Mr.T

Too bad the heater core isn't accessable like in the old days.

It may be that the core is partially plugged, but if that was the case I thought that with lower coolant flow and normal air flow there would still be some measurable temperature drop at the heater hoses. That's what made me wonder if the air is mostly bypassing the core somehow.

Best of luck on this,

Rednroll

Well, back again. Heater still not fixed.

However, what I noticed recently is that my coolant seems to have dropped in level over the course of time. My overflow was originally at the max fill line level after raising the front end, burbing and topping off the coolant levels to make sure it was full. Now it's currently at the min line level on the overfull and when I start it in the mornings, I'm again hearing one of my original symptoms of an air sloshing sound from inside, likely air going through the heater core.

So I really think I have a leak somewhere in my cooling system. Rather than guessing and just throwing parts at the cooling system, I'm currently shopping around to purchase a radiator pressure kit tester to see if this leak will expose its ugly head for me under pressure. Trying to find a radiator pressure test kit $100 or less that will fit our JK's but isn't junk.

I'm thinking I may have a tiny radiator leak or I just read this discussion thread where it seems an intake manifold gasket leak seems to be a common problem and could be where my coolant is escaping as well.
Can't find coolant leak location! - JKowners.com : Jeep Wrangler JK Forum

SpartanToJo

Rednroll,

Did your JK happen to come with a Lifetime Powertrain Warranty that is still intact? If so, your water pump is covered. Just tell them that it is leaking. I have had them replace min twice so far at no cost. (I do have 230,000 miles on her...)

I have all of the same heater issues. My fix is to flush/reverse flush the heater core thoroughly every Fall just before the weather gets crazy cold. This usually gets me warmth through February and into March when things start thawing out. I've done this for the past five years.

Good Luck!

Rednroll

I had the lifetime powertrain warranty, I missed my 5 year inspection window, so likely not intact.

A water pump replacement, even on my time/dime would be welcome if that's the problem but I'm highly doubting that one. I'll really wish I still had my lifetime powertrain warranty if this ends up being an intake manifold gasket leak but that now looks like a warm weather weekend project if I have to go there.

I flushed the heater core previously, helped for 30 minutes then went back to poor heat. I'm not sure if the HC flush got my heat back temporarily or if it was the filling/burbing that I did after flushing the heater core. I'll back flush the HC again if needed. I really think it's a hard to find leak somewhere in the cooling system at this point. Hoping a radiator pressure tester kit will help me track that down if that is the case.

I decided I'm going to go to HF and pick up their radiator pressure tester kit $72 with their 20% off coupon. The good radiator pressure tester kits seem to be in the $250 and up price range, which isn't worth it for my use. At least if I find out the HF doesn't work out for me, I can return it to the store.

Rednroll

Well...............
I THINK I FINALLY FOUND IT!!!!

1st thing was that I had to refill my coolant, it took me an entire gallon of coolant to fill it back up and I knew it was previously full because I had filled it, burbed it, and top it off over the course of a week.

It's the infamous radiator end cap leak. I guess mine decided not to start coming apart until 120K miles on the ticker.

The leak was on my driver's side end cap. What I found is that the leak wasn't apparent until I took the pressure up on the tester to 18psi which is exactly where the OEM radiator cap is set at. Once I hit 18psi, I could hear a small hiss sound come out from the driver's side end cap. Wiggle that end cap and I could hear other small leaks rear their ugly head.

The likely reason I never saw coolant on the ground is because the leak was so small, only started to happen above 18psi, and any coolant coming out was being caught by my AEV skid plate directly below it which likely got blown out when I was driving on the highway.

I couldn't get a good picture of the leak but this gives some insight.

Driver side end cap view from above.


Zoomed in, liquid observed.


Time for a new radiator. Not a simple repair, but I'm happy it wasn't the intake manifold gasket.

Mr.T

Nice, that pressure tester paid for itself today!

Rednroll

Well as MLK once said..............................

"I HAVE HEAT AT LAST............HEAT AT LAST!!!"


I replaced the radiator this weekend, it took me much longer than I though it would. This is the 1st time in a long time where if I held my hands for too long in front of the vents while turned up high, they felt like they were going to get burned. Hopefully, it lasts. Now I'm hoping for some cold weather to test it out.

That HF radiator pressure tester definitely paid for itself.

Thanks everyone!!!

Mr.T

That's good to hear, and it's nice to know the HF pressure tester works well.

Rednroll

Yep, if anyone is interested on how the pressure tester works on the JKs. The kit doesn't have a specific JK adapter. It has a "Chrysler" generic adjustable adapter. You take the adapter on the bottom left and fit it with one of the top 3 plungers. The one in the middle I have circled is the one that fits Chrysler vehicles. You then put that where the radiator cap goes and tighten it down to form the seal. Additionally, I needed to put a hose clamp on the return reservoir hose to complete the pressure seal. After that, then just pump like a bike hand pump to build up the pressure.

Rednroll

Hey, guess what? I'm back again.....heat is back to meh....just blowing out semi warm air.

So my heater was working great for about 2 days blowing out hot air, and now it's just blowing out warm air. The thing I notice that's different since replacing the radiator is that it seems to be blowing air out more evenly temperature wise across the front vents.

While I was replacing the radiator, I decided to fill the heater core with CLR and let it work and do another reverse flush. The CLR sat in the heater core this time around for about 24 hours. The 1st time I did the reverse flush of the heater core, I left the CLR in for about 3 hours.

What I noticed when doing the heater core flush this time is that when I drained the CLR into a clear milk jug, there was some grey flakes that settled on the bottom of the jug. (Edit: Clue to Symptom #3) Not a lot, just a thin layer of flakey silt at the bottom of the jug. However, why would I get good heat for 2 days and then just go back to warm air? I've checked the coolant level and when I take off the radiator cap, it's still filled right to the top after 1 week of driving.

I'm thinking my most likely scenario is that I have a partially clogged heater core and therefore not getting the flow through it that it needs to produce good heat. Now that it's spring, I'm thinking of bypassing the heater core and letting it soak for a week or 2 with some kind of cleaner. I've been using CLR, but is there something better I should use? I also noticed when using the CLR that it produces bubbles coming out of my HC inlet/outlet hoses. So was considering it may not be a good idea to completely seal the heater core with a cleaner, therefore not letting any pressure build up escape. Any thoughts?

I'm also considering replacing the thermostat. I don't think that's the problem, but it's a cheap/easy replacement. I'm definitely not having any overheating temp problems. Jeep warms up and temp dial stays in the center.