Originally Posted by Mike in CA

So I just did a DIY post break-in oil change of my 991 GT3 and thought I'd share some information from the experience with those who might be interested. Before I get started, I'd first and foremost like to thank John (911slow) our esteemed moderator, who provided me with information on the procedure. I'd also like to give kudos to Aldo at Suncoast, with whom I worked to straighten out some issues with getting the correct parts included in their 991 GT3 oil change kit.

Why DIY? Well, in addition to saving a coupe of hundred dollars there's the satisfaction of doing the work (I like to think of it as fun stuff) on your car yourself. In my case it's a 45 minute drive to the nearest dealer so in addition to being enjoyable it's actually more convenient. Anyway, whatever the reasoning, if you're interested in changing the oil in your GT3 yourself, read on. Some of this may be obvious to those who regularly do their own changes….

What you'll need:

8 quarts of Porsche approved engine oil (I use Mobil 1 0W40)
Spin on Porsche OEM filter 9A1-107-203-90
Sealing ring for sump plug
Sealing ring for oil tank plug
8mm Allen/hex key
T30 Torx bit or driver
oil filter tool
oil catch pan (12qt is a good size)
container for used oil

Preliminary stuff:

You're going to need to get at least an additional 3-4 inches of clearance under the car. More would be better. Whether you have a lift or use a low profile jack and jack stands or make your own ramps out of 2x12 or similar I recommend keeping the car level as opposed to just lifting the back end. You'll be sure to get all of the old oil out that way. It's particularly important because the overfill tolerance on the 991 GT3 is tight. If you leave any oil behind it will be more difficult to accurately gauge how much needs to be put back in. I never drain the oil cold. It flows better with some heat in it and you'll be sure to capture any impurities that may have settled out with the oil sitting in the pan and oil tank.

So to begin:

Once the car is off the ground safely and securely (not just on a floor jack) you're ready to start.

1. Remove engine guard/diffuser. Remove 11 screws with Torx T30 driver or bit. Tip: Remove the screws around the perimeter first. Make the last screw you remove one of the center ones; the guard won't tip as you remove the other screws and you won't have to balance the guard with one hand until you take out the last screw. EDIT Later models have a plastic retaining clip in the center of the engine tray that my car didn't have so after you remove the 11 Torx screws the tray is still in place. To release the retaining clip push up in the center to release a pin, then the clip can be removed.
2. Lift the engine lid and remove the oil filler cap. This is per the spec and will facilitate oil draining.
3. Position your catch pan under the oil tank. Loosen the oil tank plug with the 8mm hex bit and unscrew by hand. Make sure the old sealing ring isn't stuck to the tank. Wear latex gloves. Oil will gush out so be careful. Avoid scalding from hot oil.
4. Once the oil from the tank begins to trickle you can slide your catch basin over far enough to be ready for draining the sump. Loosen the sump plug with the 8mm hex bit. EDIT You will find two drain plugs in the sump, one at the front and one at the rear, plus the oil tank drain plug. For the sump, the workshop manual only mentions removing the front plug and that's what I did, but you can obviously remove both if you choose.
Same cautions as step 3 although the oil flow isn't as dramatic. Tip: The profile of my ratchet made it very difficult (no, impossible) to get a straight shot on the oil pan plug with my 8mm hex bit due to other parts in the vicinity of the plug. Neither a straight or angle extension worked either. I had to remove the hex key from the socket and then use a crescent wrench on the key with it inserted in the plug. EDIT There are "stubby" allen wrenches available that will make removing the drain plugs easier. You can find them here: http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
5. A second small catch pan will come in handy as you remove the oil filter. It's possible a band type oil filter wrench might work, but the space you have to work in is small. To avoid problems I purchased the specialized low profile Porsche oil filter tool from Suncoast which fits over the end of the filter ($55). It accepts a 1/4 ratchet drive, but again none of my ratchets would fit in the available space. The trusty crescent wrench worked fine over the 27 mm hex fitting on the tool. Loosen and remove the filter.

Let everything drain for a while. I give it enough time for almost all the dripping to stop; about 1/2 an hour or so which coincidentally was enough time to have lunch…..moving on…..

6. Install the new filter. Put a light film of clean oil on the filter gasket and spin the filter on. Recommended torque is 15 ft/lb but I challenge anyone to get a torque wrench on the sucker. My recommendation is to tighten it as much as you can by hand, then use the tool to give it another 1/4-1/2 turn . Don't over tighten!
7. Reinstall the oil pan plug with a new sealing ring. Torque is 30 ft/lb but given the issues in step 4 above, getting a torque wrench in the available space will be difficult. In the absence of a torque wrench, tighten firmly but again, don't over tighten. It's a steel plug in aluminum threads and you don't want to lean on it and risk stripping them.
8. Reinstall the oil tank plug with a new sealing ring. Recommended torque is 22 ft/lb.

Finishing up:

9. Add oil. The tolerance between minimum level and overfill is small; only .5 quart. Oil capacity with filter change is 7.5L or 7.92 quarts. To avoid overfilling (which can damage the catalytic converter) I initially added a bit over 7 quarts. EDIT I've changed that to 7 quarts even to avoid confusion over what a "bit" is. Also, the engine is so sensitive to overfilling that I think it best for people to be more conservative. Once the engine is up to temperature and you can get a good measurement on the gauge you can add more if necessary. Be sure to replace the oil cap.
10. IMPORTANT. Mentally double check that the plugs and filter have been tightened up. Make sure that all rags or towels that may have been used to sop up oil are removed from the engine. (Fire risk!) While the engine guard is still off start the engine and check for leaks.
11. If all is well, reinstall the engine guard. Start with the screws in the middle. The screws are steel and the oil pan is aluminum so take care. Start all the screws by hand then tighten with the T30 Torx bit. The tightening spec is 7.5 ft/lb but you just want the screws snug against the rubber washers attached to the guard.

Car back on the ground and you're done. (except for the cleanup!)

It actually took longer to write this than it did to do the change, if I subtract the time I spent figuring out a couple of things and taking pictures and notes. Next time, from start to finish I don't expect the whole process to take much more than an hour. It's really one of the easier engines on which to do a DIY oil change. Give it a try.

For reference see the legend below and the pictorial for the correct oil levels on the gauge.

A - Oil level maximum reached
B - Oil level minimum reached
C - Recommended oil level for optimum engine operation
D - Oil level below minimum
E - Oil level above maximum

Originally Posted by Jickel180

For the .1s that have a G series motor replaced. Which oil filter do we order? Same as the .1 RS now (if it's any different)?

Originally Posted by GrantG

If you look here, you see there are 3 different oil change kits:

https://www.suncoastparts.com/product/991GT3OFK.html

I think the 2014-2015 models use one filter and the 2016 use the newer filter (and 2018+ use new filter plus a larger oil drain plug on the sump).

If you have a factory replacement - check the part number on the factory-installed filter when removing.

I would assume the G corresponds to the filter used on the 2016 (newer - I think part number ends with a "1").

Originally Posted by ljahearn

A .90 came off of it (last oil change was done as part of CPO recert 1 year ago) so a .90 went back on it.

Originally Posted by derdasf

Hello all. I am a recent new owner of a 2018 GT3 and a new owner of my first Porsche. This is a great thread and thanks to all who have contributed. Over the many years i have enjoyed building and working on my own vehicles. Primarily i have been an American Muscle Car enthusiast and as i stated earlier did a lot of work on my own. So we (son and I ) ventured out to do the first oil change. That went very well based on the insight gained from this thread and my own experience. However, I have several questions for those of you more experienced in the flat six world.
1. I switched from Mobil 1 0W-40 to Motul 8100 Excess 5W-40. I must say the engine sounds much better at idle, smoother, less mechanical noise and overall seems to like the change.
Question: Even though all seems well, I have noticed increased oil temps of any where from plus 10 to plus 20 degrees for the same water temps as prior. In fact the other day (94 degree day) i saw both water and oil temp hit 210 and 218 respectively while idling. I have driven in temps at 94 degrees prior to with 0W-40 and did not see these temps. Has anyone else experienced this when switching to 5W-40?
2. Besides the higher temps, on my way home this evening, (80 degrees outside) water temp was recording 173 degrees (first time I have seen that low) and Oil at 198. 198 degrees in my opinion was reasonable however never saw a water temp that low with an oil temp at 198 after driving for awhile.
Question: Is there a way to run a check on the sensors through the computer to ensure accuracy and the sensors are reading nominally? In other words a self test that indicates sensors are in range and reporting correctly?

Thanks for any responses in advance.

Originally Posted by derdasf

Hello all. I am a recent new owner of a 2018 GT3 and a new owner of my first Porsche. This is a great thread and thanks to all who have contributed. Over the many years i have enjoyed building and working on my own vehicles. Primarily i have been an American Muscle Car enthusiast and as i stated earlier did a lot of work on my own. So we (son and I ) ventured out to do the first oil change. That went very well based on the insight gained from this thread and my own experience. However, I have several questions for those of you more experienced in the flat six world.
1. I switched from Mobil 1 0W-40 to Motul 8100 Excess 5W-40. I must say the engine sounds much better at idle, smoother, less mechanical noise and overall seems to like the change.
Question: Even though all seems well, I have noticed increased oil temps of any where from plus 10 to plus 20 degrees for the same water temps as prior. In fact the other day (94 degree day) i saw both water and oil temp hit 210 and 218 respectively while idling. I have driven in temps at 94 degrees prior to with 0W-40 and did not see these temps. Has anyone else experienced this when switching to 5W-40?
2. Besides the higher temps, on my way home this evening, (80 degrees outside) water temp was recording 173 degrees (first time I have seen that low) and Oil at 198. 198 degrees in my opinion was reasonable however never saw a water temp that low with an oil temp at 198 after driving for awhile.
Question: Is there a way to run a check on the sensors through the computer to ensure accuracy and the sensors are reading nominally? In other words a self test that indicates sensors are in range and reporting correctly?

Thanks for any responses in advance.