Overheating Engine

[sneuman]

Had a belt break this weekend while motor-sailing, which shut-down the heat exchanger. By the time I realized the engine was overheating, the smoke was pouring out of the engine box and the temp gauge was pegged over. Of course, I immediately shut down the engine, but I'm not sure how long it was overheating.

I changed the belt (luckily had a spare) and let the engine cool down. Restarted, everything seems fine.

My question: if the engine seems to run OK, is it safe to say there was no permanent damage? If not, what are the consequences?

[Ex-Calif]

Take a good look at the oil. After overheating the cooling is only being done by the oil. Overheated oil will smell bad and be black.

Probably a good idea to change the oil and the filters as soon as practicable.

As far as the overheating event, it's not a good thing and damage is possible.

When you change the oil, you can cut the filter open and examine the paper element inside. There are cutters made for this purpose that look like tube cutters - It is common prectice in the aviation business to cut the spin on filters open so you may have to source it at an aviation shop, borrow one or take your filter to teh airport mechanic and beg him to cut it open for you.

You can use something else but nothing like a hacksaw that will create its own chips. Cut it around the circumference at the base end. Carefully open it and remove the paper element. The paper element flows from inside to outside so you will need to carefully cut the element open and lay it out.

You are obviously looking for metal particles. Bronze for bearings, shiny hard metal for things like rings and cylinder walls. If you have metal you have problems and further troubleshooting will be required.

If you find metal (depending on what it is) you may do a compression leak down check and to look for ring and cylinder damage. Borescoping the cylinders is also a technique.

I don't mean to be a scaremonger, just giving you some options. The engine is probably fine. We had a belt break too. Same symptoms and she's running fine a year later.

[sneuman]

Thanks Dan. I will definitely take your advise on changing the oil and filter and see if the forensics are doable.

[nvyseal1]

A warped head or thermostat damage is a possibility of a severe overheat. Watch for any indication of coolant leaks at the head gasket or the oil increasing in quantity on the dipstick, an indication of coolant intrusion via the head gasket. If those symptoms don't occur, I would say your engine temp. didn't stay high long enough to do any permanent damage since the motor appears to be running fine now. The oil and filter should be changed as a precaution as Dan already recommended. Jim

[Ex-Calif]

Excellent point on the potential head warpage or head gasket damage. Oil in the water or water in the oil would be a terrible sign to see if this happened.

Once again - a single overheting event with the engine shut down as soon as the problem is identified is probably not a problem.