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2006 Hammerhead w/ Fresh Water Cooling System Overheated at hour 15

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Sorry for the length, but the details are relevant:

We own a 2006 LSV w/ HH and fresh water cooling system. We completed the 10 hr break-in by the book 2 weeks ago and took the boat out for the first full day of wakeboarding last Sunday. We rode for 4-5 hours with full stock ballast, wedge deployed, and 5 people in the boat without incident, and the boat and wake exceeded all of my expectations and ran perfectly.

Around mid-day, we had to run approximately 2 miles up river to pick up one of our crew who was joining us late and I opened the boat up to around 44-45 mph for the very first time. She ran great for about 2-3 minutes and at the same exact time I saw the "CHECK ENGINE" message on the dash, I saw a stream of smoke coming out from under my arm in the general area of the throttle assembly. I can't adequately describe my initial fears/thoughts...

The adrenaline kicked in HARD and I throttled back to neutral and shut down the engine as fast as possible, grabbed the fire extinguisher at my feet and told all passengers to move to the bow area immediately. I made my way back to the engine compartment and saw smoke coming out from around the locker and engine compartment doors. I pulled open the engine cover prepared to hit it with the extinguisher but the cloud that came out was so thick that I could not even see the engine from 2 feet away. After a few seconds spent looking for the flame to target w/ the extinguisher, I realized that it was steam and not smoke, thank God.

The bilge area, the engine compartment, and the storage lockers on both sides of the engine were covered in coolant. I let the boat cool down and started her up again about 5-10 minutes later, but she quickly overheated again, and we had to paddle to shore. Thankfully we were close to our dock, and the wind was not too strong. My buddy waiting on the dock had feared the worst and was watching what he thought was a catastrophic boat fire and was unable to do anything.

Finally got her on the trailer and back home, pulled the stern drain plug and filled a single 5 gallon bucket with coolant and then another 1/4 of a bucket before she was dry. Tried to hose down the engine and storage/bilge areas to get the coolant out, but could not get it all. Took the boat up to the dealer the next day.

The dealer has had the boat for two days and "thinks" that the problem was that the lip on the heat exchanger "fill pipe" (not sure what the technical name for this is, but it looks a lot like a radiator cap on a car engine) was bent and therefore the cap was not securely on or in place. In addition, for those of us with the HH engines and fresh water cooling systems AND heaters, there is an issue identified by Indmar with low coolant fluid levels due to the heater option. I will try to get a better explanation for this, but I think the heater ties into the fresh water cooling system at some point and increases the system's coolant capacity and requires a topping off of the coolant above and beyond the manufacturer's specifications for engines NOT equipped with the heater.

Turns out that my dealer has only sold 2 HH engines with fresh water cooling systems (ever) and they were both 2006 boats, and they both had overheating/coolant level issues within the same month.

Just thought those of you with this setup may want to know. This is also a good lesson learned, KEEP A GOOD EYE ON YOUR GAUGES. We had all been out to dinner the night before and joked about how the marine fire extinguishers were not really expected to put out a serious fire, and that we should be prepared to leave the boat in a fire. I was the one who vowed to stay and fight the fire...not that we had a fire, b ut we sure thought we did for a moment or two. Not as funny anymore.

Last point of note: The dealer told me that this engine has a "limp" mode which puts the engine in a protective mode and limits the RPMs when it starts to overheat. This is designed to prevent the operator from damaging the engine. WELL, this limp mode never kicked in for me in this situation. FYI.


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It sounds more like one of the coolant lines was loose or disconnected. Especially if you got that much coolant out in the bilge...

I have the FWC and a heater on my 05 Monsoon, and I have noticed that you need to keep an eye on the coolant reservoir to make sure that the appropriate coolant levels are maintained... I agree that it may only be an issue when the boat arrives new and that the coolant may not have had a chance to get all of the air bubbles out of the system (Mine is also tied into the heater).

Good luck!


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interesting. i have had FWC on my Monsoon with never a fluid level issue. It should have come from the factory with the proper level. i usually check the level at least once a week (and actually have never had to add any). i am going to change it this year for the first time. Also make sure you check your corrosive diode (i replace mine once a season, i am in brakish water). i also clean the exchanger at the end of the season.

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i have the HH with fwc and optional heaters and have had no issues 160 hrs

Update from the dealer yesterday indicated that i this problem has shown up in a number of 2006 boats with this configuration.

jgouveia3- our dealer said that they actually fill the fluids for the engines when they are delivered from the Malibu factory, not sure if this is true of all dealers/boats or not, FYI.


The dealer thought they had the problem fixed yesterday and went out to water test it. Dealer said that as soon as he got over 4,000 RPM the engine temp JUMPED from ~160 degrees to over 200. On top of that, the line connecting the heat exchanger to the overfill reservoir ruptured. They could not tell me if this was b/c of the temp of the fluid in the hose (causing it to melt) or the external temp of the exchanger which the hose comes into contact with (also causing it to melt).

They pulled the boat and contacted Indmar technical department who told them they have seen this problem and are now working with the engineers to resolve it. Not what I was hoping to hear obviously, as we now loose another early season weekend of riding/boating.

Will keep you all posted on developments.

Thanks for the feedback so far.


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OBSKI, Mike and Vin- thanks for "feeling" my pain. Appreciate the condolences!!


Not much to report other than Indmar telling my dealer that they have had at least three (3) 2006 boats with HH engines, fresh water cooling (FWC) systems AND heaters with this same problem. They (Indmar) are now thinking it is the heater and how it is tied to the FWC system and/or the HH engine.

I do not know how the heater is connected to the FWC system and/or the engine for that matter. I am sure that some of you do, but I cannot speak on the technical merits of this issue at all at this point. As soon as I hear more from the dealer I will post whatever I can decipher and articulate to you all.

Next step is to ask if they can just disconnect the darn heater and let me have the boat back until the Indmar engineers sort it all out.

Thanks to those of you that have provided feedback, it is nice to know others can relate to not having your brand new boat at home, on the dock, in the water, etc...


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they should be able to by-pass real easy. just make sure they drain the antifreeze in the heater, so it doesn't get all over the boat.

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FINALLY heard from the dealer who has had our new boat for over 2 weeks now. Indmar has confirmed that an issue exists with the raw water intake "restrictor" and the dealer claims to have resolved the issues as of this morning. I am psyched to be getting the boat back and will press the dealer for more details while I am there today. Will post more when I know more.

As a side note; Indmar told our dealer that this is a problem that they have been seeing quite a bit of, so others with the HH and FWC system should take note so that you can recognize the symptoms as early as possible. It appears that the engine overheating has been happening above 3800 RPM. This is consistent with my specific situation, FWIW.


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So, on the closed cooling systems, the heater is on a loop off of the engine?

sorry, i missed this. yes, the heater is off a loop of the engine (at least on the Monsoon). So we run antifreeze. the good things about that: less corrosion, don't have to drain for freezing, and don't need the low RPM fix.

one bad thing about closed cooling, can't use the standard raw water shower, need to used the $200 more one...

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Okay, that makes sense, thanks for the reply. So does the shower run off of the heat exchanger?

no, it has its own. I haven't put one in yet, because of the cost, and I don't think I would use it too much. I usually go from dry suit to shorty. it would be nice to have. Here's a link to what it looks like:

Heatercraft Closed Cooling Shower

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The boat is back home safely!!

The service guys told me that Indmar directed them to increase the amount of flow going into the "exhaust dumps". This is the part of the engine that directs the raw water from the FWC system into the exhaust system and then out of the boat (down stream of the engine). These "dumps" look like 6-8 inch long, 3-4 inch diameter tubes, with metal collars on both ends that attach them to the exhaust system. There is one on each side of the engine and they are oriented bow to stern, and angled down (from bow to stern) at approximately 45 degrees.

The service guy increased the flow to the dumps by drilling an extra hole (either 7/8 or 7/16) in the junction between the FWC hose and the top of the dump. I know this is incorrect terminology for these parts, I tried to follow all of the technical discussion and even had them show me what was done, but was still a little vague on the terms. I can take pics if anyone needs a visual, just let me know.

My dealer noted that they expect to be seeing a lot of this similar problem/issue since they have already had multiple 2006 boats with BOTH the Hammerhead and the Monsoon power equipped with FWC that exhibit the exact same symptoms. I will say it again, if you have this setup keep a close eye on your engine temp when exceeding 3,800 RPM.

Last point, I left the boat with a half tank of gas and they burned almost all of it (more than 5 water tests) and told me that fuel is not covered under warranty, and my tank is completely drawn down. They did detail the boat interior and bilge area to try and remove the coolant chemicals under warranty.


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do provide pictures. the FWC systems used now must be completely different than what is on my factory installed '00 RLX Monsoon. my system doesn't have "dumps" that run bow to stern (not that I know of anyway). i have only every seen my BU and one older corvette edition with FWC.

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