I'm in the same boat. Flushed my heater core, new NAPA 195* thermo, heat takes forever to get good and warm, but still not as hot as I feel it should be.

I know my core has a slight leak so I will probably be replacing it in the near future...ugh

 

i have a mopar 195 stat, flushed the system, properly burped it, ensured i have no pin holes and i still get wimpy heat too. next on the list is ditching the heater valve like cruiser said. if that doesn't work, the dash is coming apart.

 

Short of swapping the core, I wonder if there is a way to get a peek in there to see if there is a mouse nest or something.

Hank, I did see some stuff on treating the core with CLR. I took it easy, and it didn't seem to help. Was warned too much too long might eat through it. BUT. I might try it stronger, longer, as a last shot before actually swapping it out.

 

I was thinking of trying that too. I know mine has a pinhole leak because I can smell coolant quite strong on cold startup if I start it with the vents on. It goes away after a minute or so though, and I haven't seen physically where it is leaking anywhere but it must be. CLR might make that a bit worse though. A few others here have recommended some Alumiseal or something, but I will NOT be putting any sort of stop-leak junk in this XJ. I've been cleaning up a mud mess since I got it before the new year.

Looking forward to your results! I wish I had an easy way to pump/circulate the CLR mixture through the core instead of it just sitting in there. Any ideas?

 

5-90 came up with this copper pipe and manual valve setup here in post #8,

https://www.cherokeeforum.com/f2/ren...9/#post2299608

I've had a little aluminum powder work more than a few times. It's not gummy, it's just powder. Bars-leak IS gummy!

 

That reminds me of a Three Stooges episode, "A Plumbing We Will Go"




My heater core hose has a garden hose valve attachment, but I don't see in what way it is beneficial. I have a high-powered nozzle that fits easier into the end of the hose.

 

My 89 doesn't even get half way to 210 normally. Only goes to the very first small tick mark. I does go up when wheeling or in traffic so I get the feeling the thermostat is either stuck open or missing. It does blow slightly warm air and after about 15 minutes my wife will stop complaining about how cold it is.

 

Golly. It seems that different T-stat housings can have very different passages. I was gonna' clean and use the iron one, but I'm having second thoughts.

 

I had the same iron one and same thought. Ditched it and bought a new one.

Let's regroup, guys.

First off, I have had problems with 5 Napa stats made by Stant.

Secondly, what is your gauge indicating?

Thirdly, are both hoses at your heater core about the same temp as your upper radiator hose when warmed up?

Fourthly, the heater blend air door can be misadjusted, allowing cold air to mix with the heated air. Easy fix.

Start at "firstly".

 

Any tips on that "easy fix"?

 

Yep. Poke your noggin under the passneger side dash. See tha cable up to your left?

Watch it while moving the Slide lever on the heater control from Cold to Hot.

Make sure the door lever under the dash moves all the way to it's stop. If not, squeeze the clip on the wire and adjust it so it does.

HEY, WAIT A MINUTE! I said start at "firstly" not "fourthly".

 

Haha! Well, I get to cut because I have verified my 195* temp with a digital probe.

And, again, thanks much, I'll check that

 

I'm having issues as well so I'm going to follow this thread!

 

First and a halfly, ditch the heater valve and replace it with pipe/tubing along with plugging the vacuum line that runs to it.

 

Flintstone, what step are you on?