Another 4bt overheating issue

[Shannon Ritzert]

I just took my boat out for a test run after upgrading the cooling system.  I’m having overheating issues, and looking for suggestions.  I installed: larger expansion tanks, new heat exchangers, new impellers, all new hoses. in the lower elbow that attaches to to the water tube, that attaches to the expansion tank, I installed a 3/4 elbow that goes to the expansion tank, and a 1” elbow with a 1” hose that goes to the rear of the block at the casting/freeze plug.  Much like Francis did on his post.  This 1” hose runs under the engine to the next fitting in the back of the block. a couple of years ago, I installed the SBMAR 165 T-stats, and rebuilt the raw water pumps.  I have great raw water flow.  I’m wondering if the hose running under the engine is an issue, if the expansion tank is to high above the engine, or maybe the expansion tank caps are too hight psi?  These are rated at 15psi.   any suggestions are appreciated, Im on the coast for the rest of the day, and tomorrow morning, I’d love to solve it, plus I can answer any questions easily.  I will include pictures, though they may not be attached to this first post, for some reason I have issues getting pictures uploaded.  

Topic

[Tony Athens]

Look at the picture.

 

[Shannon Ritzert]

Adding more pictures

this is the linc to some of the guidelines I used: https://www.sbmar.com/community/topic/4bt-and-tonys-tips-coolant-upgrades/

 

[Shannon Ritzert]

I have one 3/4” hose from the expansion tank to the brass 90 on the lower elbow.  I have one 1” hose on the othwr brass 90 of the elbow, that runs to the back of the back of the block.  I came up with that from this forum.  <br /><br />

I have no vent lines in the turbo.  My thermostat sender for the gauge is on the back of the turbo.

 

I used brass fittings because they sweep instead of making a sharp 90 degree.  I’m also a marine dealer, and got them at cost.

 

vent lines are 3/16.  I used the restrictors from the original expansion tanks.

[Tony Athens]

That second 1″ hose that goes to ?? That looks like a total  NO-NO.  Where did you come up with that?

The make-up one to the X-tank look generally right  although is could be run better. 

Is there a vent line on the top of the turbo?  It goes where?  

A couple of things– You do not need brass/bronze fitting for coolant–Hurts nothing but your pocket book

Vent lines– Be sure they are no more than 3/16″ ID or have a restrictor  (1/8″ is good)  If the vent lines are too big ID you will overheat as all the water flow to the x-tank from them by-passes your HX.. In this case, BIGGER is not better.

Pictures–no close-ups–need to see it all  and how all is routed/connected.

 

 

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