99 jeep wrangler heat problems

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  #1  
Old 01-30-08, 02:11 PM
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99 jeep wrangler heat problems

I have a 99 jeep wrangler sport, 4.0 6 cyl. This morning on my way to work it started overheating. I changed the thermostat and gasket seal. No more overheating, but now I don't have heat. It is blowing out cold air. I know it's not as cold where I am as say the mid west , but 19 degrees isn't exactly warm. What do I need to look for and at? Thanks in advance for any help.
 
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Old 01-30-08, 02:36 PM
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To your knowledge has anyone put radiator Stop Leak in it? If so, your heater core may be clogged up. If you take the heater hoses loose from the engine, and hook a garden hose up to the lower (return) hose and let it vacate or back flush the heater core it should work fine. Take note of the crud you back flush from the core, it will amaze you.
 
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Old 01-30-08, 04:21 PM
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Not to my knowledge. I will give it a shot and hopefully it will do the trick. Thanks.
 
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Old 01-30-08, 04:31 PM
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Did you let it run long enough with the cap off, heater on, and bleed out all the air ?
 
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Old 01-30-08, 04:38 PM
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I didn't turn the heat on until I had the cap back on. I did let it run for a few minutes or so with no cap on and it did a fair share of gurgling and chugging. I plan on doing a full flush tomorrow and see what happens.
 
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Old 01-30-08, 04:45 PM
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Originally Posted by chandler View Post
To your knowledge has anyone put radiator Stop Leak in it? If so, your heater core may be clogged up. If you take the heater hoses loose from the engine, and hook a garden hose up to the lower (return) hose and let it vacate or back flush the heater core it should work fine. Take note of the crud you back flush from the core, it will amaze you.

point me in the right direction on the location of the hoses I need to take off and which one I need to run the hose in. There are two smaller ones on top, one hooked to the radiator and one hooked to the compressor, than of course the bigger hoses at the top and bottom of the radiator.
 
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Old 01-31-08, 03:30 AM
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You are looking at the air conditioner hoses. Look at the firewall on the passenger side. There are two hoses entering the firewall going to your heater core. Trace them to their other end. It is easier to flush from that point. The one closest to the thermostat is the inlet side. You want to flush from the other one. Remove both, let the inlet flop loose and push water through the outlet side. This will back flush the heater core.
 
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Old 01-31-08, 06:04 AM
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Question

Not saying you did but is it possible the thermostat was put in upside down? this will cause your problem.
 
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Old 01-31-08, 02:03 PM
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Thermostat is in the right way, still no heat. Flushed the system, still no heat. A lot of crap though. It doesn't seem like any pressure is building up. I ran my car for 30 - 45 minutes and was immediately able to remove the radiator cap. Is this normal? After the flush my car seems to run a little cooler than it did before. It usually ran a little over half way, now it is a little under. I am contemplating killing my wallet and taking it into the shop, I don't know.
 
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Old 01-31-08, 02:47 PM
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this is possible

It is possible in this day and age to have a faulty new thermostat. You can either remove it and boil it in water and then stick in cold water and see if it opens and closes. It might be open all the time. It should be closed when cold and open when boiled in a pan of water.
I assume your heater was working good before you replaced the thermostat?
How about the cap is it new? also make sure you have the right temp thermostat and right pressure cap installed.
 
  #11  
Old 01-31-08, 03:58 PM
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I had the cap off of the radiator and when it reached the right temp I could tell the thermostat opened up. I could see the coolant start swirling, but I may try replacing the new one I just put on it and see if that helps. A day or so before my jeep overheated I noticed that the heat was a little cooler than usual. Not too much, but enough to notice. It was still hot air. The cap has been on there since I bought the jeep in 2003.
 
  #12  
Old 01-31-08, 04:48 PM
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Don't be afraid of reving engine a bit during bleeding, to aid in pushing the coolant through heater core a little more, especially if your core is up high on the fire wall, above engine. Chrysler had a little problem with that at one time in the Caravans, where the coolant wouldn't cycle properly because of the lift required. Once you reved it a bit, you could feel a temperature change, but at idle, it would almost stay cold. Are you sure your temperature control is working good, can you hear things moving? Feel your hoses going into the heater at firewall, do they feel basically same temperature, or is one cool & one really hot ? Is there a valve in one hose that controls flow, that you can take out and bypass with a fitting ( copper tubing, and hose clamps) temporarily, to see if that valve may be the problem?

Just a couple of thoughts.
 
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Old 01-31-08, 08:26 PM
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I revved the engine for a few minutes while we were bleeding the air out. Nothing changed in the temp of the air from that and idling. The temp control seems to be working fine. Both of the hoses stay the same temperature at all times, pretty cool to the touch. It is my understanding that one of them should be hot? Though that could be wrong. There is no valve on either of the hoses. I found a place that will LOOK at it for $30. Maybe I'll take it there.


Actually now that I'm thinking about it. When I got home today one of the hoses was really hot and the other one cool. I'm not sure if it was because that one hose was so close to the engine.
 
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Old 01-31-08, 08:37 PM
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Hot coolant should be going in, and slightly, just noticeably cooler coming out. (still pretty warm, but certainly not cool)
Flow problem somewhere. For $30, it's worth it for a proper diagnosis.
 
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Old 02-02-08, 06:28 AM
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Ok, last post before I head to the shop. Started to overheat yesterday when I was close to my house. I put a new cap on it with the pressure release handle on top. When I lifted the handle, coolant went straight into the overflow jug. I made it back home and repeated the same process. Same thing, only this time a bunch of coolant filled the container. I checked the hoses on top and bottom of the radiator and the top was hot, but not the bottom. It was still cold. Any last advice before I head to the sharks?
 
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