How hot is too hot

[KREW2]

Yesterday I motored for about two hours, when I returned to my moorings the engine seemed a little hotter than usual (volvo 2002 raw water cooled) the alarm had not gone off and the rocker cover was very warm to touch. I checked the exhaust and the water flow looked a constant but seemed a little weak. Today I went over and fired up the engine after about ten minutes the the water flow stopped completely I checked the impeller the centre was turning but the blades were not rotating, my question is if I was still able to put my hand on the engine can I assume it had not overheated too much?

 

[pyrojames]

If you can still put your hand on it, even if you have to take it off again very soon after, it is not too hot.

 

[Lakesailor]

Yep, Drive your car for a couple of hours and then open the bonnet and rest your hands on the cam covers. Ouch.

 

[nigelhudson]

Running a raw-water cooled engine hot will encourage the deposition of salt build-up within the engine. If it was only a couple of hours then it shouldn't cause a problem but it might be wise to check in the thermostat housing to see if there is any significant salt deposition.

 

[bilbobaggins]

[ QUOTE ]
I checked the impeller the centre was turning but the blades were not rotating

[/ QUOTE ]

This sounds like a failed impeller. It was once commonplace for the centres to rip away from the outer parts holding the blades - a manufacturing defect, I understand - and it is possible for small bits of rubber debris to partially-block the tubes, so a very careful inspection of what comes out is necessary. If it's not all there, anything missing has to be found and extracted.

Anyway, replace it with a 'known good' item; if the one you take out is OK after inspection, then you can keep that as a 'get-you-home' spare. I suppose you know the trick of using a plastic cable-tie to hold all the impeller blades compressed until it is nearly fitted home into its housing, then slipping off the cable tie......

/forums/images/graemlins/wink.gif

 

[alec]

I have a raw volvo 2001.

My engine water throughput was a little on the low side like yourself.

Underneath the engine is a water drain plug. My mate undid it and nothing came out. Shoved a screwdriver and gradually masses of mud and weed ( I am an East Coast mud sailor) came out. Water then flowed like a good'un and engine seemed much quieter.

 

[aidancoughlan]

[ QUOTE ]
I suppose you know the trick of using a plastic cable-tie to hold all the impeller blades compressed until it is nearly fitted home into its housing, then slipping off the cable tie......


[/ QUOTE ]

Pure genius !

 

[KREW2]

[ QUOTE ]
This sounds like a failed impeller

[/ QUOTE ]
Yup definitely, but not immediately apparent, at first glance all looked intact and ok. It was only when I removed the impeller that I noticed the screw which fits through the metal drive hub was not inline with the outer rubber which holds the blades, thus indicating that the blades were slipping and not rotating at the right speed to pump the required amount of water through. Thanks for the replies and I now feel more assured that I have not cooked my engine.