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 change transmission oil on a Porsche 944

THE WHY?

If your 944 is 25 years old like mine with just over 120,000 miles on the clock then you may have noticed that the gear changes are not as smooth as they once were or maybe your gearbox is whining a bit. Then it's quite possible your gearbox / transmission needs some fresh lubricant.

THE TASK

Quite a simple one really. This is what you'll need.

17mm Hex bit
Torque wrench
Anti-seize thread lubricant
Swepco 201 gear oil (Approx £50) - You get 3.8 Litres in the bottle, the transmission needs 2 Litres
A large syringe
Bowl to catch old lubricant

THE HOW TO

(Amateur mecahnic Job Time approx: 1 hour)

If your transmission is still attached to the car then it's probably best to give it a 10-15 minute drive to warm the old oil up so that it flows out more easily. My transmission was already off the car so I just had to make sure it was on a level surface. The transmission is located under the rear of the car. Take an empty bowl and place it under the left hand-side of the transmission ready to catch the old oil. On the left side of the transmission you will find two identical oil drain plugs situated to the right and below the drive shaft mount.

Start by cleaning off any dirt or rust around the threads on both drain plugs, give them a spray of penetrating oil too. Remove the upper plug first (in case the lower one is seized then you haven't lost all your oil with no way of putting fresh oil back in). Then remove the lower plug using a 17mm hex key, the oil should then start to flow out. Once all the old oil has flowed out stick your finger in the hole and feel around checking for metallic particles left in the bottom of the transmission. If there are then your tranny may need a little more attention than just an oil change. Now is a good time to inspect the condition of the drain plugs. Mine were pretty old and roughed up so I decided to change them for new ones, only a couple of quid each from Porsche. Notice the tapered thread on the drain plugs.

Now apply a little anti-seize thread lubricant to one of the drain plugs and tighten it into the lower hole to a torque of 20Nm. Now fill the syringe with Swepco 201 gear lube which I bought from here and pump it into the upper right hand hole. Repeat until the oil comes level with the bottom of the hole you are putting the oil into. Once you're there apply the same anti-seize thread lubricant to the remaining drain plug and tighten to 20Nm. Job done.