Greetings all, I was watching the episode of Jay Leno's garage featuring the white 308 [forgot the year]. While the owner was explaining some of the modifications that he made, something that caught my eyes and ears was that he upgraded the radiator cooling fans from a 348. It appeared to be a direct swap. Has anyone done this, and if so, how, and what fans [if other then stock 348 fans] were used? I live in Florida and would like to perform this update/upgrade. Any advice/comments/suggestions from the collective would deeply appreciated. Thanks!
The OEM just needs setting up properly. This summer I took my Dino GT 4 to Switzerland for a few month to compete in gruelling classic rally + climb other passes in none competitive mode . Some high ambient temps 25/30 degrees C , and steep hills . Obviously I was a little apprehensive......is it gonna blow up . There were 40 cars inc another 4 308s and a 328 so in good company . Often the water temp would rise from 6 o clock vertical being normal , to 5 or near 4 o clock on accents 30 / 40 mins of 2nd and 3 rd gear @ 4000 to 5000 rpm but low road speeds due to continuous hair pin bends . The oil temp not as much maybe between 6 and 5 . Both would return back to 6 o clock on the descents . So I started to read around the subject . There’s a general perception out there ( on this forum too understandably) that the 308 cooling system is just about up to the job and thus fails in hot climates . Some even think its inadequate . It’s a pressurised system so the expansion tank cap health is important. Perhaps change this .MAN marine diesels recommendation is to change both expansion caps regularly every 2 years for example . Then the coolant fluid needs to be the correct spec . Again refer to the service schedule. Wrong dilution can have an adverse effect . Radiator.....has it been flushed out ? In a 40 year old car it’s gonna gunk up more so if the coolant fq change interval has been neglected ? Had the system been regularly bled ? There’s a little valve top RHS of the rad .This needs opening now and again when hot to bleed air .Any air in the system will accumulates the top of the rad say 5 to 15 cm thus reducing its efficiency as the surface area is reduced by X% . I did notice after hard charging up alpine passes if the water gauge started to creep past 6 ( vertical down on a clock ) there was air when I opened the vent at the summits. Same run later after bleeding and the gauge remained at 6 vertical . Foam filler Make sure the rad has sufficient foam filler all around the sides so forward facing ram air while moving is forced through the finned core and doesn’t escape round the sides or more importantly that gap at the top. At the top there should be a piece of softish foam attached under the hood , so when it’s closed it forms a nice tight seal . I used a bit of self adhesive water pipe insulation foam attached under the hood to form a nice seal = huge improvement on cooling . The fin core density is excessive on 308 ,s so the block of ram air will meet resistance and try and escape round the top and sides ....path of least resistance. So make sure it can’t . There’s a lot of threads on changing the fans .The “ go to solutions “ which is I think where you are ? One I picked up on was the distance between the blades and the radiator. The mounts are basic circular clamps and if disturbed for what ever reason it’s an easy trap for the tech to fall into to replace them say with a 15 mm gap ...blade to rad core . It should be 2/3 mm that close .Makes a huge difference......again we are back to the huge fin density . So with big air gaps at the sides and perished foam on top if the fans are positioned too far away , what’s happening in slow ( minimal ram air effect ) traffic is the fans are just kicking air around the sides and over the top NOT enough is passing through the core . So it’s easy at first thought with a cooling issue on a 308 to simply chuck a new different bigger fan at it , in my view there’s an underlying problem out of spec that needs attention. When the 308 cooling system is set up correctly as it left the factory it works fine in hot weather and hot climates. Southern Italy gets hot in the summer and in the alps there’s are some looooooong steeeeeeeep hills to climb . That’s my experience. It’s the sum of all the little things not just one part .
I rebuilt my OEM fans on my ‘82 308GTSi with new brushes works like a charm. New foam around radiator. Re cored radiator with 2 less fpi (fins per inch) way better air flow.
It may be that 348 fans fit, however modern generic high-performance Spal fans will probably give you even better performance. I agree that it is a airflow problem. My car does fine at any ambient temperature as long as it is moving. When it idles for long periods (20 minutes for my car) the temperature rises unacceptably. As already mentioned, there are also other ways to improve cooling system performance.
Florida resident here also... here's how I upgraded them: https://www.ferrarichat.com/forum/threads/308-new-cooling-fans.576278/
Sorry for post bombing your thread, mate! I got confused looking at my tiny phone screen with my old eyes. I'm running a similar thread
