98TJ Heat Issue
 

I'm looking for any ideas on this one, as it doesn't make much sense
to me:'

I drove to get lunch, and sitting in the drive-thru line, turned on
the heat. It was probably around 10 degrees Fahrenheit with the wind-
chill. The engine was about 3/4 warmed up, at which point, I should
(and have in the past) feel some nice heat. . But, all I got was cold
air. Very cold air. Heater controls all looked good, so I left it on,
and sat there, until the needle was vertical, and still, cold air.

So I turned the engine off, until I got my order, and fired it back
up, and immediately had heat.

At the time, I turned the engine off, as I suspected a stuck
thermostat, but later realized that the heater-core is always on the
same loop as the engine as far as the coolant goes, so that couldn't
be it. Any ideas? This is the first time this has happened, so I'll
post more if it happens more.

Any ideas?

Re: 98TJ Heat Issue
 

Dave wrote:
> I'm looking for any ideas on this one, as it doesn't make much sense
> to me:'
>
> I drove to get lunch, and sitting in the drive-thru line, turned on
> the heat. It was probably around 10 degrees Fahrenheit with the wind-
> chill. The engine was about 3/4 warmed up, at which point, I should
> (and have in the past) feel some nice heat. . But, all I got was cold
> air. Very cold air. Heater controls all looked good, so I left it on,
> and sat there, until the needle was vertical, and still, cold air.
>
> So I turned the engine off, until I got my order, and fired it back
> up, and immediately had heat.
>
> At the time, I turned the engine off, as I suspected a stuck
> thermostat, but later realized that the heater-core is always on the
> same loop as the engine as far as the coolant goes, so that couldn't
> be it. Any ideas? This is the first time this has happened, so I'll
> post more if it happens more.
>
> Any ideas?

Always.... :)

Vac leak, possibly a cracked hardline or something that took a bit
of heat from the engine to soften up and be able to seal. I'd check
the hard lines running from the intake rail for splits or loose soft
connections.

Although, IIRC the blend door is a stepper motor. In that case low
vac would have just kept the output stuck to one setting.

If it's electrical or a stuck blend door (Guess if it got water
in there it could freeze the rubber seals and make the door stick)
Heat would then free it.

I'm out of ideas. :/

--
DougW

Re: 98TJ Heat Issue
 

Dave wrote:
> I'm looking for any ideas on this one, as it doesn't make much sense
> to me:'
>
> I drove to get lunch, and sitting in the drive-thru line, turned on
> the heat. It was probably around 10 degrees Fahrenheit with the wind-
> chill. The engine was about 3/4 warmed up, at which point, I should
> (and have in the past) feel some nice heat. . But, all I got was cold
> air. Very cold air. Heater controls all looked good, so I left it on,
> and sat there, until the needle was vertical, and still, cold air.
>
> So I turned the engine off, until I got my order, and fired it back
> up, and immediately had heat.
>
> At the time, I turned the engine off, as I suspected a stuck
> thermostat, but later realized that the heater-core is always on the
> same loop as the engine as far as the coolant goes, so that couldn't
> be it. Any ideas? This is the first time this has happened, so I'll
> post more if it happens more.
>
> Any ideas?

Always.... :)

Vac leak, possibly a cracked hardline or something that took a bit
of heat from the engine to soften up and be able to seal. I'd check
the hard lines running from the intake rail for splits or loose soft
connections.

Although, IIRC the blend door is a stepper motor. In that case low
vac would have just kept the output stuck to one setting.

If it's electrical or a stuck blend door (Guess if it got water
in there it could freeze the rubber seals and make the door stick)
Heat would then free it.

I'm out of ideas. :/

--
DougW

Re: 98TJ Heat Issue
 

DougW wrote:
> Dave wrote:
>> I'm looking for any ideas on this one, as it doesn't make much
>> sense
>> to me:'
>>
>> I drove to get lunch, and sitting in the drive-thru line, turned on
>> the heat. It was probably around 10 degrees Fahrenheit with the
>> wind-
>> chill. The engine was about 3/4 warmed up, at which point, I should
>> (and have in the past) feel some nice heat. . But, all I got was
>> cold
>> air. Very cold air. Heater controls all looked good, so I left it
>> on,
>> and sat there, until the needle was vertical, and still, cold air.
>>
>> So I turned the engine off, until I got my order, and fired it back
>> up, and immediately had heat.
>>
>> At the time, I turned the engine off, as I suspected a stuck
>> thermostat, but later realized that the heater-core is always on
>> the
>> same loop as the engine as far as the coolant goes, so that
>> couldn't
>> be it. Any ideas? This is the first time this has happened, so I'll
>> post more if it happens more.
>>
>> Any ideas?
>
> Always.... :)
>
> Vac leak, possibly a cracked hardline or something that took a bit
> of heat from the engine to soften up and be able to seal. I'd check
> the hard lines running from the intake rail for splits or loose soft
> connections.
>
> Although, IIRC the blend door is a stepper motor. In that case low
> vac would have just kept the output stuck to one setting.
>
> If it's electrical or a stuck blend door (Guess if it got water
> in there it could freeze the rubber seals and make the door stick)
> Heat would then free it.
>
> I'm out of ideas. :/

Might have just gotten some water in it, frozen enough to stick the
door, later the ice melted and problem solved.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

Re: 98TJ Heat Issue
 

DougW wrote:
> Dave wrote:
>> I'm looking for any ideas on this one, as it doesn't make much
>> sense
>> to me:'
>>
>> I drove to get lunch, and sitting in the drive-thru line, turned on
>> the heat. It was probably around 10 degrees Fahrenheit with the
>> wind-
>> chill. The engine was about 3/4 warmed up, at which point, I should
>> (and have in the past) feel some nice heat. . But, all I got was
>> cold
>> air. Very cold air. Heater controls all looked good, so I left it
>> on,
>> and sat there, until the needle was vertical, and still, cold air.
>>
>> So I turned the engine off, until I got my order, and fired it back
>> up, and immediately had heat.
>>
>> At the time, I turned the engine off, as I suspected a stuck
>> thermostat, but later realized that the heater-core is always on
>> the
>> same loop as the engine as far as the coolant goes, so that
>> couldn't
>> be it. Any ideas? This is the first time this has happened, so I'll
>> post more if it happens more.
>>
>> Any ideas?
>
> Always.... :)
>
> Vac leak, possibly a cracked hardline or something that took a bit
> of heat from the engine to soften up and be able to seal. I'd check
> the hard lines running from the intake rail for splits or loose soft
> connections.
>
> Although, IIRC the blend door is a stepper motor. In that case low
> vac would have just kept the output stuck to one setting.
>
> If it's electrical or a stuck blend door (Guess if it got water
> in there it could freeze the rubber seals and make the door stick)
> Heat would then free it.
>
> I'm out of ideas. :/

Might have just gotten some water in it, frozen enough to stick the
door, later the ice melted and problem solved.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

Re: 98TJ Heat Issue
 

Hi Dave,
Check the coolant level at the radiator, cold. Many times an air pock
may fill the theater core. Those dried deposits should be back flushed out,
every two years alone with the coolant regular change.
God Bless America, Bill O|||||||O
mailto:----------@----------.com


"Dave" <dmcglynn@gmail.com> wrote in message
news:021e8fb0-fb14-412c-91f0-fba6f041e230@a35g2000prf.googlegroups.com...
> I'm looking for any ideas on this one, as it doesn't make much sense
> to me:'
>
> I drove to get lunch, and sitting in the drive-thru line, turned on
> the heat. It was probably around 10 degrees Fahrenheit with the wind-
> chill. The engine was about 3/4 warmed up, at which point, I should
> (and have in the past) feel some nice heat. . But, all I got was cold
> air. Very cold air. Heater controls all looked good, so I left it on,
> and sat there, until the needle was vertical, and still, cold air.
>
> So I turned the engine off, until I got my order, and fired it back
> up, and immediately had heat.
>
> At the time, I turned the engine off, as I suspected a stuck
> thermostat, but later realized that the heater-core is always on the
> same loop as the engine as far as the coolant goes, so that couldn't
> be it. Any ideas? This is the first time this has happened, so I'll
> post more if it happens more.
>
> Any ideas?



--
Posted via a free Usenet account from http://www.teranews.com

Re: 98TJ Heat Issue
 

Hi Dave,
Check the coolant level at the radiator, cold. Many times an air pock
may fill the theater core. Those dried deposits should be back flushed out,
every two years alone with the coolant regular change.
God Bless America, Bill O|||||||O
mailto:----------@----------.com


"Dave" <dmcglynn@gmail.com> wrote in message
news:021e8fb0-fb14-412c-91f0-fba6f041e230@a35g2000prf.googlegroups.com...
> I'm looking for any ideas on this one, as it doesn't make much sense
> to me:'
>
> I drove to get lunch, and sitting in the drive-thru line, turned on
> the heat. It was probably around 10 degrees Fahrenheit with the wind-
> chill. The engine was about 3/4 warmed up, at which point, I should
> (and have in the past) feel some nice heat. . But, all I got was cold
> air. Very cold air. Heater controls all looked good, so I left it on,
> and sat there, until the needle was vertical, and still, cold air.
>
> So I turned the engine off, until I got my order, and fired it back
> up, and immediately had heat.
>
> At the time, I turned the engine off, as I suspected a stuck
> thermostat, but later realized that the heater-core is always on the
> same loop as the engine as far as the coolant goes, so that couldn't
> be it. Any ideas? This is the first time this has happened, so I'll
> post more if it happens more.
>
> Any ideas?



--
Posted via a free Usenet account from http://www.teranews.com

Re: 98TJ Heat Issue
 

On Mon, 3 Dec 2007, Dave wrote:

> I'm looking for any ideas on this one, as it doesn't make much sense
> to me:'
>
> I drove to get lunch, and sitting in the drive-thru line, turned on
> the heat. It was probably around 10 degrees Fahrenheit with the wind-
> chill. The engine was about 3/4 warmed up, at which point, I should
> (and have in the past) feel some nice heat. . But, all I got was cold
> air. Very cold air. Heater controls all looked good, so I left it on,
> and sat there, until the needle was vertical, and still, cold air.
>
> So I turned the engine off, until I got my order, and fired it back
> up, and immediately had heat.
>
> At the time, I turned the engine off, as I suspected a stuck
> thermostat, but later realized that the heater-core is always on the
> same loop as the engine as far as the coolant goes, so that couldn't
> be it. Any ideas? This is the first time this has happened, so I'll
> post more if it happens more.
>
> Any ideas?

If your thermostat is stuck open the engine won't make any heat.
Happened last winter in my `69 4L XJ.

Re: 98TJ Heat Issue
 

On Mon, 3 Dec 2007, Dave wrote:

> I'm looking for any ideas on this one, as it doesn't make much sense
> to me:'
>
> I drove to get lunch, and sitting in the drive-thru line, turned on
> the heat. It was probably around 10 degrees Fahrenheit with the wind-
> chill. The engine was about 3/4 warmed up, at which point, I should
> (and have in the past) feel some nice heat. . But, all I got was cold
> air. Very cold air. Heater controls all looked good, so I left it on,
> and sat there, until the needle was vertical, and still, cold air.
>
> So I turned the engine off, until I got my order, and fired it back
> up, and immediately had heat.
>
> At the time, I turned the engine off, as I suspected a stuck
> thermostat, but later realized that the heater-core is always on the
> same loop as the engine as far as the coolant goes, so that couldn't
> be it. Any ideas? This is the first time this has happened, so I'll
> post more if it happens more.
>
> Any ideas?

If your thermostat is stuck open the engine won't make any heat.
Happened last winter in my `69 4L XJ.

Re: 98TJ Heat Issue
 

On Dec 3, 7:32 pm, "J. Clarke" <jclarke.use...@cox.net> wrote:
> DougW wrote:
> > Dave wrote:
> >> I'm looking for any ideas on this one, as it doesn't make much
> >> sense
> >> to me:'
>
> >> I drove to get lunch, and sitting in the drive-thru line, turned on
> >> the heat. It was probably around 10 degrees Fahrenheit with the
> >> wind-
> >> chill. The engine was about 3/4 warmed up, at which point, I should
> >> (and have in the past) feel some nice heat. . But, all I got was
> >> cold
> >> air. Very cold air. Heater controls all looked good, so I left it
> >> on,
> >> and sat there, until the needle was vertical, and still, cold air.
>
> >> So I turned the engine off, until I got my order, and fired it back
> >> up, and immediately had heat.
>
> >> At the time, I turned the engine off, as I suspected a stuck
> >> thermostat, but later realized that the heater-core is always on
> >> the
> >> same loop as the engine as far as the coolant goes, so that
> >> couldn't
> >> be it. Any ideas? This is the first time this has happened, so I'll
> >> post more if it happens more.
>
> >> Any ideas?
>
> > Always.... :)
>
> > Vac leak, possibly a cracked hardline or something that took a bit
> > of heat from the engine to soften up and be able to seal. I'd check
> > the hard lines running from the intake rail for splits or loose soft
> > connections.
>
> > Although, IIRC the blend door is a stepper motor. In that case low
> > vac would have just kept the output stuck to one setting.
>
> > If it's electrical or a stuck blend door (Guess if it got water
> > in there it could freeze the rubber seals and make the door stick)
> > Heat would then free it.
>
> > I'm out of ideas. :/
>
> Might have just gotten some water in it, frozen enough to stick the
> door, later the ice melted and problem solved.
>
> --
> --
> --John
> to email, dial "usenet" and validate
> (was jclarke at eye bee em dot net)

Riiight :) The regular coolant change :) That would be a good idea.

On the way home from work, it seemed to heat up normally, but I
noticed a couple strange things that don't seem familiar.. when the
engine warmed up, the heat was warm, but not hot . . but when I was
moving, or even when I revved the engine, the heat would get hot. At
the same time, I also noticed that when at idle, when the heat was not
as hot, my oil pressure guage would creep up to about 40, and then
when I revved the engine and the heat got hotter, the oil-pressure
dropped back down to about 25 or so..

Multiple problems showing up here?

The frozen blend door is quite possible, as the entire jeep was
encased in 1/4" of ice on Saturday night, and then an entire day of
rain followed.. I will check the coolant, and keep an eye on the
situation, and report any other strangities that show up.

Thanks for the help guys!