991 coolant flush
05-03-2016, 08:49 PM
#1
Rennlist Member
Thread Starter
991 coolant flush
Anyone have a DIY procedure or link for draining and re-filling the coolant on a '14 991 3.4L?
I did some searching here and on Youtube but did not find much.
I did some searching here and on Youtube but did not find much.
05-03-2016, 10:38 PM
#2
Rennlist Member
If I may ask ..... why do you want to change the coolant?
05-04-2016, 02:53 AM
#3
It's my understanding that you need a PIWIS II tester in order to open all the valves and cycle the pump in order to flush the coolant. The cooling system in the 991 is very complex with all sorts of baffles and heat exchangers to promote faster warm-up and better efficiency. Plus with all the plumbing to run the coolant to the front radiators there's no single low point to drain from.
05-04-2016, 10:55 AM
#4
Rennlist Member
Thread Starter
05-04-2016, 11:01 AM
#5
Rennlist Member
Thread Starter
It's my understanding that you need a PIWIS II tester in order to open all the valves and cycle the pump in order to flush the coolant. The cooling system in the 991 is very complex with all sorts of baffles and heat exchangers to promote faster warm-up and better efficiency. Plus with all the plumbing to run the coolant to the front radiators there's no single low point to drain from.
05-04-2016, 11:56 AM
#7
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I'm hoping this pro-active step is not so necessary on the 991 like it is on the 996 and 997 series. Time will tell. I'll probably have my coolant done at about the 6 year mark (70,000ish miles). This will give me time to see if the pump should be done proactively, after we see a few more years of service life info and common mods of failure.
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05-04-2016, 11:58 AM
#8
Burning Brakes
Not exactly correct Arcoril..... The PIWIS tool is only used for the bleeding process, but you can drain and refill coolant without it (but you SHOULD bleed with any refill!). There are multiple drain points, but no need to cycle fluid through "baffles or valves". When filling, you will need a vacuum tool (Porsche lists "filling device 9696 for vacuum-filling). I am guessing any decent vacuum tool would be sufficient.
I think this might have been described elsewhere, but just for those curious about the process....
Of course, make sure the coolant is cool before doing any of the following!
Prelim work:
From Engine
Using a vacuum filler, connect the filler and return hoses, and set the pressure level to 8 bar. If you need help with vacuum filling, that is for another post....
Once you get the refill done, simply replace the underbody panel, wheel well liners and front wheels, and you are good to go! (Of course you should BLEED the system, which is where you'll likely need the PIWIS tool).
Disclaimer- I don't recall if there are any additional steps for the third, center or X51/PowerKit radiator. Could be that you will have to remove the front bumper cover to access the hoses, but should be just like the process for side radiators....
I think this might have been described elsewhere, but just for those curious about the process....
Of course, make sure the coolant is cool before doing any of the following!
Prelim work:
1. Remove front wheels
2. Remove front part of front wheel housing liner
3. Remove rear underbody panel
You drain coolant from several locations:2. Remove front part of front wheel housing liner
3. Remove rear underbody panel
From Engine
1. Open the coolant cap under engine-bay lid
2. Put a pan or bucket to collect coolant under the following drain plug positions(2):
3. Unscrew drain plug on the thermostat housing
4. Unscrew drain plug on the coolant guide tube
5. Let coolant drain
6. Screw-on the two drain plugs removed in steps 3 and 4 above, using new sealing rings (tighten to 25 Nm or 19 ftlb)
From Radiators2. Put a pan or bucket to collect coolant under the following drain plug positions(2):
3. Unscrew drain plug on the thermostat housing
4. Unscrew drain plug on the coolant guide tube
5. Let coolant drain
6. Screw-on the two drain plugs removed in steps 3 and 4 above, using new sealing rings (tighten to 25 Nm or 19 ftlb)
1. Place collection pan or bucket under location of coolant hose
2. Pull off coolant hose (there are three hoses for supply and return to the side radiators - the one you want to pull-off is the lower one...)
3. Remove spring clamp on plug-in coupling
4. Point hose down into bucket and let drain
5. Refit the spring clamp
6. Check the O-rings and replace if necessary (coat with lubricant)
7. Refit the coolant hose and pull to check that it is secure
Underbody Pipes at Rear2. Pull off coolant hose (there are three hoses for supply and return to the side radiators - the one you want to pull-off is the lower one...)
3. Remove spring clamp on plug-in coupling
4. Point hose down into bucket and let drain
5. Refit the spring clamp
6. Check the O-rings and replace if necessary (coat with lubricant)
7. Refit the coolant hose and pull to check that it is secure
1. Place collection pan or bucket under drain point
2. Remove the spring clamps
3. Pull-off coolant supply and return hose, and collect draining coolant
4. Refit spring clamps
5. Check O-rings and replace if necessary
6. Re-fit coolant hoses after draining
7. Pull on hoses to be sure they are securely held in place!
With all coolant drained, and hoses, clamps etc. back in place, you can move on to refilling coolant... Leave the coolant cap off as that is where you'll connect your vacuum filler.2. Remove the spring clamps
3. Pull-off coolant supply and return hose, and collect draining coolant
4. Refit spring clamps
5. Check O-rings and replace if necessary
6. Re-fit coolant hoses after draining
7. Pull on hoses to be sure they are securely held in place!
Using a vacuum filler, connect the filler and return hoses, and set the pressure level to 8 bar. If you need help with vacuum filling, that is for another post....
Once you get the refill done, simply replace the underbody panel, wheel well liners and front wheels, and you are good to go! (Of course you should BLEED the system, which is where you'll likely need the PIWIS tool).
Disclaimer- I don't recall if there are any additional steps for the third, center or X51/PowerKit radiator. Could be that you will have to remove the front bumper cover to access the hoses, but should be just like the process for side radiators....
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SpeedCircuit (01-28-2021)
07-12-2021, 09:06 PM
#9
Instructor
Not exactly correct Arcoril..... The PIWIS tool is only used for the bleeding process, but you can drain and refill coolant without it (but you SHOULD bleed with any refill!). There are multiple drain points, but no need to cycle fluid through "baffles or valves". When filling, you will need a vacuum tool (Porsche lists "filling device 9696 for vacuum-filling). I am guessing any decent vacuum tool would be sufficient.
I think this might have been described elsewhere, but just for those curious about the process....
Of course, make sure the coolant is cool before doing any of the following!
Prelim work:1. Remove front wheels
2. Remove front part of front wheel housing liner
3. Remove rear underbody panel
You drain coolant from several locations:
From Engine1. Open the coolant cap under engine-bay lid
2. Put a pan or bucket to collect coolant under the following drain plug positions(2):
3. Unscrew drain plug on the thermostat housing
4. Unscrew drain plug on the coolant guide tube
5. Let coolant drain
6. Screw-on the two drain plugs removed in steps 3 and 4 above, using new sealing rings (tighten to 25 Nm or 19 ftlb)
From Radiators1. Place collection pan or bucket under location of coolant hose
2. Pull off coolant hose (there are three hoses for supply and return to the side radiators - the one you want to pull-off is the lower one...)
3. Remove spring clamp on plug-in coupling
4. Point hose down into bucket and let drain
5. Refit the spring clamp
6. Check the O-rings and replace if necessary (coat with lubricant)
7. Refit the coolant hose and pull to check that it is secure
Underbody Pipes at Rear1. Place collection pan or bucket under drain point
2. Remove the spring clamps
3. Pull-off coolant supply and return hose, and collect draining coolant
4. Refit spring clamps
5. Check O-rings and replace if necessary
6. Re-fit coolant hoses after draining
7. Pull on hoses to be sure they are securely held in place!
With all coolant drained, and hoses, clamps etc. back in place, you can move on to refilling coolant... Leave the coolant cap off as that is where you'll connect your vacuum filler.
Using a vacuum filler, connect the filler and return hoses, and set the pressure level to 8 bar. If you need help with vacuum filling, that is for another post....
Once you get the refill done, simply replace the underbody panel, wheel well liners and front wheels, and you are good to go! (Of course you should BLEED the system, which is where you'll likely need the PIWIS tool).
Disclaimer- I don't recall if there are any additional steps for the third, center or X51/PowerKit radiator. Could be that you will have to remove the front bumper cover to access the hoses, but should be just like the process for side radiators....
I think this might have been described elsewhere, but just for those curious about the process....
Of course, make sure the coolant is cool before doing any of the following!
Prelim work:1. Remove front wheels
2. Remove front part of front wheel housing liner
3. Remove rear underbody panel
You drain coolant from several locations:
From Engine1. Open the coolant cap under engine-bay lid
2. Put a pan or bucket to collect coolant under the following drain plug positions(2):
3. Unscrew drain plug on the thermostat housing
4. Unscrew drain plug on the coolant guide tube
5. Let coolant drain
6. Screw-on the two drain plugs removed in steps 3 and 4 above, using new sealing rings (tighten to 25 Nm or 19 ftlb)
From Radiators1. Place collection pan or bucket under location of coolant hose
2. Pull off coolant hose (there are three hoses for supply and return to the side radiators - the one you want to pull-off is the lower one...)
3. Remove spring clamp on plug-in coupling
4. Point hose down into bucket and let drain
5. Refit the spring clamp
6. Check the O-rings and replace if necessary (coat with lubricant)
7. Refit the coolant hose and pull to check that it is secure
Underbody Pipes at Rear1. Place collection pan or bucket under drain point
2. Remove the spring clamps
3. Pull-off coolant supply and return hose, and collect draining coolant
4. Refit spring clamps
5. Check O-rings and replace if necessary
6. Re-fit coolant hoses after draining
7. Pull on hoses to be sure they are securely held in place!
With all coolant drained, and hoses, clamps etc. back in place, you can move on to refilling coolant... Leave the coolant cap off as that is where you'll connect your vacuum filler.
Using a vacuum filler, connect the filler and return hoses, and set the pressure level to 8 bar. If you need help with vacuum filling, that is for another post....
Once you get the refill done, simply replace the underbody panel, wheel well liners and front wheels, and you are good to go! (Of course you should BLEED the system, which is where you'll likely need the PIWIS tool).
Disclaimer- I don't recall if there are any additional steps for the third, center or X51/PowerKit radiator. Could be that you will have to remove the front bumper cover to access the hoses, but should be just like the process for side radiators....
08-10-2022, 03:44 AM
#10
A very timely thread. I have a 2012.5 991.1 with 64K miles, I had the coolant flushed 4.5Y ago, is it time to change it again. With its age is it worth doing the thermostat and coolant pump. Or why change it if its not broken?
Thanks.
Thanks.
08-11-2022, 09:25 AM
#11
Instructor
I would just leave it be, unless your water pump is toast. I struggled to properly bleed the system when I DIY'ed my Boxster water pump. More recently, the dealership struggled to do the same when they replaced my 991.2 water pump. They had to keep the car a few extra days as the cooling system was not operating optimally, in their words.
AFAIK, they did not replace the thermostat.
AFAIK, they did not replace the thermostat.
08-11-2022, 12:09 PM
#12
Rennlist Member
What is the actual change interval on the coolant? All I can find reference to is checking the levels and topping it off, but nothing about actually flushing the system entirely.
08-11-2022, 12:34 PM
#13
RL Community Team
Rennlist Member
Rennlist Member
Coolant has a finite life, shortened by heat cycling and contamination.
4yr/40k seems reasonable. Several Porsche dealers state 30k and 40k for coolant maintenance, which amounts to inspection and replacement if it's bad.
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koala (08-11-2022)
08-11-2022, 12:42 PM
#14
Rennlist Member
I've read at least one mention of it being lifetime, but that's a sham. Coolant is supposed to be flushed every couple years, but virtually no one does that and modern coolants are usually good to 4 or 5 without much issue.
Coolant has a finite life, shortened by heat cycling and contamination.
4yr/40k seems reasonable. Several Porsche dealers state 30k and 40k for coolant maintenance, which amounts to inspection and replacement if it's bad.
Coolant has a finite life, shortened by heat cycling and contamination.
4yr/40k seems reasonable. Several Porsche dealers state 30k and 40k for coolant maintenance, which amounts to inspection and replacement if it's bad.
