Forums, Engine, Gearbox, Stern Gear, etc, Engine alarm issue

marisco at 22/05/2016 17:22:04
I’m getting an alarm problem…

About 10-30 seconds after starting engine the overheating alarm sounds – not normal volume but fairly quiet – you need to put your ear close to the panel. Also the blue overheating light doesn’t come one. It’s like it’s doing a half hearted effort.

The engineer thinks the engine temperature is fine. He has tried 2 sensors. When he shorts the alarm circuit manually the overheating alarm sounds loudly and the blue light comes on – as expected.

Wondered if any advice on what the problem might be or what I should try next ?

BUKH DV20 1977 I think..

many thanks,

Paul

Galatea at 23/05/2016 01:11:19
I assume your engine is raw water cooled? The VDO temperature alarm sensor tends to corrode, let salt water inside, and fail. I think VDO might have made it especially for Bukh. Many years ago they replaced mine under warranty, but the replacement also failed. Seems like a bad design.

marisco at 23/05/2016 18:22:24
Yes raw water cooled. Maybe I need to try another sensor ! paul

Galatea at 24/05/2016 00:31:46
See if you can find one that matches the thread. I couldn’t and ended up sealing the broken sensor with epoxy and learning to live without temp alarm.

Keny at 24/05/2016 18:55:29
Hello Paul
Welcome to boating. Are you sure that the audible alarm is only for overheating? Usually it sounds
for other things as well.
keny

marisco at 24/05/2016 20:15:33
I think so, but not totally sure..

Keny at 25/05/2016 09:09:32
Do you have warning lights for oil pressure and battery charging?
Are they bulbs or led’s?
If they are all connected to the audible alarm they all need isolating to find the fault including the alternator.
keny

Keny at 26/05/2016 08:46:19
Just had a thought that the two wires on the sensor may be crossed over – this would have this effect but of course your temp. gauge would’t work.

marisco at 31/05/2016 21:36:52
Update – all sorted ! Excellent engineer from Lymington installed new sensor (the previous one faulty and wired incorrectly !)

George Isted at 31/05/2016 21:45:06
Great, I’m pleased it’s all sorted :-)