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Center Radiator Installation

Pelican Technical Article:

Center Radiator Installation


8 hrs





Applicable Models:

Porsche 986 Boxster (1997-04)

Parts Required:

Center radiator, brackets, hoses

Hot Tip:

Cut your front bumper instead of buying a new one

Performance Gain:

Cooler running engine

Complementary Modification:

Replace side radiators and hoses
101 Performance Projects for Your Porsche Boxster

This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your Porsche Boxster. The book contains 312 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 950+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Boxster owner's collection. The book is currently available and in stock now. See The Official Book Website for more details.

The 2000 Boxster S design included the front mounted radiator used on the Porsche 996 and the venerable GT3, as well as some Tiptronic-equipped cars. The larger, more powerful engine dictated the use of the front mounted radiator in addition to the two standard side radiators. Adding the front-mounted radiator is a good upgrade for cars that will be driven in hot weather or have undergone some performance modifications. In particular, if you're going to be taking your Boxster out to the track someday, I indeed recommend the installation of the additional radiator. It will provide some significant added protection against overheating, as it typically reduces the highest operating temperatures by about 10-20°F (7-12°C) after installation.

The first step is to gather all your needed parts and pre-assemble the radiator assembly on your bench (see Photo 2 and Figure 3). Pay careful attention to the radiator inlets and outlets as well as the frame tab locations, as it's very easy to assemble this backwards the first time. Lay out all your parts and make sure that you have everything that you need, prior to tearing apart the car. This project details the installation on a 1997-04 Boxster, but the upgrade kit for the 2005 and later cars is very similar (different part numbers).

Next, jack up the car, remove the two front wheels, remove the front bumper cover and the lower part of the inner wheel well liners (see Project 68 for instructions on the bumper cover removal). Next, remove the air scoops, detach the air conditioning condensers, empty the coolant, and loosen the radiator assembly so that you can drop down the whole assembly (see Project 32 for instructions on these tasks).

Replace the lower hose on the passenger side with the new three-way hose that will feed the radiator. Use new adjustable hose clamps, as shown in the bottom of Figure 2. Rotate the hose so that the small section of the hose is properly oriented to mate with the top of the center radiator port. Now, replace the hose on the upper left side, again positioning the small portion of the hose so that it will mate with the top of the center radiator when installed. This left-side hose twists and bends in a crazy pattern - use Photo 5 as a guide on how to properly route it.

You may find that when installing the new three-way hoses into your Boxster, the diameter of the hoses are larger than the input pipes. This is because the standard Boxster pipes that feed coolant to the front of the car are smaller than the ones used on the Boxster S or the 996 (which use the center radiator). The solution is to replace the standard pipes with the 996 / Boxster S pipes for the left upper side of the car, and the lower right side of the car (see Figure 7). In order to mate these larger pipes with the smaller pipes that run down the center of the car, I used a Boxster S hose and a standard Boxster hose, cut them in two, and installed a reduction fitting in-between (see Figure 6). There may be other ways of accomplishing the same task, but this seemed to be the easiest at the time.

Now attach the center radiator to its position in the center of the car. Loosely attach the radiator using the two top M8 bolts and the corresponding speednuts that clip into place on the chassis (see Figure 4). Attach and clamp the left and right hoses to the radiator: loosen and remove one of the M8 bolts if you need to gain enough room to secure the hose. When the hoses are secure, attach the remaining M8 bolts and speednuts and secure the radiator to the chassis.

When installing this center radiator into my Boxster, I encountered some interference between the air conditioning hoses and the bracket for the center radiator. Your car may or may not have the same problem, as the hoses are somewhat flexible, and tend to be in slightly different places on different cars. To protect the air conditioning hoses from damage, I used some rubber hose as insulation and wrapped the air conditioning hoses as a precaution (see Photo 4 and Figure 8).

To finish, reattach the radiators, air conditioning condensers and tighten up all of the hardware that holds them in place. Refill up the car with the coolant you removed, or use a new quantity of coolant equal to what came out when you disconnected the radiator hoses. Start the car up and let it run for a few minutes to check for leaks.

After confirming that the car is leak-free, attach the rubber surround onto the center radiator, install the left and right rubber air guides, and reinstall the wheel wells and the bumper cover. You have a few options for modifying the bumper cover. You can purchase a cover with the center radiator hole already pre-drilled, which is a very expensive option, considering that you also have to paint it. You can also use a bumper cover from an early 996. Or you can cut your own insert out as per the instructions I provide with Figure 9.

When everything is buttoned up properly, bleed the entire cooling system as described in Pelican Technical Article: Coolant Replacement / Coolant Flush. Over the next few days, check the coolant level regularly, and also check for coolant leaks when you park the car.

The factory thermostat starts to open at about 187° F (86° C) and only fully opens at almost 210° F (99° C). This means that the effects of the front mounted radiators are limited until the engine gets very hot. For this reason, I recommend installing a low-temp thermostat in conjunction with the center mounted radiator upgrade. See Project 34 for more details.

Here's a photo of a Boxster S with the center radiator installed from the factory.
Figure 1

Here's a photo of a Boxster S with the center radiator installed from the factory. The rubber air guide inside connects to the inner retaining piece and channels air through the center radiator.

Here are most of the parts that you will need for your center radiator installation.
Figure 2

Here are most of the parts that you will need for your center radiator installation. The parts are available from as complete kits for either the early (1997-04) or late (2005-08) Boxsters: A- Left side radiator hose (996-106-665-57) B- Front rubber air guide (996-575-141-02) C- Front bumper cover trim piece (986-505-551-00) D- Right side radiator hose (996-106-666-55) E- Upper radiator bracket (996-504-487-02) F- Radiator spacers (Qty 4- 930-113-430-00) G- Hose clamps (Qty 2 999-512-666-09, Qty 4 999-512-551-00) H- Mounting hardware (Qty 4 - Hex Bolt M6x12 - 900-378-036-09, Qty 4 - Speed Nut M6 - 999-507-550-02, Qty 2 - Hex Bolt M8x16 - 900-378-074-09, Qty 2 - Speed Nut M8 - 999-591-869-02) I- Lower radiator bracket (996-504-485-02) J- Center radiator (996-106-037-51) K- Front bumper cover inner retainer (986-505-555-00)

This photo shows the new center radiator with the upper and lower mounting brackets installed.
Figure 3

This photo shows the new center radiator with the upper and lower mounting brackets installed. This side of the radiator faces the rear of the car. Pay close attention to the tabs on the radiator brackets: the top tab attaches near the front, the bottom tab attaches near the rear of the bracket. When installed, the radiator will be facing slightly upwards at an angle.

Here are some installation details for mounting the front radiator.
Figure 4

Here are some installation details for mounting the front radiator. Upper left: I found that the radiator bracket leaned against the air conditioning hose and would probably damage it if it wasn't protected. So, I used a small section of old radiator hose and zip-tied it around the air conditioning hoses to protect them from wear (lower left). The lower right inset photo shows the proper orientation of the speed nut fasteners: the chassis should already have the small mounting bracket built-in.

Here's a useful diagram showing the routing of the hoses for the three radiator setup.
Figure 5

Here's a useful diagram showing the routing of the hoses for the three radiator setup. As shown in the photo, you need to replace the lower radiator hose on the right side of the car, and the upper radiator hose on the left side of the car. The center radiator "taps" into the hoses for the left and right radiators and provides additional cooling.

One of the problems with the upgrade kit is that the pipes on the regular Boxster are smaller than those on the Boxster S.
Figure 6

One of the problems with the upgrade kit is that the pipes on the regular Boxster are smaller than those on the Boxster S. The trick is to cut the hoses and create a step-down hose using a copper pipe reducer available at any good hardware store (outside diameter 1.25" x 0.875"). A- The regular hose and the larger Boxster S hose are shown side-by-side. B- Cut both hoses at similar points. C- Insert the reducer into the larger diameter hose. D- Join the two pieces together and secure with hose clamps.

These two photos show the left and right side of the inner wheel wells with the larger radiator pipes installed (yellow arrows).
Figure 7

These two photos show the left and right side of the inner wheel wells with the larger radiator pipes installed (yellow arrows). In addition to the larger diameter pipes, you also need to install the plastic larger diameter pipe retainers (green arrows). One end of the pipe attaches to the new three-way radiator hose (red arrow), and the other end of the pipe attaches to your custom-made hose with the reducer piece installed (blue arrows).

Shown here is the center radiator installed just prior to putting the front bumper cover back on.
Figure 8

Shown here is the center radiator installed just prior to putting the front bumper cover back on. Note how the air conditioning hoses have been wrapped with protective rubber (old radiator hoses) since the upper center radiator bracket tends to wear into them.

If you wish to save some money, you can drill out the opening for the front radiator yourself and reuse your old bumper cover.
Figure 9

If you wish to save some money, you can drill out the opening for the front radiator yourself and reuse your old bumper cover. A- Line up the retaining piece with the inside of your front bumper cover. It should be centered between the left and right openings, and fit flush against the curve of the bottom of the cover. B- Using a marker, trace the outline of the opening and the slots for the retainer as well. C- Using a Dremmel tool and a milling bit carefully make your cuts in the cover. It's okay if you're not 100% accurate, as there is a front trim piece that fits over the opening and frames it. D- This shows the opening cut out along with all of the small slits needed for the retaining piece. E- Test fit the outer trim piece and the inside retainer to make sure that they fit together well. F- Here's what the final assembly will look like before it's painted.

Comments and Suggestions:
Harold Comments: Further to Steve W's comment above, he has a good point.

Why not cut back the Boxster S three-way hose where it connects to the hard line, then reduce that down to a short section of the original Boxster hose, to then fit onto the original hard line.
Pelican guide does the same thing but further upseteam meaning two extra short pipes purchassed unnecessarily.
February 15, 2018
  Followup from the Pelican Staff: I don't have experience with that. If you try it or figure it out, let us know. We'd love to see the photos or process. - Nick at Pelican Parts  

Hello everyone, I am having the most difficult time configuring how to install a CSF 7053 Center Radiator for 996-GT3/GT2/Turbo-997GT2.

There are three coolant hose nozzles on the radiator that utilize quick connect/disconnect hoses. With the 996C2/986 Boxster Center/Third Radiator kit being sold by many parts vendors today, there is no imagery or diagram of how the rear/underneath hose schematics for a person to follow.

While visually looking at the two side radiator and how the hose connect, there seems to be large hose connections at the bottom and top with the bottom hose connection being the closest and most accessible to the center radiator.

If the center radiator taps into the lower side-radiator, it would call for a z-shaped quick connect style hose, otherwise, I can't even identify how the center radiator would tap into the top hose of the side-radiator. sadly, such center radiator kits are sold without detailed installation instructions and even when I look thoroughly thru the OEM catalogue, I can't seem to identity how exactly the center radiator connects/taps into the standard system.

I also don't know if the third, smallest hose connection nozzle connects to a smaller diameter hose or if it needs to be plugged up. There are two types of plugs/stoppers available to the center radiator for certain configurations:

1. 996-106-545-71 | 996T Center/Third Radiator “Stopper” / Radiator Plug
2. BEHR 996-106-901-00 RADIATOR DRAIN PLUG

After reading numerous online articles on center radiator conversion installs, it seem that not all necessary parts are included in such kits, nor are there visual diagrams of how exactly the center radiators tap into the main cooling system.

Does anyone have detailed instructions and a COMPLETE parts list to make the CSF 7053 Radiator work on Boxster986 non S/Carrera C2 chassis?

Can anyone email me or post a picture of how the hoses connect to the center radiators off of the car?

As of right now, I have all the hoses that come with the Boxster/C2 center radiator conversion kit minus any quick connect/disconnect hoses or copper hose reducers that I may also need.

Unfortunately, no dealer, sales staff at Pelican or even CSF themselves have been able to supply answers to my questions or supply visual diagrams of the center radiator setup for 996-GT3/GT2/Turbo chassis, which what help installers reverse engineer / visually identify the connection points.
July 24, 2017
  Followup from the Pelican Staff: Does part of this look like it will help? /how-to-cool-a-cayman/

I don't have any instructions on my end to share. - Nick at Pelican Parts
Bill Comments: I am almost done with this project and no leaks after filling antifreeze. You can get the copper adapters at most home improvement centers or plumbing stores. They are called 3/4" x 1" couplers, both ends are female and be careful because some stores had the male to female couplingscalled street couplings. Make sure one end fits over a piece of 3/4" pipe and the other end over a 1" piece of pipe. I also put some black hi-temp RTV on the fittings after I first started them on and more after to fill in the gap. It really looks better and may keep the copper piece from corroding too.

Another question about the heat sensors for the fans was asked and the answer is they both have sensors that work independently. They are those metal tubes with the wires going into them their called thermocouples that clip to the radiator mount subframe. I am having a problem with that center trim piece. As the slots are not factory perfect on my cutout, the front trim won't stay on and since they don't clip in, I need to know how the factory ones stay on. They must use that double sided tape like the rear trunk lid has or maybe weatherstrip cement or something. Please let me know as I need to get it finished.
August 23, 2016
  Followup from the Pelican Staff: I don't think a cement or weatherstrip will hold it for very long. You can try a weatherstrip, but also attach it using a tie strap. - Nick at Pelican Parts  
rem503 Comments: How do you attach the new front shroud to the new opening in the bumper - part 986-505-551-00-g2x m100? Are there clips for the 19 plastic tabs?
March 20, 2016
  Followup from the Pelican Staff: The tabs should pop into slots in the bumper cover. - Nick at Pelican Parts  
sac2dude Comments: Do you guys have the copper adapters available? I cannot locate that size anywhere! Lowes, Home Depot, Amazon...
May 2, 2012
  Followup from the Pelican Staff: I bought these at Lowes - they were on the shelf in the back. I suspect they are there, they were indeed a bit difficult to find. I don't think that HomeDepot had the correct ones though. - Wayne at Pelican Parts  
Joe Comments: The parts list left out the U-clamps needed to hold the Front Bumper Trim Peice to the Front Bumper Inner Cover Retainer. The part number is 999 507 707 00, 19 required.
July 30, 2011
  Followup from the Pelican Staff: True enough, thanks for the tip! - Wayne at Pelican Parts  
rjf Comments: I have an early 996 1999, build 5/98 without a center radiator. Can I add the center radiator as you describe for the Boxster? What extra parts are required? What parts listed aren't needed? Any extra steps / pifalls?
February 27, 2011
  Followup from the Pelican Staff: Yes, the center radiator on the 996 installation is almost exactly the same as on the Boxster. The main differences are only in the pipe diameters on the Boxster - you don't have to mess with those. The pipe diameters should be larger on the 996, so that you don't need the reduction pieces described in the article. - Wayne at Pelican Parts  
keith Comments: Which radiator has the fan sensor on it?


How do I get to it?
December 10, 2010
  Followup from the Pelican Staff: The radiators don't have sensors in them to the best of my knowledge. The water temp sensor is located on the engine itself, on the front part near one of the water channels. See Figure 2 in the tech article here: for the exact location. - Wayne at Pelican Parts  
DDebono Comments: When you tap into the left and right radiators, how much spillage should I anticipate?

How much additional coolant do I need to add for the center radiator?

What about air pockets in the coolant system?
November 13, 2010
  Followup from the Pelican Staff: Anticipate about a half gallon to a gallon for the first radiator, and then less for the other two. A big kitty litter bin should do fine for catching all of the coolant. For air pockets in the system, bleed it when you are done according to my article here: - Wayne at Pelican Parts  
Joe Comments: Are the all the pipes on a Boxster S the larger size, 1.25"id? I wonder if it would be good to replace the piping all the way back to the engine with the larger size?
November 3, 2010
  Followup from the Pelican Staff: Yes, all of the pipes on the 'S' are the larger size, the same sized used on the Carrera 996. If you're looking for the maximum flow through the pipes, then yes, you can replace everything on the car all the way back to the engine. However, this is quite involved, costly, and I don't think it's terribly necessary. The Boxster in this article is using the adapters with a 3.4L and it runs very cool, even out on the track at Willow. - Wayne at Pelican Parts  
Ricardo Comments: Do you guys have a part number for a 987 2005 kit? or how do I place an order to install this kit on my Boxster?
August 11, 2010
  Followup from the Pelican Staff: We're working on a kit right now, I will forward your request to Glenn in sales in the meantime. Thx. - Wayne at Pelican Parts  
s_wilwerding Comments: One more question, then - other than from a salvage yard, where would I get the Boxster S hard lines and brackets?
June 29, 2010
  Followup from the Pelican Staff: All the parts are available right here at Pelican:

Upper Left Side:

996-106-611-53 - Hard line/pipe with big downward angle, on upper left hand side of car, (larger size)
996-106-414-55 (Qty 2) - Plastic clips for above hard line

996-106-623-02 - Left upper side "S-shaped" hose for non-S Boxster (thinner hose)
996-106-623-53 - Left upper side "S-shaped" hose for Boxster S (larger hose)

Lower Right Side:

996-106-615-54 - Hard line/pipe with slight downward angle, on lower right hand side of car, (larger size)
996-106-419-52 (Qty 2) - Plastic clips for above hard line

996-106-627-02 - Right side "S-shaped" hose for non-S Boxster (thinner hose)
996-106-627-52 - Right side "S-shaped" hose for Boxster S (larger hose)

Just punch these numbers into the search engine. I'll also have my staff make a conversion kit in the next few days.

I would also pick up some screw-type hose clamps instead of the pinch-type ones, as clearance is very difficult in there.

- Wayne at Pelican Parts
Steve W. Comments: OK, I think I finally figured out what you did with the reducer.

In the middle of the car, you stepped up from the Boxster to the Boxster S hoses, and everything from the hard lines forward are Boxster S size.

Rather than replacing the mid-hoses, why can't I cut the new hoses that came with the third radiator kit and step down to the hard line using the hose that came out of the car?

That would seem a little simpler than replacing the mid-lines and the hard lines.

June 29, 2010
  Followup from the Pelican Staff: That's a good question. In order to reduce the hose, you need a big hose and a smaller (diameter) hose with a coupler in-between. The three-way hose is only available for the cars with the larger diameter hoses, so there is no smaller hose to use to mate with the existing hard lines in the car. So, if you cut the hoses at the areas you indicated, you would have to go to your local auto parts store and search through their inventory to try to find a smaller hose that you could graft onto the end of the three-way hose. Also, access is very limited in that area.

Since there are two versions of the S-Hose that connects to the rear hard line available, it's very easy to source the two hoses, cut them, and then join them with the adapter. Plus, the access to work in the wheel well is much better than working behind the radiators. - Wayne at Pelican Parts

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Page last updated: Sun 3/18/2018 02:12:10 AM