Pelican Technical Article: Water Pump & Thermostat Replacement Wayne R. Dempsey
Time: 2 hours
Tab: $450
Talent:
Tools:
Swivel socket set
Applicable Models:
986 Boxster (1997-04) 987 Boxster (2005-08)
Parts Required:
Water pump, thermostat, and gaskets
Hot Tip:
Install the low-temp thermostat for better performance
Performance Gain:
Protects your engine against overheating
Complementary Modification:
Replace radiator hoses
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.
Check out some other sample projects from the book:
The modern, water-cooled Porsches have been known to have cooling systems that have some troublesome problems. Two of the principle areas of failure are the thermostat and water pump.
Begin the replacement process by jacking up the car (Pelican Technical Article: Jacking Up and Lifting the Boxster on Jack Stands) and removing the lower plastic tray that covers the front part of the engine and the coolant hoses. Disconnect the lower hose that is attached to the water pump (see Figure 4), and let the coolant empty into a five gallon or larger bucket. If you are replacing your thermostat too, then now would be a good time to disconnect the hose attached to it as well.
The next step is to gain access to your water pump. This requires the removal of the main belt (see Pelican Technical Article: Drive Belt Replacement). You may also want to remove the right side (passenger) seat as well, in order to give you more room to work. With the belts removed, the front of your engine should be relatively accessible. Seven bolts attach the water pump to the engine, and access to some of them may only be achieved from underneath the car. I recommend using a flex 10mm socket to get into the tight spots.
When the engine was assembled, Porsche installed the coolant manifold and the water pump together. Therefore, they use a shared gasket, which you must cut apart in order to remove it from the engine. Photo 2 shows the gasket removed from the water pump housing on the engine, and Photo 3 shows where you must clip it in order to remove it. The new gasket must also be modified prior to installation (see Figure 3). With the pump removed, check the inside bore where the water pump fits for debris or corrosion. With a wire brush, remove any corrosion or debris that may have built up there. Clean off the water pump mounting surface on the engine and install the water pump with the new gasket. Tighten down the bolts to 10 Nm (7 ft-lbs).
At this time, I also recommend that you remove the thermostat housing (located below the water pump) and replace the thermostat as well. The thermostat is a relatively cheap part that can fail quite easily, which leads to your engine overheating. Simply disconnect the thermostat hose if you haven't already, and unbolt the thermostat from the engine. The thermostat used to be sold separately from the thermostat housing, but now Porsche and the aftermarket suppliers simple sell the whole assembly as one integrated unit.
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 engine needs to get very hot before it starts sending its coolant to the front radiators. For this reason, I recommend installing a low temperature thermostat in place of the factory one. LN Engineering has developed a thermostat that starts opening at 160° F (71° C) and is fully open at about 180° F (82° C). Lower coolant temperatures translate into lower oil temperatures, and the dyno tests that LN Engineering has performed on the cars with the low-temp thermostat installed have revealed a small increase in HP (typically about 5HP). It is my guess that Porsche designed the thermostat to open a bit later in order to help the cars run a bit hotter, which typically helps with emissions testing and the burning off of water out of the oil, which can then lead to longer oil change intervals. Installing the low-temp thermostat is a smart idea for engine longevity: it's available for about $175 from PelicanParts.com.
Figure 1
Disconnect the main hose to the thermostat, as indicated by the red arrow. In order to gain enough clearance to remove the thermostat, you typically need to disconnect the water pump hose shown by the yellow arrow. For the tight spaces near the thermostat, I recommend using a swivel-foot socket (green arrow and upper right inset photo).
Here's what the engine looks like with the water pump removed. For the 1997-04 Boxsters, you need to cut the old metal seal in order to get it off, as part of it is still trapped in the engine off to the right (it's a dual-purpose gasket). With the new gasket properly trimmed, it should fit into place (lower left).
The water pump seal needs to be trimmed prior to installation (1997-04 only). The part off to the right is separate from the water pump, and is typically only used when rebuilding an engine. Trim the seal at the yellow marks and use the part on the left. The upper left photo shows a brand new water pump. The lower left shows a new thermostat and seal. The newer-style Boxster thermostat is integrated into its aluminum housing.
The water pump is located next to the crankshaft on the right side of the car. Access to the pump is obtained through the access panel behind the seats, and from below.
Comments: Does anyone apply sealant to the mating surfaces or is the the gasket adequate to seal the pump?
May 21, 2012
Followup from the Pelican Staff: I typically like to supplement most gaskets with a tiny bit of sealant - this methodology has helped me greatly in the past. - Wayne at Pelican Parts
Cj
Comments: If a thermostat is 175 how much is a pump Jesus thes Porsche parts are a crime? Why so much for a thermostat?How much is the standard thermostat?
March 1, 2012
g60
Comments: Hello, just replaced the water pump following article. Not too bad, some screws are hard to reach, and different in size, but I manage to get them out with a modified "L" shaped tool get the 10mm flex socket and attach the leg and tape the joint to secure the "L" shape. No need for the wrench. As I said, the screws are different in lenght, make sure you remember the right order I used the new gasket as a guide, removed the screw and placed it in the new gasket one by one in the right order. I wouldn't mess with the thermostat, you will have plently in our plate just with the water pump replacement, and IMHO it is not needed, the whole low temp thermostat concept is not accurate, the engine will ultimately run at the same operating temperature, it would just take longer to get there, which I think is not good. Besides you will save the cash and the work. Trust me, the water pump itself is plenty. Good luck.
February 6, 2012
Devin
Comments: Do you recommend applying any sealant on the gasket and surface? Is the gasket by itself adequate?
January 15, 2012
Bull
Comments: I have a question-- for a 2000 Boxster S-- how is the water pump pully attached? Along with that, what would cause the pully to seperate from the shaft?
December 6, 2011
Followup from the Pelican Staff: I believe it's just a big nut that is attached on there from the factory. New / rebuilt pumps come with the pulley attached, so there's really no need to remove it. If the pulley has separated from the shaft, I would think that is a rebuilding / manufacturing error from the factory. I would replace the whole pump asap. - Wayne at Pelican Parts
01986320s
Comments: Wayne, I just ordered the L&N thermostat for a 2001 986S from Pelican today, and have one question. If I remove the OEM thermostat while the car is on ramps, can I just reuse what coolant drains out, or do I also have to perge the system of air also? thanks for any additional information.
June 24, 2011
Followup from the Pelican Staff: Yes and yes - you should be able to reuse coolant, but you will still have to go through the coolant bleeding process that is documented in the coolant flush article in our tech articles section here. - Wayne at Pelican Parts
Jville
Comments: I would just like to say thank you this Forum, its going save me $$$$ which I surely need to repair my car myself, I've replace two water pumps in two years @ not less than 9 hundred per job at two different repair shops, so I will be ordering my parts from you real soon.
May 11, 2011
Followup from the Pelican Staff: No sweat, thanks for your continued support! - Wayne at Pelican Parts
puma
Comments: I think this article is in the wrong place. It is listed under "Suspension" articles.
February 27, 2011
Followup from the Pelican Staff: Yup, you're right. I will fix that right away, thanks. - Wayne at Pelican Parts
Check out some other sample projects from the book:
