Fuel Cooler or Bad Fuel

[cww]

My original Detroit fuel coolers on my 6-92TA replacement engines, installed around 1992 or so had their zinc pencils installed on the top of the cooler. While I replaced these annually they always had the lower half inch looking like a mushroom at the tip with the upper part looking new. The tip usually broke off in dust on removal as it was wider than the hole. As Fanfare is stored in brackish water for about half the year I interpreted this as the residual raw water seeking a level in the cooler where most of the zinc's protection was exposed to air instead of conductive and protective water. The small portion in the water was depleted leaving them ineffective. It did take about 15 years for this to degrade the cooler. After one went bad I replaced both with new DD coolers. These now have the zincs on the bottom of the cooler, much more exposed in the water. A little harder to service but probably an improved design. Fingers crossed. Be sure to look for this on replacements.

I gotta be honest, I think most of the time this problem is because people don't even know they're there. I knew to replace the heat exchanger and water pump zincs, I didn't notice the ones in the fuel coolers until I ruined one.

 

[cww]

IMO, fuel coolers are relatively cheap, I'd replace no matter the result of the pressure test on the old ones. Understanding the pressure test on old ones is important to confirm source of the water in the fuel.

He's got 92's so they have a more complicated setup that's a combined fuel cooler, transmission cooler, and I don't know if it also has anything else in it. I do know they're substantially more expensive than the normal ones for the 71's your boat and mine have. On my boat they were only +/- $1k apiece brand new from DD, not that big of a deal. I still felt awful about it because $2k that I wasted on my own stupid mistake is like $10k that something that wasn't my fault cost me, if that makes any sense. I have been changing the zincs every 6 months since then and had no more problems.

On his 92's I think they're more like $4k apiece new, he may be able to get a used one for a good price right now, a lot of boats bit the dust in the recent hurricane season and are being parted out. I'd check ebay.

 

[Sadey]

I’m going to take the conservative route and remove and replace the coolers. Any tips or tricks on removing those from anybody that has done it?

 

[cww]

I’m going to take the conservative route and remove and replace the coolers. Any tips or tricks on removing those from anybody that has done it?

Did the pressure test reveal a pinhole?

 

[Sadey]

I didn’t pressure test them. Pretty much have to take them out to pressure test so I’m just going to replace them. The one does show signs of corrosion on the outside. So for $2300 I’ll consider it preventative maintenance.

 

[JD5652]

I didn’t pressure test them. Pretty much have to take them out to pressure test so I’m just going to replace them. The one does show signs of corrosion on the outside. So for $2300 I’ll consider it preventative maintenance.

$2300 each ? ... or for two?

 

[Freeebird]

$2300 each ? ... or for two?

That’s for the pair.

 

[Sadey]

$1176 each plus shipping from Mr. Cool. I sent a couple of pictures to the sales rep that I didn’t think were very clear but the minute I sent them he replied back, yep, we have those. They’re dual purpose coolers. They cool the return fuel from the rail and they circulate coolant through the cooler to the oil cooler. They are returnable for a possible restocking fee, but he said I’d be a fool to replace only one even if the other one didn’t need it.

 

[cww]

That's an excellent price for the combo coolers.

 

[Sadey]

Turns out it was the fuel cooler on the port motor. No pressure test needed, only water came out of the fuel port on the cooler. The port cooler was not original, it was definitely replaced at some point. It would appear they may have used an impact wrench or asked Arnold Schwarzenegger to help tighten the U-bolts down. In the picture you can see how the U-bolt squeezed the housing, which must’ve put enough pressure on the fuel lines inside that the vibration wore a hole which allowed the water ingress. I had all of the water sucked out of the tank, and the racors are water free now, no strawberry milkshake in the bowls. I’m a Christian, I believe God stepped in and protected us on this one. We were spending one night in Apalatchacola, where the current and wind was pushing us towards the boat docked 10’ behind us, then head to Carrabelle through a very narrow channel with shallows on either side. After a night in Carrabelle we’re headed to Steinhatchee, which has no power or water to spend the night. Then we have the 130 mile run to Anclote to anchor. Then finish the trip to Longboat the next morning. Prior to this, there were a number of spots that would’ve been very inconvenient or even dangerous if we had lost both motors. But this point was the most critical as we were a day away from crossing the Gulf. Of course, if we had lost both motors due to water both generators would have s#*@t the bed also. Thanks to Scott, the recently installed inverter system would’ve given us 330Ah, but would that have lasted until Seatow or the Coast Guard came to rescue us? No good reason to ponder what could have been however it is a good time to assess worst case scenarios and what to do and what to have on board to deal with the situation should it arise.

 

[Eddieclemons]

Thanks for taking the time to share this valuable experience with us. Safe travels.

 

[SKYCHENEY]

Redundancy is your friend. Always run each engine off of it's own tank. Never combine battery banks. And don't pee into the wind.

 

[Sadey]

Sage advice! Thank you as well Eddie.