As you might have read, I ran into some trouble on a recent drive:...
As you might have read, I ran into some trouble on a recent drive: https://www.ferrarichat.com/forum/threads/got-my-355-home-with-the-luckiest-of-radiator-pipe-leak-fixes.581345/#post-146121928 I'm 99% sure it's the return pipe that is the one I field-repaired with some rust-oleum high-temperature wrap (see attached photo). There is some sort of pinhole leak or crack - I haven't gotten up on a lift to see it properly - at the very bottom of the pipe, where you see the tape wrap. It spatters coolant from one specific spot when under high rpm stress and the system is fully sealed (i.e., tank cap tight). So frustrating and baffling that this developed at all. This pipe (https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/355-group/f355-m2-7-1995/cooling-system-nourice/158249-pipe.html) is ~$500 at Ricambi, but that doesn't bother me as much as the prospect of its removal and replacement. On my '95, there's a little bit of room to work with up front in the bay, but I'm having a hard time seeing this as anything other than engine-out to really do it right. Only about a year after my last engine-out for the major. Happy anniversary! Anyone a) seen the same problem in the same pipe(s), b) fixed it themselves, and/or c) done so without dropping the engine? If the right way to do this is to engine-out, I'll do it that way. Just hoping it's avoidable.
I would be more concerned with why it happened then with repairing it at the moment because if you don't correct the underlying cause it will happen again. My guesses would be: 1- stress fracture. Something is not aligned or supported correctly and there is bending stress on the pipe and it is starting to crack from metal fatigue. 2- internal corrosion. Less likely unless there is something wrong with the coolant.
It's not really fun with the engine in, but it is doable if you remove enough stuff. You could have it tig welded for $50.
By the way if you want to repair it for the time being i have a very solid suggestion. Install an aluminum sleeve over the damaged part using JB Weld. I have a decent about of experience using JB Weld and it is outstanding in many ways. It can handle 500 degF continuously and if the surfaces are prepped correctly the bond is Really reliable. Order a thin wall piece of aluminum pipe with an inside diameter a hair larger then the coolant pipe outer diameter. Cut the coolant pipe in half by the hole. Thoroughly clean with a soap, dry, and lightly sand coolant pipe. Cut sleeve from aluminum tubing that will overlap cut coolant pipe at least 1.5" in both directions. So 3" long sleeve. I would try for 4" if it could make it work. Apply very thin coat to inside of sleeve. Apply slightly thicker coat to coolant pipe. Install sleeve. Let set DRY for 48hrs.
Thanks @GTUnit - To your original point - indeed, it's baffling how this could happen. I was wondering if that pipe could be unusually stressed, but I don't see anything obvious. Need to get up on a lift and get a flashlight on all of the bracket points for the whole system and make sure nothing got loose/crazy. Assuming this is just a quirky part failure and not the effect of some other sinister, hidden cause: Taking a "just fix it to drive until the next major" approach, I really like the JB Weld hack. Was also thinking about clamp-and-adhesive with some other rubber radiator hose as a sleeve. In both cases, I just need a straight section of replacement tubing, lucky as I am that the break is where it is.
That was my thought. Or Flextape. Wrap it a couple of times and put some clamps on the ends. Tea, I said Flextape.
I love this stuff and use it often. However, I have never done this type of repair with it. It the patch is large enough - in terms of surface area - and the bonded area sealed well, this might work. It's as much the pressure as the heat. I'd agree that you should have enough room in there for the tube replacement without an engine out.
Just to semi-officially close the thread; cut-and-flare was my chosen route, and I wrapped the cut with some quality 1 3/8" silicon hose from Pegasus Racing. Leak appears to be fully checked. The final result almost looks like it was designed that way. Who am I kidding – this is still a hack, but I think it's the best I can do until the next major since replacing the piping seems impossible without dropping the engine. There's just not enough room to work between the engine and firewall. Need new radiators, too - both sides are corroded, but at least not yet leaking. Still mystified as to how this leak formed; couldn't really see anything when looking at the pipe. Sure feels like a one in a million failure.