Potential Engine Damage Overheating 2006 PCM 350

[kzundel]

Question for the experts:
Potential engine damage 2006 PCM engine was run without lake water recirculation. (My son forgot to open the valve last time it was run on land) Motor was run for 15-20 minutes. Was running at 3000rpm across lake and smelled somthing burning. Saw white smoke trailing from the back of the boat. Shut engine down immediately. Opened Engine compartment with fire extinguisher at the ready, but no smoke in engine compartment.
Note: engine temp guage never exeeded 175 degrees no engine overheat warning.
Engine compartment smelled like burning fiberglass. Removed engine cover and no burnt or melted wires gaskets were visible. Discovered closed water inlet valve. Opened valve.
Let engine cool for 1 hour. Engine restarted and idled fine. Concern about engine dammage returned to boat ramp at low rpm. Engine ran as ussual with no signs of misfire hesitation etc.
Concerend about very bad burnt fiberglass smell in the engine compartment. What parts should be inspected and or replaced after an issue like this? Will obviously replace impeller, as was run dry for 20 minutes. Engine Thermostat was replaced less than a year ago.
Did i get lucky or am i waiting for the other shoe to drop.
Any advice is welcome.
kzundel

[kzundel]

Am digging deeper into the exhaust system to figure out where the burning fiberglass smell is coming from and check to see what is fried.
just put a new fresh air exhaust on the boat last year will have to remove the exterior exhaust to check internal flappers for damage.
this is a 2006 Air Nautique 226 it looks like it has a fiberglass muffler behind the engine, will be difficult to inspect hoses clamps and fittings.

Want to insect as much as possible before taking it to a shop.
Would a compression test of all cylinders be the best way to check for any internal engine issues?
Thank you again for the help.

[AGGIE00]

I’d suspect the temp gauge didn’t climb because there was no water running across it. That’s a long time to run with no coolant and considering it was smoking your engine is probably toast. It will consume a tremendous amount of oil now.


2010 SANTE 230

[Infinity]

Eh, no point in jumping to conclusions like that yet, especially since the boat ran good back to dock....its possible you dodged a bullet. I would say that compression test would be a good idea....leak down test perhaps even better. Yes, there is a chance that there are problems and you certainly want to be sure before running boat so you don't make a "possibly minor" problem now... worse, by running it before checking it out thoroughly. Do you have an rubber exhaust hoses? Could be where smell came from.

In Spring of this year, I was with a friend on 2017 Supra SA with supercharged engine, dealer had just replaced the thermostat. He idled boat for 15-20mins while people talking and dude got his wakeboard on, etc....nailed throttle to get him up and about 45 seconds later the alarms started going off and some smoke from engine. Long story short the impeller cover was not put back on properly, temps hit around 200 according to gauge. Part of exhaust had rubber hose (which is what was smoking cause of heat)..he pulls out his throw-over pump and starts dumping water over the engine to cool it down (I was like....."don't think you should do that"). We are probably a mile from the launch when this happened. After 8-10 mins of that he start the engine to idle toward the dock (I am telling him I REALLY think its a bad idea), only takes a couple mins before it overheats again and alarms going off.....he does this a couple times and the last time actually throttled up to get some speed. (I really started jumping up and down on that one, lol).
He finally agrees its bad idea and dude comes by 5 mins later and tows us to dock. He had already phone the dealer previously and too their credit within 30mins there was a tech at the dock who got inside the boat and 30mins later had the impeller fixed, the codes cleared and boat ready to go. Tech actually mentioned that it did not look like he had overheated the boat too badly (I kept my mouth shut)!
We ended up spending the next 5-6hrs surfing and playing. I have been on boat 2 times since then and no issues that I am aware of.

BTW, I used to have a boat where you had to shut the valve to run on the hose and I ALWAYS taped a sign to my steering wheel before closing the valve to ensure that I could not forget because of hearing stories exactly like this. May be something you wanna do in future to help you remember to open it when done so you do not have this issue again.

[AGGIE00]

You’re right, maybe a little harsh in my assumption. I am curious to see where this goes. In my experience, overheating and then smoking is caused by collapsed oil rings. Hot enough for that and the heads warp or crack. The good news is that’s not a very expensive long block.





2010 SANTE 230

[Joshua J Rowe]

I'll go ahead and make a few assumptions.

Engine that new likely has over heat sensors, I would expect it to shutdown if temps were nearing damage. That's pretty standard on automotive engines of that age.

The exhaust is cooled by the water, just like the engine. Exhaust temps are like 1500 degrees, fiberglass resin is not a fan of this.

If you are lucky the smoke was the fiberglass resin cooking. In that period of time you could have cooked the rings or trashed the head or head gasket which could give you white smoke from burning oil or steam from boiling water.

A compression test would be great, 10% difference in pressure between cylinders is within acceptable range typically.

If engine temps were high the engine oil might show it. Engine oil gets thick and tacky when it gets cooked. Its early in the season so I assume not many hours on fresh oil. Oils change color quick when they get too hot. If its black already, or is tacky, you cooked it.

Don't freak out. Check the oil and compression. If both look ok and the boat fires up like normal you are probably just fine.

If it runs good just run it. I would go with fresh oil no matter what after that type of thing.

[CharlieP]

Been working on these Chevy V8s blocks my whole life and never seen something this minor be a major. My bet is that you're fine. You'd literally have to get the block red hot. Think cast iron pan in a 500 degree oven isn't going to do damage. Those GM blocks are tough as nails. Run her until she gives you a fit. In an abundance of caution, give her some fresh oil as it can potentially break down and wear out pre maturely in high heat. And for good measure new plugs as penance. Keep an eye on her water temp being too LOW now, might need a new thermostat. Those often go bad after getting hotter than 215-225.. Have a great rest of the summer on her...and enjoy the "fresh air"!