Gents,
I noticed the heater wasn't doing anything a couple of weeks ago so I flushed the core out and got a pretty good flow going. Some heat cam out of the vents but not the 140F the manual say it should be.
Yesterday I checked the blend door actuator after removing the glove box. It cycled completely so the actuator is OK and temperature did change so the door seems to be OK. All of the other doors work as well but I'm still at around 100F max at the windeshield.
Gents,
I noticed the heater wasn't doing anything a couple of weeks ago so I flushed the core out and got a pretty good flow going. Some heat cam out of the vents but not the 140F the manual say it should be.
Yesterday I checked the blend door actuator after removing the glove box. It cycled completely so the actuator is OK and temperature did change so the door seems to be OK. All of the other doors work as well but I'm still at around 100F max at the windeshield.
It's a sleepy 4.0 :smile2:
Temperature in the block is 215F and warms up pretty quickly. The hose to the heater core is hot (too hot to hold) and the return line is cooler but not by much. I'll get an IR gun and see what the difference is. This has me baffled.
I'm considering removing the blower to see if the AC core is plugged up and I was thinking of drilling some holes in the heater box and running a scope inside to really check the doors. That will be this coming Friday. Has anyone done this?
You probably don't want to hear this, but it sounds like it may be time to install a new heater core. If the flow through the core is limited, then it can't provide enough BTU's to keep up with the heating demand. I suppose you could try doing some kind of chemical flush on the core, but then you risk creating a leak. That would mean swapping the heater core right away.
HH3, I'm leaning in this direction. I've isolated the core and I tried the chemical flush. I tested the system pressure up to 30 psi first to see if I had any weak spots. The flow seems to be OK but I wouldn't really know for sure.
Reading through various threads t seems that an air lock will produce the same symptoms.
I did a fwd and rev flush a couple of times and the water pump is new. It was installed by someone else. That doesn't mean too much if the part is faulty.
Chris Hager (moderator) did a write-up on the seals that are in the vent system. The seals deteriorate over time and leak air inside the dash. Maybe someone can help with the link.
I did a fwd and rev flush a couple of times and the water pump is new. It was installed by someone else. That doesn't mean too much if the part is faulty.
I wish I had better drawings of the complete HVAC assembly. In my other Chrysler I drilled access holes to boroscope inspect the AC and heater cores for debris and to inject foam cleaners to clean the fins. A couple of more holes were added for the doors to check their movement.
This beats the heck out of tearing everything down just to find that the doors work.
The problem with the Jeep is that I'm not sure where to put the holes and don't want to puncture something important. I have the service manual but it's really not much help.
^^^ Thanks for the offer but I like the manual setup. Photos of the outside of the box from multiple angles, top and bottom would go a long way to helping me find the best places to drill. If it's easier to email them I'll send you my address by PM.
^^^ Thanks for the offer but I like the manual setup. Photos of the outside of the box from multiple angles, top and bottom would go a long way to helping me find the best places to drill. If it's easier to email them I'll send you my address by PM.
Continuing on today, I took off the cap and let it run for 20 minutes. At the end of this, the heater feed hose was really hot to the touch and the return was COLD. The heat register were putting out air at a temperature of about 70F with an outside temp of 9F. It's starting to look like a plugged core and it's getting worse so tomorrow its the CLR and drill pump routine in a closed loop. I really hope this works otherwise its tear down time.
I still plan on drilling inspection holes to check the door action and the evap core face for dirt/trash.
Continuing on today, I took off the cap and let it run for 20 minutes. At the end of this, the heater feed hose was really hot to the touch and the return was COLD. The heat register were putting out air at a temperature of about 70F with an outside temp of 9F. It's starting to look like a plugged core and it's getting worse so tomorrow its the CLR and drill pump routine in a closed loop. I really hope this works otherwise its tear down time. I still plan on drilling inspection holes to check the door action and the evap core face for dirt/trash.
As I write this I'm using a drill pump to circulate CLR through the heater core only. The rest of the system is blocked off. Bucket of water and clr pumped the cold side of the core and then from the hot side dumped back into the bucket (reverse flush). Lots of foam as the calcium carbonate dissolves. It's be 30 minutes so I'm off to flush and reconnect everything.
Edit: Well, there is more heat but nowhere as much as there should be. It liveable but if the temps go down to -35 it's not going to cut it. Next it's "check the doors" time and if they're ok the its a new heater core.
Gents, I noticed the heater wasn't doing anything a couple of weeks ago so I flushed the core out and got a pretty good flow going. Some heat cam out of the vents but not the 140F the manual say it should be. Yesterday I checked the blend door actuator after removing the glove box. It cycled completely so the actuator is OK and temperature did change so the door seems to be OK. All of the other doors work as well but I'm still at around 100F max at the windeshield. Any ideas????
Success. Even after all the preceding work I finally found the "solution". I got fed up and felt "what the hell" so I filled the heater core with 100% CLR and let it sit overnight (17 hours). The flushed out CLR had a huge pile of crap in it and.......the heater now works properly and no leaks. Most of the junk was light brown and looked like scale. If there was any calcium in there is was gone.
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