VDO dual temperature gauge question

[chinita]

Please excuse my ignorance! This is a little difficult to explain.

I have a new (to me) Bukh DV20 FRESHWATER cooled.

The temperature gauge (one needle) is expressed in 'Freshwater Temperature' on the upper curved bar and 'Seawater Temperature' on the lower curved bar.

Both bars are slightly different and, when the needle reaches the mid point (green) sector of the upper bar, it is starting to enter into the end of the green (towards red) on the lower bar.

Do only need to consider the freshwater temperature reading (as it is a freshwater cooled engine)?

I am pretty sure the seawater side is ok as I have just replaces seawater pump seals and impeller and there is plenty of water coming through the exhaust.

Does one gauge monitor both elements - with one needle!!?

My guess is that it is a 'universal gauge' for use with whatever cooling system you have; much as the Rev Counter has two gauge rings - inner for DV20/25 and outer for DV36.

TIA

 

[nigelmercier]

when the needle reaches the mid point (green) sector of the upper bar, it is starting to enter into the end of the green (towards red) on the lower bar...

So what you are saying is that your freshwater appears colder than the seawater? I think you need to take some measurements, perhaps with a laser IR thermometer: http://www.amazon.co.uk/exec/obidos/ASIN/B009RUPQGW/dolcetto-21

Handy to have on a boat.

 

[chinita]

Thanks Nigel. Nice bit of kit, not sure what I should point it at though!

What I really need is for someone who has the same gauge to explain it to me.

 

[nigelmercier]

Thanks Nigel. Nice bit of kit, not sure what I should point it at though!

What I really need is for someone who has the same gauge to explain it to me.

You point the device at the things you want to measure the temperature of, in the case the exits of the heat exchanger.

There will be two sensors, might be worth checking they have not been swapped.