Yea, a lot of folks overlook that exhaust sparger (Shower Head). It has small holes around the outer perimeter so shower raw water into the exhaust flow and those little holes can get plugged.
CAT 3126s overheating/running hot after sucking up mud
- Thread starter mrsrobinson
- Start date
mrsrobinson
Well-Known Member
I am not clear on the HEX and coolant, I will need others to chime in.
The boat is in fresh water. No growth that I am aware of and everything was clean 3 months ago when we brought it down from Maryland to VA. It's my assumption based on tribal dock knowledge the water is good, no growth.
Yes, BOTH engines. Yes, same run speeds.
There was a long, long, long discussion on these Hx's and removing the end caps earlier this year.
The answer is -
The end cap the raw water hoses connect is also where the tube bundle flange seals. If the end cap is pulled and the tube bundle becomes dislodged it will leak the engine's coolant. There is an O-ring for the end cap which seals to the tube bundle flange and an O-ring in the Hx body flange that seals the other side of the tube bundle flange. One side of the tube bundle is raw water and the other antifreeze. To remove this cap first take off the pressure cap on the expansion tank then carefully remove the end cap bolts, remove the end cap then put a couple of bolts back in to hold the tube bundle flange tight to the Hx body.
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mrsrobinson
Well-Known Member
Thanks, I removed the inside one, the one that feeds from the raw water pump. I did not get any antifreeze dripping/leaking, only a little raw water. Reading your comment I should have seen antifreeze?
I have the O-Rings you reference, I did not replace them though when I reinstalled the inside cap. Wondering if I should have now.
I have the O-Rings you reference, I did not replace them though when I reinstalled the inside cap. Wondering if I should have now.
Not necessarily it will leak. If there is any pressure on the engine coolant side of things and that end cap is off, that pressure will easily dislodge the tube bundle and it will definitely leak. That is why I recommend removing the expansion tank cap and reinstall a couple of the bolts when that cap is off to hold the tube bundle tight to the Hx body.
- Jun 2, 2008
- 5,024
- Boat Info
- 1998 450 Sundancer, Achilles dinghy w/15hp
- Engines
- 3126 Cat's
My lesson on my inside port h/e was a bucket with 5 gallons of coolant in it.
(and again thank you everyone for your patience & my education)
Now the other end cap (without the hoses) has two O-rings and when it is removed it will leak engine coolant.
One O-ring seals the cap to the Hx body and the other to the tube bundle end ring. Between the inside of the cap and inner O-Ring is raw water and between that inner O-Ring and outer O-Ring is engine coolant. Scroll down through this starting here -
Official Caterpillar3116/3126 Thread | Page 58 | Club Sea Ray
Like @The Bill Collector says get a bucket ready to recover any coolant leaking.
One O-ring seals the cap to the Hx body and the other to the tube bundle end ring. Between the inside of the cap and inner O-Ring is raw water and between that inner O-Ring and outer O-Ring is engine coolant. Scroll down through this starting here -
Official Caterpillar3116/3126 Thread | Page 58 | Club Sea Ray
Like @The Bill Collector says get a bucket ready to recover any coolant leaking.
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mrsrobinson
Well-Known Member
Phew, my head is spinning at this point. Amazing information/insight/comments - I just don't know where to start now, what to do next 
Thanks for the link to the HEX conversation.
Thanks for the link to the HEX conversation.
mrsrobinson
Well-Known Member
For clarification, the marina service shop is not saying don't do a short haul to check the grates. They said save your money and test the water pressure at the raw pump by removing the hose, put it in the bilge or bucket, check pressure, then do a backflush and check for pressure again. And use a clear hose to check for cavitation and air bubbles. Finding clear hose that big will be fun.
- Jun 2, 2008
- 5,024
- Boat Info
- 1998 450 Sundancer, Achilles dinghy w/15hp
- Engines
- 3126 Cat's
On the bright side, you are going to have a sh**-ton of experience with your engines in a very short time period. I hope you have started a maintenance log book, dates, actions, engine hours, and part numbers...
mrsrobinson
Well-Known Member
Agreed, started a log from day one that I'm updating regularly. I do this for me as well as for a future owner of the boat.
mrsrobinson
Well-Known Member
I did a short video clip of all the adapters, couplers, reducers and such that helped me figure out how to do these raw water flushes with the coolers on the boat. I hope this helps someone, it took me a while to figure it out.
https://photos.app.goo.gl/HRmv1aXdW2xQeHo16
https://photos.app.goo.gl/HRmv1aXdW2xQeHo16
mrsrobinson
Well-Known Member
Pics from 4 to 5 weeks ago of the port engine raw water impeller that I replaced, inside of the same raw water pump, and port engine inside HEX cap. Notice in the photo where the raw water impeller is still inside the how squished and twisted the right hand side in the pic the impeller was, the side closest to the engine. Maybe that's normal though.
Let me know if anything in these pictures tells you anything. Again none of the fins on the raw water impeller were missing.
Let me know if anything in these pictures tells you anything. Again none of the fins on the raw water impeller were missing.
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douglee25
Well-Known Member
All looks normal. Impeller gets squished to one side... The opposite side is where the physical water is rotated around the pump body and pushed into the engine.
Could you possibly have missed installing the keyway correctly? And on both engines? Do you see good water flow out the exhaust when it runs now?
Could you possibly have missed installing the keyway correctly? And on both engines? Do you see good water flow out the exhaust when it runs now?
mrsrobinson
Well-Known Member
I definitely got the keys right on both impellers, and yes there's good flow out the thru hull exhaust on both engines.
douglee25
Well-Known Member
Forgot to mention, that tube bundle is definitely dirty. Enough to do what you're seeing?? Debatable.
mrsrobinson
Well-Known Member
I pulled the plastic bits out, after that things looked pretty good but I didn't take a picture. Are you stating in addition to that it looks dirty?
Doesn't appear anything wrong with the photos except for that pump housing.
The O-Ring doesn't look healthy and clean. If there is even the slightest air leak on that pump cover it will malfunction and not pump enough water to cool at the higher RPM's.
Spic n' Span that thing; new O-ring with silicone grease or better yet Alco Metalube on it.
The O-Ring doesn't look healthy and clean. If there is even the slightest air leak on that pump cover it will malfunction and not pump enough water to cool at the higher RPM's.
Spic n' Span that thing; new O-ring with silicone grease or better yet Alco Metalube on it.
Woody
Well-Known Member
In pics #2 and 3 looks like dings on the inside edge of the pump, maybe from prying. Can't tell from pics if they contribute to your problem but they shouldn't be there.
douglee25
Well-Known Member
Whatever is at the 4 - 5 o-clock area. That looks dirty to me. Did you go to the other end of the tube bundle and take the cap off?
