very weak heat in a 98 tj

[hscrugby]

So now I'm guessing it's my heater core is kind of mungy, it looked crappy when I had it out for replacing the ac in that box, but i was stupid and didn't replace it. (No where had em in stock, and I didnt' want to wait 3 days)
So now that it's cold I'm really regretting that.

So my question, could it be anything else causing the issue? failing water pump, etc? Is there an easy way to check water pressure? I mean, I can replace a water pump in 30 minutes. (well 2 hours once I've drained coolant, drank beer, looked at it, drank beer, wandered off, drank beer, etc)
Heater core is a solid day of work, not including the beer drinking, plus have to evacuate/disconnect AC etc, etc.

Oh yea, it's with the 4.0. Not that that really matters.

 

[RHSCTJ]

The heat in my 97 tj sucks too. It doesnt flow enough air to fill the cabin because the heater core is clogged with mud. Also a 160* thermostat. If your jeep is getting up to regular temp its probably not water related, just a dirty core like you said.

 

[RHSCTJ]

Regular engine temp that is

 

[GotWood]

I would try a thermostat first, easy and cheap to fix.

 

[hscrugby]

I would try a thermostat first, easy and cheap to fix.

Yea, it's got a new thermostat.
Well, new last spring when I replaced the radiator cause it was leaking.

Stupid plastic pieces glued to metal radiators.

So yea, I guess it's the core. I did clean the outside to make sure there was no mud on it, but i guess it's the inside.

 

[Blkvoodoo]

feel the hoses to and from the core, if they are hot you have flow thru it.

I'd be damn sure I covered every base before I tore the dash apart again. It don't get any eaisier the second time.

Sure you don't have a blend door problem?

 

[hscrugby]

feel the hoses to and from the core, if they are hot you have flow thru it.

I'd be damn sure I covered every base before I tore the dash apart again. It don't get any eaisier the second time.

Sure you don't have a blend door problem?

Well, I "do" have a blend door problem.
When I put the hvac box back in last time I scraped the damn tab off that holds the cable.

I didn't realize this until I had it all bolted back up, so I said "f it" and the cable "usually" works, but sometimes it pops off so I have to reach over and "help the blend door" along and reseat the cable.
But that's easier than taking the thing off.

The hoses both feel hot, until I turn the fan up on high, then the one cools off, A LOT.
So I think it's just a lack of flow going through it.


(Yes, I know I'm being that guy that's really trying to avoid the obvious problem because I'm lazy and it's a PITA to fix)

I'm still tempted to try and flush the heater core, and then maybe try one of the higher flow water pumps to see if that works well enough

It REALLY was a PITA to take that thing off.

 

[Blkvoodoo]

Well, I "do" have a blend door problem.

The hoses both feel hot, until I turn the fan up on high, then the one cools off, A LOT.
So I think it's just a lack of flow going through it.

That info tells me you have a blend door issue, the other hose cools off because AIR is flowing over the core, cooling it down.

The hot air just isn't making it out the vents.

 

[Ron]

That info tells me you have a blend door issue, the other hose cools off because AIR is flowing over the core, cooling it down.
The hot air just isn't making it out the vents.

ditto....also (make sure you have an all metal heater core before trying this) disconnected the 2 heater hoses. Using a water hose try forcing water through one and see how much flow restriction you have. Next Blow through the core to get all the water out (compressed air and some fitting to seal the hose helps) fill with greased lightning (if you used bars leak etc. to fix the radiator this will dislodge it a bit) let soak for 30 minutes (3 beers) next you want to blow this out and re fill with CLR and let this soak about 4 beers. flush and reconnect.....that will clean all junk outta your core.

 

[hscrugby]

ditto....also (make sure you have an all metal heater core before trying this) disconnected the 2 heater hoses. Using a water hose try forcing water through one and see how much flow restriction you have. Next Blow through the core to get all the water out (compressed air and some fitting to seal the hose helps) fill with greased lightning (if you used bars leak etc. to fix the radiator this will dislodge it a bit) let soak for 30 minutes (3 beers) next you want to blow this out and re fill with CLR and let this soak about 4 beers. flush and reconnect.....that will clean all junk outta your core.

It is all metal, I might try this again. I tried with clr once. (I DID use the stupid stop leak when i had a leaking freeze plug at the back of the block)
When I first tried it, hardly any water came through, but then quite a bit came through. I guess it seems likely that it got clogged again.

Thanks

(and yes, I'll keep rambling, etc until tomorrow afternoon when I actually work on it)

 

[hscrugby]

Well, since I KNOW everyone was on the edge of their seat wondering.
Water pump was bad.
Reason water pump was bad was the fan clutch was toast. Stupid mud/etc.
So hooked everything up, started engine to run it for a bit, then burp to get the rest of the antifreeze in, and realized I forgot to hook one of the clamps on a hose.

oops.
OH well, hope AF breaks down before it soaks to my well.

Now to eventually go buy more antifreeze so I can fill it up again.
Stupid jeep. (well, stupid owner thinking he's a mechanic)