Rear Heater Pipe Failure: How to Repair with Heater Hose

[DaveInColumbus]

On Friday my wife called me to say that she noticed a large puddle of orange fluid by the right front wheel of our 2000 DGC. Uh oh. Well, it was 90F and she's due to give birth in three weeks, so I told her to head home and keep an eye on the temp gauge. If it shot up, stop immediately and I'd come get her. She made it home, and when I pulled into my driveway after work, my eyes confirmed what I thought the problem to be: broken rear heater pipe. There was at least a gallon of coolant that had run down my driveway. Well drat. We were hosting a birthday party for our sons on Saturday, and that left Sunday. 90F all weekend and my garage is full of crap. Well, my brother helped me reinstall the 18,000 BTU 220V window A/C unit in the garage. That would make it livable.

I researched this forum and found another thread on this topic, but it focused primarily on how to replace the pipes. That's not what I did. I have made my van roadworthy by cutting the offending pipes and using heater hose to effect a repair. I took lots of pictures, and I'll give a blow-by-blow description. This is a long post, but if you have this problem (and you *will* if you live north of the Mason-Dixon line) you may find this quite helpful.

From this forum, I already knew that the lines in question ran from the engine down past the tunnel under the driver's seat. I also knew that they were held on by a single bracket. When I got under my van, this is what I found:

Broken Heater Pipes, Looking Forward.jpg

This photo shows the two pipes, looking forward. (In the other thread, the shot was rear-facing.) The two aluminum lines on the right are for the rear A/C. The pipes are the two black lines on the left.) You can see the massive corrosion where the heater hose attaches to the pipe. You can also see the bracket that holds the lines, attached to the van's underbody. The run from the engine to rear heater core goes like this, at least insofar as I examined it (I didn't go all the way to the heater core):

Steel pipes from the engine.
5/8" heater hose.
Aluminum pipes back to... ?

The heater hose connects the steel lines to the aluminum lines.

Broken Heater Pipes, Showing Bracket.jpg

This photo is from the center line of the van, looking at the same pipes. (Sorry about the lack of uniform focus; I had to shoot quite close to the pipes.) There is a threaded fastener sticking out through the underpan. The bracket attaches to it with a push clip that grabs the threads. This type of fastener is designed for each of assembly, but it's a real bear to remove. Clearly visible is the rust at the ends of both pipes.

I have no idea which pipe had the leak. There was coolant on both, and both were severely corroded. And frankly, I didn't care. As I was looking at the pipes I remembered the other thread, and I could see that it would take me hours of work above and below the van to replace the pipes. Reference pending child and I didn't really want to spend several nights doing this. So, what if I could cut the pipes forward of the corrosion and use two longer hoses? Could that work?

The first thing I did was to determine which tool could make the cut. Thankfully, the point of failure was not behind something like the catalytic converter or front subframe. I had two choices: reciprocating saw or pneumatic cutting wheel. I had the van up as high as my jack could go, and the saw fit. I determined it would be easier than the cutting wheel.

I headed to Harbor Freight to buy some more blades. I then hit up Advance Auto for several feet of 5/8" heater hose. So equipped, and already owning many hose clamps (also from Harbor Freight) I started with the saw. I had to keep a VERY firm grip on the saw, which wanted to chatter around. I bent the tip of the blade on the underpan. But once I got the saw set, it mowed right through the pipes.

Heater Pipes, after Cut.jpg

Here is the mayhem. I made sure to cut the outboard line farther aft than the inboard. This would ensure that I could get clamps onto the hoses without interfering with each other. Notice how corroded the pipes are, even forward of the cut. I'll have more commentary on that later.

Heater Pipes, after Cut 2.jpg

Here is another angle. Clearly visible are the aluminum pipes to which the heater hose did (and will again) attach. I later pulled off the pipes still on the bracket.

I then installed the heater hose. I double clamped the forward connections since I had sawed off the nipples. I reused the spring clamps.

Heater Hose Installed.jpg

And the repair is complete!

The van drank about six quarts of water. Later I'll pull the thermostat and the lower radiator hose to flush the system out and replace with a 50/50 mixture. What I could see in the radiator was very, very clean. Impressive.

I burped it a couple of times and let it heat up. Normal temps. Heat front and rear. All is well -- for now. I'll follow up this post with a second offering my opinion on the heater pipes.

[DaveInColumbus]

Close Up of Corrosion.jpg

This photo is a shot of the pipes I cut off of the van. You can see just how badly corroded they are, near the nipples. It was worst where the pipes were welded to the bracket.

Clearly this is a design flaw. They probably saved some money using painted steel, but aluminum would have been a far better choice.

My pipes weren't just rusted at the bracket. They are badly corroded all the way up to the engine, as far as I could see. I scraped off as much bubbled paint as possible. I don't want any more moisture trapped in there. I already know I have to replace the pipes but I'm not ready to do that yet so I'd like them to last a bit longer.

What causes this? My opinion: these pipes are neither wrapped in heat insulation nor shielded. They are exposed by line-of-sight to the exhaust manifold, downpipe, and catalytic converter. The heat transfer off of these items is primarily radiative, and worse, the pipes are black. I'll bet the paint just can't hack it. Over time, the paint bubbles up and moisture can get trapped in there (when the van is cold, of course). If you live in northern climes, as do I, then you may also get salt under the paint. The combination of water under the paint, potential salt, and thousands of heat cycles causes the pipes to perforate, and you have a nasty leak. I formed this conclusion when I saw the corrosion and bubbly paint all the way up the pipe. Yes, the pipe ruptured at its lowest point, but that's expected since that's where water will remain the longest. Still, if this were a point flaw, I wouldn't see the corrosion all the way up the pipe.

Replacing the pipes with an OEM part will buy me about... eight more years, right?

On the plus side, I also looked at my rear brake lines for the stupid, stupid junction the Chrysler engineers made. That junction mated dissimilar materials and ruined the stainless steel brake line. It corrodes and perforates. Looks like my van already did that. Somebody has replaced the rear brake lines with compression fittings and everything is alllll hunky dory. I won't worry about that ever again.

One other problem: While looking under the hood in blazing hot daylight today, I notice the left front strut tower has an inordinate amount of rust and a little delamination. That may force me to pull the strut to clean it up and POR 15 everything. Naturally, I'll put new struts on it and replace the sway bar end links while I'm at it. I'm also thinking about spending a few hours under the van to POR-15 the corrosion at the seams. I need this van to last! Overall, I'm pleased with the condition of the body at eight years and 65,000 miles -- aside from the ominous signs in the left front strut tower.

[alvin]

Good that you noticed the pipes were corroded all the way and will need further fixing.
I believe what makes this failure even worse on 2000 and later models is the change to silicate-free coolant. The green coolant actually seals small leaks when silicates are exposed to the air. My pipes were corroded just like yours but
only had pinhole leaks in them.

[DASander]

I performed the exact same repair as you, and it failed almose immediately. I too was planning to replace the steel pipes when I could get a chance, I just wanted to get the van back on the road again. If the cowel is removed and you have a lift the job is not too bad. It became quite clear to me that this pipe is installed in the van before the drivetrain. I had to bend the pipes a little to get clearence when putting it in. Not a fun job. You'd think chrysler would have addressed this problem, instead of selling the exact same part as a replacement, for $155.00

[vgb14]

I had this same issue on my 94 Grand Caravan. Just an fyi - to combat the corrosion on these and other steel pipes under my 94 and 98 Grand Caravans, I coat them with Rust Check rust inhibitor. I've been doing this for a few years with good results. I believe this product is used a lot in the marine industry. I have rust-check in a green aerosol can, which is thicker, and in a red can, which is thinner. I use the thick formula. It resists moisture, does not harm plastic or rubber parts and lasts a very long time - I reapply it every year, which is probably overkill, because I still see it present when I re-spray. Btw, I'm not endorsing this particular brand - I am sure there are other similar products out there. Hope this helps someone.

[ESADORNED]

Beautiful, a photo step-by-step. This is a fabulous post. Thank you thank you.

KC.

[DaveInColumbus]

Originally Posted by DASander

I performed the exact same repair as you, and it failed almose immediately. I too was planning to replace the steel pipes when I could get a chance, I just wanted to get the van back on the road again. If the cowel is removed and you have a lift the job is not too bad. It became quite clear to me that this pipe is installed in the van before the drivetrain. I had to bend the pipes a little to get clearence when putting it in. Not a fun job. You'd think chrysler would have addressed this problem, instead of selling the exact same part as a replacement, for $155.00

I'll pull the cowl (and hood) to effect this repair, but sadly I have no lift. Other people have said they just let the pipe get scratched while installing it, and then painting it once it's in the car.

Right now, I'm much more concerned about my strut towers. Man. That issue escaped my notice when I studied these vans before buying one. It wasn't on my inspection list.

[alvin]

It has been said here and on Allpar that the tube assembly can replaced without removing the intake plenum. I don't see how that is possible, but maybe with a lift, there will be enough room to maneuver the old part out and the new one back in. If you only have ramps or jackstands, I believe it is necessary to remove the intake. I also unbolted the converter from the exhaust manifold and moved it to the left side, just letting it sit on the crossmember.

[DASander]

It can be done, but it is a MAJOR PITA. The worst part is you can't see where the pipe is going, you have to feel where it goes with your hands, and it is one tight fight.

[davidshah]

Hi Dave,

Thank you very much for showing how to fix the problem. I have 2002 T&C with 56000 miles on it. And started having no heat problems about a month before. Antifreeze was completely gone so I filled in and got it going. But in just about 15 days same problem occurred. A friend of mine is certified Lexus/BMW/Mercedes/Honda mechanic. He was sure that it was cracked block or head gasket leakage. I got stuck on the road yesterday, my Van just overheated so much I had to pull over. Fortunately it was an independent auto shop and I asked them to do pressure check on my Van. They found leakage in the rear pipes - all rusted just like you have shown. Because of the pressure check those cracks widened and leakage became very noticeable with puddle underneath the vehicle.

Thank god for Google and this forum and you - I got my answers. I fixed it last night and boy it is nice to have warm Van with less than $35 expense and not worrying about big expense of engine block.

Thank you very much. Keep up good work everybody.