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cdn_olds_94

Welding coolant pipes.

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Before putting my 94 Cutlass Vert away for the winter, I was chasing a coolant leak. I've traced the leak to a metal coolant pipe on the right side of the engine compartment that has pinholes from some form of corrosion at a mounting tab. I want to remove and clean up the area and weld the pipe. My son say's I can't weld it. The pipe is steel not aluminum, so I think it can be fixed Has any one done this type of repair or do you just look for a replacment at a yard.

Edited by cdn_olds_94

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Fabricating a new one would be a better idea. Welding thin stuff sucks, the welder has a tendency to blow right through. It would be ugly as sin and very brittle if it did work.

I weld exhaust but even on that I weld at a slip joint so it's double thick or my MIG will blow holes if I'm not tentative enough. 

A really experienced professional welder with a TIG might be able to fix it but I bet even they wouldn't guarantee anything. 

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One would not attempt to *mig* the piping but either brazing or *hard* soldering (silver) will do the job.

Silver soldering does not require the amount of heat to flow the solder that brazing rod requires.

One still needs at the very least a Mapp gas set to do the job, propane will not get hot enough.

I take it that the pipe you're referring to is the return pipe from the heater core back to the coolant pump manifold that runs along the frame rail, I had to do this very repair some time ago as well when one of the welded support tabs cracked at the weld and a seep began.

 

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Yeah no reason why you couldn't weld it, although you may just be playing 'whack-a-mole' with the leaks if the thing is significantly corroded.  If I recall, the replacement isn't that expensive, about $30-$40 as a Dorman part that comes in a huge box.  Probably more of a hassle to remove the old one intact without damaging it further, than to just cut it out in pieces and fit a new one.  Was pretty easy to fit on the 3.1, especially with the engine rocked forward and the main engine wiring harness connector disconnected.

 

Part number on the 1992 was Dorman 626-100.  $37 from Amazon w/free shipping, comes in a giant box that probably costs that to ship.  Strange that I can't even find it on Rockauto, but still seems to be available on Amazon.  

edit:  Canada link, a little more obviously....  Gone up $20 since I ordered mine back in 2014.  The whole bottom of mine was rotted, the metal was so thin I could basically deform it easily with my fingers. Basically running it through the wheel well almost was not GM's most brilliant moment, although the rest of the car has minimal rust other than the rocker panels are rusting from the inside out.

https://www.amazon.ca/gp/product/B000C1237K

 

 

Edited by pitzel

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Dorman 626-100 looks like that part on the passenger side engine bay(LQ1) that runs down and back along the frame right to the "rear" of the engine right? Did the earlier 3.1MPI use this part as well?

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6 hours ago, rich_e777 said:

Dorman 626-100 looks like that part on the passenger side engine bay(LQ1) that runs down and back along the frame right to the "rear" of the engine right? Did the earlier 3.1MPI use this part as well?

Yup.  That's what I put it on.  The LH0 engine.

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12 hours ago, 55trucker said:

One still needs at the very least a Mapp gas set to do the job, propane will not get hot enough.

 

MAPP gas hasn't been made for over a decade.  What's sold now is "MAP-Pro", which is NOT the same thing, but you're supposed to think it is.  It's deliberate deceit on the part of the manufacturer and packager.

https://en.wikipedia.org/wiki/MAPP_gas

The bigger problem is that by the time you see corrosion on the outside of the tube, the inside can be even more rotted.  Replacement of the tube is the best solution.  If I couldn't get a pre-fabricated replacement, I'd bend one from copper plumbing tube, bead the ends, and clamp it to the hose.

Edited by Schurkey

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9 minutes ago, Schurkey said:

I'd bend one from copper plumbing tube

Wow...  Crazy, crazy overkill..  But it'd never rust out again, that's for sure :).  

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1 hour ago, Schurkey said:

MAPP gas hasn't been made for over a decade.  What's sold now is "MAP-Pro", which is NOT the same thing, but you're supposed to think it is.  It's deliberate deceit on the part of the manufacturer and packager.

https://en.wikipedia.org/wiki/MAPP_gas

The bigger problem is that by the time you see corrosion on the outside of the tube, the inside can be even more rotted.  Replacement of the tube is the best solution.  If I couldn't get a pre-fabricated replacement, I'd bend one from copper plumbing tube, bead the ends, and clamp it to the hose.

Yeah,

ok, now you're splitting hairs.....agreed, the true Mapp was as you state discontinued, but one still can purchase the propylene/propane gas known as Map-Pro.

 

I get mine from Bernzomatic.

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13 hours ago, pitzel said:

Yeah no reason why you couldn't weld it, although you may just be playing 'whack-a-mole' with the leaks if the thing is significantly corroded.  If I recall, the replacement isn't that expensive, about $30-$40 as a Dorman part that comes in a huge box.  Probably more of a hassle to remove the old one intact without damaging it further, than to just cut it out in pieces and fit a new one.  Was pretty easy to fit on the 3.1, especially with the engine rocked forward and the main engine wiring harness connector disconnected.

 

Part number on the 1992 was Dorman 626-100.  $37 from Amazon w/free shipping, comes in a giant box that probably costs that to ship.  Strange that I can't even find it on Rockauto, but still seems to be available on Amazon.  

edit:  Canada link, a little more obviously....  Gone up $20 since I ordered mine back in 2014.  The whole bottom of mine was rotted, the metal was so thin I could basically deform it easily with my fingers. Basically running it through the wheel well almost was not GM's most brilliant moment, although the rest of the car has minimal rust other than the rocker panels are rusting from the inside out.

https://www.amazon.ca/gp/product/B000C1237K

 

 

One will not find that part listed for the LQ1 engine, as it is intended for the LH0 (T) engine only. The difference in the pipe is the length of the rubber end & the vertical pipe at the coolant manifold. The LQ1 item places the vertical pipe in a slightly different location than the LH0 pipe to accommodate where the LQ1 coolant manifold on the very front of the engine front cover is. The manifold nipple is parallel with the centreline of the engine, the LH0 nipple is clocked at approx 30 degrees. The rubber hose for the LQ1 is much shorter than the LH0, but because the LH0 item does have a longer hose it *might* work, but there's no guarantee it will.

Edited by 55trucker

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Wow, I just learned I've never used MAPP gas.

On that note, a MAPP torch works really cool with the aluminum rods, aluminum tubing would be an awesome replacement. 

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18 hours ago, 55trucker said:

One would not attempt to *mig* the piping but either brazing or *hard* soldering (silver) will do the job.

Silver soldering does not require the amount of heat to flow the solder that brazing rod requires.

One still needs at the very least a Mapp gas set to do the job, propane will not get hot enough.

I take it that the pipe you're referring to is the return pipe from the heater core back to the coolant pump manifold that runs along the frame rail, I had to do this very repair some time ago as well when one of the welded support tabs cracked at the weld and a seep began.

 

That is the pipe I'm talking about. Sounds like this is something that happens alot with the age of the car and where the part is sitting. I have access to an Oxy-Acetiline unit so I will try brazing the repair.

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38 minutes ago, 55trucker said:

I take that you'll get into this in the spring?,

If you have any problems attempting this give me a call, I'll lend a hand

Since the car is in my garage for the winter, I was going to start it in March . Thanks for the offer of help. I'm let you know.

 

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