running an engine too cold?

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running an engine too cold?

Postby flygt4 » Wed Sep 16, 2009 8:26 pm

My thermostat is stuck open on my ute.

This causes the engine to run cold and it only just gets above the bottom cold line on the motorway. are there any downsides to driving it like this in the short term? I have a new thermostat on the way.

only thing I can think of is that the glow plugs will remain on 10-15min longer than usual and may have ill effects for the battery/charging system.
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Re: running an engine too cold?

Postby tsoob » Wed Sep 16, 2009 8:41 pm

flygt4 wrote:My thermostat is stuck open on my ute.

This causes the engine to run cold and it only just gets above the bottom cold line on the motorway. are there any downsides to driving it like this in the short term? I have a new thermostat on the way.

only thing I can think of is that the glow plugs will remain on 10-15min longer than usual and may have ill effects for the battery/charging system.


short term shoulde be fine but it wont like to rev hard or be stressed
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Postby Crampy » Wed Sep 16, 2009 9:29 pm

It'll use $hit loads more fuel if running cold.
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Postby Mr Revhead » Wed Sep 16, 2009 10:18 pm

oil wont get to temp
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Postby flygt4 » Wed Sep 16, 2009 10:27 pm

Crampy wrote:It'll use $hit loads more fuel if running cold.


which is still SFA compared to a petrol.
Its mostly motorway driving which gets the temp up above baseline anyway. in 50km zones it drops back a bit though.
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Postby evil_si » Wed Sep 16, 2009 10:34 pm

generally glow plugs are on a timer not temp contolled so you wont have an issue there

the only real downside is more wear occurs while an engine is cold,
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Postby Crampy » Wed Sep 16, 2009 11:44 pm

flygt4 wrote:
Crampy wrote:It'll use $hit loads more fuel if running cold.


which is still SFA compared to a petrol.
Its mostly motorway driving which gets the temp up above baseline anyway. in 50km zones it drops back a bit though.

True that. Realised it was diesel after I read it again.
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Postby flygt4 » Thu Sep 17, 2009 6:45 am

Crampy wrote:
flygt4 wrote:
Crampy wrote:It'll use $hit loads more fuel if running cold.


which is still SFA compared to a petrol.
Its mostly motorway driving which gets the temp up above baseline anyway. in 50km zones it drops back a bit though.

True that. Realised it was diesel after I read it again.


if it gets any more economical after i replace the thermostat i may actually cry :lol:
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Postby evil_si » Thu Sep 17, 2009 9:06 am

if its thirsty on the diesel,
does it black smoke under acceleration?

could be the injectors are worn and the fuel/ injection pump needs re calibrating or just winding the fuel screw in a tad
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Postby Leon » Thu Sep 17, 2009 9:09 am

flygt4 wrote:if it gets any more economical after i replace the thermostat i may actually cry :lol:


If you think you're crying now, wait until you realise that it is going to take you seven hours to drive over the Rimutaka's
;)
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Postby flygt4 » Thu Sep 17, 2009 6:46 pm

evil_si wrote:if its thirsty on the diesel,
does it black smoke under acceleration?

could be the injectors are worn and the fuel/ injection pump needs re calibrating or just winding the fuel screw in a tad


nope its unbelievably economical, I thought the fuel gauge was broken for the first couple of days :lol:
I'm used to driving a petrol, but i'm a convert now. it never seems to smoke at all from what i can tell either.
and its not too gutless really , its a 2.7L so its has plenty of poke from idle, 5th gear covers pretty much all driving above 40km.
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Postby Leon » Thu Sep 17, 2009 7:06 pm

flygt4 wrote:5th gear covers pretty much all driving above 40km.


Right up to the top speed of 58kph :twisted: :twisted:
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Postby flygt4 » Thu Sep 17, 2009 10:23 pm

Leon wrote:
flygt4 wrote:5th gear covers pretty much all driving above 40km.


Right up to the top speed of 58kph :twisted: :twisted:


it actually accelerates quite easily from 100km to 120km, it won't win any prizes for sheer pace, but its grunty enough to clear most traffic confortably within a passing lane sized gap.

doesnt really want to rev much due to running cold I think , 3000rpm is about as exciting as it gets atm.
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Postby flygt4 » Mon Sep 21, 2009 7:23 pm

got the new thermostat in this evening, which is just stupidly easy on a nissan diesel, as the housing is pointing upwards and in clear view, and they have an easily accessible draincock.

what a difference its made. the engine is now quieter, and revs way more freely, all the way through to 4k :lol: It has also cleared a few suspicious noises/rattles that were concerning me, although I can't be sure how long it was driven like that and if any damage was done to the bottom end during the time the previous owner had it. I have a feeling the reason the previous owner sold it was they didnt know what was wrong with it.

and parts prices seem very reasonable on the slightly older stuff, as it only cost $40 and a few more for the gasket.
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