Temp increase

[Dave_Knowles]

Hi,

Someone the other day posted that he experienced a water temperature increase when the blower was on but unfortunately I can't find the string. Last weekend I had the same thing and wandered if anyone could give a reason for this. The amount was not considerable but enough to notice on the gauge.

<hr width=100% size=1>Take care.

Dave

Dave Knowles
Southampton - UK

http://www.MyCleopatra.co.uk

 

[tripleace]

does the guage move when the blower is switch on and off.

if so, I had the same problem on triple ace and it was a poor neutral connection. ie grounding out via another route.

trying switching blower off and on and watch.

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[Dave_Knowles]

No, the temperature will go down gradually when the blower is switched off which leads me to the conclusion that it is affecting the engine cooling. I would add though the difference is not great.

<hr width=100% size=1>Take care.

Dave

Dave Knowles
Southampton - UK

http://www.MyCleopatra.co.uk

 

[martynwhiteley]

Difficult to think that it could be an actual temperature rise, and not just an instrumentation quirk.

If it is an actual rise (I suppose this could be measured by locally checking temp with a separate guage), then let's see what could cause that? The only things I can think of are:-

1. The added power draw on the alternator causing increased engine load, thus running hotter. (This will always happen to a 'microscopic' magnitude, but unless your blower was stolen from a 747, it's hard to believe that the actual temp rise would be noticeable on a guage).

2. If the blower is extracting from the engine room, then could it be possible that it is reducing the availability of 'combustion air', below that required for effecient running, therefore causing lower power output and a hotter engine if the same revs are to be maintained. (again very unlikely!).

It does seem like it should be an instrumentation problem, and as already suggested, bad earths can be a popular cause.

Also, if the cable feeds to the senders/guages are undersized, or badly connected, then the running of the blower could cause a voltage drop to the temp guage, thus
reducing the signal from the temp sender unit. Perhaps the blower supply is wrongly taken from the instrument panel + supply, and is reducing all instrument voltages when it is running. Or the blower supply cable is overheating and in a conduit next to the water temp sender wire?

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[ballena]

I was the one who posted the thread.

It is definately the earthing of the blower and instruments as I have made temp measurements of the engine whilst running, finding the bad earth is proving to be a real problem as the loom is very complicated, although I have narrowed it down to the circuit that supplies cabin lights,nav lights, macerator and cockpit lights.

Best of luck

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