Coolant Leak Won't Stop...

I would simply vote for the replacement hose ID being too big. The tube has 40mm OD and your hose 41 ID. I have industrial metric hose here with 40mm ID. It's what I always used and never had a leak problem. And I use the cheapest clamps.

Best Regards
Martin

 

Like discussed via PM, John.
I have just sent you two pieces of metric coolant hose, heavy duty truck and industrial application stuff. Each 100mm long and exactly 40mm ID.

Best Regards and good luck with it
Martin

 

Thorn -

Let's try to help you here.

1) YES, the pipe can be pulled without removing the motor. I'd pull the driver side rear wheel and wheel well liner, and you'll see it's right there.

2) When I did my resto, I bought a set of "uprated" black silicone hoses. Came as 40mm, but - for love or money - neither me nor my master mechanic who came over to have a look could get them to hold fluid perfectly. I actually got 38mm hoses instead, rubbed a dab of radiator hose grease that they sell for $1 a pack at the autoparts store counter on the inside lip, and - voila - installed.

3) If you can't get a closed system up to pressure, check your expansion tank cap, which can fail and be barely noticeable. Easily replaced with an uprated version (search here for threads on Stant, or check Superformance.co.uk for a visually similar to OEM higher pressure version).

4) If you actually have a pipe structurally failing, there's obviously the chance that the same is occurring in the other aluminum pipes. There are five, plus the monster tubes that run through the center tunnel under the car. You could be doing some fishing for answers. BUT...

5) This system take 6 gallons of coolant, which is ~ = 1 metric crap-ton. Be sure you've drained it thoroughly and don't have air trapped somewhere, which might mess with your pressure testing. I installed an auto-bleeder valve at my radiator. You've got to bleed the hell out of that system.

6) Failing all else, I actually had to replace this very pipe because my car's previous owner mis-adjusted it, and the clutch tensioner bolt sheared into it. Superformance UK makes stainless replicas, but it turns out there were about four slightly different versions of this particular pipe made (US/Euro/carb/qv etc), and I recall there being a fitment issue. I still have the scarred-up OEM aluminum one in my basement, which can be easily and inexpensively repaired by any shop that can weld aluminum. Happy to mail it to you if you can't find a used one on eBay or Ferrparts, and want to take a shot.
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Just went downstairs to see what I have "in stock," and I've got these, if either appears to fit your dimensions (I have a US carb car and see you've got a Euro QV). Otherwise, I note that Superformance NOW lists aluminum replacements, but good luck matching which pipe you need with their thumbnails:
Cooling Parts for Ferrari 308, 208, 288 GTO & F40 - Superformance
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Dan at Ricambi is a good and honest person to deal with. They offer excellent service, but occasionally their site will show a NLA part as available, and your order will be canceled. Also check with them to see if their replacements are aluminum or stainless steel, if that matters to you. The pipes don't actually contact each other inside the connecting hoses, but some worry about using dissimilar metals in the system. Ferrparts is a great go-to for used salvage parts if you can stomach their worst-in-class customer service and attitude.

I used SRI kits for fuel and coolant hoses. They provide the correct and best clamps, but we actually sent back their "standard" 308 coolant hose kit and requested 2mm smaller for the pipe hoses, which they had available for other models. Solved the problem, but don't forget the lube while installing.

 

After a flush with water, pucker up and suck hard on any suspect areas (or dish soap and blow into one end with a compressor while blocking the other end.) hope it's this pipe!

 

My thought exactly, the blow not the suck. Tape up an end and submerge and blow.

 

I don't remember you identifying "exactly" where the leak was coming from. Inspection mirror and contortions are necessary! Disassembly isn't gonna solve your problem unless you get lucky, such as this pipe is the culprit. That pipe looks fine, even with it's little flaw. You will end up replacing it which is fine, but you might still have the leak. You have to find that leak on the car before continuing, unless you want to remove all coolant related parts in the area of the leak. Then if it's not obvious to the naked eye, you still have to recreate pressure. Not easy when parts are off the car. Just sharing a little shadetree experience.

 

We chased down a coolant leak for days one time. The stuff likes to flow around and give false positives related to the leaks exact location. Turned out to be the pump! Exactly where you would think it would be, but for some reason it just didn't seem like that's where it was. If we would have started disassembling where we "thought" the leak was, we would have wasted a lot more time. You need the car to be running in "real world" condition to chase those pesky leaks! Start the car, inspect for leak, when you see coolant, rinse and repeat until you narrow it down.

 

IIRC, my car holds 2 1/2 gallons coolant completely dry. You're able to put 6 gallons in your system???

 

You are 90% done with the diagnosis although it will be a hassle now. You need to do the old fuel line to the ear trick. Pressurize system until you hear the hiss then fuel line to ear and use the open end to move around and locate that hiss exactly. I have had leaks that I was sure from component x only to find that under pressure component z was squirting very fine stream onto x. And I could even argue that by tightening the connection you were keeping excess pressure from leaking so that the pressure available for the leak increased.

Or maybe it is the pipe. Duct tape off one end, dry throughly, fill with water and food coloring. Locate leak.

 

Or you could find a way to catch the leaking coolant and recycle it while driving.

 

Exactly!!! That stuff loves to run along creases and down pipes...you have to find the source before any more disassembly...and you will! Either put this pipe back on or replace it...refill system, heat up the car and keep searching...you will find it! You must follow the coolant, even where you think there is no way it could be the source.

P.S. You don't have to use "any" coolant to test for leak...the green just makes it a little easier...put some food coloring in it!

 

Just consulted the manual, which specifies ~5 gallons for the system. I was off by a gallon. Then it came back to me; the reason I said 6 is that I mixed up a batch of 2 gallons of antifreeze to four gallons of distilled water when I filled it. But yes, this car takes a LOT.

My Jeep recently took less than 2 when my water pump failed and everything emptied through the overflow hole.

 

Hiss? Turn off all accessories! Hiss = Steam...Has to have moisture related. Go to any parts store and get a stethoscope. $10! And an inspection mirror or one of those $50 gizmos with a little screen. That will narrow it down...You'll find it!

 

One assumption I've had from reading your posts is that you were CERTAIN that the pipe or hose is the source of the leak.

Some other areas to look at would be:

- The water pump (both mating seal and the nipple that connects to the long skinny hose, which can corrode). Very easy for coolant to travel stealthily in the engine "vee" to the driver side and drip down, which happened to me on startup when we replaced that corroded nipple and the threads of the new one didn't match up correctly.

- There also is a heater hose nipple on the rear bank cylinder head (driver side) that can - and usually does - badly corrode over time. The long heater hose that runs through the driver door sill hooks up there. CAUTION: If you find this to be the culprit, the nipple screws into the head, despite appearing to be cast into it. Uprated replacements are under $100 (Ricambi shows the stock for $7), but HAVE A PRO EXTRACT THE OLD ONE. You're in for machine work pain if something goes wrong.

- If you look down with a telescoping inspection mirror and flashlight, there also are two rubber connector hoses on the pipe that sits down in the engine vee between the water pump and the pipe you currently think is problematic. It's hard to access and thus seldom serviced properly with the rest of coolant pipes/hoses.

 

I just welded mine.
It was coming for years, broke lose from clamp holding pipe away from oil filter base.

I haven't welded aluminium before with TIG, but after couple of practice runs, got very nice patch.
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