How to remove and replace a Porsche 944 fuel tank (Square Dash Model)

THE WHY?

If you've ever asked yourself "Should I buy an early (square dash) or a late (oval dash) 944?" then this article may be the deal breaker. Having put my 944 in for a service my mechanic discovered a leak that appeared to be coming from the fuel tank. No big deal I thought, I'll buy a second hand one from a breakers or ebay. However upon further investigation it turns out Porsche significantly changed the material of which the fuel tank is made from between the early (square dash) and later (oval dash) 944. The square dash 944 (and 924) has a fuel tank made from steel, whereas the oval dash model has one made from plastic. More investigation reveals that the fuel tanks are also of different capacity (oval dash has the larger 80 litre capacity, compared to square dash's smaller 66 litre). Even more investigation finally concludes that the plastic fuel tank will not fit the early (square dash) 944's as the cross-member that supports the transmission is non-removable and therefore blocks the insertion of the larger plastic fuel tank.

So the options I had were:

a.) Buy a new steel fuel tank from Porsche for near £1500.00!
b.) Repair the old tank
c.) Buy a good 24 year old fuel tank from a breakers £40.00

I went for option 'C'.

For the record and from research on forums it seems the steel fuel tanks are susceptible to cracking due to the vacuum that causes the fuel tank to contract and expand. They are also susceptible to corrosion, externally and internally.


THE TASK


You'll need the following tools and a lot of patience and a spare pair of hands:

Socket set
Spanners
Couple of screwdrivers (flat and cross-head)
Container to empty petrol into
Clamp-able pliers
Trolley jack or two
Axle stands
Waxoyl (Spray version) - optional
3M Scotch Weld 80 Spray Adhesive - optional



THE HOW TO


(Amateur mechanic Job Time approx: 2-3 days)

You want to start by emptying the fuel tank as much as possible before you start. I did this by driving the car until the fuel light came on solidly on the dash.

The next thing to do is disconnect the battery, as fuel and sparks don't mix.

Now undo the fuel cap to release any vacuum or pressure in the fuel tank.

Next slide under the rear of the vehicle and locate the main hose between the lowest point of the fuel tank and the fuel pump. If you have a fuel clamp or a pair of clamp-able pliers then clamp the hose nearest the fuel pump and proceed to undo the jubilee clip that fastens the hose the fuel tank.

Below is a photo of the fuel pump with the main hose removed.

With the jubilee clip loosened get your empty container positioned below the tank to catch the remaining fuel. Wriggle the hose off the fuel tank and catch all the excess fuel until completely drained. You can now undo the much smaller hose that is also connected to the lowest part of the fuel tank.

Jack up the rear of the car as high as possible and set it on axle stands.

Now remove the rear section of the exhaust by undoing the 3 connecting bolts on the exhaust tube in the centre of the car and then unhook the rear box from its rubber hangers (shown below).

Next remove the four bolts that secure the exhaust heat shield (shown below) to the underside of the car.

Now remove the transmission (See this post for instructions)

Now it's time to get inside the car. Start by completely removing the carpet from the boot area.

Next pop out the rear quarter window on the fuel cap side and completely remove the interior panel of the same side (See this post for instructions)

Lay down the rear seat and un-clip and pull back the carpet from around the side of boot of same side to expose the fuel filler cover (Shown below)

Undo the surrounding screws, not forgetting the two small nuts at the base of the cover. Then as shown in the photo above position a screwdriver in behind the cover either side and pull towards you. The cover may resist at first because of the black goo it is secured with, but it will come away eventually to expose the filler hoses (shown below).

Undo the jubilee clips on all the hoses and pull off, with the exception of the largest hose which you can slide upwards to reveal the corner inlet of the fuel tank.

Now lift the large silver heat shield square located on the floor of the boot to expose the plastic cover for the fuel sender. Prise this up to in turn expose the sender wires. Make a note of what wire goes where and disconnect them all (shown below).

Get back underneath the car and locate the two large straps at either end of the fuel tank (shown below)

Undo the bolts and unhook the straps, the fuel tank is now only supported by the steel cross member it is wedged over.

Get your hands behind the rear most edge of the fuel tank and pull down. Keep wriggling the tank up and down checking that the fuel filler hoses aren't trapped. This part takes a lot of effort and patience as the tank is an extremely tight fit over the cross member and has probably never been removed before. Trust me the tank will eventually come free. You may need to unbolt the fuel pump from its rubber mounts if it gets in the way.

With the fuel tank removed we can now clearly see the fixed cross-member that stretches the width of the car underneath and the fuel filter bottom right (shown below).

As stated at the beginning of the post I decided to source a replacement tank from a breakers yard, it had a bit of dent in the side and some surface rust that I cleaned off. I then Waxoyled the whole tank to prevent further corrosion. I would also recommend you get them to pressure test the tank as I did. This helps prevent the problem of putting a tank back on that is the same or worse than the one that came off. It may also be worth checking the condition of the rubber hoses as they may have started to perish and go hard after 24 years of use and replacements would probably be a good idea.

Here are a few photos of the replacement non-leaking tank that I sourced from a breakers (note the expansion tank hanging off the bottom of the photograph and the fuel sender top left in the first photo).

Not shown in the photos is the large foam pad that sits around the fuel filler neck part of the tank. I carefully removed this before spraying the tank with Waxoyl. It was then finally put back on and stuck down with 3M Scotch Weld 80 spray adhesive before the tank was reinstalled.

Tank installation is the reverse of removal.

For more information on the steel fuel tank cracks and repair procedure if you can't source a replacement tank then follow this forum post. It also shows the differences in dimensions of the early and later 944 tanks side by side.

How to remove and replace the headliner on a Porsche 944

THE WHY?

If you've owned your 944 for a while and like me searched the internet to discover the pros and cons of owning one then you've probably discovered that the sun roof mechanism can become a little troublesome after 20 odd years of use. This often requires investigation of the gears and worm wheel mechanisms behind the rear headboard where the lifting arms are located. Unfortunately this also requires you to either peel back the headliner or cut holes in it so you can get at the mechanisms. Inevitably the headliner often tears leaving the inside of the car a little less than perfect (See below).

THE TASK

Philips screwdriver

Flat head screwdriver

Fat & thin rolls of double-sided sellotape

New headliner material

Lots of small bulldog clips (I used about 24!)

Scalpel (or craft knife)

Hair dryer or heat gun (optional)

THE HOW TO

(Amateur mechanic Job time: Approx. 1 day)

(Part 1 - Removing the headliner)

Start by picking a nice sunny break in the British weather and start as early in the day as you can, you'll need it to do a proper good job. It may be worth noting that if your sun-roof isn't working and you plan on fixing it then I'd do it before you install a new headliner. My sunroof repair guide will be up shortly.

Firstly completely remove the sun-roof from the car, this won't be going back on until the very end. Now unscrew the dozen screws that hold the rear headboard on and remove it.

Beneath it you should see headliner material stretching all the way to back window seal or like mine you will see the sunroof mechanism because the headliner had already been previously messed with.

Now turn your attention to the screws securing the sunvisors, remove all of them along with the sunvisors.

 

Next unclip the rear view mirror from the windscreen and prise out the cabin light that sits above where the rear view mirror was and disconnect the blade connectors and tape them up with insulation tape (We don't want any cabin fires). Tip: Use a flat-bladed screwdriver to prise the side out opposite to the switch first.

 

Now you're ready to remove the sun roof wind deflector. Start by prising out the microswitch button in the centre mount as shown in the photo below.

Here's the underside of the button once removed, you can see the two tabs at the longer end that hold it clipped in place.

Here's what the centre mount looks like with the button removed, note the screw in the centre and remove it.

Now you're ready to remove the mounts at either end of the wind deflector. Unscrew them and be careful to support the weight of the wind deflector as there are two fragile wires attached to the microswitch beneath the centre mount.

You should find that the only thing keeping the wind deflector attached to the car is now the two wires, either cut them and connect them back together later like I did or spend ages trying to prise the delicate microswitch out of it's housing. (Wind deflector completely removed below)

Now unscrew the two recessed mounts where the sun roof would usually clip into and you're ready to remove the front headboard.

To remove the front headboard get your fingers in along the edge that is closest to sun roof opening and gently but firmly pull down. It feels like you are going to break the headboard but it's just because it's been stuck there for 20 odd years. There is a little adhesive underneath it so you will just need to tug and wiggle it free. You may find it is really sticky along the the windscreen edge, just be careful and patient. (Photo below shows front headboard removed)

With the front headboard removed you can now carefully lift up the rubber trim that goes all the way around the hole left by the sun roof, being careful not to bend it.

After that it's time to remove the rear quarter windows. From the inside of the car start by getting a flat bladed screwdriver underneath the lower corner (nearest the rear of the car) of the rubber around the window. Once you have enough lifted to get your fingers underneath then do so. With your other hand begin to push that same corner outwards whilst peeling back the rubber further around the window. Once the window is half out move to the outside of the car where you can pull the window out. Be careful of the rubber running down the side of the doot pillar as it hooked over a lip of sorts on the outside of the car. 

Now go back inside the car and remove the little clothes hooks that are attached to the door pillars. You can also pull away the rubber seals around the edge of the door openings. You don't need to do the whole door, just enough so you can expose the edges of the headliner.

Now you just need to roll down the lining that is wrapped around the door pillar just enough expose the end of headliner, as we will be reusing this as it is not damaged.

Finally pull away the rubber seal around the top of the rear hatch opening.

You can now finally pull away all the old headlining from inside the car (Photos below show the headlining completely removed).

 

 

Depending on the condition of the headlining you may be able to salvage it and use the template to make your own headliner. Here's what the old headliner looked like once removed, pretty shabby.

And the now the new one I bought from ebay.

(Part 2 - Installing the new headliner)

Being the first headliner I've ever installed it was pretty much trial and error, but the end result was well worth it for the cosmetic difference it made to the inside of the car.

To begin with you will need to gather a suitable pile of bulldog clips (clothes pegs may even work), the more you have the easier it will be. Get 1 wide and 1 narrow roll of double-sided tape and a craft knife.

Step 1.

Start by loosely clipping the new headliner around the inside of the sun roof opening.

Step 2.

Make sure the parts of the headliner that go around the door pillars are sitting central on the pillar, remove and adjust the clips until you have got this spot on.

Step 3.
Remove the clips along one of the shorter edges of the roof opening and apply a strip of the narrow double sideed tape over the lip. Stick the headliner to it and re-clip. Repeat on the other side.

Step 4.
Now along the longer edges of the roof opening one at a time do the same as step 3 with the double-sided tape and re-clip. If the material doesn't seem to be fitting at the corners, don't cut or trim it just yet as you want to leave it until the last possible moment. You can always peel back the liner and re-adjust as you go along.

Step 5.
Stretch the headliner towards the back of the car around the rear hatch opening. Again clip it along the entire length until you are happy with the fit.

Step 6.
Move onto the liner around the door and quarter window. Depending on the material you have you may need to use a heat gun or hair dryer to get it to stretch around the door pillar.

Step 7.
We are going to leave the front section right until the end as it takes care of itself when the front headboard and fittings go back in place, so leave it for now. Instead concentrate on getting the fit and stretch right all the way around the rest of the car re-adjusting where necessary and adding double-sided tape as needed. Once you are satisfied with the outcome you can begin to trim some of the excess material away and reattach the rubber trims. Begin by re-applying the sun-roof rubber trim as everyything stretches away from it making sure you fold a little of the excess headliner over the trim lips and edges.

Step 8.
Re-apply the rear hatch rubber.

Step 9.
Roll up the lining on the pillars before re-fitting the quarter windows. Make sure the pillar edge of the window pushes in first starting with the bottom corner. Use a screwdriver to pull the rubber over the lip from inside the car (work your way around from pillar edge bottom corner to hatch bottom corner to top hatch corner and finally to pillar edge top corner) until the window is back in place.

Step 10.
Make two holes in the headlining so that the wires for the sun-roof switch and interior light can poke through.

Step 11.
Trim the headlining around the windscreen pillars and tuck behind the the trim on these where necessary. Now take the headboard and manouvre it into place. Take one of the sun visor clips and screw it into place. Do the same with the other. Re-attach the sun-visors completely.

Step 12.
Re-connect the wind deflector microswitch wires and re attach the wind deflector.

Step 13.
Re-attach the sun-roof clip housings.


Step 14.
Re-attach the clothes hooks to the door pillars.

Step 15.
Re-attach the rear headboard making sure you've trimmed enough of an opening for the sun-roof lifting arms to poke through the headlining.

And now the finished article.

How to repair heater control valve on a Porsche 944 (Square Dash Model)

THE WHY?

One of the good things about the 944 is that it doesn't take long for the engine to warm up, which is great in the winter when you need to de-mist the inside of the windscreen and heat the passenger compartment. However it's not so good in the summer if like mine your heater is always giving out hot air even when the heater slider is set as far over to the left handside (the cold setting) as possible. This is caused by usually one of two possible problems. Either the hot/cold slider has a broken cable or the heater control valve (HCV) is faulty. It is usually the heater control valve (HCV).

THE TASK

It is important to note here that the HCV and heater mechanism are completely different on the square dash 944 model to the oval dash 944 model. Oval dash owners should look here and here as this guide is only for square dash owners.

This job is relatively simple (if a little fiddly) and should only take an hour or two.

You will need the following:

Long & small flat bladed screwdrivers
Long-nose pliers
Heater Control Valve (approx £20 from Porsche main dealer)

THE HOW TO

(Amateur mechanic Job Time approx: 1-2 hours)

Firstly it's important to know what the HCV actually does. The HCV is basically a tap that allows hot water from the engine to enter the heater matrix. When you set your heater to hot the tap opens and lets hot water into the matrix and when you set it to cold the tap closes stops the hot water entering the heater matrix.

It's also important to understand how the heater controls work on a square dash 944 as I've seen alot of confusion over this on some forums. There are 4 controls for the heater. This is what they do:

Upper left slider controls the direction of heat (footwell & centre)
Upper right slider controls the direction of heat (centre & windscreen)
Lower slider controls the hot or cold setting
Dial to the left of the sliders controls the fan speed (Off & speeds 1,2,3)


To begin with it's important to make sure the cable that goes from the hot/cold slider to the HCV is not the fault. Start with the lower hot/cold slider all the way over to the cold setting as shown below.


Now open the bonnet and locate the heater control valve which sits tucked down at the back of the engine smack bang in the centre. Below is a picture of the heater control valve.


Because the heater slider is set to cold the heater control valve should have its white arm all the way over to the left hand side (as shown below). You can even see the cable extended.


Now go back inside the car and move the hot/cold slider all the way towards the hot setting. Go back and look at the HCV and you will now see the white arm has moved all the way over to the right (as shown below).


If the white arm of the HCV is not moving then your problem is with the cable. Either the cable has become disconnected at the HCV end or at the hot/cold slider end. Or the cable has broken in the middle somewhere. If the arm is moving you now know that it is very likely that the HCV is the fault.

To remove the HCV you will first need to remove a small metal clip that locks the black outer of cable to the HCV. Do this with your fingers or a pair of long nose pliers. DO NOT LOSE THE CLIP otherwise the cable will not be able to work the HCV. Now unhook the inner cable from the small hole at the end of the white arm on the HCV. Next you will need to undo the 2 hose clips that help secure the 2 hoses to either side of the HCV. Once this is done twist and wriggle the HCV loose from the hoses. Do not be alarmed if water comes out of either hose whilst doing this, just make sure you don't allow the lower of the two hoses to hang down once you have removed the HCV as water will go all over your clutch, just wedge it so that it's upright.

Below is an image of my new HCV (left) against the old HCV (right). Note the washer in the middle that appears to have come loose inside in the old HCV.


You are now ready to install your new HCV. Installation is the reverse of removal. By far the hardest and most important part is re-attaching the metal clip around the black outer of the cable, it took me several attempts and you might be advised to familiarise yourself with how the clip works with the HCV before you attach the hoses to the new one.

One last important thing is that you may or may not have to top up your coolant level as some will be lost when you removed the HCV.

How to remove sound absorber from the bonnet / hood of a Porsche 944

THE WHY?

The benefits of removing and replacing the sound absorbing material from the hood is that it prevents the engine heat from damaging the exterior hood paintwork, it absorbs some of the noise from the engine and also stops the old material depositing itself all over engine bay.

THE TASK

This is one of those jobs that there's no easy or quick way of doing, it purely comes down to sweat and elbow grease. Saying that anyone can tackle it, you just need patience and determination. Allow about 8 hours to remove all the sound absorbing material.

You'll need the following:

Plastic edged scraper (I used a white body filler spatular)

A large plastic or disposable sheet - to cover the engine bay

Cellulose Paint Thinners (I used 4 bottles of this!)

White Spirit

A mini roller and tray (use the cotton roller, not the sponge type)

Something to scrape the gunk into - I used a dustpan

Some latex gloves to keep the gunk off your hands

THE HOW TO

(Amateur mechanic Job time : Approx 3 hours per side)

Firstly cover the entire engine bay with a sheet otherwise it'll be a nightmare to clean all the old gunk off afterwards. Now unlike mine yours might still have all, some or bits of the original sound absorbing material clinging to it, so remove as much of this as you can until you're left with about 1mm of the combined glue and foam layer.

Now the fun begins. You need to soften up the dried glue and foam layer by rollering on the cellulose thinners in 30cm sections several times over and then quickly scraping this off with the plastic scraper until you are left with just the glue. Repeat as necessary. If you look at the image below the right hand section is after the cellulose thinners has been used and the left hand section is still to do.


Now, once you're left with just the glue on both sections we switch to the white spirit and use the same method of rollering it on. You can afford to do larger sections with the white spirit as it doesn't evaporate as quickly as the cellulose thinners. The picture below shows the glue completely removed from the left panel using the the white spirit.

And now the finished article....



Now, see my post on how to install new sound absorbing material here