Technical modified thermostat problems

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Technical modified thermostat problems

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Aug 26, 2007
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I used the guide to modify my stat a while ago (https://www.fiatforum.com/cinquecen...nq-sei-stat-cooler-running-gt-switch-mod.html)

But after my h/g change and new rad the car permanently ran too cool ruining MPG, and making the car sluggish.

I thought that maybe the stat was stuck open, so today in a spare 5 mins, whipped it off to check, all appeared closed?? so tested it, blocked the hole in the housing with silicone, then filled the stat housing with cool water, it showd the seal was useless leaking all the water away, so I replaced the old stat innards, and tried again, no leaks. plummed it all up, put it on the car and it runs fine now.

Anyone else have the problem of the modded stat not sealing properly?
 
Well, turbo Cinqs knock out twice as much power and therefore twice as much heat as a stock NA motor, so they need all the help they can get.

There's an argument that most engines make better power with a low temp thermostat, but it's really only applicable to race engines.

Fit one to a stock motor and you're likely to just use a bit more fuel.
 
It'll probably drink a bit more fuel, but a bigger worry is that the oil may warm up slower. This will increase engine wear.

I find the cooling fine, unless there are problems: my 1241 seems never to go over 90 (which is fine) until you turn the engine off (heat soak) and my Sei nevert overheated in 4 years and through 2 heatwaves.
 
The cooling on Cento's is not the best but should be good enough in normal conditions

However on my NA cinq i have seen high temps in mine especially in low gear work steep hills etc. Now I run a std stat in my NA cinq but run an oil cooler with a thermostatic sandwich plate i personally think that this is a much better (but much more expensive) solution and have no cooling issues in any conditions.

Only in standing trafic in warm weather do i ever have the fan cutting in and the car runs a nice steady 85 degrees most of the time
 
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It's a cost and space thing really, the bigger the oil cooler the quicker it cools and the more it costs.

If you check Aarons oil cooler post i run the same one as that which is for a turbo so is ott for an NA but fits nicely behind the bumper at the passenger side (with the oval hole opened up) and if you have a thermostatic plate that makes sure you don't overcool. This also leaves plenty of room for more power upgrades in the future.

A word of warning though some sandwich plates mean you may not be able to run a std filter and might have to go for the R5GT or Clio williams ones (or anything with an M20 thread that will fit TBO)

Even if you don't do anything else to the car you will be able to sell the cooler on if you change the car in the future
 
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