Decision on right radiators for daily driver/weekend AX 2004 4S

Radiators need replacement. I am torn between going with the OEM Behr units given I have been spending a lot on preventative/corrective maintenance having just done the AOS and coolant tank, and previous to that, the whole suspension. I am NOT cutting corners, no cheap units, and I do think there is something to say for OEM (in this case the Behr units sans the fancy Porsche stamping). Obviously there are better design and efficiency advantages to the CSF units, but in perusing PCA forums and a few other sites to include Renntech, Pelican Forums, and Planet9, the CSFs really shine when you are tracking the car on a steady basis, and may not be necessary for the lower key DD work/AX. The car may see a track day once or twice a year, but it will primarily remain a DD and cone carver which doesn't stress the car (IMO) outside of the occasional downshift for a lane change, or a spirited and enthusiastic weekend early morning back road carving session. Just sort of torn between this decision. I will have to change my alternator soon (OEM), so this is a factor, and I am fine not upgrading, but I am in no way not using OEM or OEM manufacturer. Thanks!

Did you determine your leak is coming from the radiator? The mahle behr are perfectly fine for any situation. And what�s wrong with the alternator?

You'll probably want to take a look at the condensers to see if they're crapped up or still passing air effectively, any radiator will be limited if its behind a corroded condenser. The only potential argument I've heard for CSF when it comes to autocross is that the metal connection points may hold up better to a ill placed cone strike, but I would also expect new parts to not be as brittle as something on the car for 10+ years regardless.

You may want to confirm this but my 40AE, which has the same bumper / front end as the 4S uses the Turbo radiators which are slightly larger (thicker?) than regular C2 radiators. With that you should be more than fine for road use and even track. Its far more crucial to keep them clean and not caked in road debris and other junk that will fly in there. Some people do the bumper off cleaning once a year but with the amount of miles I do it's a twice a year service for me. Taking off the bumper and cleaning them with a pressure washer is super easy and greatly extends their life.

Factory replacements will be fine for your car. No need to upgrade for your usage.

Thanks for all the input and just finalized the order with OEM/Behr/Mahle. I have hairline fracture in the right front passenger side that made it's presence known a few days after getting a new coolant tank and replacing the AOS. The tank crack was about a 3/4 inch crack but was "holding", and with the new AOS, it likely pushed that pressure elsewhere. The leak is small, but I noticed late last week in stop and go traffic in the afternoons, my temps are hovering north of 180, but cool down when I get moving. The radiators, hoses, and clasps are all original as in the original gear installed on the car, and I did the full clean and wipe down after taking off the bumper to ID the exact spot for the leak. Saw some pink residue and a light spray and it looked like it was coming from the top hose on the passenger side. So... per typical Porsche owner, going to do both and replace the three major hoses on each side with new clasps. Thanks again and feel good about this. Do not feel good about the stupid pressure sensor switch for the oil which I attempted twice and could not unseat the old unit without thinking I would strip. Played it safe, cut my losses, and will take it to my indie to just get it done. Any tips, advice for DIY radiator changes are welcome, especially if they relate to a CS4 given the parts overlap with the turbos. I have the AirLift II on order, and just need to get a good set of hose clamps.

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+1. My OEM rads are probably down 20% efficiency, and yet, even on the track, still keep temps under control. For AutoX and street use, the front fans are the most important thing to keep the engine cool.

The install is pretty straight foward. There r spring clamp tools that much better then pliers. If u go with worm drive clamps as replacements, heat cycle the car a few times before putting the front bumper in and retighten. Its not unusually for a hose to drip a few hundred miles after install due to new rubber and heat.

If I can eliminate a plastic tank on a cooling system... It's gone. Just had two many crimp assembled radiators fail. They are a service item. I did the CSF and happened to catch a sale, I think they cost me about 150 more than the street price of the Behr, but I also did the center radiator add-on (Package deal .... ) They are thicker, and well built visually... Too bad you can only see the center one in the car.

God damn, it appears my rear engine cover fan has failed. Took it to family's, and have another car, but can't catch a break. The light next to the fan is getting power, and granted have not voltage tested it yet, but hopefully the fan itself is just dead give the light shares the same wiring... Wishful thinking I guess, which means it is not going to be that.

Its super common for the temp sensor on the right side of the engine to fall out.. depending on where it falls the fan will run a lot or never.. It sort of resembles the front bumper sensor in the right hand intake.

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In order to drain and completely refill the coolant system, have you seen this DIY? I followed it, and it worked great. https://rennlist.com/forums/996-foru...pump-tips.html

Currently occupied with family but any chance you can send a pic on the actual car? Mine is currently at a relatives garage while I borrow something else until I figure this out. Regardless, the fan is definitely not running when it should, and we hit 88-90 today in Northern VA. This is really good to know. Also, for reference, is this the part ( https://www.pelicanparts.com/More_In...&SVSVSI=0684)?

Much obliged and will take a look!

It looks like this: https://www.pelicanparts.com/More_In...20bay%20sensor its black all plastic IIRC and its just behind the power steering pump on the back side of the first intake downpipe. There is a sort of C shaped area it inserts into. all black of course so easier to not see anything.. LOL When it pops out, it kinda curls up and lands down between the intakes runners on mine.

Here. As stated, it just slides/snaps into between the first two intake runners, but falls out.

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If you have a durametric you can activate the fan (to determine whether it actually works or not). I�ve had my car for close to 8 yrs. and has only seen/heard that fan run once (besides via durametric).

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Most people never experience the engine compartment fan running. It rarely comes on. I think before replacing all these parts a durametric would be a wise investment.

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Hey funny we both wrote essentially the same thing at the same time!

Great minds� 😬👍

If ya own a 996, ya need a good test device, Durametric, or similar.. Ya just do, too many little gremlins that the dealer will hit you for a grand to check out that take 30 seconds to clear the fault on..

I just did the job on a 987, and a 986 multiple times. Take your time. The AC condensors and lines get in the way a little bit. If you have the center third radiator that line adds a little bit of work (on the 996 they should still be a solid rubber hose connection, not like the annoying spring clips on the later cars). Behr should be fine. If you're interested in custom radiator ducts, let me know I have a few more yard signs! The one below lasted 17 hours on VIR last August.

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spec boxer is becoming the new spec miata

Thats Champcar! Surprisingly, Champcar is a lot cleaner racing than it used to be. We were running 4 OA in hour 6 and one of my driver's put it in the tire wall on his out lap :/ Got it back together in 90 minutes and had it back out there for a 17OA and 7th in class finish. Sooooooooo much work.

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This is f--king epic! Much thanks again for the conversation. Ordering the Durametric as my next major purchase. Cycled fans using AC and all good! Just not used to a car with a temp gauge that is so "lively". This is definitely a learning process, and the RL 996 community has been absolutely fantastic in all capacities. Thanks so much! These are special cars... and your occasional frenemy...

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Thanks, I forgot to mention for this conversation too! I verified the sensor is there. All good in that tight hood.