How to Replace Purge Valve (The easier way)

I've recently had issues with my 987.1 Cayman 2.7L hot starting and especially starting after filling the tank. Initially a little bit of throttle on start alleviated the problem but I decided to fix the actual issue. I had trouble finding a good DIY and didn't want to have to take off the intake runners or disassemble any of the other engine components as some other people said they did, so this is my process that I hope can help save someone else some time. Overall this took me around 2.5 hours but it should be much quicker following this guide, I could probably do this job again in around an hour. You will need: 10mm socket/ratchet (wheel liner nuts) very small 8mm wrench (bracket bolt) Pliers Flashlights T30 (engine cover) and T20 (wheel liner) Torx Bits Magnetic Retrieval stick Non large hands (the smaller the better) Finger dexterity Patience Nice to have: Step stool Towels/tarp Cleaner for the engine (light degreaser is what I used) + a rag. Cleaning the engine beforehand spares your hands and the interior of your car from lots of dirt and grime migration. I didn't get any pictures for steps 1 or 3 but they should be pretty self explanatory or you can find quick guides for those as well. You will be getting in and out of the trunk of the car a lot during this so it has to be stable once jacked up. Also a step stool or box, would be nice to make climbing in and out easier as would a towel or tarp to protect your interior from the dirt and grime. 1) To start, you will have to be able to jack the car up, remove the rear left (drivers side) wheel and then remove the two wheel liner pieces using a 10mm and a T20 torx bit. 2) Locate the purge valve hose quick connector at the bottom of the image. It can be found behind where the wheel liners were removed from. It is pointed out by the red arrow below and then in the second picture it is show in the red circle, it is the farther left hose. Disconnect it by squeezing the two sides of the hose and pulling. Then free it from the slot a couple inches above the joint by pulling the hose outwards. 3) Next remove the foam engine cover, and metal engine cover (five T30 bolts) 4) This is where it gets tough. There is a single 8mm bolt that holds the purge valve hose to the underside of the left intake runner. You will need a very small 8mm wrench to get this bolt out and it will take some time and some fiddling. The post the bolt screws into can be seen circled in red. Unscrew the bolt and have a magnet ready underneath to catch it. Pictured above the bolt has already been taken out and the bracket dropped. 5) Now go back to the disconnected hose in the wheel well and snake it up through the engine, and go back to the engine and pull the valve outside from under the runner. This may take a couple trips between the wheel well and trunk. Here the purge valve can be seen moved out from underneath the runner (red). You also want to detach the hose with the blue line from the fitting circled in yellow. 6) Disconnect the electrical connector by pulling the metal clip out and then pulling the electrical connector out of the valve. I did this while it was under the runner but I believe it would be easier to do once moved outside. 7) Now using a pair of pliers squeeze the hose clamp and move it down the hose and separate the valve from the hose outlined in blue in step 5. This will take quite a bit of force to separate the hose and some people had success with heating it up, I just pulled really hard. 8) Now you are good to finish snaking the purge valve and its hose out of the car. 9) Install your new hose making sure to route it back under the runner and snake the bottom connection back down towards the bottom of the car but leave some slack so you can reconnect everything while the valve is outside of the runners. 10) Reconnect the blue outlined hose from before and slide the hose clamp back over. Then reconnect the electrical connector and put the metal clip back into place. 11) Maneuver the purge valve under the runner and position the bracket underneath the post. 12) This is by far the most difficult part of the whole job. One stupid little bolt. Now I would zip tie the bracket up so it stays in place against the post which will make screwing the bolt back in much easier. My combination zip tie contraption is shown below. It took me probably a good 15 minutes to get this bolt started into the post, it is very tedious and will cause you a great amount of frustration probably. Be sure to have your magnet retrieval stick ready or in place below the bolt. Finish screwing in the bolt (or give up and zip tie the valve somewhere to keep it in place as other people have done). 13) Finish snaking the hose through the engine compartment down to its connector at the bottom of the car, connect it and place the hose back in the holder a couple inches above the joint. 14) Re-attach the wheel liners, wheel, and engine covers. Lower the car and torque the wheel to spec. You're finished. I hope this post can help someone else do this job and if you find it useful or have any questions let me know.

@V1Rotate - thanks much for this wonderful contribution to our forum! I'm going to do 2 things with it. I'm going to move this copy of it to our 987 Tech subforum.. and then I'm going to copy it to the general DIY forum. When you have a moment - please visit New Member Introductions and introduce yourself and your car. A few photos would also be great! Thanks again for a great first post! And welcome to Planet-9, the Friendly Porsche Forum!

Great write up. I used this as a guide to get my old purge valve out. Took me about 45 minutes to get the old part out and 30 minutes of that was trying to get that 8mm bolt out. What a PIA. I have no idea if I am even going to be able to get it back in. I also tied a string to the end of the hose before snaking it out, to help with snaking the new part through when it comes in. Thanks again for this writeup with pictures, very helpful. 👍

I need to replace my purge valve and spent over an hour trying to put a wrench on the 8mm bolt. What's the secret? Which end of the engine did you attempt from? Back? Front? I was standing on the left side of the car trying from the front of the engine, no joy. Super frustrating.

OK, was able to get the 8mm screw removed. The secret was to lie on the right side of the trunk and put both hands under the intake manifold. Wrench in the left hand comes in from the transmission side. The right hand comes in from the front and guides the wrench onto the screw. You will be able to see both the wrench and the screw. There was just enough room to get 30° of rotation on the wrench. Magnet at the ready to capture and remove the screw. I tied paracord to the lower end of the existing purge valve. The paracord was transferred to the new tube once I had removed the existing valve. This ensured the new tube followed the same route as the old tube. No drama getting the screw back on. Specific tools used are shown in the image below. I didn't remove any panels to get access to the lower disconnect. Was able to reach it using the middle tool in the image below. Start, idle, acceleration and cruise seem slightly smoother. The problem I'm hoping this solves is an intermittent near stall when stopped. For reference this was performed on a 2006 Boxster S w/Tiptronic. Presently has 143k miles. Was purchased Apr 2024 with 125k miles.

I used a 10mm plastic pipe cutter and cut the pipe immediately to the left of the valve (without removing the hard plastic pipe or M8 screw/retainer. I then fitted a J30 R9 9.5mm hose (less than 10cm) to the cut pipe and to the new valve with SS clips. Everything was accessible without any hassle. The valve is secure given the short length of pipe, the clip still in situ, and everything works.

How did you get access to cut the line close to the valve? From the cabin hatch?

From above the manifold, immediately to the left of the old purge valve, not from the cabin. I used a cheap pipe bladed cutter designed for small diameter air/water plastic pipe, so it was small enough to reach between the manifolds.

@Shredder61 Purge valve replacement may be in my near future, but following this thread it seems that others have replaced the entire assembly from the point where the valve attaches to the underside of the intake manifold with the dreaded 8mm bolt, to the lower attachment point under the vehicle, new hose and all. Sounds like you replaced just the valve and left the original hard line/hose intact, with no need to detach it from under the vehicle. Is that correct? Is there any need or upside to replace the whole assembly? Seems like your method cut out a lot of labor.

Correct, I didn’t replace the entire assembly -the hard pipe is held securely by the 8mm bolt/bracket and the new pipe is short and very stable. My only precaution was to cut the pipe with a blade and not a saw, to ensure that no debris could enter the new valve. In my situation, the failed valve revealed itself in the extremely hot weather because fuel vapour was passing from the tank into the air intake at start up. It was a straightforward repair this way and I see no reason to replace the full pipe. Just make sure that you use the correct pipe (I referenced it). It was from WrightsAutoSupplies on eBay. Ethanol Proof SAE J30 R9 Fuel Pipe Hose BIO Methanol with or without clips 1m. I bought shorter lengths (0.3m, discussion with Matt) of the 7.9mm and 9.6mm for the 1m price, but I think it was the 9.6mm that I used (probably shorter than 10cm).

@Shredder61 What is your vehicle? Mine is a 2008 Boxster base and in my parts search I can only locate the entire assembly with hose/pipe which is ~$600. There is a listing for the valve only for $55 but the application list shows it to be for the 986. Funny thing is it looks exactly like the same one for the 987. Has me thinking, was it really changed to another part for the next generation? Tempted to buy it and try it, when looking at a part that is $550 more. If yours is a 987.1, where did you source your part?

Mine is a year 2000 986 3.2s. I paid about £30 for the valve new, but you’re correct that the 987 is likely different, BUT this might just be for the pipe bends and length, not the valve itself. It definitely looks the same and it’s a simple component. On mine, it’s a simple solenoid valve which you can test with a 9v battery (usual supply of course is 12v) and you’ll hear the solenoid clicking when you connect AND disconnect. Mine was intermittent and wouldn’t always operate, which caused issues with starting and, as I found out in the recent very hot weather, an explosive mix of gas fumes from the tank filled my air intake which blew out the air filter when I started the car! I suspect that it was also the cause of occasional difficulty in starting the car when hot. All solved.

WOW! Thanks so much for your swift response and the detailed info. That is the beauty, and value, of our Planet-9 community. I was blown away by the price of the full assembly, which is the only listing for my 987.1 The stupidly simple valve, which for your generation lists for <$60, suddenly becomes 10X more with a meter of hard plastic tubing attached. Apparently someone at Porsche realized they could charge this ridiculous amount by only selling it in this fashion. I actually may try the valve for the 986 , since its only operation is to open and close in the presence or absence of 12V. What have I got to lose, $60? If it doesn’t work, then I’ll spend the outrageous number they want, but if it does, I win this one. Either way, DIY will save me a ton so I might take the gamble. If anyone reading has any knowledge or input on this swap, I’ll be eager to hear your opinion. My issue is the hot start. Starts beautifully when cold, and fine on most warm/hot starts but occasionally when I run into a store and come out minutes later, it stumbles and sputters several times before starting, and usually needs some depressing of the accelerator to help it start.

That was exactly my issue (hot start) and it was only the very hot weather which ultimately caused a bigger issue that led me to the purge valve. It’s usually closed (at start up); if it sticks open, guess what, you get over rich mixture exactly when you don’t need it. Worth the $60 and it’s likely the very same solenoid valve. However, you can test your valve while in place by pulling the socket/plug and applying 12v to the purge valve connectors - the polarity doesn’t matter because it’s a solenoid, but it should activate (click) when you make AND break connection to power. Also, if you look here, you’ll see that the 986 and 987 are listed under the same part. See [Purge Valve Genuine Mercedes 120-078-01-45 120 078 01 45 1200780145 120.078.01.45 | Pelican Parts]( https://www.pelicanparts.com/More_Info/1200780145.htm?pn=120-078-01-45-MBZ#fitmentAnc ) Good luck!

Your post is helpful. I converted a 2008 Cayman S from a street car to a track only car. For the past 10 years I raced it in SCCA and Porsche Club Racing. I decided not to race it now however, I am planning to get it to pass California smog and drive it, instead of trailering to tracks close to home. Sonoma, Laguna Seca and Thunderhill are close enough to drive and have fun on the track. I kept everything I removed for racing, and now I need to replace the smog stuff. Cats, charcoal canister, etc. are not a problem however, the other components I need to find out what and where they go. Purge info is very helpful. I will pull my valve out and try to determine where it connects. That's a start. Any help will be greatly appreciated.

This is not going to be the best introduction to the forum.... but I decided to (gasp!) "frankenstein" the purge valve assembly. Not only was I not willing to pay the freight for the OEM assembly but frankly there was no way I was going to be able to install it properly even if I did. I just do not possess mad wrenching skillz. I can figure stuff out and muddle through but that's about it. After reading @Shredder61 s post..........My original plan was to replace the hard line with acceptable HP full injection hose run to the new valve But once i got in there and got my hands dirty I realized that that was going to be a nightmare. Once I removed the T plenum to get a better look at everything, I discovered that the vacuum line coming off the bottom went directly to the purge valve. I also discovered that there was plenty of space around and under the T plenum. I decided to roll the dice and pray that the old valve stays truly open. So...... I left it in place 😱 and a spliced the new valve into the aforementioned vacuum line. This only involved a single cut, a short length of 5/16 tubing, a reducing connector and a bunch of fuel injection clamps. That large tubing is because the nipples on the valve are different sizes! I tried all the tricks to get the original tube to fit (Hot water, soapy water, elbo grease) but finally I gave in an went and got the reducers at Autozone. Then I Painstakingly put it all back together...... and fired it up. No codes. I took it out for a rip and put it away CEL free, Slept the sleep of the righteous. Next day I fueled it up.....and prayed. She started strongly and immediately, first try. Been running like a top ever since. Worse case scenario is if the old purge valve magically closes some how, I will go back to plan A and cut the hard line back near the firewall and then run hose from there to the new valve, completely bypassing the old. You can see my "frankenstein's monster" between the intake runner and the Throttle body.

Thanks for the response, but I couldn't even see the valve through the intake runner "windows"....

Very ingenious. Now THAT is thinking outside the box.

Folks - It appears either Planet-9, or YouTube has changed how videos can be embedded in a posting here. Instead of having the video simply appear when the link is posted - it now changes the link to some "media" link BS - which forces the user to go to YouTube to view the content. The reason I suspect it's YouTube doing this is they're increasingly under pressure to restrict views of any sort of adult content, as innocent as most YouTube content is. I'll be asking our programmers about this..

Well....my solution solved the hard starts after fueling but..... I just got P0441 - Incorrect Flow. Turns out that the stand alone valve is actually for earlier years. Sigh. I will decide later if I can live with a forever CEL, but for now I need to finagle a way for it to pass the first PA inspection.

In an earlier post, I had mentioned that the standalone valve which is ~$50 but listed for the 986, is a far cry from the parts listing for the 987.1 which only comes as the complete assembly, hard pipe and all, but costs nearly $600. In viewing pictures of both parts side by side, they appear to be identical so I thought I might purchase the ‘incorrect‘ standalone valve, saving tons of money. Reading your results, good that it solved the hard start problem which is akin to my own at times, but bad by resulting in the Error Code of P0441, which leads me to wonder about the Error Code. So, if the standalone valve fixed your problem then we can assume that the valve works as designed. But could the throwing of the Error Code be a result of there being two valves in-line? Especially since the code indicates ’Incorrect Flow’? Is the ECM that sensitive to readings that pulling vacuum through two valves instead of one is giving values outside of the correct parameters? Only way to determine that is to remove the original purge valve, leaving the replacement, standalone valve to function. And if you can clear the code, and it doesn’t return upon operation, then it’s possible that the standalone valve will perform properly, and the Error Code was simply a result of pulling the vacuum through two valves. This would be great news and a revelation for those needing to replace the purge valve and avoid the Porsche tax of slapping an extra $500 for adding a meter of hard plastic tubing. This would surely put you in standing for a Technical Excellence Award!

@WTFChuck . While I think what you describe certainly could contribute to the issue, as could the fact that there is no way I replicated exactly the inside diameter of the hard line.....the truth (based on what I read) is tha, all things being equal, the Bosch stand alone valve has different internals than a 2007 and up Cayman ECU is expecting. So even though those other factors may have created a code on their own, the part itself is sending out numbers outside expected parameters. I am far from an expert, but In a last ditch effort to save the $$, and mostly the aggravation of installing the OEM assembly, I am trying to source a used assembly to Frankenstein in into the car. If I locate one, I will eliminate the old valve by bypassing it with tubing from a cut to the original hard line and splice in the example of the original true OEM valve. And then I will pray. Because , frankly, I don't have high hopes that it will work because off all the other variables we have discussed Damn shame because what I did fixed the root problem. All this said, it's still running great.....so I am not going to sweat it too too much. Big hurdle will be to get it to pass inspection.

@Irishbro Keeping my fingers crossed for you. Hope you hit upon the solution for the issue. My hot start problem only occurs occasionally, but it is annoying and at times embarrassing when it happens. Getting into the car after running into the supermarket and having it attempt to start, sputter and fail once or twice before finally starting fully, it feels like I’m driving a clunker, when in reality it purrs like a kitten and drives like a tiger. When it first started to happen I was stumped as to the cause until researching Planet-9 led me to the root of the problem. No big deal I figured, I’ll replace the stupid purge valve. Then I scanned the usual parts suppliers and was stunned to see this little plastic cylinder with a few feet of tubing was nearly $600. Was hoping for a cheaper alternative but I’ll spend the money since I like to keep my Boxster in perfect operating condition. At least I can console myself that when I DIY it, I’ll save a bundle over taking it to the dealer.

Thanks man. Frankly, now that I've actually wrenched on it (somewhat) successfully.... I know I could prob tackle the valve assembly as intended. But man, I really don't want to.

You can do it! By now you already know your way around the purge valve and what it entails, not much left but going all in. I agree, it’s not high on my list of pleasurable tasks but I’m going to have to bite the bullet since I don’t enjoy funky hot starts, and CEL‘s on the dash are even worse. By the time I finish washing my hands and cracking that well-deserved cold beer I’ll be glad I dove in.

FOLLOW UP - Soooo, I threw classic plates on my baby (Who I have named Mystique, due to her color changing properties). Bye bye emissions testing, FTW. So she is still throwing the incorrect flow codes and a CAT related code that was prob due to the AOS being shot for so long before I bought her. I may or may not mess around with getting a used Purge Valve at this point..... I need to sort a few other things first. I will now stop polluting this thread and prob start a build thread at some point. Thanks for letting me spitball here.

Thanks for participating, spitballing is only one of the driving forces behind P9..!