Porsche 944 Camshaft Gasket Replacement Procedure

THE WHY

The trouble with fluid leaks is that it often takes some work deducing what fluid is leaking (water, engine oil, brake fluid, power steering fluid - to name a few) and where it is coming from. Having previously cured and therefore eliminated two fluid leaks on my 944 (power steering reservoir bottle and one from the OPRV Oil Pressure Relief Valve area) I was determined to get to the bottom of the next one. In this particular case unlike the previous fluid leaks (somewhere above the removable engine floor pan) this one was clearly coming from the rear of the engine and making its way down the back of the grilled engine sump. Being the middle of the week I thought I'd make a post on the Pelican Parts forums to see if anyone had some ideas as to where I should be looking. The response was fantastic.

THE TASK

10mm Socket
Small/Medium Socket Ratchet
Small/Medium Torque Wrench
Multi-purpose engine grease
800 Grit Emery Paper
Degreaser
Camshaft Gasket ( Part No. 9281058902 )

THE HOW TO

(Amateur mechanic job time approx: 1-2 hours)

Here's the picture I posted to the Pelican Parts forums, you can see the dark oily trail down the back of the grilled sump.

As I said earlier the response by the board members was fantastic and if you read the post it seemed pretty clear the oil was coming from one or more of four possible places.

The possibilities were:

A.) The cam gasket housing
B.) The lower balance shaft plug o-ring
C.) Balance shaft housing to block sealant
D.) Oil pan gasket

Judging by the discussion, possibility 'A' was the first thing to check after having taken photos of all the surrounding areas. Apparently the gasket is made of cork and doesn't have particularly long lifespan. Here's a picture to show the culprit area.

The cam gasket sits between the cover and the main head block at the back of the engine bay (circles below).

The easiest way to check if it is leaking is to get you fingers under the lowest edge of the cap and check for oily matter running down the back of the block. If like me you find some then wipe it dry and then give the car a good drive before you check again. If the oil has returned you know the gasket needs replacing.

As per a suggestion on the forum I followed the description on Clarks Garage (right at the bottom of the article titled "Rear Cam Housing Gasket Replacement)

Removal of the cam gasket and cap is fairly straight forward and involves undoing 3 x 10mm bolts, the lowest one is a bit difficult to get to so you will probably need a small 10mm socket and ratchet. With the three bolts undone and a little wiggle the cam cap and attached engine hoist loop will come off in your hands.

As you can see from the following two pictures there is a clear amount of oil present on the lower edge of both the engine hoist loop and cam cap cover.

(Engine Hoist Loop)

(Cam cap cover)

Now turning the cap over shows the charcoal-like remains of the cork gasket itself

Without scratching the metal surface of the cap try to remove the old pieces of gasket with a blunt object like a plastic scraper or bicycle tyre lever.

Next I cleaned up the cap with some degreaser and then laid down some fine 800 grit emery paper on a flat surface and lightly rubbed the flat mating surface of the cap to remove any fine pieces of gasket and dirt.

Here's a picture of the new OEM gasket from Porsche.

And here it is alongside the cleaned-up cap

Now take a small amount of engine grease and lightly coat one side of the gasket before aligning it on top of the cap. This helps create a good seal as well as aiding the re-installation procedure.

Next I cleaned up the surface of the engine block with some blue tissue paper making sure there was no old bits of gasket, oil or dirt.

Before installing the cap make sure you apply some more grease to side that will pressing against the block as well as remembering to attach the engine hoist loop. Do all three 10mm bolts up to finger tightness and then STOP.

This bit is very very important. The bolts must be correctly tightened using a torque wrench to 8 Nm (6 ft-lb). This is very important to make sure the cap seals evenly all round. Again I would suggest you get yourself a small/medium sized torque wrench as the bottom 10mm bolt is very awkward to get to.

And finally a picture to show the finished result.

How to remove and replace OPRV (Oil Pressure Relief Valve) on a Porsche 944

THE WHY

Since purchasing my 944 I'd always been aware of a slight fluid leak, but since none of the fluids (engine oil, power steering, water, brake fluid) seemed to be disappearing at any great rate and there were other more pressing issues I decided to put investigating it on the back burner.

Having now decided to tackle the problem I firstly discovered I actually had two fluid leaks, one from a power steering hose going from the reservoir to the pump which I dealt with right away by replacing the hose. The second however seemed to be coming from the engine but it was difficult to tell where from due to the oily grime all over the bottom of the engine and aluminium floor tray. So now the rest of the story follows how I went about identifying the cause of the oil leak and how the OPRV (Oil Pressure Relief Valve) fits into the story.

THE TASK

You'll need the following:

Karcher or other brand Water Pressure Washer
Gunk Spray Engine Degreaser
10mm socket
17mm socket (if you have the old style OPRV)
24mm socket (if you have the new style OPRV)
Ratchet socket wrench
Long socket wrench extension bar
2 x Axle Stands
Trolley Jack
Torque Wrench
Plenty of tissue or old rag

THE HOW TO

(Amateur mechanic job time: approx. 30mins - 1 hour)

Start by jacking up the front of the car and support on the first or ideally second stage of the axle stands.

Remove the seven 10mm bolts that secure the aluminium under-tray to the bottom of the car and remove the under-tray.

The picture above was taken after I'd degreased the underside of the car. I tried various methods of scrubbing, wiping and pressure steam cleaning but by far the best was pressure washing.

The best method I found was to let the engine run for 10 mins to warm it up, then spray Gunk Engine Degreaser over all the oily blackness you may have (Do not spray it near the belts or any bearings). Let the degreaser have 5-10 mins to take effect and then simply blast off with the water pressure washer (There's hardly any electrics on the bottom of the car but avoid them at all costs). Spraying the washer in quick bursts is the best method. Repeat as necessary and wipe down anything that looks oily, not forgetting to also clean all the oil of the under-tray too.

Now you have a clean canvas to identify your leak. Unless the leak is bad you probably won't be able to see it straight away, so this is where some patience comes in. Either leave it jacked up over night and see if you can identify a drip in the morning or re-attach the under-tray and do a few miles to put the engine under load which usually force the oil out of the place it is escaping. When you jack the car up again, you'll be able to see the area where the oil is dropping on the under-tray and then just trace it back up into the engine well.

The oil on mine was falling onto the left hand-side of the under-tray so I started to investigate in this area as shown my the orange arrow below.

This is where I found a drip coming off the end of the OPRV (Oil Pressure Relief Valve) nut.

Here's a couple of photos to show you what to look for (The nut has been removed but you can see the port it screws into)

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THE OPRV - here's where it gets complicated:

83-86 models will have a 17mm or 24mm nut
87 models onwards will and should always be 24mm.

Picture shows the difference between the 24mm on the left, 17mm on the right.

The 17mm nut may also look like this one below as well (photo taken from another Porsche source)

If you have the 17mm nut then you have the OLD discontinued OPRV, which can look like one of the two versions shown below (Difference is in the style of the nut and and piston). There are 4 pieces to each version, the nut, aluminium washer, spring and piston.

From the 87 model onwards a new OPRV was produced along with a retro-fit upgrade for people with the old style valve.

Here's the NEW retro-fit valve (944 107 035 11) for 83-86 models

And here's the one (944 107 035 02) for 87 models onwards

 And here they are side by side, 83-86 on left, 87 on right. (Main differences are in overall in length and the taper on the thread).

Both these newer style valves are serviceable to a degree in that you can replace the external and internal O-rings using this procedure below which was posted by a kind chap on the PelicanParts forums. Note valve type A requires two different size O-rings for the internal and external, whereas type B uses the same size O-ring for the internal and external.

The photo below shows what one of the newer OPRV's looks like when you take it apart. Note the aluminium sealing ring far left, damaged black internal O-ring in the middle and what should be a thicker green O-ring at the end (also damaged). If you need to replace the entire valve they aren't cheap either, £250 from Porsche.

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OPRV removal

Take a 17mm or 24 mm and socket extension bar that should be long enough to enable you to ratchet it from inside the wheel arch.

Once I had it removed I ended up with this

Notice the small nut that was inside the piston that some previous enterprising owner/mechanic had used as a space packer. I also found the spring to be 3-4 coils shorter than it should be, so who even knows what vehicle it was from. So not only did I have a leak from ORPV, I now had to replace the OPRV and at £250 that's quite a hit.

So here we are the OLD alongside the NEW

Installing the new OPRV is the reverse of removal, making sure you use a new aluminium sealing ring and lightly oil the o-ring and length of the valve to aid it's insertion. You should then use a Torque wrench to tighten to 45Nm.

Finally re-install the under-tray, run the car making sure the oil pressure gauge doesn't exhibit any strange behaviour and you're done...........well almost.

After doing all this I still found I had more oil leak coming from the same area, it now looks likely it's the gaskets for the Oil Cooler that the OPRV screws into. This looks a bit of an ugly job and not having the time to do it I'm going to get a mechanic to sort it out. For anyone that wants a go here's the procedure and here's another.

Finally here's the Porsche bulletin that goes into a few pages of detail on the OPRV. (Click the pictures for larger versions)

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.