Overheating

single

single

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The boat engine was getting too hot so i brought the thermostat home and just put it in a glass of boiling water.It opens about as much as a hairline crack so i assume its had it? Anyway is there anywhere on-line i can order one (Thornycroft T95) or do i just match one up at the motor factors?
 
I think you should be able to get a replacement from a car shop - so long as you know the operating temperature, which should be marked on the original.

Rob.
 
I'll try tomorrow.I'm just supprised how few spares are on-line for that engine.
Incidentally how much should it open in boiling water.Its got 80 degrees stamped on it.
 
single said:
I'll try tomorrow.I'm just supprised how few spares are on-line for that engine.
Incidentally how much should it open in boiling water.Its got 80 degrees stamped on it.
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It should just start to open at 80C.
Id expect it to be fully open before it got to 100C. Sometimes they have the fully open temp marked on them too.

Is the engine directly or indirectly cooled.. there is usually a significant difference in the thermostat opening temps. It would be wise to ensure that you have one opening at the correct temp rather that at the original temp of the old one.
 
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single said:
Indirectly with sea water through exchanger.I guess its the correct one as i bought the engine new a few years ago.
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I came back to say presumably fresh water cooled at 80C. Should be fully open at around 95C I'd guess
 
single said:
Indirectly with sea water through exchanger.I guess its the correct one as i bought the engine new a few years ago.
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The temp stamped on the thermostat is normally the temp the engine will run at. If it's indirect, 80C is very cool. Normal operating temp for most engines whether petrol or diesel is between 82-90C, with boat engines generally running at the lower end of this.

Rule of thumb, I always used to take 82 as a "summer" thermostat, and 88 as a winter stat. Much older engines (pre 1960's), in cars at least, with lower rad pressures ran stats as low as 78. Modern cars now run 90 or higher.

Higher running temperatures give better efficiency, but also give less safety margin in the event of cooling system problems (reduced flow, blockages, belt slipping etc) so there is a trade off.

If you can I would replace the 80 with an 82 stat. Likely to be easily available at any good motor factors.
 
Trundlebug said:
The temp stamped on the thermostat is normally the temp the engine will run at. If it's indirect, 80C is very cool. Normal operating temp for most engines whether petrol or diesel is between 82-90C, with boat engines generally running at the lower end of this.

Rule of thumb, I always used to take 82 as a "summer" thermostat, and 88 as a winter stat. Much older engines (pre 1960's), in cars at least, with lower rad pressures ran stats as low as 78. Modern cars now run 90 or higher.

Higher running temperatures give better efficiency, but also give less safety margin in the event of cooling system problems (reduced flow, blockages, belt slipping etc) so there is a trade off.

If you can I would replace the 80 with an 82 stat. Likely to be easily available at any good motor factors.
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Got an 82 now so just need to fit it and fingers crossed.Should i have got a new gasket too?
 
I believe that direct cooled engines are run at a lower temperature to minimise salt deposits in the cooling system an indirect system is much more like a car engine and can be allowed to run hotter with improvements in combustion efficiency.

Rob.
 
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