Cat 3126 raw path through the system.

[kvduff]

I have two cat 3126ta in my 450 da and I am trying to understand the water flow path beginning at the raw water intake through the Cooling system. I had originally believed that the water enters through the raw water pump then on to the heat exchanger then to the aftercooler onward to the exhaust elbow and tranny cooler and out the exhaust.
I am trying to understand how I found impeller pieces in my aftercooler when I removed them for cleaning. I would have believed that these pieces would have been caught in the end cap on the heat exchanger and could not have reached the aftercooler, clearly I am incorrrect. I have searched for some sort of water flow diagram with out much luck. Any explanation would be helpful. Thank you.

 

[carterchapman]

I thought it went from the impeller to the HE. I always found my pieces in the HE end cap...but I never did check the aftercooler, so I guess smaller pieces could get through the HE and end up there...

 

[kvduff]

I thought it went from the impeller to the HE. I always found my pieces in the HE end cap...but I never did check the aftercooler, so I guess smaller pieces could get through the HE and end up there...

Thanks for responding Carter, That was my assumption too. I did find some pieces in the heat exchangers... I thought maybe a previous owner could have back flushed the system and forced some pieces in the opposite direction. Definitely took some rubber out of where the water lines enter/ exit the aftercooler. Confused and looking to better understand....

 

[carterchapman]

Frank W always said CAT overdesigns their cooling systems. I changed my 3126 impellers often enough that I never had broken blades, but one time I checked my HE's and was amazed how many were jammed in the end cap from the PO! And they never ran hot at all!!

 

[kvduff]

Frank W always said CAT overdesigns their cooling systems. I changed my 3126 impellers often enough that I never had broken blades, but one time I checked my HE's and was amazed how many were jammed in the end cap from the PO! And they never ran hot at all!!

Exactly, I pulled probably 1/4 of an impeller out of one hx without a cooling issue.

 

[dtfeld]

When I cleaned my HEX last winter, some of the impeller blade tips had pushed well into the tubes, and I think a little more growth plugging other tubes would create enough pressure to push them through.

 

[kvduff]

Thanks Dt, clogged tubes in the hex I guess can create enough pressure to pUsh some pieces through. Any thoughts on the order of the raw water path through each of the engine components?

 

[JVM225]

Not at my boat right now, but if I remember correctly, raw water comes off the pump to the HEX and also to the fuel cooler.

 

[kvduff]

View attachment 91129 Was flipping through my library of cat manuals today and found the answer to my question. Apparently from the diagram, the water flow on the 3126 beginning at the sea water inlet, water is pulled into the strainer, then through to the fuel cooler, to the raw water pump where it is then split off to two separate destinations. The aftercooler, and heat exchanger. From the aftercooler side the water exits and is sent beyond the oil cooler. The heat exchanger side passes through and then moves to the oil cooler. Both the aftercooler side and the hex side side meet up before entering the exhaust elbow, and out to the exhaust outlet

 

[techmitch]

View attachment 91129 Was flipping through my library of cat manuals today and found the answer to my question. Apparently from the diagram, the water flow on the 3126 beginning at the sea water inlet, water is pulled into the strainer, then through to the fuel cooler, to the raw water pump where it is then split off to two separate destinations. The aftercooler, and heat exchanger. From the aftercooler side the water exits and is sent beyond the oil cooler. The heat exchanger side passes through and then moves to the oil cooler. Both the aftercooler side and the hex side side meet up before entering the exhaust elbow, and out to the exhaust outlet

Great diagram and the reversed 4 and 6 crack me up.

 

[kvduff]

Great diagram and the reversed 4 and 6 crack me up.

Took me a minute when I looked at it! Too funny