38 replies to this topic

[clipping_point]

If a 70° thermostat is fitted the thermostat will open just so much that the temperature inside the engine is held at 70°, am I right? This means that more energy will leave the internal of the engine and disappear in the ambient air. This means that the engine will LOOSE power It is the cold starts that kill the engine. Taxi cabs can run twice the length of your personal sedan, because of this fact. Operating at 70° puts the engine closer to the "cold start temperature", hence more wear will occur

[chris]

On thermodynamic point of view the best efficiency for engine is to reach the highest temperature as possible. Some adiabatic engines with ceramic pistons are under developpement within this frame ... But on "normal" engine limitations are given by material of piston, cylinder, valves etc ... It is the reason why it is necessary to have cooling circuit. Main reason to install cool running thermostat is when you upgrade your engine and you run it at the limit, this modification could may be "preserve" its reliability.

[B5M_VX]

If the engine ran more efficiently at 70 degs instead of 85, don't you think vauxhall would have set it like that?

These engines have gone under major development involving amongst other things, wear and performance at different running temps.
If vauxhall tell us that 85ish is the best then I'll go with them.
Its not just some figure they've come up with from the NA because that runs at higher temps.

You might even invalidate your engine warranty if something goes while its on there.

Unless you know hand on heart that running at lower temps won't damage your engine, I'd stick to what the experts tell us.

I am just going on what I was told when I bought mine, I aint got no waranty either

[zz_marcello]

On thermodynamic point of view the best efficiency for engine is to reach the highest temperature as possible.
Some adiabatic engines with ceramic pistons are under developpement within this frame ...

But on "normal" engine limitations are given by material of piston, cylinder, valves etc ...
It is the reason why it is necessary to have cooling circuit.
Main reason to install cool running thermostat is when you upgrade your engine and you run it at the limit, this modification could may be "preserve" its reliability.

Thats it

[mags993tt]

If the engine ran more efficiently at 70 degs instead of 85, don't you think vauxhall would have set it like that?

These engines have gone under major development involving amongst other things, wear and performance at different running temps.
If vauxhall tell us that 85ish is the best then I'll go with them.
Its not just some figure they've come up with from the NA because that runs at higher temps.

You might even invalidate your engine warranty if something goes while its on there.

Unless you know hand on heart that running at lower temps won't damage your engine, I'd stick to what the experts tell us.

I am no expert on this but just using logic without any technical engine building background aren't we missing the point between engine temperature and coolant temperature.

The cooler the coolant (within reason - we aren't talking about pumping liquid nitrogen into a hot engine after all) the more efficient the cooling process. The cooling process is necessary because otherwise it wouldn't be engineered into the engine in the first place.

Anyone who has done a sustained high speed run in a car with water and oil temp guages will know that the water temperature can be rock steady at normal operating temp while the oil temp goes into the red. I would say the oil temp is a far better measure of engine temp. The water temp is measuring the efficiency of the cooling system to do its job. Water temp stabilises very quickly after a cold start up but I still wouldn't thrash the engine before travelling a fair few miles because I can guarantee the engine would not be fully warmed up as soon as the water temp hit normal.

I agree if the thermostat opens early it will take longer for the engine to reach full operating temp - say another mile? - not a big deal to engine wear compared with other parameters like do you drive upto 3000 or 4000rpm while cold / when you decide the engine is fully warm and treat it as such / do you find that you sit in traffic with a cold engine or do you live somewhere where you can immediately get into a cruise / number of short journeys / ambient air temp /town or motorway driving etc etc etc

Frankly, if you intend to drive the car harder than the engineers envisage the average driver will (like say on track) I would say the benefits of more efficient cooling massively outweigh any potential drawbacks of which I cannot think of any. 10 degrees c difference in coolant temp vs an engine going from ambient deg C to hundreds of deg C in seconds everytime you start up cannot make a wear difference in my opinion but consitently running the engine hotter than spec will.

Just my opinion.

[Jase_MK]

I am no expert on this but just using logic without any technical engine building background aren't we missing the point between engine temperature and coolant temperature.

That's what I've been thinking all through this thread but didn't want to say anything...

[Ricky2772]

I have a 84deg. running thermo, and noticed the fan cutting in much more frequently, almost always when idling . blasting on track stays on 88-94 will see after the Hitec mods it any changes happen.

[ShinyAndy]

I wouldn't agree that there is any benefit to fitting a lower temp thermostat if the car is predominently used on the road. The cars coolant will struggle to get to temperature and if the outside temperature is low it could even never reach optimum coolant temps. I've experimented with lower temp stats before and all they did was result in a crap heater and an ECU that wouldn't let the car run properly until the coolant reached what it considered an optimum temp (sometimes never). I really don't see the benefit unless you're fitting them to a race car Fitting a lower temp fan switch can be beneficial though or even better a manually controlled one

[mags993tt]

I have a 84deg. running thermo, and noticed the fan cutting in much more frequently, almost always when idling .

Interesting - my fans don't come on until around 104-106 and then don't stop until around 100.

[Jase_MK]

OK, I'm confused. Are we talking about the thermostat that triggers the fan to cool down the water/coolant in the radiator?

[ShinyAndy]

Jase, the original question was about a thermostat not a fan switch

[Jase_MK]

Jase, the original question was about a thermostat not a fan switch

Right. A thermostat to control what though? The fan switch runs off a thermostat, which is why I got confused.

[markv]

Jase, the original question was about a thermostat not a fan switch

Right. A thermostat to control what though? The fan switch runs off a thermostat, which is why I got confused.

Should control the flow of the water either through the bypass circuit or through the radiator. If the temperature of the cooling water gets above the thermostat temperature it is routed through the radiator circuit, and otherwise (I guess) through the heater circuit?

Mark

[salopian]

9 months on - time for some current thinking here...... Any thoughts ?

[clipping_point]

If u have a seriously tuned engine, talking 210-230 HP in an N/A then to ensure low temps overall, it is a good idea. If you got a cotton air filter and a MOMO knob, then u do not need it IMHO.

[Ricky2772]

having 217hp, I ended up removing the cooler thermostat and replacing it with the std one. on the move was always too cold, 80-82...

[walkes]

2 Pence coming up...... The thermostat will cool the engine coolant more often / keep it at a lower temp This will not reduce the oil temp by much, if at all Cold start/Engine wear are cause by Low quality/Cheap oil Wrong grade oil Frozen cars. The coolant is run around the insides of the engine. Lets say for the sake of it the inside of your engine runs at 100 degrees. Just an example I have no idea what the temp will be but it's likely to be more. However Petrol boils at 180 degree.. Passing fuild through it at 85 degrees will bring the temp down somewhere between 0-15 degrees (Mid point 100 - 15/2 = 92.5) Passing fuild through it at 75 degrees will bring the temp down somewhere between 0-25 degrees (Mid point 100 - 25/2 = 87.5) your internal engine is probably running say 5 degrees lower. Does does this mean there is more dense air in the engine - NO. Does this mean there is more petrol in the engine - Possible Yes, Small, Tiny ammounts Does this mean there is more oil in your engine - Possible Yes, Small, Tiny ammounts Does this mean that your eninge is going to be smaller - I don't think so as the metal is not going to be a different size due to 5 degrees The trouble with running cooler by 5 degrees Are there any ? Personally it would be intresting to see it made a difference on a car before and after The amounts you are going to reduce the engine temp is pretty small. If is cheap to fit it not going to do any real damage. however whilst we are on the subject of cooling, if you want to make your engine really cold fit it with LPG the combustion temps are far lower !!

[clipping_point]

Well if you guys want to cool away the energy produced in the engine, this is certainly a cheap and easy mod to accomplish just that. Myself, I want the horsepower at my back wheels!

[oblomov]

Iwould say that if you're really concerned about engine temp, the way to go would be an after market oil cooler with a pre-set thermostat , either sandwich plate fitting or in line, by pas stat, that cuts in when the oil temperatures exceeds a given temp, ideally that being a few degrees over the manufacturesrs recommended engine oil temp. During 'normal' driving it would not cut in but while 'pressing on' or in hot weather it would. I have made this mod on a previous turbo charged car I had, and it worked very well. For what it's worth