Help with cooling system

Aug 11, 2011
O'day 30 313 Georgetown MD
In my humble opinion, inspection and what is acceptable is all relative. As previously stated, blowing down a hose and finding air coming out the other end, might not mean that large amounts of water will travel without much resistance down a hose. My example of this is when I commissioned my cleaned up/refreshed engine with out an inline raw water filter before the pump. With the engine running and looking at the transom, water flowed out with exhaust at a high volume and force. Once I installed the inline filter, resistance took over and the flow is less.
You mentioned in your original post, gurgling in the exhaust. Has the Vetus Waterlock been inspected. it should have nothing in it.

And then as I previously suggested , check the entire wet exhaust hose. These hoses can crack and collapse with all the heat that goes through them.

Its all about the process of elimination!
Jan 27, 2008
ODay 35 Beaufort, NC
Put the HX back in. Pull the raw water hose off where it connects to the exhaust. Stick it in a bucket, add an extension hose if you need more length. See if you have good flow at that point (this is after the HX. I have seen salt deposits in the fitting to the exhaust cause a restriction stopping flow, a previous post also noted that as a culprit. Especially if you have a right angle fitting in there where water can collect and evaporate leaving the salt.


Jun 26, 2019
O'Day 28 Lorain, Ohio
I just wanted to update this thread. We have been away from the boat for a bit because our son got married this last weekend. But it appears that the problem was in fact restricted flow in the heat exchanger. A new one is on the way. We were pretty sure that was the problem, but I wanted a guy to come out and look at the exhaust, because I am not messing with something that if not done right could kill me. Call me crazy. But the exhaust is fine, and everything seems good right up the HE, and then the flow slows dramatically. So the consensus here and at the yard is that has to be the problem.

So once again, I really appreciate the advice, even though it cost me money.
Jul 5, 2011
Oday 28 Madison, CT
Same as what was with mine. They just get loaded up after a lot of years. Thanks for coming back as we all benefit from knowing the ending of the saga so to speak.