Go Back   Great Lakes 4x4. The largest offroad forum in the Midwest > 4x4 Talk > Jeep Tech
GL4x4 Live! GL4x4 Casino







Search
Reply
 
Thread Tools
Old November 23rd, 2005, 09:17 AM   #1
Shakr
formerly square eyed rio
 
Shakr's Avatar
 
Join Date: 11-07-05
Location: Howell
Posts: 548
iTrader: (4)
Mentioned: 0 Post(s)
Default No Heat but blower fan works (Grand Cherokee)

O.K. I searched and found no answer . My Grand Cherokee (98) now has no heat . The blower works in every level, ac blows . hoses are hot so the thermostat is working , antifreeze is good and full. Temp guage reads just below 210 deg. I'd say right around 190 / 200 deg. and gets there with in 5 minutes of starting the jeep. I let the motor run with the cap off the rad. to bleed any air out and I reversed the heater hose to unplug the core but all hoses are warm/hot once engine has run. My guess is a vacum line problem not functioning the flapper ?.

Has anyone experienced this or is there a common area along the path to check , I really do not want to rip the dash apart if someone knows a quick fix.
Shakr is offline   Reply With Quote
Old November 23rd, 2005, 10:33 AM   #2
rm25x
Senior Member
 
rm25x's Avatar
 
Join Date: 11-06-05
Location: Grand Blanc, MI
Posts: 493
iTrader: (8)
Mentioned: 0 Post(s)
Default

My buddy just had the same problem. Flush out the heater core. He had tons of crap come out of his, and now the heat works great!
rm25x is offline   Reply With Quote
Old November 23rd, 2005, 10:38 AM   #3
Shakr
formerly square eyed rio
 
Shakr's Avatar
 
Join Date: 11-07-05
Location: Howell
Posts: 548
iTrader: (4)
Mentioned: 0 Post(s)
Default

Quote:
Originally Posted by rm25x
My buddy just had the same problem. Flush out the heater core. He had tons of crap come out of his, and now the heat works great!
Thats my next step but the hoses are hot ...maybe not enough flow though ...too bad my garden hose is probably froze on the back of my house.

My yj has this and I reversed the heater lines and it's worked great , I did this to the grand and nothing changed.
Shakr is offline   Reply With Quote
Old November 23rd, 2005, 12:01 PM   #4
clarkstoncracker
lol
 
clarkstoncracker's Avatar
 
Join Date: 11-03-05
Location: OC - MI
Posts: 42,279
iTrader: (39)
Mentioned: 71 Post(s)
Send a message via AIM to clarkstoncracker
Default

Definitly clean out the heater core.. Are the lines hot, or are they "warm" if you just have a trickle going through there, its probably not going to warm up..

Try putting it in neutral, or park, turn on the heater on high after it is warm, and rev the engine up, I bet you slowly get heat...
__________________
clarkstoncracker is offline   Reply With Quote
Old November 23rd, 2005, 08:25 PM   #5
rm25x
Senior Member
 
rm25x's Avatar
 
Join Date: 11-06-05
Location: Grand Blanc, MI
Posts: 493
iTrader: (8)
Mentioned: 0 Post(s)
Default

His lines would get hot too, but I think its just from convection. Once we flushed out the core, we saw why flow was limited. Couldn't believe the amount of crap that came out of it.
rm25x is offline   Reply With Quote
Old November 24th, 2005, 12:12 AM   #6
BDSjeeper
Senior Member
 
BDSjeeper's Avatar
 
Join Date: 11-05-05
Location: Saline, MI
Posts: 381
iTrader: (3)
Mentioned: 0 Post(s)
Send a message via AIM to BDSjeeper
Default

you can get a flush gun that has a garden hose and an air compressor hose hookup, shove it in the top radiator hose, disconnect the lower hose, and give er' hell.
BDSjeeper is offline   Reply With Quote
Old November 24th, 2005, 06:59 AM   #7
Yetti
Buy a Fiat! Save the UAW!
 
Yetti's Avatar
 
Join Date: 11-05-05
Location: 20 minutes south of Hell...
Posts: 14,383
iTrader: (10)
Mentioned: 1 Post(s)
Default

since I have seen every stupid trick in the book, I will tell you to be careful of using a garden hose. the best way to flush the crud out is to get to lengths of hose and take the ones from the engine off. put the new ones on and then add water from the hose and aim one at a bucket to catch what ever comes out. I have seen candy wrappers sandwitch bags and even the little foil things from additives come out of the fittings. the biggest thing to watch is to not over presure the heater core with the hose. they can put out as much as 60 psi and will cause your core to fail. it can blow the core up in the car and then you have no choice but to replace it.
__________________
Yetti
Yetti is offline   Reply With Quote
Old November 24th, 2005, 10:26 AM   #8
Shakr
formerly square eyed rio
 
Shakr's Avatar
 
Join Date: 11-07-05
Location: Howell
Posts: 548
iTrader: (4)
Mentioned: 0 Post(s)
Default

Well I flushed the core , just a little black gunk then clear water flowed , I reversed water direction and clear water came out again. I let the motor get warm/hot and revved it up ...still no heat , I took the control module out of the dash and everything is plugged in , I can select low med hi switch from floor to defrost to recirc ect. all functions work . top rad hose and both heater hoses get to a "hot " temp but I can touch them with my bare hand for a few seconds then is hot enough to be uncomfortable .

Does anyone know what the insurance pay for a totaled or stole/ not recovered 1998 grand cherokee. I dont owe any money but I'd like to get enough to buy something else. @#$% mf ing Jeep P.O.S.
Shakr is offline   Reply With Quote
Old November 24th, 2005, 10:33 AM   #9
brimy311
Smells like a Fork Liftis
 
brimy311's Avatar
 
Join Date: 11-05-05
Location: Kzoo, mi
Posts: 4,092
iTrader: (42)
Mentioned: 0 Post(s)
Send a message via AIM to brimy311
Default

it is not overheating it is? Do you have the right mix of collant/water? If it is frozen, it would cause it not to flow right. Check the upper and lower radiator hoses and be sure they are simular temps. If one is cold, you have a no flow, frozen or broken water pump.
__________________
JcrOffroad.com
Like us on Faceook!
brimy311 is offline   Reply With Quote
Old November 24th, 2005, 10:40 AM   #10
Haggar
Covered in mud...
 
Haggar's Avatar
 
Join Date: 11-06-05
Location: Oxford, MI
Posts: 17,543
iTrader: (54)
Mentioned: 1 Post(s)
Default

If the core is flowing fine, then that should be ok.

What about the valve that lets hot water into the core? Opening/closing ok?

What about the flapper doors inside the HVAC plenum which select between heat and AC, have you observed them moving correctly?

Thats all thats left to check.
Haggar is offline   Reply With Quote
Old November 24th, 2005, 12:27 PM   #11
cornfed
I have an avatar. Yippee.
 
cornfed's Avatar
 
Join Date: 11-04-05
Location: Happy Funtown U.S.A.
Posts: 4,105
iTrader: (22)
Mentioned: 0 Post(s)
Default

Quote:
Originally Posted by square eyed rio
the control module
What kind of module does it have: electronic or knobs?

I've had to replace the knob's potentiometer on a couple of my rides but not a JGC. The knob movement was irregular. You could move the knob, but the temperature wouldn't change. It was a $7.00 dealer part and a 5min R&R.
cornfed is offline   Reply With Quote
Old November 24th, 2005, 01:13 PM   #12
rm25x
Senior Member
 
rm25x's Avatar
 
Join Date: 11-06-05
Location: Grand Blanc, MI
Posts: 493
iTrader: (8)
Mentioned: 0 Post(s)
Default

Well only other thing I can think of then, is last winter on my Ram the cable popped off the door, with it stuck in the cold position. Bad part is that it was behind the glove box where it come off.
rm25x is offline   Reply With Quote
Old November 25th, 2005, 08:32 AM   #13
93yjsahara
Senior Member
 
Join Date: 11-17-05
Location: Louisville
Posts: 182
iTrader: (0)
Mentioned: 0 Post(s)
Default

ZJ's have a notrious blend door failure problem. If you search in JU, or NGCA there is quite a bit of info on the problem.
93yjsahara is offline   Reply With Quote
Old November 25th, 2005, 09:39 AM   #14
KILLER"B"468
Yankabilly
 
KILLER"B"468's Avatar
 
Join Date: 11-06-05
Location: Hendersonville Tn.
Posts: 7,945
iTrader: (19)
Mentioned: 0 Post(s)
Default

Quote:
Originally Posted by 93yjsahara
ZJ's have a notrious blend door failure problem. If you search in JU, or NGCA there is quite a bit of info on the problem.

That or the vac line came off out in the engine compartment.
__________________
being on the eastern edge of the central time zone sucks...it gets dark WAY to early.

Quote:
Originally Posted by jeepbrattt View Post
An occasional jello or vasoline wrestling match isn't out of the question either.
KILLER"B"468 is offline   Reply With Quote
Old November 25th, 2005, 10:26 AM   #15
Shakr
formerly square eyed rio
 
Shakr's Avatar
 
Join Date: 11-07-05
Location: Howell
Posts: 548
iTrader: (4)
Mentioned: 0 Post(s)
Default

I have to believe the coolant flow is good and at proper mixture all the hoses get very warm .
I think it is a flapper /electric control problem . I have the twist type selecter for hot / cold . I took it out of the dash and everything appears to be plugged in . I have function to ac, def. recirc, feet, head ect. it is just all cold air blowing.

I tried getting under the dash but everthing is in the plastic box ...I do not see a control rod for the flapper .

I let it run for over a half hour with no change to the air temp comming out the vents.

I'm gonna find that flapper !!
Shakr is offline   Reply With Quote
Old November 25th, 2005, 11:57 AM   #16
Shakr
formerly square eyed rio
 
Shakr's Avatar
 
Join Date: 11-07-05
Location: Howell
Posts: 548
iTrader: (4)
Mentioned: 0 Post(s)
Default

Update .... heat now works !!!! I'm not sure what I did but I have heat . I went to JU and read about the few who paid up to 1000.00 to replace the flapper mech. in the dash and I said F that , I'm going to locate the flapper and cut a hole in the plastic & hook a choke cable to it to make it a manual operation but I jiggled a few wires and kicked the black box and all of a sudden heat came out ...... Now I'm afraid to touch anything :)

Thanks to all for the advice .
Shakr is offline   Reply With Quote
Reply
Great Lakes 4x4. The largest offroad forum in the Midwest > 4x4 Talk > Jeep Tech
Thread Tools

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



All times are GMT -5. The time now is 09:20 AM.


Powered by: vBulletin, Copyright 2000 - 2012, Jelsoft Enterprises Ltd.
User Alert System provided by Advanced User Tagging (Lite) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd. Runs best on HiVelocity Hosting.
Copyright 2005 - 2012 Cracker Enterprises - Powered by Linux
vB Ad Management by =RedTyger=
Page generated in 0.17376 seconds with 42 queries