OEM vs. Original vs. Knock-off coolant expansion tank - How to tell?

I've encountered the issue that others have had - the v.04 Porsche cap (Blue) doesn't properly thread on my newly replaced expansion reservoir. The tank was $400, so I *** u me d it was OEM or original. Got home from a 30-minute drive today, and then coolant leaked outside the cap and down the overflow tube. I can screw on the cap fairly tightly, but then I can give it one more twist and it pops back to the top and we're back to square one. I'll need to check the reservoir part number with the shop that did the replacement. Meanwhile, is there any way to tell if this is OEM, original, or otherwise? Is there a cap that is specific to certain tank types?

Assuming you have a MK 1 and paid $400, I doubt it is a Porsche product. Where did you get it?

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Local trusted indie sourced it. I'm assuming it's the Behr OEM, but may be wrong.

I had the Porsche tank installed by FSI when they did my 3.8 build along with the blue cap. Fits like a glove and no leaks.

make life easy and just swap out the cap.

Looks like its not OEM. OEM has black lettering for min and max levels. I had the same problem recently with mine. Its held up so far but ill be changing it. BBi put it in and I though they would put an OEM one by how much they charged me for it but in the end it wasn't OEM.

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🙄

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I'm not sure that's correct about the black lettering. It may be an MK1 vs MK2 difference. Neither my original nor my Genuine Porsche replacement had black lettering for my MK1 996. It will be a little difficult to tell after it's installed whether or not it's Genuine Porsche. From my recent experience, the Porsche tanks are whiter than the others. The Porsche tank will come in packaging that is clearly marked with a Porsche part number and Porsche branding. The non-Porsche tanks come with a black cap (not the part with the bale). I just went through this with AutohauzAZ who charged me for a Genuine Porsche tank but sent me a third party tank and refused to acknowledge it. Be careful out there. The problem the OP has with the cap not tightening is very common with non-Porsche tanks.

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The original owner of my '99 C2 had the tank replaced at the dealer and it doesn't have black lettering either. FWIW, the dealer charged $301 for the tank and $460 labor in 2009.

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Thanks for the feedback, and for sharing your experience. The tank that was in my 1999 previously was almost certainly the original, and it had the same embossed lettering, FWIW. The tank came with no cap, and the threads are already not looking good at the top (likely from where they're "slipping" when the last tighten reverts to popping the cap back to the top of the threads). My local independent shop is great and I want to see what they can tell me about the part number and source. I wasn't trying to save any money, and so if original is the way to go, that's what I'll go with.

You Tube

This FCP Euro video is great, IMO: You Tube

For what it's worth, my genuine replacement expansion tank that was ordered at the dealership came with black lettering for MAX and MIN... AND the Porsche part number printed on the tank. The car was a mk2 996.

I took this pic to show the vacuum fill adapter, but you can see the black letter marks and part number. This was for my 01.

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2001 Mk1 uses the same as the Mk 2 cars.

There are mainly two versions available. The right one is from the earlier cars and super expensive. About 400-500�... The left one is from the newer ones and costs about 130�. So a lot cheaper and a genuine part also. You can swap the smaller one to the newer one. But then you need an additional part to mount the fuel filter, which costs only a few bucks. And the small plastic hose at the top is a little bit to short. That must be made a little bit longer with a coupling. Have done that on my 996 MK1 GT3.

So is that the mk2 to mk1 retrofit, then?

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I suppose it's possible for the shop to have damaged the threads with the vacuum fill adapter, but I think that's probably unlikely.

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Yes you may be right. I actually was told by them that the correct cap was a black one which I responded that it wasn't correct. They installed a non factory expansion tank and charged me over 600 dollars for it. Anyways, it was one of several frustrating things that happened with them. The others were my new brakes that they installed were not well bedded in and squeaked and vibrated and several other smaller items like cabin air filter cost and the fact they did the. full brake install then charged me to remove everything again to change the wheel bearings. Ill be changing out the expansion tank to an OEM one that uses the blue cap, the one I have now has the same issue where the cap doesn't tighten well.

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I'd like to do this swap. What is the part that is needed for the fuel filter? Thank you

That is 99611025703

I went through 2 non-OEM tanks (they sent me a replacement first) and had the same problem. Tried new caps, panicked that I had a head gasket/ overheating issue, etc. Finally went down to the Stealership and forked over the $600+ and no issues at all. Worst part was doing the dang job 3 times...

Put correct coolant in when you get the leak sorted�

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I thought this might come up. Correct as in pink, sulfite-free? The receipt I have says "OEM blue" coolant. Shouldn't any OAT or HOAT coolant suffice?

The correct Porsche coolant is pink. Just order a gallon or two from Pelican Parts, or pick some coolant up at a Porsche dealer. Having the correct coolant mixed 50/50 with distilled water is the way to go.

There are other alternatives that work just as well as OE Porsche coolant IMHO if you wanted to grab some in your local part store. https://www.oreillyauto.com/detail/c...e/afza/g405050 The Full Concentrate version is $29.99 https://www.oreillyauto.com/detail/c/zerex/chemicals---fluids/antifreeze/engine-coolant-antifreeze---vehicle-specific/df3a6469dc0a/zerex-1-gallon-purple-50-50-coolant-antifreeze/afza/g40?pos=10

Thanks for the suggestions. I'll see if I can get that sorted out. For what it's worth, the service advisor at my local Porsche dealer says that the original coolant in these was green, just like mine is now. Also, I don't think this is a problem with the threads, but the length of the threads or the amount of lip above the last thread. It wouldn't take much of a difference in material there for the top of the opening to not catch on the rubber seal in the cap and for the threads to be allowed to continue to turn rather than seat snugly. Not that that helps me much at this point! Related: It's a tight spot to get to, but am I OK to clean the dried coolant from the heat shield with just water? I don't want to foul up any electrical connectors under there...

What's right behind the heat shield? Your Bank 1 coil packs. If they have never been changed, there might be small cracks and you will get misfires. No problem cleaning the heat shield with water, but just saying, you might get your coil packs wet.

Shop is taking superb care of me, as always, and we all concur that the tank isn't going to cut the mustard. It turns out this tank *did* come with a black cap, and that seats worse than the blue cap! I said I could live with a cap that seats well, but they insisted on just doing it right and getting an original tank in there, which I agree with. Going original with the $650 tank, and that should be here next week. Many thanks to all in this thread for your advice and experiences. Why these substandard OE/OEM tanks are even sold is a mystery to me. They're garbage.

The two tanks from my pictures are original Porsche parts. No aftermarket parts. They can be ordered from porsche. The larger mk2 tank which I would prefer because of the larger capacity has the part nr: 99610615704 155$ from pelicanparts.

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I have the engine out of my car for a refresh and the coolant tank is probably 18 years old. It was replaced under the original warranty so that was before 2004/2005. So i am planning or replacing it before I put the engine back in as access is really easy then. I want to confirm that you have swapped in the newer style tank with just adding the bracket for the fuel filter.

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My fuel filter is under the car not in the engine compartment. Does that mean I would just need to lengthen the small plastic hose to make the larger tank fit? FWIW, Gaudin Porsche has the early tank for $476.00. https://www.gaudinporscheparts.com/o...ir-99610614756

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I don't get the fuel filter comment either. I'm skeptical. I think someone here confirmed that the MKII version didn't fit.

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C4 Turbo and GT3 have the fuel filter mounted to the side of the coolant reservoir where that big "C" looking place is.. Looks like it would work to me but I have never tryed it, but I definitely will when I need one before I pay $700 for a plastic tank,even though I also remember someone credible? saying it wouldn't fit..lol Who does"t want to save $500 with just a little mod??

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I'm eagerly awaiting the Ultimate MK-2 into Mk-1 Coolant Tank kit.

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I"ll put it on my list !! " So many problems, ( $ opportunity ) so little time."

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Yes, of course. When the engine is out it is super easy. But I have a 996 Gt3 Mk1 like I wrote before. But check for clearance before. Wih my picture you can estimate how much room is needed behind your old tank. And you need to make one ruber hose a little but longer in the gt3 from the Oil/Water heat exchanger.

I see a couple of Porsche dealers that are selling the newer style tank for only $116 so I think i will order one and the bracket and see if it will fit. Unless someone has a failed version of the newer tank that I can use to test fit it and report back here to everyone.

I thank you and I am sure the community thanks you….

Ordered what I now realize is a knockoff coolant tank for my 996.1... $60 on ebay. I'll update with how it fits.

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Here are a couple of pics of the tank in my 2001 and I would be happy to send you the old tank .

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Fitment isn't the issue with knockoff tanks. It's that they don't last very long and many have problems with caps not being able to be fully tightened. Some fail right out of the box.

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That would be great. I will send you a PM with my address and I am happy to pay for the shipping.! Given the price of the older style tanks I am amazed that no one has done this and written it up. I would think that Flat Six or one of the other sources would have covered it. But if it fits without major modifications I will do a write up with pictures and share it here. That would pretty much end the market for the old style tanks!👌

Got your PM, tank and bracket will go out Monday morning.

Early MK1's also have a different SAI pump so curious to see how that plays into the mix.

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I'm curious too. It looks like the difference between tanks is at the firewall end though. There seems to be plenty of clearance between the MK1 pump and the tank.

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^This^

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I have to say the ladies in Customer service at pelican are super. They answered every one of my questions, They helped get correct Porsche part numbers for hoses and that I had Identified via picture I sent them. They sent schematics, so we would each be looking at the same thing. They cam back with pricing including Porsche clamps They suggested some very popular hoses at that much mileage should be changed, so we those and clamps I was going to installing factory Porsche factory, that can with no cap. Blue filler cap was additional part number. These were super patient with me. It was my first coolant tank project. They sent me their list of item that they recommended about 7 or 8 hoses total when doing a tank, pump and low temp therm housing. The indy also the a Gold Porsche tech at a dealer. He is a fair young man, and seems to be as honest as the day is Long. The hoses the lady's picked out at pelican were correct as well as their clamps. He was very pleased with them sourcing parts. Month later I call pelican back and requested to be put in touch with the person in charge of trainings and supervising the front line sales. I told him because not only the effort but also efficiency of his sales people. I will be a returning Customer. ....no affiliation..... es

@Dharn55, Tank went out today you should se it in about a week.

I'll be watching this too, since like @Dharn55, I've got my engine out for an elective rebuild- 1999 C4. Last night I took a look. As you can see from the photos, the hard coolant pipe seems to be in the area where the newer reservoir front portion resides. Hard to tell if it will impinge or not, but it will be close. As a part of the rebuild new parts I got a new hose from the coolant reservoir to the oil/water heat exchanger. I believe that's the hose that @Jupp said needs to be lengthened slightly. Interested to see last night that the new hose is ~3" longer than the old one. @Jupp, was that the amount you needed to lengthen the hose on your GT3? Hard coolant line in area where the new reservoir may be: New hose (left) longer than old hose (right):

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That is one of the things that could interfere with using the newer tank. in 98-01 that hard line is 996.106.609.57. Starting in 2002 the line is 996.106.808.01. From the parts diagrams I can’t see exactly what the difference is. By DC Auto has the newer style used for $100 plus shipping so if it is only the shape in this area it would not be hard to swap out. I should note that the hard pipe on the other side was also updated in 2002 so this could be a challenge

Yep...callout 5:

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I had the new hose also, but had to cut it because it was a little bit too short. So I made a longer one out of the old and new one with a coupler.

To answer the original question for future reference, these photos shows a third-party tank on the left. The middle and right photos show a Genuine Porsche tank. The non-Porsche tank came in a plain box with no Porsche labeling of any kind. It's yellower in color and came with a black coolant cap. The Porsche tank was clearly marked, was whiter, and had no coolant cap.

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Thank you. I�m going to try to do this conversion. Hopefully it�s not too difficult.

Just a heads up there is an additional.bracket spot welded in for the mk2 tanks. I just finished adding it as part of my gt3 mezger swap.

I decided to order a Porsche brand expansion tank. Turns out the one I ordered is by a brand called "Genuine" and it cost me $490. I'm supposed to receive the part today and will probably ask for a refund since I feel they tricked me with the branding. Site said "Genuine Porsche". II'l take pictures when it arrives.

Waiting for the pictures. It would probably be a good idea to tell us the vendor. Thanks.

Can anyone figure out what�s wrong with this cap? 😂

It's not blue and doesn't have the 996 part number ending in 04?

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West Germany? Talk about vintage...

To my surprise, despite the fact that the ebay add said "Genuine" under brand, the part I got is a Porsche labeled part. Interesting that it says "made in germany" on it and also it's made by Geiger Technik and has the Porsche part number underneath. Another thing I noticed is that the metal hinge is much more sturdy on this part than on the bad aftermarket part my car currently has on it that was installed by BBi. Total cost of the new tank $432 dollars. Price rose since I purchased it a couple of weeks ago. Here's the link to purchase it. https://www.ebay.com/itm/192199212917

Well that eBay link shows a price of 503. Now I guess corona euro floods or vaccination has added to the total LOL Mike

Ironically I just started working on seeing if the newer style tank would fit in the older cars cars. A little background, my car is a 2000 C4 Cab that I bought from a dealer in August of 2000 with 4,000 mile on it. In November of 2000 the dealer replaced the cap on the tank under warranty and then in July of 2003 the dealer replaced both the cap and the tank under warranty due to leaking. Note in the pictures below that the tank that the dealer put in back then does not have the black labeling nor a part number on it although the invoice for the work lists the tank as 996.106.147.56. So at least back in those days the black labeling and part number on the tank was not indicative of it being a Porsche tank, I don't think the dealer would have used an aftermarket tank if they were available back then an this tank ahs been in the car for 18 years and has not leaked. So here is a picture of the old tank in the car. Note that it has the fuel filter attached to the tank with a hose clamp on the bracket. You can also see the hard coolant pipe that is under the tank. The hard coolant lines that run from the engine compartment to the midle of the car were also updated in 2002 when the engines were upgraded to the 3.6 Vario Cam Plus. Here is a picture of the two style tanks next to each other. The newer tanks are longer with increased capacity and have some differences in the placement/configuration of the hose connections and sensors connections. I want to reach out and thank a member, Just one more (Vince) for sending me his newer style tank that he had replaced due to a leak which saved me from buying a new style tank for this test to see if it would work. Here is a picture of the new style tank in the car, not fully tightened yet. You can see it is a tight fit and I am not sure is you could get it in with the engine in the car. You can also see how tight the tank fits to the hard coolant line, this is the old style line. Another picture of the tank. And here is a picture of the tank and the coolant line. You can see that the tank and the coolant line follow the same contour. The fit is close enough that I think I will put some sort of pad between then to keep them from vibrating against each other. The hoses will take some adjustment or replacement, I will need the bracket that holds the fuel filter mentioned above which costs about $12 and the newer sensors. But given that the old style tank with the Porsche label lists for $662 and sells for about $500 and the new one can be bought from dealers for less than $150 I think this is well worth it. I am going to do a little more fitment to check clearances and if everything continues to look good I am going to order the new Porsche tank and the related parts and install them before the engine goes back in the car, I am in the middle of rebuilding it (unfortunately without Nickies as I just don't have the $5,500+ to do them). I will keep all of you updated on this but I am thinking that if everything works out with this tank swap the market for the more expensive tank is going to drop like a led balloon for those who read this. It is hard to believe that this has not been tried before and I am interested on any insights or comments from sources like other shops, Flat Six and others.

Only Porsche knows why the smaller tank is 300% more expensive than the large one. I don't think many people are willing or able to remove the engine in order to save around $300, but thanks for being a pioneer on this. Btw, my 2000 C2 doesn't have the fuel filter in that area.

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The C4's have the fuel filter strapped to the coolant tank, on the C2 I believe the filter is located under the car. I am trying this swap of tanks while the engine is out of the car so it is much easier and yes the cost of dropping the engine is much more than the more expensive tank. I am going try to see if it could be done with the engine in the car. Most of the time owners lower the engine a few inches to give better access to replace the tank so while very tight it may be possible to do the swap.

Does anyone have a picture of the newer tank in a newer car? I would just like to take a look at it, and hopefully without the engine in place.

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The MK-I tank is difficult to install even with the engine lowered. I'm having trouble seeing how the MK-II tank could be installed with the engine in. I know that I wouldn't have the patience to do it even if it is doable. I appreciate your efforts on this and all of your posts.

That's an informative post @Dharn55 , thank you for the effort!

99610615704 is the part number for MK2 version? Does it require the new bracket spot welded in? That would be a deal killer for many.

Bump,any new info ?

Haven't had time to finish my project up and do a write up but i can tell you that I have tested the fit if the newer tank i my 2000 C4 and while tight it seems to fit fine. For my C4 you do need the bracket to hold th fuel filter to the tank, dont think that this would be required on a C2 where the fuel filter is located elsewhere. there is another mounting point toward the rear of the tank that clips into a bracket on the body that the older cars don' t have but the tank does not seem to move around without this. I am wrapping some insulation around the hard cooling tube that runs under the tank to prevent the tank from rubbing on this tube and vice versa just in case there is some movement. I will try to have the write up with pictures done soon!

Thank you Dharn for the update,appreciate it.

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My knock-off tank was a little smaller than the OEM tank that came out, but otherwise no issues/leaks since. However it seems like ultimately (even though I had seepage from my tank) it was symptomatic of an overall cooling issue. My driver's side cooling fan somehow mangled itself so badly it stopped working, which led to the cooling system overheating/going over pressure and i guess the weakest link was my old coolant tank. So maybe it didn't strictly need replacement, but now there's a new tank and I replaced my fan and no leaks.

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Just sent De Jeeper a PM on this mounting clip trying to source it. My friend in the part department can�t find it. I am considering adding it if it is available. Should be finishing the write up on this mod soon as I am hoping to have the engine back in my car in the next week or so!

uugh, can't believe the cost for a plastic tank. that is what i get for getting a porsche

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i pulled it off the donor car. Dc Auto should be able to pull it off any mk2 car in there yard. Just steal my pic and send it to them. They r great to work with.