Cat 3126 Raw water hoses?

JVM225

JVM225

Well-Known Member
Apr 8, 2008
6,560
New York
Boat Info
2002 410 Sundancer, Monaco Edition.
Engines
3126 Cats.
The raw water hose that goes from the raw water pump up to the heat exchanger looks like it has seen better days. It's a bendy hose that looks to be molded.
Does anyone have a part number and source for it. I've got a parts manual but I'm not having any luck identifying it.
Also, is there someplace that has a hose diagram with part numbers for the hoses on them? I want to take a good hard look at all of the raw water hoses on both engines and replace anything now that looks like it could be a problem in the coming years.
Thanks!
 
It is a formed rubber hose from Caterpillar. That hose holds the maximum pressure in the seawater system and can leave you searching for SeaTow's phone number very quickly. When it blows, you get seawater all over the injection pump, seawater pump and, in a 410, if it is the port one that lets loose, all over your generator.

The hose needs to come from Caterpillar since it is made to fit that spot on the 3116/3126. I carry spares, but I"m not in Florida this week. You should be able to find it easily in your parts manual, or get the AR# /serial number off your engines and call the parts department at your local Cat dealer. In the meantime, I"ll try to find the receipt when I bought the spare hoses.
 
Thanks Frank! Can't figure it out in the parts manual. It doesn't have any kind of hose routing diagram or show the raw water pump and heat exchanger in one image with a hose running between them.
Local dealer was not that friendly or helpful in past calls, and they haven't got a great reputation for customer friendliness around here so I'd rather get them from a Cat parts dealer on the internet who may appreciate my business a little more.
I'll probably do a search by part number or order them from Cat.Parts.Com once I have a number. Just want to make sure I order the right ones.
My genny is on the starboard side, but now that you mention it, I'll probably change that one too while I'm at it. It appears to be in decent shape but better safe than sorry. Especially with something as critical and inexpensive as a hose.
Actually wouldn't mind keeping a spare set of any raw water hoses that are unique to my motors handy. Stuff that can't be bought off the shelf is probably a good investment. Just need to identify the numbers so I can order them.
 
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JVM - I replaced those on my former 3126/410 - around $30 at the CAT dealer - just go in with your eng serial #'s - they pull the parts diagram up right before your eyes! Great service from my dealer's parts counter.
 
Local Cat parts place is a little over 20 miles away and the last time I called them to check stock for fuel filters before I took a ride out there they weren't very helpful.
They're the only source for Cat parts on Long Island so they've got a captive audience.
Just called them for this hose and they don't show it. Said he only sees a hard pipe on his diagram. If I can't get a part number here I'll have to take a picture of the hose, drive out there with it, hope they can identify it, and hopefully they'll have it in stock.
 
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John,

There are 2 formed hoses on the seawater circuit that would need to come from Caterpillar. One is a little short hose connecting the metal tube to the transmission oil cooler; the other is the hose you asked about. I bought spares for both at the same time and I am not near my boat where the spares are, so I am not sure which part number is for which hose. The Cat part numbers are 9Y-6218 (which I think is the pump to HE hose because it was more expensive) and the other was 9Y-1330.

Remember, my engines are 3116's; not 3126's, but I hope the above helps you.
 
Thanks Frank! Bingo! With your info, part numbers, and a 20 mile drive to the Cat Parts counter he was able to look at yours, translate to mine, and they had them in stock.
In case anyone else needs the info for the 3126's: The seawater pump to heat exchanger hose is #112-1122,
metal tube to trans oil cooler hose is 9S-1102, and for good measure I picked up another molded one that goes from a metal tube to the exhaust elbow #136-2258.
Just got back to the boat with them a little while ago and compared the new to the old on the motors and they look to be right.
Of all of them, only the seawater pump to heat exchanger looks funky on one motor so that will get swapped out this week. Got an extra one of those as a spare to go along with the other molded ones I picked up while I was there. Now I will have an extra of each on hand.
While all the others look and feel good, they're cheap enough to qualify as a PM project for the coming off season. So I'll be heading back there for more.
 
Great info, thanks for sharing. Running off to by some my self. Let me know how the change-out process goes. I've never changed any hoses on my 3126's.
 
When you have your HE hoses off, you can easily remove the end cap on the HE (6 bolts, O ring gasket) and check for debris in the HE. Spray the protruding ends of the bolts with some PB Blaster. The port eng is easy as you can stand right next to it. My stbd eng HE had some salt water damage to the ends of the bolts and I had to use a tap to chase the threads. Worked out great and was an easy job. I was surprised how many impeller pieces were in there - as FrankW says, CAT cooling systems are overdesigned, and I found that to be true with the amount of junk in my HEs on my 3126s...
 
I swapped out the hose I was concerned with the other day before leaving the dock. It was the hose that goes from the pump to the HE on the port motor. It took longer to get in and out of the bilge than to swap out the hose.
The same hose on the starboard motor looks to be brand new. I suspect the previous owner had it replaced in the Spring of 2016 when he had the generator replaced. All of the exhaust hoses on the boat were changed at that time. Probably because the exhaust on the starboard motor had to be removed to install the new generator.
The 90 degree hoses that go in to the trans oil cooler are both fairly accessible with the port being easier than the starboard, and the hoses that go in to the exhaust elbows are also not bad to get to with the starboard being easier than the port. All of those look pretty good on my boat but will be replaced this fall as part of a preventative maintenance project since the boat is new to me this year.
 
carterchapman said:
When you have your HE hoses off, you can easily remove the end cap on the HE (6 bolts, O ring gasket) and check for debris in the HE. Spray the protruding ends of the bolts with some PB Blaster. The port eng is easy as you can stand right next to it. My stbd eng HE had some salt water damage to the ends of the bolts and I had to use a tap to chase the threads. Worked out great and was an easy job. I was surprised how many impeller pieces were in there - as FrankW says, CAT cooling systems are overdesigned, and I found that to be true with the amount of junk in my HEs on my 3126s...
Click to expand...
Thanks Carter! That's a great idea. I'm going to do that to both HE's this fall as PM. Now I need to figure out the part number for the O rings and pick up a couple of spares on my next trip out to the Cat dealer.
Did you ever pull the hoses off of the ends of the oil and trans coolers and back flush them?
 
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