Replacement of Failure-Prone Coolant Fittings

Since many of you have encountered failure of the little plastic coolant fitting near the oil filler hose and alternator, I decided to fix it preventively. Also, I had noticed cracking on this hose that connects the reservoir to the water pump: The cracks were on the plastic T piece near the water pump. Probably from repeated heat stress cycles since this is very near the exhaust. Some of the cracks appeared quite deep, and I was concerned it would crack all the way through and become a huge leak. I had temporarily patched it with epoxy until I had time to do the repair, but that was a band-aid. Who knows, maybe it would have lasted forever, but it made me a little nervous: The replacement part is 996-106-850-05 "Filling Hose", about $30 from Sunset Porsche. For me it made sense to buy this at the same time as the updated coolant connector from Rauch and Spiegle (part number S99610622652) so I only had to open the coolant system once. I've seen other people doing this with basic plumbing parts, and that seems like a good fix, but I like the fact that the R&S part maintains the stock mounting, so there's no way the hose will get into the serpentine belt. It's quite close, and needs to be tethered in some fashion, so their nice little mounting block does the job. At $40 it's pricey, but oh well. The best price I found was at AutoAtlanta, but lots of people sell this part. The filling hose is easy to replace except the connection on the bottom of the reservoir. It is a BITCH to get to, depending on how the hose clamp happens to be oriented on yours. Removing the airbox for both of these jobs is a no-brainer, and removing the secondary air injection pump and pushing its hose out of the way helps gain some additional access. After much swearing and use of long-reach pliers I was able to get it. NOT fun or easy. The other 3 connections are easy and then it drops out the bottom and is easily replaced. Reinstalling the hose clamps is easier than removing. The coolant fitting, as many of you experienced, snapped as soon as I tried to pull the hoses off it. Made me glad I was doing this repair at a time when I have all my tools on hand, rather than on the road somewhere. A #12 wood screw is the perfect tool for getting the old nipple out of the hoses. Screw it in all the way, and then gently pull on the screw to pull the nipple out of the hose. Work it out VERY slowly and carefully so as not to fracture the nipples and potentially get plastic bits in your coolant system: Here's the broken old piece, with all pieces collected, vs. the new part: Installation of the new part is easy. The upper hose clamp can be reused since it's a spring type. The bottom one should be replaced. It seems to me that the hoses do not fit as tight on the new part as on the old ones, which is a little concerning. I will keep an eye on it to make sure it doesn't leak, and if it does, I might have to either replace the hoses with newer, gooier ones, or use a different style of clamp that I can get tighter than the OE versions.

I replaced both of those last summer. The metal fitting at the oil cooler connection is a very nice piece, I used the same one.

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Did you keep the OE clamp types, or switch to worm-gear clamps?

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I used all OE style spring clamps. On the oil cooler connector I cut off the factory crimp-style clamp and replaced it with spring clamps. I sourced new spring clamps from Pelican. Unlike alot of people I prefer the factory spring clamps.

I like the spring clamps too, when they are accessible. They provide the most uniform squeeze, and don't require any judgement on how much to tighten them. It's not clear to me why in this application Porsche uses 2 different clamp types on the same part. FYI I found the "correct" crimp clamp from the parts diagram (G99951263300) for the bottom clamp to be too large, and not give enough squeeze to hold the hose on the barb correctly even when crimped as tight as it'll go. I had to use a smaller size to get it as tight as I needed it.

Great write up! I didn't know about the Rauch and Spiegle upgraded part so I just ordered one so I'll have it on hand when I get around to refreshing cooling system stuff. BTW, what you guys are referring to as "crimp style' clamps are 'Oetiker' clamps.

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It's worth noting that a worm clamp on the oil cooler connector likely would not clear the belt. Space is tight there!

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Good point. You'd certainly have to be careful with how the worm mechanism is oriented, so it's accessible to tighten but without interfering with the belt.

I bought the upgraded part. How do you remove the bottom clamp?

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Easiest way is to jam a small flat screwdriver into the pinched ear of the Oetiker clamp and rotate the screwdriver or pry on it to un-pinch that ear. Once you open it up enough you'll be able to slide the whole clamp along the length of the hose to remove. There's probably a more elegant way, but that's effective Depending on access you could also use some nippers to cut that ear (thus destroying the clamp) and peel the remains off. During this process you'll almost certainly break the plastic fitting, and that's when that #12 screw will come in handy to remove the remains of it from inside the hose. Use lots of finesse and very little force, otherwise you'll end up shattering plastic bits and not being sure you get them all out.

I have most of my parts, wster pump, thermostat, coolant and some hoses with factory clamps still need a few more pieces. Service at Pelican parts, helped with correct Porsche clamps for each hose.

Good tips! Is that new piece (black bracket) plastic or aluminum?

The R&S piece is aluminum and stainless steel. That little piece is a work of art. Broke the plastic piece several years ago and had a piece of brass hose nipple zip-tied in place..always looked not so good. Finally got that R&S piece and love it. Also had to replace that very same hose that has the plastic coupler with nipple because it broke at the nipple. Age and heat killed that.

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Which clamps did you use?

SS worm clamps worked for me. I wanted to add that I also replaced the coolant hose that comes up from the water pump to the connector. Turns out that hose has two different sized hose ends, a little bit bigger where it connects to the water pump, and a smaller end that connects to the connector piece. Did not know that in the beginning. I ordered an OE connector hose for like $9. It has always been weeping a little bit where it connects. I really wanted to solve this problem completely and I did replacing those parts.

I imagine the different clamps are an artifact of the assembly process. I'm guessing the motor is assembled as a unit before mating it with the car, so the oetiker clamp makes sense on the assembly bench, whereas to speed assembly on the line, they use the spring clamps to attach the upper hose. Just a guess. I used stainless worm drive clamps and a brass barbed fitting on my 2000. I haven't replaced the one on the 2002, but will eventually do so with the Rauch and Spiegel part.