Pinhole leak in trans cooler line on Trailblazer

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So I found the source of my sister in laws dripping trans fluid. There was one pin hole leak spraying fluid out. From doing research it appears trailblazers have problems with corroded lines. Her lines are pretty corroded. She doesn't have much money and the vehicle is used only a little.

My solution was to buy some 3/8 inch trans hose . I slit it so I could slip it over the line and then used 3 hose clamps to pull it tight against the pinhole area. That has stopped the leak for now. I know this is only a temp fix as the lines will only get worse.

Anyone have similar issues?
 
Another way is to cut out the bad section, double flair it the ends and join with a rubber section. The real answer is to replace the lines. Rock Auto has the kits but is bit of a pain if you don't have access to a hoist.
 
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As a temp fix I'd put some grease or something onto the rest of the line to slow down any more rust. But who knows, keep an eye on the fluid level, and it might last as long as it needs to--sometimes, we get shocked when something that was needed to last, actually does last.
 
Originally Posted by Snagglefoot
Another way is to cut out the bad section, double flair it the ends and join with a rubber section.


I had seen videos on it and thought of that but realized the lines maybe in too bad of shape to do that. Also cutting it would make two large cut areas for potential leaks instead of a small pin hole.
 
Total line replacement is anywhere from 300-400.00 if a mechanic does it. I could possibly attempt it to save her labor but of course I have no hoist. She just doesn't have that kind of money to spare.
 
They haven't made Trailblazers since 2009, so it has some age on it. I have a Trailblazer and would think with a set of ramps, a new line set, and a couple hours this wouldn't be very difficult. The hardest part would be fishing the lines through the tight spaces and finding all of the hold down brackets. The lines do not appear to be very expensive but I don't know which specific model she has. You could buy the lines and install for a Mother's Day gift
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Don't forget to top off the fluid after a drive to warm up the transmission.
 
I already knew that the OP lived someplace where they salt the roads when I read the thread title!
I wish they made these lines from stainless steel.
On my Escort they don't make new transmission cooler lines any more either.
 
Yes, this is a classic issue with the gmt360. Power steering lines are usually the first to go.

The transmission lines are low pressure, so you have options.

Similar issue I had was the crimp from the hard line to flex line on my power steering high pressure line started leaking. Because gm used steel lines, you can use thse compression couplings.

Cut out the bad section, debuted the cut and you install the new segment and crank down the compression fitting.

Cost me an hour or two of my time and 28 bucks. I will snag you a pic today. Just about any hydraulic shop should be able to whip something up.
 
Originally Posted by Barkleymut
Is this a 2 year old vehicle with 20k miles, or a 15 year old car with 200k?


2003.....212,000 miles
 
I forget the routing of the lines, but like BrianF said, they're hard piped steel lines for the full length on Trailblazers. I'm wondering how horrible a job it would be to just replace the lines? 2003 on is a lot of Michigan winters. If a larger leak arises, that 4L60E will pump itself dry in short order.

I remember doing a cooler line ATF change on my 2005 trailblazer and was caught off guard when my gallon jug filled and overflowed in under 10 seconds.
 
Anyone have similar issues is a silly question. Every vehicle in the rust belt eventually gets similar issues if something else doesn't put it in a junkyard first.

You can either spend the time yearly to coat everything with rust deterrent goop, which is its own burden and expense (depending on how snooty you are about what goop to use), or wait for eventual rust problems. Many rusty parts will still outlast the vehicle's normal lifespan, but of course others won't and some in particular, like brake lines, are very important to keep in good shape.
 
Obviously the best solution is to replace the lines, but you can repair/patch up the old one if the rest of it is still good. You can probably fabricate your own line yourself too. It's no different from making your own brake lines. You can buy bulk steel tubing from the auto parts store. They sell 5/16" and 3/8" line, in addition to the 3/16" and 1/4" tubing for brake lines. You can double flare the ends and use tube nuts and unions to join 2 pieces together, just like brake line. There are also hose barb fittings that thread onto tube nuts, so you can splice in a rubber hose (which is a much better solution than using the flared end as a barb, IMO)
 
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