Center radiator install time

I'm considering doing this job today. I’ve read the 101 Projects instructions a few times. It seems to me that it shouldn’t take but 3 or 4 hours. The 101 Projects book says it should take 8 hours to do the job. Has anyone who has done this job remember how long it actually took them? How accurate is the book's estimate?

It took me about 3 hours and maybe another hour to drain and refill the system as well as install a Rennline center radiator screen...assuming you pre-assemble the radiator and frame on the benchtop ahead of time. I work slow and meticulously, but I have taken the front bumper off several times so that only took me a few minutes to get it on and off. A couple tips....You have to fit the rubber shroud INSIDE the black metal radiator frame. It does not easily slide into the frame, you have to bolt the frame together with the rubber shroud in place. There are holes in the frame where the rubber tabs fit. This is easiest with two people as the rubber likes to pop out the opposite side you are holding, over and over. Also the hose routing on the driver's side is a bit confusing, I ended up re-doing it a few times to find the best position. I think I have a photo somewhere of the final positioning I settled on. The factory diagram is not easy to discern. Also when you refit the bumper having an extra person helps as you will have to play around with the rubber center radiator shroud to get it in the right position...a little more difficult if you fit a radiator screen since you can't reach through.

Good tip Nickshu. I was able to get the shroud into the frame after the install, but we had some words.. If you got the full factory parts set up, I agree, 3-4 hrs max.

OK, thanks! I've not taken the bumper off a Porsche yet, but I've done lots of other cars. How easy is it to get the bumper re-installed and aligned properly? I'll be working alone(like normal) but will have potential help later this afternoon, so I might just get as much done as possible this morning and finish with some assistance this afternoon. I was trying to decide between doing the center radiator or doing a review on the LN skid plate this morning. Finally have a day off after working 15 hour days the last couple of weeks. I'm feeling lazy...but Porsche!

I have all the factory parts(some used and some new)...except for two hose clamps. I figured a regular small worm gear hose clamp would work. I'll double check the parts before starting.

Oh yea, the drivers and passenger hoses are easy to confuse. How would I know ?! Check those part numbers The worm clamps are preferred for these tight spaces imho. Bumper should line right up without my fuss. Don't be afraid to muscle it little.

Three hours is pretty optimistic. I'm not saying it can't be done in that time, but I know in my case, there is usually some "mission drift" as I start to dig into the car (just little stuff I find that I want to fix "while I'm there"). Getting the car up an jack-stands and removing the front wheels can easily take close to an hour on it's own. Removing the front bumper, while fairly simple can also be fiddly, and you have to make sure to bag all the screws/connectors and note where they came from (this is the difference between doing the job yourself and someone who doesn't care, and that know the car will be long gone from his shop when you figure out that your bumper is loose and there are connectors missing...) you'll have to remove the front underbody plastic panel as well - this is probably another 40 min to 1 hr. by the time all's said and done. See where I'm going with this? We're already in close to two hrs. and haven't even begun the actual job. Realistically, installing and hooking up the radiator itself is going to take an hour or two - some of the working spaces are REALLY TIGHT, and if you don' get the hoses all the way onto the connections and well clamped you will have leaks when the system gets up to temp/pressure. With this in mind, it would be a good idea to pressure test BEFORE you put everything back together. As with almost everything else I've done to my car, there's nothing particularly difficult about the job overall, but there are a lot of details that need attention. If all goes well, everything should go back together a little quicker than it came apart (as long as nothing broke in the process)... I think if you give yourself 5-6 hrs. and take your time, you shouldn't have too many problems. Good Luck

Well work called and my day off disappeared. Glad I hadn’t started when they called or else I’d had to Uber my way to work. Hopefully I‘ll get a chance to do it tomorrow.

Post some pics if you get a chance. Tertiary radiator is on my short list of mods before next track day. Debo sends.

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I literally just finished this job on my 99 C4 this afternoon. Took my time and did it in two 4 hour sessions. Most of the time has been just double checking everything and bleeding the cooling system. Did the 160F thermostat, center radiator kit and put the correct pink colored Porsche coolant back in.

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Can you tell me how these two are different? Thanks! https://www.pelicanparts.com/More_In...hoCUx0QAvD_BwE https://www.pelicanparts.com/More_In...BoCP4wQAvD_BwE

Well it took me just under 4 hours. That was the first time I’d removed the front bumper. BMW could learn a LOT from Porsche. I think that since Porsche 993s were hand built, that the designers still made the 996 easy to build/work on. Current 911s might not be easy to work on, but 996s definitely are! My camera man was 3.5 hours late so I didn’t get an pictures. The hardest part was trying to figure out how to route the center radiators left hose.

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Top one is for 996 and bottom one is for 997. I was able to put together my own kit and saved a TON of $$$. I bought some used parts from DC Automotive and new parts from Pelican. Used radiator & mounts, and rubber scoop. New bolts, nuts, and hoses. It was under $400.

I just put mine in place - took <1 hr to install but I haven't connected the lines but I've taken the front off before. Everyone enjoys pics! - coming from the guy that didnt take any pics... haha

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Then you can probably finish in a couple of hours. I kept cutting a little bit out of the black plastic and refitting the bumper. Also I kept routing and rerouting the left side hose. If I did another, it would probably be around 3 to 3.5 hours. Next mod for me will be installing a deep sump in a couple of weeks. Then maybe I�ll install a low temp thermostat and adjust my coilovers a little lower.

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I didn't bother trying to cut the plastic insert - I just bought the one with the cutout knowing i'd never get it the way I wanted it

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I might do the same the next time I clean out my radiators. I didn�t get mine perfect.

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That moulded plastic is very hard to get and get looking good. Replacement was $100 I think from memory - should be even less for y'all over in the U-S of A

Do any of you subscribe to this theory below? It was put forth by another member and I just cut and pasted it here from another post on a related topic. I�m debating adding a center rad over the winter. His post: ************************************************************************ ************ A friendly word of warning - there is a problem creating the right amount of radiator area for both driving around at 30 mph on a cold day and racing round a track close behind another car on a hot one. The thermostats only control flow and if the radiator area is too much for any given situation the flow is minimal. Because the engine only allows about 10% of the coolant to enter the cylinder block (the rest goes straight into and out of the cylinder heads) low flow can allow the cylinders to run very hot internally. You do not notice this because the coolant is mixed together again before it passes the temperature sensor or travels back to the radiators but low flow overall results in unbalanced cooling to the cylinders. Because that makes the oil between the pistons and the cylinder walls hotter it also makes the viscosity thinner and then any free silicon particles that have become loose from the cylinder wall can impinge more on the piston coatings resulting in premature scoring. So in conditions when you didn't need an extra radiator (which is most of the time) it can be contributing to cylinder scoring and not preventing it. The extra radiator is only beneficial in those conditions when the standard thermostat is wide open and the engine is still getting hotter. To sort this we made a housing that fits between the feed to the third radiator to house a thermostat set at a slightly higher temperature than the main LT thermostat so it only opens when the engine would have started to get too hot anyway. All this proven with multiple tests in different conditions - that revealed that in most normal conditions and driving - one radiator would be sufficient. However we have not yet managed to productionise this additional thermostat for retailing but while you are figuring out how to connect them - you could allow a hose to bend away and fit to our 996 third radiator system before joining to the centre radiator and achieve the same outcome (or simply make one yourself or fit a proprietory one). On our race cars we actually went further and split the outlet from each bank (because bank 1 ran cooler) and made a "Y" outlet housing to hold 2 thermostats (throwing the original single thermostat away) to make sure each bank ran at the same temperature and then fitted another thermostat before the third radiator and that covered all conditions maintaining good cylinder temperatures and hence reliability.

Yes, to some degree (pun intended Hahaha) Admittedly I added the 3rd rad because I found one for a good price and like the look of having that centre section open rather than the plastic panel there. ​​​​​​ I haven't experienced any overheating issues so it will stay disconnected for now.

Cool days are few and far between down here. Although my drive this morning was in 60 degree weather, which is REALLY cold for Houston. The typical winter day down here is in the 50s. My gauge was slightly lower than normal, but I'm not sure whether it was the radiator or the cold day. I had my Snap-On scanner attached during an extended test drive on Saturday and found that the factory temperature gauge is REALLY inaccurate. Almost worthless really.

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Just about everything, including the price... The 997 version won't work on the 996 - different hoses, brackets & connections. If you really want the best deal available for the third radiator kit go to www.Carnewal.com Depending on the exchange rate you'll save a substantial amount of $

The bore scoring theory under conditions that are too cold is a decent theory. If they instrumented a car, all around the 6 cyl, and took point source temps, and that led to bore scoring I guess I'd move it from theory to postulate. Here's the question that I don't know the answer to which will be critical to determine if this is correct. In a typical car(not the 928) the cooling circuit will start at the discharge(pressure side) of the water pump, have a small bypass to the engine for early heat, then proceed to the heater core, then the radiator(s), then to the engine cases where thermal transfer takes place, then finally to the thermostat which regulates the engine temp at the EXIT of the heat generator(engine), and then to the low pressure side of the pump. However, there are a few cars which do it different and place the thermostat at the beginning of the circuit, before the water enters the engine, and goes in reverse direction, through the rad, heater core, and pump. If this is the case for the 996 there is some possible merit. But - knowing that the temp stamped in the thermostat is the desired regulated engine temp, it would seem to me that the flow is in the normal direction, with the engine case maintained at the thermo regulated temp of 192F. If it is true that the regulation is done at the end of the circuit, after the heat sink(engine) then really I can't see how the limited flow would factor in to cold spots and induce bore scoring unless the outside temp were in the -20F region and the engine was run and shut off, and run and shut off with short cycles. Aside from this extreme type of use case, all of the engine will come up to temp, and the differential between the coolest and hottest parts of the liquid jacket will be a matter of a few deg F, maybe at most 20F, where the hottest parts are the heads at 192+, and the coldest part is where the rad water enters the engine at maybe 170F. This might be a problem if the delta was very confined, but the water jacket around the engine, including the heat soak of the lubricated parts leads me to consider this argument of bore scoring rather specious. YMMV, contents have settled, objects in mirror, and may cause **** leakage.