Heater not very warm

[Gunner]

I poked around looking for somthing to do with this but couldn't find anything specific. Since I have owned my XJ the heater has never really gotten very hot. It will keep the chill off and the windshield defrosted but thats about it, gloves and a coat are needed. Nothing leaks everything seems to work just not very well.. Bad heater core? Bad controls? Replace, or put on gloves and stop being a sissy la la??? Any ideas?

[90xj06]

do this it really worked. http://www.olypen.com/craigh/heater.htm i dident go and get hoses and stuff and just held the hose on the fittings wile someone else turned on the water. i got soaked but it was raining out anyway. and it is hot now.

[Gunner]

Perfect I'll give it a shot. What kind of "stuff" came out? How much antifreeze?

[90xj06]

not much antifreeze and it was a orangey scale rusty stuff. it doesn't look like much but it is enough. i would pick up a gallon of antifreeze and what year do you have it may be more. i have a 90' and it lost very little.

[Gunner]

I have an 89, and I usually have some LowTox laying around. Did you pretty much get the bulk of it out the first shot or did it take a while? Thanks for the info. This will make snow wheeling much more enjoyable.

[MjTjNJ]

could be that your valve (vac controlled) is not opening up all the way. Play with the valve and see if you can get it to loosen up. It's right on the firewall on the heater hoses as they pass into the core.

[Gunner]

I'll try that too. Gotta tinker with the thermal fuse anyway, it's been either on hi or off since I have had it too. But it's only been 5 or 6 years. I didn't want to rush into things.. Thanks for the info

[Saudade]

Could be a bit of both. You can observe the action of the heater valve and see if it's moving when you select heat. You can also move the arm manually to see if it's stuck.

When I flushed out my '88, I drained it as best as I could, then I removed all the hoses and tstat cover. Everything got a good flushing with a garden hose. I srayed directly into the waterpump, the tstat hole in the block, the radiator, the valve and each end of the heater core. I could hardly believe the crud that came out of the core.

Once I got it all back together, filled and burped, I checked the temp coming out of the center vent at full heat. Using one of those small probe thermometers, it read about 140F.

[Gunner]

Of the stuff you just mentioned I have recently replaced. The only thing that I haven't touched is the core. I'm kinda worried about what is going to come out.

[Gunner]

Ok this figures.

went to flush the core. Bunch of crap camp out. The upper line to the heater core broke off. So I tried to button up what I could and the lower line towards the thermostat broke off. Nice. Real Nice. One of the hoses had the AMC logo on it... Guess I needed to replace these,,, But for crying out loud... Talk about a 20 min project gone wrong. I hope I can salvage the core. Not to mention I also replaced the thermostatic fuse in the hvac cause I only had HI or off and the fancy nickle something or other broke off when I pulled it out. note to self don't wait 16 or 17 years to tinker with stuff. OR just be fine with luke warm heat on HI... I felt like I was stepping on my own. Well you know..

[90xj06]

when you get this all settled you will be amazed how much heat you will get.

[Gunner]

Ok guys be careful when messing with the cooling lines that go into the heater core from the t-stat. The fun little replacement fitting for the hoses is $66. The good news is that the resistor for the heater motor is only $7

[Saudade]

Gunner: Sorry to hear that this has gone a bit "south" for you. Almost all of my "should take only an hour or less" fixits on my '88 have been almost all day affairs. This usually includes several trips to the parts store. The first one is th get the parts I need. The second is to get the parts I forgot or broke or some kind of tool to get the job done.

[90xj06]

what kind of fittings? i have no fittings just some hose clamps? and hose.

saudade:i know what you mean. im going through the same thing with my starter.

[Gunner]

I guess it's the "y" fitting that spilts the hoses between the heater core and the reservoir bottle, from the t-stat. The one I had, had one plastic end (to the heater core) and it just broke right off. But your right, it's pretty typical for a simple job to turn in to an all day or night adventure. But at least I'll have new hoses, and if the heater works better thats just a bonus.

[90xj06]

i pulled the heater valve 2 mirrors and the coolant bottle for 25 bucks. got to love it when the owner of the salvage yard is your dads friend. :)

[Gunner]

Nice work..

Got mine all back together.. You can weld with the heater and I have all ranges of the blower motor. Took less time to replace what I broke, than it took me to break it... Typical.. Would have gone to the bone yard but I have seen what they had to offer and it was more than likely worse than what I had..

[90xj06]

ya this one was brand new. i hope to get a headliner a passengers fender and front headlight piece and bumper.

[scca28]

do this it really worked. http://www.olypen.com/craigh/heater.htm i dident go and get hoses and stuff and just held the hose on the fittings wile someone else turned on the water. i got soaked but it was raining out anyway. and it is hot now.

I just did this a week ago on my '88. I never had any real heat to speak of in the two years I've owned it. I had a big catch pan underneath just to keep my driveway clean. I have a pinpoint nozzle for the garden hose, just the right size to fit inside the core tubes. I saw big blobs of crud coming out with brown water, kept going until the water was clear. When I emptied the pan there was a bunch of sludge left in the bottem. It felt like sand, but when I put a magnet in, it stuck to the magnet. So, my question, could this have been some sort of stop leak put in by the previous owner, or is this just the normal junk that collects in a cooling system over time? I know the water pump was in bad shape when I brought the vehicle and I replaced it right away, but could this material have come from the old pump bearings? One good thing, nothing broke during the flushing operation, and so far no leaks from the core. And oh yeh, cookin' heat now!

[90xj06]

ya, it works good. i had zero heat before now it is hottt. and that was on vent so it could be hotter.

[BIGSLVRXJ]

Just for future reference if you have an old"er" heater core flushing it can make it go bad. I just did mine today and immediately after I started the heep up it started spewing onto the pass. floorboard. It just made my weekend plans for me I guess.

[90xj06]

well yes there are some risks but more good than bad.

[BIGSLVRXJ]

well yes there are some risks but more good than bad.
Oh, agreed completely just thought I should kind of point that ever-looming fact out to everyone thinking of doing this.

[90xj06]

oh, yes go a head. great to hear both sides of the out come. but may i suggest that you back flush the block and radiator while your at it. kill 2 birds with one large stone and a bb gun. :)

[Saudade]

Just for future reference if you have an old"er" heater core flushing it can make it go bad. I just did mine today and immediately after I started the heep up it started spewing onto the pass. floorboard. It just made my weekend plans for me I guess.

Unless you overpressured it and split it open (I'm not suggesting you did), then the core was bad anyway and the caked up crud was holding it together. The good news is that you've caught it where you can work on it and not have it go when your away somewhere.

S (always pointing out the bright side.)