgrade- use a blower motor out of a Blazer,I think.
Someone who has done this want to explain it?
I haven't done it yet, because I don't want to go thru all the trouble
of pulling it apart.
Tookie - Denham Springs, LA
88YJ,"Money Hungry"
4" lift, 33" TSLs, Lock-Rights
PosiLock, 4.10s

Tookie

While you have it apart, now is the time to do the blower motor
upgrade- use a blower motor out of a Blazer,I think.
Someone who has done this want to explain it?
I haven't done it yet, because I don't want to go thru all the trouble
of pulling it apart.
Tookie - Denham Springs, LA
88YJ,"Money Hungry"
4" lift, 33" TSLs, Lock-Rights
PosiLock, 4.10s