Port Engine Overheating

[RickieT]

How much DexCool should I purchase to fill back up when I install the heat exchanger? 1 gallon? 2 gallons?

[RickieT]

Had the bottom of the boat cleaned and the diver found a big plastic bag in the intake. cleaned the heat exchanger and filled with new coolant. Hopefully this took care of it. Praying the new impellers aren't ruined from the bag.

[mjk1040]

Rickie; which pickup had the bag in it? Each engine has it's own pickup. The closed cooling system may need to be bled off to properly fill the system, look for a brake type bleeder screw, if not you may still see overheating. I thinking you are getting to the root of your issue. If your getting premixed antifreeze I'd get 2 gallons. Good luck man!

[RickieT]

Took the boat out both had perfect temps at higher speed! All is good now...at least for now...lol

Thank everyone for all the input!

Rick

[mjk1040]

Until the next issue!!! Have a good season!

[dtlag]

Rickie,

Did this fix your problem? I'm having the same problem on my Carver 406. The coolant disappears, but is nowhere to be found.

Thanks!!

[390Express]

Source of the post Rickie,

Did this fix your problem? I'm having the same problem on my Carver 406. The coolant disappears, but is nowhere to be found.

Thanks!!

I had the same issue, mine puked out of the radiator cap, I believe, and was evacuated out of the bilge by the pump.

The issue that I'm having is, my over fill reservoir will be near empty, I'll add a small amount, then it will puke out everywhere. It's done it three times now. I think what's happening with mine is, I have air in the system, and its burping its way out, but making a mess in the process. I don't really see an air bleed anywhere, so I guess I just have to deal with it for the time being.

[bud37]

The first thing would be to pressure test your closed cooling side........you want something a little more definite.....take a sample of your oil and a sample of your coolant....send to lab to look for products of combustion in the coolant and coolant in the oil....that will pretty much put to rest the issue of it maybe being a head gasket.

There are many other reasons for coolant dissappearing, coolers, exhaust, line leaks, bad pressure cap, etc......but consistent over pressure in there is fairly telling.

Dtlag, welcome to the forum.

[tomschauer]

If your reservoir runs low and then over flows it may be riser gaskets or the heat exchanger. When the engine is cold you may have higher pressure on the raw water side letting water into the system. When it gets hot you would have your fresh water (anti freeze) bleed into the raw water system and out the exhaust. You may want to check and make sure you have sufficient freeze protection for the winter until you find and solve the problem.

Best of luck!

[390Express]

Source of the post If your reservoir runs low and then over flows it may be riser gaskets or the heat exchanger. When the engine is cold you may have higher pressure on the raw water side letting water into the system. When it gets hot you would have your fresh water (anti freeze) bleed into the raw water system and out the exhaust. You may want to check and make sure you have sufficient freeze protection for the winter until you find and solve the problem.

Best of luck!

Thanks Tom. For the winter I always winterize the freshwater side of the motors, and after winterizing them I disconnect both ends of the heat exchanger and pull all of the block drains and riser/manifold plugs completely out. There's no sense leaving the RV antifreeze in the system where it's not needed. I'll see what I can do about pressure testing the manifolds and risers this spring. I think I just have air in the system, but I can't find any sort of bleed screw or way to get the air out of the closed loop, other than let it keep burping and refilling the reservoir.