This little cable on my 96 Cherokee's heater valve is broken. Is this why I get little to no heat? If so can I jury rig the valve somehow so I do get heat (I live in the Yukon, so I don't care if I can't shut it off). One hose going into the cabin gets hot, the other just lukewarm. Maybe flushing's the solution?

 

You can eliminate the heater control under the hood and always have hot water going to the heater core.
If all you lack is a repair on that vacuum hose to have the heater control working that is an easy fix too.
I'd have to go outside and look at my 96's but you may be able to tie the valve open with a zip tie on the mechanism to allow hot water flow.

 

To clarify what Bmoney said, you are looking at a vacuum operated valve controlling the flow of coolant to the heater core. But you have me confused, is it a cable or a small, hard plastic hose? There are several hard plastic hoses run under the hood, they are vacuum lines. If that one is broken, then the rest are likely in bad shape also.

Don't know your knowledge level, but vacuum leaks are BAD. They cause the engine to run poorly. Replace ALL of the vacuum lines under the hood and the Jeep will likely run better.

As far as the bypass valve, you can delete it (pull valve and install barbed fitting, or install new hose from engine to heater core) or repair the vacuum line and put it back into operation. Many folks on the forum (myself included) delete the valve as they are prone to failure.

 

Thanks... Yes it would be a hose not a cable. I did try tying the valve open (with the little lever going to the up position) but this didn't seem to result in more heat... But maybe I'll try again with a zip-tie and make sure I have it tight enough.

If deleting the valve is what it takes to get heat then I'll give that a try.
Meanwhile I'll read up on the vacuum lines as I don't know about them, but it sounds like it might be time to learn... Here is where I confess there's a similar looking thin hose dragging on the ground from under the middle of the Jeep. Are the lines easy to replace?

 

You could zip tie the valve open until you get around to repairing the vacuum line / lines.

The fact that you are getting any heat with the vacuum line disconnected is slightly disturbing.
The valve is probably corroded / broken. And the heater core is most likely gunked up.

 

Ditch the valve. Cap the line, and don't look back. Stay warm.

 

Ditch it.

 

Ridiculously easy to replace vacuum lines. Match up the size of the nipple to the correct hose (hose comes on rolls in sizes of 1/16" increments), cut hose to same length as existing hose, ****** old hose off, slide new hose on. The hose just slips over a nipple. Replace the hoses one by one.

Now, here is where it gets tricky. It is likely some of the components the vacuum lines operate (like that heater core bypass valve) no longer function and are not needed. When I replaced all of the vacuum lines on my 90 I deleted a fair amount of the vacuum operated widgets. Many of the components are emissions items, may not pass inspection without them. Not a concern for me, if it is for you then may need to replace these components if they are broken like mine were.

 

Yeah . Deal with the vacuum lines after deleting the POS valve.

 

Help!

craigjacob1 was right, something disturbing was going on with my 96 XJ. Yesterday the upper radiator hose exploded when the car overheated.

At the risk of going on too long here are the details... More or less coincident with the heat disappearing, the last few times I've driven the temperature gauge has been a little erratic, reading slightly higher than usual, but not getting near the red, & dropping again. Also the electric fan was broken off at the mount and gone. I wishfully hoped the absence of the aux fan explained the weird readings... (I thought I could get by without replacing the fan till spring, plus I don't drive much in winter). I also just sort of assumed the engine was generally losing cooling efficiency, that my biggest problem was lack of a defroster, and that the car would make it to spring maintenance time.

The second to last time I drove, the needle went up to the red while I was coming uphill in low gear, then stayed hot at idle. Yesterday I had to get groceries and stupidly tried to squeeze out one more slow short trip, on a -10 day, before getting this problem sorted out. The needle went into the red but didn't overheat beyond that. I was going down a one-lane mountain road and started coasting in neutral, hoping the engine would cool as I made it down someplace I could turn around or at least park without blocking other people. Of course I should have shut the car off immediately, but I just had the wrong instinct at the time.

The temp gauge maxed out. There was a bang. The cabin filled with steam. I pulled over, shut the engine off, and left the car, glad nothing was on fire. The hose had blasted open where it joins the engine.

Now that I read more it sounds like thermostat failure can cause stuff like this... Here's some more wishful thinking/gross optimism that maybe the head gasket was not destroyed: I had to shut the engine off - it was still running with a normal sound at the time of the explosion and when I shut it off; the engine didn't really seem especially hot to the touch afterwards; the car oil looks normal, antifreeze is dirty but level normal; the water pump and radiator have both been replaced (but not the hoses). The engine's never overheated before, always ran perfectly, and I've been a careful driver of this thing to a fault for 20 years (if karma matters) never hard/careless on the engine. Till yesterday.

Is there any chance it will run OK if I put in a new hose and thermostat, top up the coolant, and try to start? And hope I can at least drive it a few miles to where I can store it till the weather's warm enough to investigate further? Or is there something else to try? THANKS!!

 

A new radiator hose and an extensive flush of the cooling system for sure.
A new thermostat / coolant temperature sensor would be a good idea.

This should at least get you to a point that you can check to make sure nothing else is going wrong.

Otherwise you will want to replace the electric fan (if it is missing or not working).
A lower radiator hose would not be a bad idea either.

That is where I would start anyway...

 

Ok, thanks... Somebody's going to help me check at the spark plugs for coolant today, so maybe I can figure out if I've wrecked the head gasket. It might be too risky to try flushing the system with water in the cold, in case the car doesn't start and it freezes and cracks things up, but I can drain & replace the coolant & try a new hose & thermostat. And maybe start watching DIY head-gasket changing videos.

 

Pretty happy. All the spark plugs are dry and look good. These were some durable engines! So I've ordered a new upper hose, to start with, and thermostat. I'll put those in, and at minimum drain/refill/burp, and give it a run. Also when that electric fan was falling out it looks like it banged up the radiator a little, so I'll keep an eye out for leeks there.

 

http://www.jeepforum.com/forum/f11/w...n-plug-202904/

I wouldn't fear flushing the coolant and getting stuck with water freezing in the block. The above link shows where the drain plug in the engine block is located. If needed, pull the drain plug and leave it out until spring.

 

Only problem is the drain plug is a 5/16" square drive and nearly impossible to access with the engine in the vehicle and the exhaust manifold on.

If it's Renix, you can at least remove the coolant temp sensor and accomplish that task.