Technical 82 degree thermostat, keeps the car cooler!

[hmallett]

I have a reservation about this mod. If you're using a thermostat that keeps the engine coolant colder, then the ECU will pick up the lower temps, and keep the engine on the cold cycle for longer, meaning more fuel, and an increased likelihood of bore wash, and premature engine wear. The engine has a certain temperature range that it performs optimally at, and the factory radiator thermostat and fan thermostat will be set to keep it in this range.
I wouldn't worry about high under-bonnet temperatures. The Coupe 20V Turbo get incredibly hot under the bonnet, and that survives OK. If you think the fan can't keep up at maintaining the temperature, then you could try new coolant, with
water wetter, or a more efficient radiator (such as aluminium).
H

 

[custard]

for N/A cinqs yes,but the turbo cinqs were never designed for the type of heat under the bonnet.
also i dont know how it would affect fueling with the second injector set up. i'll hopefully be setting mine up with an oil cooler & temp gauge soon.my turbo seems to keep its coolant temp down quite well so it will be interesting to see what the oil temp is like as i avoid long journeys just now till i can get the cooler fitted

 

[arseofbox]

Yeah...turbo Cinq engine bays become like sauna's very quickly when parked idling!

 

[custard]

sometimes when i get home on a hot day i sit with the engine off and the bonnet up for a while to let some heat out. some venting/louvering of the bonnet is definatly on the list

 

[J333EVO]

I have a reservation about this mod. If you're using a thermostat that keeps the engine coolant colder, then the ECU will pick up the lower temps, and keep the engine on the cold cycle for longer, meaning more fuel, and an increased likelihood of bore wash, and premature engine wear. The engine has a certain temperature range that it performs optimally at, and the factory radiator thermostat and fan thermostat will be set to keep it in this range.
I wouldn't worry about high under-bonnet temperatures. The Coupe 20V Turbo get incredibly hot under the bonnet, and that survives OK. If you think the fan can't keep up at maintaining the temperature, then you could try new coolant, with
water wetter, or a more efficient radiator (such as aluminium).
H

Its a fair piont, but a car only runs on its cold cycle when its cold, ie below 40degrees not 82 that this lower thermo opens at which in itself is only 6degrees lower than factory, if it was still running cold cycle 6degrees before the thermo opens I would serious consider the cars ECU woudl need replaced, the engine still heats up at the same rate, this is tried and tested on R5GT Turbo's running 11sec 1/4 miles and Cosworths, and all maner of Jap stuff. And to get bore wash from a single injector would need some doing as thats an action that needs a hell of a lot of fuel to do.

As soon as you tunr your car in any way, be it exhaust, filter, cam, head work etc etc you are removing the engiine away from factory anyway introduceing more heat so it makes sense to "tune" the cooling system accordingly.

I've done it, my car runs as it should, and with the amount of Cinqs which suffer over heating and head gasket failure, I think anything to lower temps, even by a small amount are good for this car.

Aaron.

 

[HP]

Spurred on by the weekend's hot running and this thread, I've had a play myself. Bought the stat listed above (Halfords HTK 602, only a fiver) and took the old stat of Spare Engine 2 in the garage. The stat comes apart fairly easily, shown below are the parts from the Cinqy stat and the new one:

A is the new thermostat which has been cut to get the guts out (God Bless the Dremel!)

1 is the new stat spring

2 is the old stat spring

X is the old stat innards

Y is the new stat innards

Housing - if you can't work that out......

Retainer - holds the innards and spring in. Just press and turn to remove.

Note that this housing is slightly different to Aaron's - it's a genuine Fiat one (not sure if Aaron's was or not).

In true "I can do science, me" style I found a thermometer in the garage and started fiddling. The standard thermostat innard X has a large rubber seat, which sits inside the recess you can see in the housing. It needs to move quite a long way before it will allow a reasonable flow, as it needs to come all the way out of the recess - about 1/8" approx.

I found out how these beasties work in the process of doing all this. If you look at X and Y above, they have a pin sticking out one end. What happens when they get hot is that the pin pushes out, and against the spring tension the innards move back, lifting the stat off it's seat.

The results of my experiments (I didn't have an Igor to assist me, unfortunately) are as follows:

Using the standard stat, things just start to move at 85'c. Bear in mind though that it'll have to get hotter than this to get the thing properly out of it's seat.

Using parts 1 and Y, things don't start moving until 89'c - this I thought wierd as it's an 82'c donor stat.

Using parts 2 and Y (had to open out the end of the spring just slightly to allow it to seat on the new innards) things start to open at 87'c - I tried this as I thought the new spring felt like it was under a lot of tension. Still too high for an 82'c stat though.

Finally sussed the problem. The pin on Y is shorter than that on X, so it needs to get hotter and extend more before it can move off it's seat. Solution - chuck something down the hole for it to sit on. Using the lovely Dremel again, I chopped the head off a small self tapper (approx. 2mm thick) and carefully placed it in the hole. Thermostat still closes properly, but the result now - it starts to lift off it's seat at 82'c. Bingo!

This stat may well control better than the standard Fiat one too, as it just seats nicely around the hole, not inside it - so when it opens it should flow more straight away.

Just need to fit it and see now

 

[adz182]

nice one pete if i pay u can u build me one cuz i got confued half way thro that my car was over 90' on mway so something ent rite

 

[peaster2k]

Pete,

Here are two better photos of the housing units I have, again first one from 1108 Punto 55 Engine and the second one from a 1242 Punto 60 engine. There is cleary a different in the length of the pin on each of the thermo units, I am just wondering whether the 82 thermo we have bought will fit directly into the 1242 Putno 60 thermo housing without modifications. I think I will have to be trying that and see what happens.

David

 

[HP]

It's all a bit confusing this stuff. I started off looking for a Bravo or Punto 1.2 16v stat, as the Haynes manuals say the 16v one opens earlier than the Cento. Guess what - they're the same part number according to the Fiat parts CD and Halfords data books!

David - Try to figure out how much gap you've got between the end of the pin and the end of the hole it goes into. Ideally there should be none, but the stat should be seated closed when assembled. I can test it for you if you like, I guess me egg pan is buggered now anyway!

 

[HP]

nice one pete if i pay u can u build me one cuz i got confued half way thro that my car was over 90' on mway so something ent rite

I think a lot of it at the weekend was the weather. Mine was aiming for 95'c on the water and 100'c on the oil most of the way back from York - and I wasn't caning it. And I have an oil cooler!

I haven't tried it in the car yet, might be a week or two until I get to - but I could try to make you one up if you like. Have you an old spare 'stat hanging around - even one from a breaker would do as they're about £12 each new. You're looking at £17-£18 just for parts (without postage) if you need all new.

 

[AIJ29]

Peaster
I`ve stripped down the thermo from my 1242 and the pin is also shorter than the one in your 1108 thermo,
Maybe the 1242 thermo is the one to use?
Cheers
Adrian

 

[peaster2k]

Peaster
Maybe the 1242 thermo is the one to use?
Cheers
Adrian

Yeah maybe, I think I am off outside to start pulling mine apart.

David

 

[peaster2k]

I have put the new 82 Thermo into the 1242 housing and it works a treat, dunno the operating temps yet (waiting on thermometer). But I had the standard 1108 thermo and the new 82 thermo in the same pan when I was testing them, and the new 82 thermo opened sometime before the standard 1108 one did. So fingers crossed when I test them with a Thermometer they will be ok.

I tried both springs, the one from the 1242 thermo and the one that came with the new 82 thermo, I found that the spring supplied with the 82 thermo allowed the thermo unit to open just before the standard the 1108 thermo did. So I changed the spring to the one supplied with the 1242 thermo, I found that the this allowed the 82 thermo unit to open quite a bit before the standard 1108 thermo did, a bigger gap between than in the first instance (spring from the 82 thermo)

Pete, which spring did/have you fitted to yours?

Oh, some more photos for you's lot.
1st Photo: 1242 Housing with 82 Thermo + 1108 Standard Thermo
2nd Photo: 1242 Housing with 82 Thermo
3rd Photo: 1108 Standard Thermo

HTH, Thanks

David

 

[Liam]

This thread is coming along well, any ideas for cleaning the thermo housing whilst it's out?

I was thinking Gunk and then some metal polish.

Liam

 

[J333EVO]

Got to say Pete and David this is what the forum is really all about, exchanging thoughts, processes etc etc, really enjoying reading what you have to say on something i started.

I think i must have been lucky when I did mine cos it all matched up great and opened earlier no problem.

Aaron.

 

[peaster2k]

This thread is coming along well, any ideas for cleaning the thermo housig whilst it's out?

I was thinking Gunk and then some metal polish.

Liam

What about a wire brush on the end of a drill first to get most of the crap off? I cleaned the old gasket up on both housing units with a stanley knife blade then a wire brush on the end of the dremel. Mine looked so much better after I had the unit fully covered in water and bought it up to temp so the htermo opened.

Got to say Pete and David this is what the forum is really all about, exchanging thoughts, processes etc etc, really enjoying reading what you have to say on something i started.

I think i must have been lucky when I did mine cos it all matched up great and opened earlier no problem.

Aaron.

Thanks for the commments aarron, tis the northeners setting the standards again

. I don't mind passing on what I have learnt. Always think photos help , I have more at a higher resolution if anyone would like a copy.

Thanks

David

 

[mase]

i've been gettin a bit confused from time to time with this, but i think i have cleared it up.

basically i need a 1242 thermo housing, and a 82 degree thermo from halfrauds, (actually i think jamies has 1 i can nick) then use the spring from the 1242 thermo and stat inners from the 82 degree therm all in the 1242 therm housing?

now for a proper newbie stylee question, where the bloody hell is the thermo in the engine bay? i havent had a change to have a search!!!

also pete, im gonna be quizzing u about oil coolers sometime in the next few days, so have your "i can do science, me" hat on

p.s: how funny is that "i can do science, me" post from pete, i can just c him now in his garage with an engine in bits saying that.... legendary :worship:

 

[AIJ29]

Peaster
How come the spring retainer on the bottom of your thermo`s are a different way round?are they like that from new?or have you had to swap it around to get them to line up?
Cheers
Adrian

 

[jamie86]

Alex I have one that just needs fitting I will show you were it is when you come get the car...


Basically just below the coilpacks though....

 

[peaster2k]

Adrian,

You mean the 1108 thermo, thats the way it when I removed it from the engine. It will not fit over the spring any other way.

HTH

David