Heater no worky

[vertigoExplorer]

My heater in 94 eb doesn't work. The fan comes on, but no heat...The temp gauge doesn't rise a whole lot..any opinions?

 

[camaro_guy_z28]

The first thing i would do is check/replace thermostat

 

[camaro_guy_z28]

Also this would be a good time to do a complete flush of the cooling system if that hasn't been done in a while

 

[savant]

I had problems with no heat from my 1991. Like yours, the fan worked fine, and the temp. gauge didn't move much. As far as I can gather, no one's temp gauge moves all that much.

The problem with mine was rust sediment buildup in the heater core itself. You should do a flush on your entire coolant system to get good results, but spend time on the heater core itself, and flush it good in both directions to ensure that it's clear. Mine had big plugs of solidified rust-dust in it.

My heat works like a charm now.

Also, a word of warning. Once I got the system flush thoroughly, my radiator started leaking. The same rust that was clogging the heater core was clogging some rust holes in the radiator. Keep an eye out for that.

 

[vertigoExplorer]

thanks, everyone. All input is appreciated.

 

[Positive Vibes]

What they say, get your radiator flushed and change the Tstat.

 

[shak]

Heater No worky!

My Heat is gone too! Butl it just so happens that I'm sitting here in my garage with a '91 Navajo behind me with all the coolant hoses off (upper, lower, and heater hoses), and the upper radiator hose spout is off too to get at the thermosat.... and a new radiator is propped up against the front bumper, ready to go in. Before, I took the old leaky radiator out, I did the prestone kit back flush procedure...you know...the heater hose tee, back flow preventer, garden hose deal with a jug of coolant system cleaner for good measure. The system was/is pretty gunked up with stop leak, lime, old antifreeze...etc. Particularly, at the heater core...lots of goo there when I removed the heater hoses.
While I've got the old heater hoses off, I think I'll use a transmission funnel and pour a strong, but diluted mixture of the coolant cleaner into the heater core at the firewall where the inlet/outlet tubes stick out into the engine compartment. Then let it set for awhile! Next, I'll use the Prestone backflush kit and a new piece of hose hooked to the inlet side of the core with a garden hose and the old hose to the outlet side run to daylight. Easy does it on the water pressure, when you turn the hose on...if the core is gonna leak, I wanna know now before I put all new hoses, a thermostat, and new radiator and new coolant in the system and button it up. Believe it or not the heater hoses looked like the originals...and they were ready to bust at all the connectons...I'm sure the heater core is original too...so cleanin' the crud out is probably gonna spring a leak in it! I'll keep ya posted on the progress today...shak

 

[njguy_2000]

No heat as well

Got a 91 navajo same issue. Now I have a new engine and still no heat. I changed the radiator, water pump and therm. with the new engine and still no heat.. Going to get a new heater core this week and giver er' a shot with a complete flush before I crank it over. I'll let ya know if this works or not, winters coming quick...

 

[darrellx14]

mine works.. but it takes FOREVER to get nice and warm.. do you think mine is sorta clogged, like just enough to make it take awhile to get heat?

 

[Darrman]

I planned ahead this summer and when I put a new radiator in, i did a full flush, the heater was a little weak before then, now it will melt you in the seat on low. The people I bought it from had cracked the rad, and dumped in a can of the sealant mud, made a mess of all the hoses.

 

[marragtop]

Another way to do the heater core is to pull it out and backflush it upside down. You get a lot more crud out of it that way. Only a 15 minute job on the Gen I explorers.

 

[pinoyesv6]

does anyone have directions to backflush the heater core and change the thermostat? possibly with pictures?

 

[EMG7895]

Search its very very simple. You'll know when the heater is working well, as was said above it gets very hot even on low, I very rarely turn the fan past halfway.

 

[savant]

For a guide with pictures, I suggest Haynes. Yeah, I know, haynes sucks for really complex work, but for thermostats, it's plenty good.

As for flushing the heater core, mine was new, but my 91 had so much rust in the system that even with all new parts (radiator, hoses, heater core, thermostat, etc) the core clogged up after a few weeks. I disconnected both hoses from the heater core and used a prestone flush kit from the auto parts store. It's actually pretty nice, and cheap too.

It lets you hook your garden hose up to your system and flush it. I ended up flushing the core in both directions. Got tons of rust sludge out, and now the heat works great, and has worked great for the last year.

 

[Creager]

Wow, so my heater JUST hit the ****ter today. For YEARS that thing would SCALD me it would get so hot. As of today, i cant put the lever on full heat and it puts out a little, little, little bit of heat; Hardly anything at all. Any my cooling system is FULL of rust, so im gussing this might be my issue? any thoughts? I didnt think the cooling system hooked up to the heater. Where is the heater core located? im at work so i cant go look at the truck just yet. Thanks for the info.

 

[Peter Westling]

Creager, I just posted a picture in another thread from the service cd that shows you the core..
http://www.explorerforum.com/forums/showthread.php?t=148015

 

[Creager]

Creager, I just posted a picture in another thread from the service cd that shows you the core..
http://www.explorerforum.com/forums/showthread.php?t=148015

haha awesome man, thanks.

 

[Peter Westling]

What the heck, since I did the other picture you'll get the rest too...
A thread is not a thread without images as somebody said...

As it was stated:

Heater Core


Removal and Installation

1. Allow the engine to cool. Following all safety precautions (refer to «Section 03-03») and using a thick cloth, turn radiator cap slowly to the first stop. Step back while pressure is released. When the pressure has been released, tighten the radiator cap on the radiator.

2. Disconnect the heater hoses from the heater core tubes and plug the hoses.

3. In the passenger compartment, remove four screws attaching the heater core access cover to the plenum assembly. Remove the access cover.

4. Pull the heater core rearward and down, removing it from the plenum assembly.

For installation, follow removal steps in reverse order. Tighten hose clamps to 2-3 N-m (18-27 in-lb). Check and add coolant as required. Check the system for proper operation and coolant leaks.

 

[Peter Westling]

I messed something up in the upload process.. any way here is the image...

 

[F14CRAZY]

Yeha my heater core was plugged last year. $80 from Ford and it was better.

Even with a new 190 degree thermostat, Michigan winters keep my Limited from bearly reaching the NORMAL zone, so I put cardboard in front of half the radiator.