High efficiency cooling system upgrade
#141
#142
#144
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Last edited by ascanio1; 02-27-2024 at 11:05 AM.
#145
#147
#148
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I'll have to ask my mechanic to measure the distance marked in red in the photo in post 129
However, in post 112 Craig mentions that the total height must be minimum 42mm, and stroke travel 6-7mm.
I'll post a photo when cold:
![](https://cimg6.ibsrv.net/gimg/www.jaguarforums.com-vbulletin/2000x1504/img_20240227_wa0078_0794db36fc8d4c3de18a13c837c02c1135fd6437.jpeg)
Last edited by ascanio1; 02-27-2024 at 11:35 AM.
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Peter3442 (02-27-2024)
#149
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![](https://cimg3.ibsrv.net/gimg/www.jaguarforums.com-vbulletin/632x1124/thermo_68487740428a7a0410f35acf0f12b6ab73656465.jpeg)
42mm is the distance you want, from the largest flange to end of foot. This is when fully hot. The cold and stroke measurements are simply a way to avoid having to measure a hot thermostat.
The 6 cylinder 4.2 EFI cars use the same thermostat as the V12, and I measured a 4.2 housing last night and it was 42mm.
Last edited by Jagboi64; 02-27-2024 at 11:31 AM.
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#151
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Greg in France (02-27-2024)
#153
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That will be perfect.
If I was wanting to keep a V12 cool, the things I would address in order are:
- Remove the radiator and make sure the fins are clean. The space between the AC condenser and the radiator can collect all sorts of leaves, grass, etc that block the radiator.
- Proper thermostats
- Proper fan clutch
- System bled completely
Then I would move on to smaller stuff, like making the sure the ignition timing is correct, fan shroud fits closely, aux fan working etc.
If I was wanting to keep a V12 cool, the things I would address in order are:
- Remove the radiator and make sure the fins are clean. The space between the AC condenser and the radiator can collect all sorts of leaves, grass, etc that block the radiator.
- Proper thermostats
- Proper fan clutch
- System bled completely
Then I would move on to smaller stuff, like making the sure the ignition timing is correct, fan shroud fits closely, aux fan working etc.
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#154
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I don't claim experience or knowledge in this matter but, to me, this thermostat travel (or stoke) question seems paramount.
One could have the best radiator, fans, etc but if the valve only redirects 50% of the coolant flow to the radiator then, at best, one can expect only 50% of total efficiency 🤷🏻♂️
Correct me if I'm wrong, but this 42mm valve travel/stroke seems key to me.
For future reference, to close this thread, the thermostat valve tested here is this one: David Manners 82°C Thermostat Valve V12 series III GTS101
Thank you to all who helped (Craig, Doug, Greg, Grant, Peter, Paul etc ... I'm sure that I forgot someone, apologies)
Tommaso
One could have the best radiator, fans, etc but if the valve only redirects 50% of the coolant flow to the radiator then, at best, one can expect only 50% of total efficiency 🤷🏻♂️
Correct me if I'm wrong, but this 42mm valve travel/stroke seems key to me.
For future reference, to close this thread, the thermostat valve tested here is this one: David Manners 82°C Thermostat Valve V12 series III GTS101
Thank you to all who helped (Craig, Doug, Greg, Grant, Peter, Paul etc ... I'm sure that I forgot someone, apologies)
Tommaso
Last edited by ascanio1; 02-27-2024 at 01:08 PM.
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Peter3442 (02-27-2024)
#155
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Of course, it's best to have both systems working properly.
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ascanio1 (02-28-2024)
#156
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It can be a bit of a chicken and egg situation. In many cases 50% capacity is sufficient, such as in cold weather with the heater on full. If the radiator is blocked and all the coolant goes to a radiator that is 90% blocked, you still don't have sufficient heat shedding ability. 50% of the coolant going to a perfect radiator is still a better system than a blocked radiator.
Of course, it's best to have both systems working properly.
Of course, it's best to have both systems working properly.
#157
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I am now looking for the larger alternator DAC5224 for my twin SPAL electric fans.
No, for some reason mine is a 75AMP but, remember, mine has many many miles so it could have been replaced.
- SNG Barratt and Simply Performance do not carry it.
- Jack Weston @ DM told me that they do not carry the 115 AMP, I found these on their website: https://jagspares.co.uk/alternator-1...-5-3-dac5224-3 are these compatible or are they overkill?
- I also found these: https://www.autodoc.co.uk/car-parts/oem/dac5224
No, for some reason mine is a 75AMP but, remember, mine has many many miles so it could have been replaced.
#158
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115 Amp? That's giving around 2 horsepower in old money! The fans night hit that running at maximum, but that's only a brief peak demand. Most of the time, it must be much less. And the battery is there to deal with intermittent peaks. I would be inclined to see how things go with the 75 Amp alternator. If you see the battery is suffering, upgrade; otherwise stick with the 75 Amp.
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