No Heat

Topic: No Heat (Read 1491 times) previous topic - next topic

No Heat

October 20, 2012, 11:48:44 PM

Alright guys it's starting to get a bit chilly out and I've noticed that suddenly my heat decided to stop working. Now, similarly I noticed that my a/c was not getting as cold as it was over the summer a few months ago, but I didn't worry about it because well it wasn't hot out anymore. And hey I'd had heat earlier in the summer when I fiddling around with stuff to see what worked (terrible game btw).

So here's where's it at:

It certainly feels like there is water moving into and out of the heater core, but the return line is slightly cooler than send line.

The heater door moves corresponding to the heater lever. This was verified outside of the heater box by me dropping the glove box and fiddling around a bit.

You'll get an initial blast of heat once you turn the fans on, but it seems like that it's just the heat naturally building up in the heater box as it soon gives way to cold air.

Personally I'm leaning towards either the heater core being plugged, the door lever arm having broken off the heater door/gate, or something having crawled into my dash and making a mess of things.

Just curious as to your own personal opinions, thoughts, experiences etc. I'm pretty sure I'm going to be taking the dash apart, but all the same It would be nice to not be heading into the thing completely blind.

Oh and the heater core was replaced in 2005, but hey that's not exactly yesterday.

No Heat

Reply #1 – October 21, 2012, 01:22:36 PM

Check for the easier stuff first; pinched or broken blend door vac lines, or broken/bound up actuators. If everything checks out there, then the core would be the next step. Is the T stat plugged and and taking a long time for the engine to warm, and is the water pump good. These too will affect and give symptoms as you've described

No Heat

Reply #2 – October 21, 2012, 02:03:19 PM

Try disconnecting the the core and using a garden hose to flush and back-flush. See what comes out. You may not want to cut the end off your hose, but it works best that way. Maybe you get a foot of 5/8 heater hose and a garden hose repair kit and make an adapter.

No Heat

Reply #3 – October 21, 2012, 07:50:05 PM

Well luckily I've ditched the factory setup for the heater hose, so it'll be real easy to plumb some garden hose up to one of the two rubber hoses I have bolted to my intake manifold. And concerning the blend door lines, I get air flow out of all vent positions be it defroster, floor, vent, etc. But, I guess it's worth taking a look at my troubleshooting/schematic manual one more time, but I don't recall any actuators being in direct line to heat flowing across the core.

No Heat

Reply #4 – October 21, 2012, 11:19:50 PM

Sometimes the barrier in the heater core seperates and bypasses the core. We had a lot of these in older chevys. If you are running a 160-180 stat it is difficult to get good heat in very cold climates. Blend door is a must to check and the core should be changed out. Flushing the core with a garden hose works very nicely. In the shop we have a flusher that uses water and air. Sometimes when i flush a core the that comes out is beyond belief. Also you have to flush the core in both directions!! Good luck winter is upon us:hick::hick:

No Heat

Reply #5 – October 22, 2012, 12:27:38 AM

Well my thought was on the blend door, if it's stuck, or not working, then it won't allow much if any warm air through.

No Heat

Reply #6 – October 22, 2012, 12:41:04 AM

I think you can safely eliminate the Blend Door as a possibility, first, because the car's too old for an electronic actuator unless we're talking about eatc. Either way, if you start out with heat and you lose it, your core is cooling off, why? Because You've got a flow problem. Either that or you're really low of coolant.

No Heat

Reply #7 – October 22, 2012, 06:14:54 AM

You'll get an initial blast of heat once you turn the fans on, but it seems like that it's just the heat naturally building up in the heater box as it soon gives way to cold air.

Well once the blend door is checked for proper operation. Weather electronically or cable controlled that is that. The fast cooling of the air over the core can only be 3 things. It is clogged the core is blocked with junk or it is not getting a good flow of coolant. If the heater hoses are both the same temp check the in and out temps with a inferred temp gauge to see the difference. Check to make sure the heater hoses are not blocked or restricted with junk. Also make sure the connections to the block for the hoses are not corroded inside the fittings. You can easily check this without removing the core. Question what is the engine temp running at???

No Heat

Reply #8 – October 22, 2012, 11:06:02 AM

if there is in the fins of the core like i think tom also said above, the only way i know to clean out the fins is to remove the speed control resisitor and aim up and to the left to blow air up in there.

the EATC systems have a larger device that can be removed to give you a larger opening to work with to do this but the car we are talking about doesnt have eatc from what i am seeing.

I believe the bypass piping has been removed also from what i am reading so yeah, back wash the core or.... here is an idea..................

-cut the bottom off a 2liter pen 15e bottle
-stuff a 12 inch long hose on the end of the bottle where the cap would go.
-attach the other end of the hose to your core
-add a 3' long hose to the other side of the core and elbow it down to the floor, then plug off this hose with a cap of some sort
-pour in a light mix of draino / water into the core using your pen 15e bottle funnel to fill the core up and then let it sit for a while.
-pull the plug on the lower hose you added to drain the core then garden hose out the core again in the opposite direction.

Perhaps a bleach water mix might be better in this application.

No Heat

Reply #9 – October 22, 2012, 01:17:57 PM

Engine temp is good (180 - 190) and it's a new motor, new hoses, etc etc, right now though I'm stalling getting into it. Today, I'm replacing the brakes in my jeep, but yeah you guys have confirmed most of my suspicions. I'll plan on making a mess once it's not raining out side some time next week hopefully, at the very least I can peek under the dash to check for the visually obvious before I start flushing coolant and pumping bases through my heater core :)

Will let you know how it goes, but if it turns into a heater core swap this thing is gonna get parked for a while. If I'm pulling the heater core I'm pulling out the dash and making a new beautiful aluminum one as well.

No Heat

Reply #10 – October 23, 2012, 04:01:54 AM

This may be of some use in the future.........http://www.coolcats.net/help/heatercore.html