If only - Some of the items on that list you posted up are not correct, ie the Borg 425671 is rated at 71C and 54mm dia. IMO these are not suitable. Primary flange diameter, secondary disc diameter, stroke, temperature rating, bleed hole etc etc all need to be evaluated when selecting the thermostat. Unfortunately most thermostat manufacturers dont help in the selection process and Ferrari are about a useful as a chocolate ashtray. Best Tony
U r absolutely right. U have to get one the fits. That's just common sense. But the point is, it's an off the shelf item, nothing special. A lot of people around here don't seem to get that. These aren't Ferrari specific parts, as is the case with many parts on 3x8s. They will spend $100 or more on a $5 part.
Like you say some dont follow common sense but also some folks are not technically minded as well so just want a easy solution, unfortunately they pay the price and Ferrari tax with it. There are countless examples of cross manufacturer parts worldwide but with this part there are numerous variables to take into account. Best Tony
I think this is well said. Obviously, I've been trying to find the right part and I think I understand the variables. But realistically matching them up to an off the shelf part is not easy. I guess I could order a half dozen potential units and test them. But it's much easier and cheaper to just pay for the Ferrari part.
Absolutely, i have a box full of redundant thermostats that should have worked but didnt, errors in manufacturers technical details & drawings resulted in the part not fitting etc etc. Had i just bought the part from a Ferrari distributor then i would have saved myself a whole heap of cash and aggro. So being technically alert i still got screwed Best Tony PS not all parts with the "genuine Ferrari part" label are correct either. see .... https://www.ferrarichat.com/forum/threads/replacement-thermostat-housings-warning.581110/
Assuming the drawing is to scale in the WSM, and under cold conditions, here are the dimensions. Image Unavailable, Please Login
I should say +/- 0.5mm. Also, I have a Meyle 0282800010 T-sat that was recommended to me and all the measurements seem ok. There is one small difference. When HOT the OE T-stas is supposed to to extend to 44.5 mm. The Meyle only extends to about 41 or 2 mm. However, I suspect that the OE T-stst will bottom before it reaches full extension and suspect that the Meyle will as well. However, if it does not I don't think a 1mm is going to make much difference. Particularly in light that the replacement from Maranello Classis doesn't have a plunger to close the "cold loop" at all.
Honestly, don't think it will make a difference if it's 54 or 56. But if that is the case the drawaing must off a little The Meyle measure 54mm.
I mentioned it earlier, but I emailed them and asked about that... they seemed indicate the part they have listed is incorrect that I should use the /b part, which does have a plunger. I wrote: ===== I need a new thermostat for my 1985 308 QV. This seems like the correct part: https://www.ferrariparts.co.uk/part/ferrari/109671?id=54892 But it lists an alternative that does not seem correct: https://www.ferrariparts.co.uk/part/ferrari/109671-a?id=383880 I say it doesn't seem correct because it does not have the "plunger" that I understand is needed to stop the flow of hot coolant to the pump when the engine has warmed up. Can you confirm which part I would receive if I ordered 109671? Or that the new part is correct? ==== They replied: ===== Yes the Thermostat’s can be rather tricky! Infect you require part number 109671/b =====
Doesn't it have a rubber gasket?" I wouldn't be too sure of that, I mean we're just going by the photo on the website. It could just be the wrong picture.
You could be right but in essence you want that port to close 100% so all the water at normal operating temp passes through the radiator circuit and not a proportion to short circulate through the engine block in a recurring cycle. Temps will elevate and could tip into overheating.
I didn't measure the new one when I put it in, pretty sure I got the one from Superformance. The old one is here on the bench, it was a Wahler and it's 54 without the gasket. FWIW both of them (new and old) work(ed) perfectly fine.
The 2 MM does make difference. From experience. The 54 MM can be made to work as well, but you need to insert a 1 MM wide ring of a correct thickness (and material) inside the rubber "c" ring, other wise the T-stat, can, and will move to the side a bit, allowing the T-stat to cant in its housing, which also allows the rubber "C" ring, to get partially dislodged from where it should be, and you don't get good bottom sealing on the stopper. A piece of 1MM diameter copper or silver, wire, properly formed on a mandrel, works as a proper ring to insert inside the rubber "C" ring. If you find a correct dimension T-stat, for under $50, I would sure go that route first. Doug
Since I'm old and retired and have noting better to do I just went through the Behr and MTE-Thompson catalogs for T-stats.For Behr the only possibility that I found (might have missed one) had major dia. of 54mm, plunger dia, 35mm and cold plunger depth of 33.5mm. For MTE, thes ame, 54, 35, 33. MTE says that the hot extension of the plunger, regardless of model, is a minimum of 8mm. Assuming Behr is the same, then hot length is 41mm. These are stated for, Behr, Isuzu, Jag, Land Rover, Mazda, Nissan, Porsche, Saab and Volvo. The MTE say it's for VW. The Meyle I have comes with an o-ring which would seal the T-stat even if a little off center. Bottom line, guys have been replacing these T-stats for many years with Behr, Mahle, Meyle, whatever, without problems. Let's not create one. I'm done here.
Haven't people also been talking about how marginal the 308 cooling system is and how their car runs a little warm for years? Perhaps there is some correlation? Certainly my goal was not to sir the pot with this post, I was just confused at what I was finding and wanting to do the right/best thing. For me the answer is clear, I will run my original thermostat and hope it doesn't fail! But if it does, the Ferrari, Superformance, etc units will certainly get the car going again, even if perhaps not as optimally. Thank you for your time and knowledge!
FWIW the plunger plate is spring loaded so the hot extension is greater than the distance of the cold position to seat, so it's not a critical spec. As far as claims that a 54 mm thermostat will "cant" or "dislodge" - first time I've ever heard of that, got pictures? Also, as previously noted, Ferrari never manufactured thermostats, they have always been off the shelf components.
No, I don't have a pic, I don't do photo blogs on every car maint procedure I do, but when i removed the T-stat housing several years ago, with a 54 MM T-stat, i found the rubber ring, partially out of position above the T-stat edge on about 45* of arc,and it had been that way for while, based on coolant/compression marks, and the t-stat was not level to the lower housing, which I assume may not let the lower disc seat, or maybe it would seat, it wasn't canted that badly. I didn't see any indication there would be any catastrophic failure involved, but it wasn't right. I found GT parts had the Behr (IIRC) 56 MM part for about $45 or so. Doug
see post 63 (on the 246 housing) https://www.ferrarichat.com/forum/threads/replacement-thermostat-housings-warning.581110/page-7 The spring loading on the plunger is there to apply force to the seat when fully extended when at max temp. The overall travel is critical. If the total extension doesnt allow the plunger to reach the thermostat housing and block off the port then you will get seepage of coolant through it. That will lead to a increase in the overall engine temperature. Under normal conditions you will not notice the slight increase. Up to you if you think the 54mm stat is OK, I wished it was as there is much better choice but personally I dont think it is.
https://www.awitalian.com/product/thermostat-109671.html/ https://www.ferraripartsexchange.com/products/thermostat-109671 https://www.autoepoca.it/portfolio/ferrari-109671-water-thermostat/ https://www.autoepoca.it/portfolio/ferrari-109671-water-thermostat-308/ Check them out. Behr seems to be the common. Last two from the same vendor.
