Coolant leak

[Shazam]

Hi guys. The CJ has been in storage all winter, but started about every 2 weeks and driven a little while. Last week I noticed a coolant drip. Upon review its coming from one of the heater hoses where it goes into the firewall. I also noticed a little coolant by the neck mount of the radiator hose.

Is this an indication of anything serious - or just the time to tighten the bolts, clamps, etc? Many thanks.

 

[phyrph0enix]

The coolant hoses going into the firewall are to the heater core, which is made of very soft metal. When I got my jeep the core was so rusted it bonded to the hose and collapsed. I would take the hose off and inspect the fittings for any crush, then retighten- maybe with new worm clamps.

Just see if that works since it's (almost) free.

Metal fittings expand at a higher rate than the rubber hoses. This makes the fit tighter as it heats up. Over the winter, the fittings contract, loosening the fit.

Good luck

 

[Coach]

I had a leak that sounds similar to yours and it ended up being my heater core giving up. Picked up a new core, rebuilt the heater box, and installed the blazer blower and it is better now than it was new.

If it ends up being a heater core, there are some really good write ups on this site and a few others.

Best of luck.

Coach

 

[phyrph0enix]

Just bought a new core yesterday. ~$40 at AutoZone. Pretty self-explainatory... Just be mindful when removing the heater box - there's a lot of stuff there that doesn't get moved around very often that might crack on you (namely the vent hosing). If you decide to get the upgraded blower motor, it's part# PM102. NOT PM105... which is what comes up for a Blazer 350 w/ a/c. It's only ~$20 at the Zone.

Bon Chance!

 

[Coach]

Just bought a new core yesterday. ~$40 at AutoZone. Pretty self-explainatory... Just be mindful when removing the heater box - there's a lot of stuff there that doesn't get moved around very often that might crack on you (namely the vent hosing). If you decide to get the upgraded blower motor, it's part# PM102. NOT PM105... which is what comes up for a Blazer 350 w/ a/c. It's only ~$20 at the Zone.

Bon Chance!

Yes, he is correct, I learned that only after I was test fitting the blower motor, luckily, they swapped it out for me.

May end up needing a new defroster hose. I was able to make all the seals out of foam I had and shaped them to get a netter fit than stock. Used a jig saw to make the blower motor hole bigger, way easier than I expected that to be.

 

[Shazam]

Thanks guys. Good info. I re-seated the 2 heater hoses - pushing them against the firewall then tightened all the clamps. That did it...just as I hoped but wanted info in case there was more to it. Thank you all.

 

[cjdizzle]

need help on a coolant leak. new here so help would be appreciated. ran my 81 CJ7 for about a month. its summer, but cool mornings, so i ran the heater. no leaks till i got it home in the evening. it dumped a large amount of coolant OUTSIDE the truck. i cant see where its coming from the engine side, and theres no leaking coolant inside the cab. everything looks ok from the outside.its almost under the passenger seat. could it be the heater coil/box? any help is wanted

 

[Coach]

need help on a coolant leak. new here so help would be appreciated. ran my 81 CJ7 for about a month. its summer, but cool mornings, so i ran the heater. no leaks till i got it home in the evening. it dumped a large amount of coolant OUTSIDE the truck. i cant see where its coming from the engine side, and theres no leaking coolant inside the cab. everything looks ok from the outside.its almost under the passenger seat. could it be the heater coil/box? any help is wanted

I'm far from an expert, but the coolant system is one that I have been battling for a few months now. If it isn't leaking in the floorboard of your passenger side, you might look at the two connections where it comes out of the firewall below the battery tray. Those are the backside of your heater.

After that, you only have a few other possible locations for the leak. You have the other ends of the two hoses going into your heater, just follow them and check. Stange thing I learned in the process is a couple of the smaller hoses are different diameters at each end. You can buy the special hose that is made for the part, or buy a coupler that will splice two different diameter hoses together.

Hope you find the leak, I'm finally replacing my radiator, since it leaks off and on when the corrosion inside stops filling the holes.

Coach

 

[buffy1231]

need help on a coolant leak. new here so help would be appreciated. ran my 81 CJ7 for about a month. its summer, but cool mornings, so i ran the heater. no leaks till i got it home in the evening. it dumped a large amount of coolant OUTSIDE the truck. i cant see where its coming from the engine side, and theres no leaking coolant inside the cab. everything looks ok from the outside.its almost under the passenger seat. could it be the heater coil/box? any help is wanted

On the newer CJ's, they included a drain to dump the coolant through a 90 degree tube on to the tail edge of the passenger wheel well(the flat portion on the bottom). Its another tell tale sign of a leaking heater core. Sorry to be so late lol only several years https://www.jeep-cj.com/forums/images/smilies/smile.gif