NissanDiesel forums

What affect does switching from a 180° F to a hotter thermostat say 190° F or 195° F have on the SD22?

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Diesel Scout

WONDERFUL heat in this cold Ontario winter:-)

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The old 'six gun' was as popular as the cell phone in its time and just as annoying when it went off in the Theater.

I know your Scout has the SD33.

A higher thermo does not make the engine heat faster ... only higher. Consider the coolant valve before the heater and the heater core itself if you're concerned about warming your passenger cab.

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-Philip
Passed 08May2008
My friend, you are missed . . .
1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"

Philip,

Do you think it would help improve the MPG?

The heater is fine.

Carey

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Diesel Scout

water temp.
the thermostat measures the water at point that the hot water leaves the engine.in older cars the temperature gauge on the dash is also at this point.this may have no relation to water temps in the rest of the engine or oil temperatures.

temp issues.
i once read an artical about an old english mini driven across the usa to set a fuel economy record.they found that they needed very hot water and air at first then cold air and an average temp water to achieve best unburnt fuel/horse power ratio.
modern cars do this with water temp control on the lower radiator hose,they allow cold water to come back in when water at the bottom is at operating temp,water at the top may be 20% above boiling as long as there in no steam.

temp choices are dependant on use,if its always used at slow speed in cool conditions it depends on how good the water is cooled in the radiator,air speed.
at high vehicle speeds/high loads the same heat transfer rules aplies but the heat will be spread across the engine.it most likely to need more flow of water and hope that there is more air to shift the heat.not all the heat is transfered through water cooling.

the weather here is moderate,i often have to restrict air flow to get optimum tuning-cars made in australia have to handle 40-50 celsius days,its up to the owners the winterise the cars if you live in the cold south.
you see this with japanese cars as here they have big radiators and in japan/europe they have small radiators and big fans and air ducting.

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WCJR31 Skyline.3.0 manual.wagon
R31 SKYLINE/Passage GT/PINTARA
LPG Ford Falcon 99-06 93 Disco
Local Shire Southern Zone Mechanic.

I have experimented 160 / 180 / 192 degree thermostats. In temperate weather, there was no differnce in MPG that I could tell. But when ambient temps were less than 60 degrees AND with a 160 thermostat AND some diesel fuel formulatons, there was more combustion knock/rattle ... Colder weather costs MPG.

What is your MPG ... given a certain trip?

Best MPG has always occured during hot weather, low elevation, and less than 60 mph. Now that I have a pryometer, keeping the exhaust temperature less than 700 degrees keeps my throttle down.

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-Philip
Passed 08May2008
My friend, you are missed . . .
1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"

Philip,

MPG is still right at 24 MPG in my Scout with the Tug SD33 (MZ pump setup). I too have gotten the best MPG in warm temps and a 60 MPH or less for my 60 equally less that 2200 RPM.

I have two spare thermostats 192° & 195° I guess I'll try them to see how it does. I just noticed that with my new radiator my temp guage reads way lower.

http://www.binderbulletin.org/forums/sh ... hp?t=78313

Thanks

Carey

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Diesel Scout

The thermostat controls the coolant temperature until ... the thermostat becomes FULL open which then .... makes the radiator flow control the coolant temperature.The old radiator was the coolant temperature control due to restriction in the radiator core.

But now with a 'good' radiator, the coolant temperature is back to being regulated by the thermostat.

_________________
-Philip
Passed 08May2008
My friend, you are missed . . .
1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"