I had the day off today and decided to tackle an overdue project of flushing the heater core on my 99 TJ 4.0. I've owned this TJ for about 18 months and although there are a number of upgrades on my list, I've been prioritizing overdue maintenance for the most part since buying this TJ.
One nagging issue has been that the heater barely worked and pushed out warm air at best. So today I finally decided to tackle it. The job was made very easy and mostly mess free with some tubing and hose adapters I bought at home depot.i figured I'd post a list of what I bought and the process in case it's helpful to anyone else.
Items used:
-10 feet of ¾" inside diameter tubing
-10 feet of ⅝" inside diameter tubing
-Cheap squeeze grip hose sprayer with a threaded end for hose connection
-⅝" hose barb with hose adapter
-¾" hose barb with hose adapter
Here's a pic of the setup I used:
I started by removing the heater core hoses at the firewall. With the hoses removed I cleaned up the copper nipples as best I could with some sand paper. Then I connected the ¾" tubing to the top heater core outlet and the ⅝" tubing to the lower outlet.
Next I attached the larger tube to the spray nozzle and ran the smaller tube into a 5 gallon bucket.
I started spraying water thru the tubing and was astonished at how nasty the brown sludge was that came out the other tube! The hose was dark brown the entire first flush until I'd filled the 5 gallon bucket.
I emptied the bucket and repeated this process using the other hose and back flushing the system the other direction. Again a ton of brown nastiness until the bucket was full.
I repeated this process of flushing in both directions a total of 5 times each direction before the water was running clear. This is what was left over in the bucket after the flush.
After that I reconnected the heater core hoses, topped off and burped all air out of the system and let her idle until fully warmed up. I got in and cranked the heater full blast and was astonished at how hard and hot it was blowing!
Very satisfying to resolve this heater issue as I was planning a trail run up into big bear in a couple weeks and wasn't looking forward to not having a working heater!
Hope this proves helpful to someone else.
One nagging issue has been that the heater barely worked and pushed out warm air at best. So today I finally decided to tackle it. The job was made very easy and mostly mess free with some tubing and hose adapters I bought at home depot.i figured I'd post a list of what I bought and the process in case it's helpful to anyone else.
Items used:
-10 feet of ¾" inside diameter tubing
-10 feet of ⅝" inside diameter tubing
-Cheap squeeze grip hose sprayer with a threaded end for hose connection
-⅝" hose barb with hose adapter
-¾" hose barb with hose adapter
Here's a pic of the setup I used:
I started by removing the heater core hoses at the firewall. With the hoses removed I cleaned up the copper nipples as best I could with some sand paper. Then I connected the ¾" tubing to the top heater core outlet and the ⅝" tubing to the lower outlet.
Next I attached the larger tube to the spray nozzle and ran the smaller tube into a 5 gallon bucket.
I started spraying water thru the tubing and was astonished at how nasty the brown sludge was that came out the other tube! The hose was dark brown the entire first flush until I'd filled the 5 gallon bucket.
I emptied the bucket and repeated this process using the other hose and back flushing the system the other direction. Again a ton of brown nastiness until the bucket was full.
I repeated this process of flushing in both directions a total of 5 times each direction before the water was running clear. This is what was left over in the bucket after the flush.
After that I reconnected the heater core hoses, topped off and burped all air out of the system and let her idle until fully warmed up. I got in and cranked the heater full blast and was astonished at how hard and hot it was blowing!
Very satisfying to resolve this heater issue as I was planning a trail run up into big bear in a couple weeks and wasn't looking forward to not having a working heater!
Hope this proves helpful to someone else.
