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996 3.4 header tank remove / refit instructions(as promised)

Lloyd Six

Well-known member
Joined
4 Nov 2008
Messages
879
Note to moderators - can you move this to 996FAQ?

Ok, as promised I have put together instructions to enable DiY on certain common faults. To start with C2 / C4 3.4 header tank remove and refit, I really do hope this helps a few out as it has taken a lot of time and effort.

These instructions will also be the same for 3.6 models except you will need to remove the obstructing air pump first.


Tools required:

A pair of mole-grips
17mm open end spanner
19mm open end spanner
Flat ended screwdriver
10mm deep socket
Long nose plyers (pref. with 45deg bend like in photo)
x1.jpg


Also need some rag - or steal one of the other halves favourite tops!
x2.jpg


Enough antifreeze to top up or do a complete change.
Out of preference I am using 4 litres of Red long-life concentrate.
(Testing the strength afterwards this has given me upto minus 29deg which is fine) This is made by Comma & is Porsche approved
x3.jpg



Ok, lets go... open the engine cover
x5.jpg


Remove the air trunking, simply twist, push pull, you will get the jist, it eventually pops out. If not you will notice push down clips, apply pressure to those using the flat ended screwdriver.
x6.jpg


Set the mole grips to a gap of say 10mm ish
x7.jpg


Now clamp the mole grip onto the top hose clip, slide the clip down the hose to enable pulling the hose off, do the same with the lower one.
x8.jpg


The hose that comes in from the rear at the top of the tank is difficult to get at so this is where 45deg angle long nose plyers come in
x14.jpg


Undo the 10mm nut
x10.jpg


Use 19mm spanner to crack the front brass fuel union. Don't panic, you get hardly any fuel come out, just a tiny spray when right at the top of the thread. Detach from rail and tuck to one side
x12.jpg


Now use 17mm spanner to do the same on the union just next to it
x13.jpg


Under the tank you will see a 2" bore alloy water tube held to the chassis by a C-clip. Simply pull out of the clip
x16.jpg


Push it down and out the way as much as possible, the more the better but you'll find it will only drop by about 1"
x17.jpg


Start to wriggle the tank towards the engine by about 1 - 2", once it has come that far it will then push downwards and out of the Black retaining bracket
x18.jpg


Now you can unclip the hose out of the top of the tank
x15.jpg


Ok, almost ready to pull out. Now just look at the situation, tie back / tuck away all hoses and pipes that are in the way around the tank, the more room you can make the better, the tank is wedged in there.

Now start to manipulate as gently as you can the tank to come out, take your time and ** BEWARE - there is a level sensor in the base of the tank, they are VERY BRITTLE so do not force the tank and snap this off.
Once you have got half way out reach underneath and disconnect the loom using the flat ended screwdriver on the locking clip.
x21.jpg

x22.jpg


Once out you can easily remove the sensor, looking straight at the sensor just twist anti-clockwise it then comes out
x23.jpg


Use the flat end screwdriver to pry off the overspill hose
x24.jpg


Make sure the receiving area is something like this (all pipes tucked away & the 2" alloy pipe pushed down)
x28.jpg


Next step has 2 options

OPT. 1 = Fit overspill hose to new bottle and the level sensor then gently manipulate tank back into place (BEWARE - of the sensor again, don't force it, they break easy)
x25.jpg

You can clip the loom on at this stage or when it is in place
x26.jpg


OPT 2 = Fit the overspill pipe but wait until tank is mounted on bracket and insert the sensor last, although tricky this is in my opinion the easier and safer way, REMEMBER TO LOCATE THE HOSE INTO CLIP before you attach the tank to the bracket otherwise you will not have room
x30.jpg

x29.jpg


Nearly there, attach all the hoses back on, reconnect fuel lines, clip loom to level sensor if you haven't already and then pour in the antifreeze. Then use as much water as needed to bring to level
x31.jpg


With tank cap off start engine and leave ticking over, the level may drop a few inches just keep topping it back up to level. After about 2 - 4 minutes it will stable then fit cap but put purge clip in up-right position
x32.jpg


Take car on a short run then check level, top up if required, attend to leaks if needed. Leave the purge clip up for a few drive cycles to get as much air out of the system as possible.
 
Excellent job Lloyd!

It makes it a little easier if you loosen the engine mounts at the back to drop it down an inch or so.
 
Richard H said:
Excellent job Lloyd!

It makes it a little easier if you loosen the engine mounts at the back to drop it down an inch or so.

Thanks Richard, any extra tips / advice on this would be great, eventually have the ultimate set of instructions.

I assume you mean the mounting by the header itself? What is, in your opinion the easiest way to slacken off that mounting? (I will be honest here, I have never had the need to touch a 996 engine mount)
 
Yes - the mountings on each side of the engine carrier frame at the back of the engine. If you get under the car you will see where the studs from the hydraulic mounts come through the frame. There is an M12 nut on each one which you can undo with a deep socket to drop the whole engine. Don't remove them completely or you are in trouble!!
 
Brilliant write up to what I understand is a very common issue. I wish this had been available last year when I paid my OPC to do this very job for me!

I'm happy to tackle the DIY stuff providing I have this sort of guidance.
 
Excellent work Lloyd
10 out of 10!
 
Great work and write up - moved to the 996 FAQ section - keep 'em coming... :thumb:
 
Brilliant guide Lloyd, who needs an OPC with guides like this. Much more fun (and -££) to do it yourself.
 
Thank you for the instructions. Very detailed and the pictures are really helpful. Meant to replace my own tank with a write up after but my local indy charged so little to do it I let him suffer instead.
 
ALL HAIL - WE HAVE SEEN THE HANDS OF LLOYD !

Nice one Lloyd, by far the best photo/methodology for a replacement that most garages say is a right pig.

Can you do a similar one for removing socks from behind radiators, or perhaps coins from the drum of a washing machine?
 

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