I've been searching for a coolant leak for a little while and over the winter, the front end of the car was up on jack stands and I finally was able to find puddle of coolant. It was a pretty decent size too, and while test driving it for the past 2 days, I've gone from the "Full" line to about 1.5" below the "Add" line in the reservoir. Underneath the car just now (after driving the car 40 min home from work and it sitting a few hours), there are no obvious signs of a leak. Only on one of the bolt heads under the car is there a little bit of green (green arrow in the picture.) Upon further inspection, I think the insulation foam for this heater hard line is soaked and I'm guessing it is cracked from road debris (possible evidence from the torn insulation, blue arrow in picture below)



It looks like these hard lines are not reproduced, and are no longer available from GM. What are my options then to repair/replace? Do I have to find a good parts car?

Mine are still in good shape, just a hose that's leaking. I plan on using PVC tubing if I ever loose a hard line. You could have some stainless made up at a fab $hop. PVC is good up to 600 degrees, if your coolant gets that hot you won't be worried about a leak

The idea of PVC doesn't sit well with me in and automotive application.

A thought occurred to me this morning, if the crack ends up being so close to the connection point, maybe I can just cut out the bad section and replace with silicone hose up to the heater core?

What about welding the crack? (searching shows these lines are coated aluminum)

If the pipe is leaking , it is probably beyond repair .You could just take the piping off and have a pipe fab shop replicate it -big bucks . Most people just replace the rotted piece by clamping in a piece of rubber hose .Or replace both pipes with new rubber heater hose from front to back like I did with an 85 I used to own .

*edit* Thats an air conditioning line in that pic isnt it?

[This message has been edited by 2.5 (edited 03-19-2015).]

quote Originally posted by 2.5: Thats an air conditioning line in that pic. The heater/coolant tubes are one on each side more near the doors.

There are two heater core lines running up the center, I thought. The radiator coolant lines are on the outside, near doors.

If the foam is the only thing wrong, then leave it. Is the pipe corroding?

[This message has been edited by jaskispyder (edited 03-19-2015).]

quote Originally posted by jaskispyder: There are two heater core lines running up the center, I thought. The radiator coolant lines are on the outside, near doors. If the foam is the only thing wrong, then leave it. Is the pipe corroding?

Hmm, I thought the insulated ones were AC.

(Pic is red X for me)

[This message has been edited by 2.5 (edited 03-19-2015).]

quote Originally posted by 2.5: Hmm, I thought the insulated ones were AC.

Yeah, I couldn't remember, so I had to pull up a pic.

My picture in the first post is under the car from front looking back, the lines I'm picturing are on the passenger side of the fuel tank. These are definitely heater core lines and right where they bend up, they connect to a rubber hose which then mounts directly to the heater core.

For reference (because I've seen this confusion in the other topics about this part), the hard lines for the AC look very similar but run on the driver's side of the fuel tank. jaskispyder's picture above is very useful to show where they are from the engine compartment side.

Note this is for my 1986 GT (I will add this to the first post for future reference.)

quote Originally posted by wftb: If the pipe is leaking , it is probably beyond repair .You could just take the piping off and have a pipe fab shop replicate it -big bucks . Most people just replace the rotted piece by clamping in a piece of rubber hose .Or replace both pipes with new rubber heater hose from front to back like I did with an 85 I used to own .

wftb, this thought occurred to me but is it safe to run a rubber hose down the length of the car on the underside? Are you saying some people might slip some heater hose over the hardline where it's cracked and clamp it down, like a bandage?

Why not run a couple of copper or aluminum pipes in place of the ones that leak, flair the ends to insure the rubber hoses seal and the problem is solved.

Was the leak caused by an impact? If the it was and the pipe is in good condition, one way would be to use a hose clamp and a piece of heater hose to cover the hole. I have use this to patch hole in pipe or tubes in various locations.

As the previous posted suggested splicing is a new piece is also a good idea. Parker Fitting has compression fittings that are good for several thousand PSI that could be used. You would need to go to an industrial supply house to get them.

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