How hot is too hot? Monsoon 450

[Bobdog]

Quick question. How hot is too hot for 2016 Malibu LSV with monsoon 450? Headed home the other day and a rider told me she smelled smoke. Shut the engine down right away and was towed in. Engine temp read 450. Steam was coming from drivers side ballast compartment. I had just checked temp,oil pressure, and speed a few minutes earlier and everything was normal- engine temp was 165, and oil pressure was 60. 

First question is why didn’t a overheat alarm go off, and secondly how hot can the engine get without causing major damage or failure?

[Rednucleus]

is 450 a typo??!! If not that would be considered too hot IMO

[shawndoggy]

450 is definitely about 275* hotter than you're looking for.

[Bobdog]

Sorry, typo.  Engine temp was 240 when I shut it down. Impeller changes annually. 

[Bobdog]

It was hot- I could hear something boiling. Would that have been oil in oil pan? Checked the oil and it looked fine. Have searched but can’t find any parameters on engine heat. 

[Padge]

240 is pretty hot in my opinion

[JeffK]

240 is hot for a boat.  Not insanely dangerous yet, but hot.  You may have a blockage somewhere in your lines.  Most cars will run around 210 while the boat will run in the 160-170 range, so I doubt your oil was boiling or you caused any damage to the motor, but your manifolds or muffler may have some issues.  I'd pull a few of the big hoses and look inside to make sure you didn't toast them.  And that sucks to do b/c they aren't very flexible.  You likely didn't have enough water going to your heat exchangers/manifold.

[boardjnky4]

240 won't kill it, but you have a problem that needs to be addressed.

[Fman]

To start I would pull your impeller and check it, even though you replaced it they can still fail.  Sometimes they will spin on the spline.  If it looks good I would replace it anyway. Also would do an oil change seeing as you hit 240+ temps.

[Steve B.]

If the boats under warranty, take it in. You may want to take it in regardless, might be the quickest way to figure out what went wrong.

Steve B.

[Sixball]

Do you look at the heat exchanger screen each year?   It will make sounds if its plugged up.  I would also change the impeller after this anyway. 

[Woodski]

Be a little careful on comparing automotive coolant temps to a boat, particularly if you have raw water cooling.  Antifreeze and water under pressure have a much higher boiling point than does water at ambient pressure levels.  You can have localized boiling in various spots at water temps above 212 F and the sensor may not be located at the highest temp spot.  If, after the gauge peaks and then starts to drop if the engine is still running, you are reading air temp which means water boiling and lack of cooling water in the system.

As noted, you probably have some debris lodged in the system and / or the impeller needs replacement.  Once back up running, I suggest a frequent (like every session) check of oil level and color and make sure temps stay stable.  If mine, I would have an infrared thermometer gun handy and do a spot check on the manifolds just to ensure they are running at similar temps, it is very easy to internally melt the plastic fittings that the hoses connect to. 

The guns are cheap, available at many outlets:  https://www.harborfreight.com/Non-Contact-Infrared-Thermometer-With-Laser-Targeting-69465.html

They don't really have to be super accurate, you are looking for significant variation, so 'cheap' works in this case.  I feel it is a great tool to keep in the boat, quick diagnostic tool to check manifold temps or even thermostat outlet temps, oil temp, etc.

[boardjnky4]

A 2016 with a Raptor would be a closed cooling system. My guess is that you're low on anti-freeze. In a pinch, you can fill it with bottled water to get you through the day.

[Fman]

20 minutes ago, boardjnky4 said:

A 2016 with a Raptor would be a closed cooling system. My guess is that you're low on anti-freeze. In a pinch, you can fill it with bottled water to get you through the day.

Good catch but isn't the impeller still cooling the heat exchanger for the anti freeze?  Is it common for anti freeze to drop in these engines?  I would think if it were leaking you would see something in the bilge?

Just a DIY hack guess but spiking to 240 seems like it would be a drastic loss of cooling immediately...if he were low on coolant would it not be a little more gradual?  Just askin'....

[boardjnky4]

1 minute ago, Fman said:

Good catch but isn't the impeller still cooling the heat exchanger for the anti freeze?  Is it common for anti freeze to drop in these engines?  I would think if it were leaking you would see something in the bilge?

Just a DIY hack guess but spiking to 240 seems like it would be a drastic loss of cooling immediately...if he were low on coolant would it not be a little more gradual?  Just askin'....

Yeah I'm not really sure, to be honest. Sometimes you get an air bubble or two that comes out, then it sucks coolant out of the reservoir. If it sucks too much, it sucks air and compromises the entire system.

Honestly, it could be a number of things. But checking the coolant reservoir is the quickest easiest thing to check.

[DockRocketeer]

16 hours ago, Bobdog said:

 

Edited June 27, 2018 by DockRocketeer

[JeffK]

4 hours ago, Woodski said:

Be a little careful on comparing automotive coolant temps to a boat, particularly if you have raw water cooling.  Antifreeze and water under pressure have a much higher boiling point than does water at ambient pressure levels.  You can have localized boiling in various spots at water temps above 212 F and the sensor may not be located at the highest temp spot.  If, after the gauge peaks and then starts to drop if the engine is still running, you are reading air temp which means water boiling and lack of cooling water in the system.

As noted, you probably have some debris lodged in the system and / or the impeller needs replacement.  Once back up running, I suggest a frequent (like every session) check of oil level and color and make sure temps stay stable.  If mine, I would have an infrared thermometer gun handy and do a spot check on the manifolds just to ensure they are running at similar temps, it is very easy to internally melt the plastic fittings that the hoses connect to. 

The guns are cheap, available at many outlets:  https://www.harborfreight.com/Non-Contact-Infrared-Thermometer-With-Laser-Targeting-69465.html

They don't really have to be super accurate, you are looking for significant variation, so 'cheap' works in this case.  I feel it is a great tool to keep in the boat, quick diagnostic tool to check manifold temps or even thermostat outlet temps, oil temp, etc.

Fair point