Cooling system refresh
09-04-2022, 10:57 AM
#1
Cooling system refresh
955 Turbo runs a bit warmer than i would like and we have a big trip coming up next summer so I would like to get the cooling system up to scratch before we leave.
Car has ~220k km and yucky looking coolant, no leaks.
Any time you are below about 40km/h for more than a few minutes, the temperature creeps up over the middle of the gauge fairly quickly - even in the depths of winter.
Using the Torque app and a non contact tachometer, I have identified the main cooling fan as being on the way out. With AC off, I have no fan at all until 96c, then the fan runs at full speed until the temp drops to 93c, then nothing til 96c again, ad nauseum. With AC on, the fan will run at full speed most of the time, but occasionally not at all under 96c (i guess the AC pressure isn't high enough in winter to trigger full fan speed). At no point do I get anything other than 0rpm or 1400rpm from the fan, no variable speed operation at all. I believe it should start ramping up speed slowly from 93c, which mine definitely does not do. From what I've read, this means the in-built fan controller is dying.
Aside from the cooling fan, when off-roading I have seen the temperature go over 100c even on days that aren't extremely hot. Once, I had to stop and let it cool @ 105c (on Torque) halfway through a climb, on a mild day. Given that I have full fan speed by 96c and the temp keeps climbing, I'm thinking partially blocked radiator or worn water pump impellor is hampering things.
I don't like spending money unnecessarily, but I do want this thing to be reliable through hot Australian summers so I am thinking this is a good time to do a full cooling system refresh.
Does this list look ok? Anything I've missed or brands in here I should avoid?
What other hoses should I be changing while I have the front apart?
Should I bother replacing serpentine belt idlers/tensioners?
Water pump - Graf (metal impellor, with gasket) $60 FCP
Water pump pulley - genuine $60 FCP
Thermostat - Borg Warner (oem) $15 FCP
Expansion tank - Rein (oem) $94 FCP
Expansion tank cap - Rein (oem) $8 FCP
Radiator - Nissens $200 Europa
Fan - genuine $620 Europa
Coolant - genuine $41 FCP
Serpentine belt - Continental $104 FCP
Thermostat housing gasket - Elring $7 FCP
Thermostat housing o ring - genuine $3 FCP
Engine coolant pipe o ring - Elring $2 FCP
Top radiator hose - genuine $51 FCP
Bottom radiator hose - genuine $62 FCP
Car has ~220k km and yucky looking coolant, no leaks.
Any time you are below about 40km/h for more than a few minutes, the temperature creeps up over the middle of the gauge fairly quickly - even in the depths of winter.
Using the Torque app and a non contact tachometer, I have identified the main cooling fan as being on the way out. With AC off, I have no fan at all until 96c, then the fan runs at full speed until the temp drops to 93c, then nothing til 96c again, ad nauseum. With AC on, the fan will run at full speed most of the time, but occasionally not at all under 96c (i guess the AC pressure isn't high enough in winter to trigger full fan speed). At no point do I get anything other than 0rpm or 1400rpm from the fan, no variable speed operation at all. I believe it should start ramping up speed slowly from 93c, which mine definitely does not do. From what I've read, this means the in-built fan controller is dying.
Aside from the cooling fan, when off-roading I have seen the temperature go over 100c even on days that aren't extremely hot. Once, I had to stop and let it cool @ 105c (on Torque) halfway through a climb, on a mild day. Given that I have full fan speed by 96c and the temp keeps climbing, I'm thinking partially blocked radiator or worn water pump impellor is hampering things.
I don't like spending money unnecessarily, but I do want this thing to be reliable through hot Australian summers so I am thinking this is a good time to do a full cooling system refresh.
Does this list look ok? Anything I've missed or brands in here I should avoid?
What other hoses should I be changing while I have the front apart?
Should I bother replacing serpentine belt idlers/tensioners?
Water pump - Graf (metal impellor, with gasket) $60 FCP
Water pump pulley - genuine $60 FCP
Thermostat - Borg Warner (oem) $15 FCP
Expansion tank - Rein (oem) $94 FCP
Expansion tank cap - Rein (oem) $8 FCP
Radiator - Nissens $200 Europa
Fan - genuine $620 Europa
Coolant - genuine $41 FCP
Serpentine belt - Continental $104 FCP
Thermostat housing gasket - Elring $7 FCP
Thermostat housing o ring - genuine $3 FCP
Engine coolant pipe o ring - Elring $2 FCP
Top radiator hose - genuine $51 FCP
Bottom radiator hose - genuine $62 FCP
09-05-2022, 09:57 AM
#2
RL Community Team
Rennlist Member
Rennlist Member
Sounds like your thermostat is the current issue where it's not opening early enough, not opening enough, or both.
09-06-2022, 02:24 AM
#3
other than going with the g40 from zerek... much cheaper and better in every regard, you want to jack up the rear driver side to drain the radiator and also take off the 2 hoses under rear of the front driver tire behind the fender ligner. wet vac and some compressed air and doing the water pump and all the upper hoses including the air line under the plenum... you should be able to drain 4.2 to 4.4 gallons from it (measured when filling.
do 3x of these with distilled water though heat cycles.
this is about the ONLY way to flush out the coolant system. its about 4.8 to 4.9 gallons but there is a LOT of crud in there if its not looking decent. don't bother with chemical flushes unless the liquid is brown.
get a vacuum fill setup from amazon.
no need to change out the fans unless there testing out bad, same with the radiator. that is a HUGE task to get that out.
you got lucky on the coolant tank not exploding... good job. no need to replace the pulley either unless its bad.
While you have the plenum off, do the starter instead of the radiator.
there are some parts you want to go genuine and you can save some $ going with OEM stuff but not Porsche boxed. Check out Uropa PArts and also gaudian. don't be afraid to call the local dealership for you and ask if they can get you a deal on these parts as well. i have had better success with deals on proper parts this way. Put it this way, i did a $2,300 parts list for the coolant system and the timing chian for about $800 with proper parts.
food for thought.
rock auto has a genuine REMAN Bosch starter for $250.
you might want to check the divination on bank 1 and 2 for the timing chain. its about the mileage that they tend to be at the end of life.
do 3x of these with distilled water though heat cycles.
this is about the ONLY way to flush out the coolant system. its about 4.8 to 4.9 gallons but there is a LOT of crud in there if its not looking decent. don't bother with chemical flushes unless the liquid is brown.
get a vacuum fill setup from amazon.
no need to change out the fans unless there testing out bad, same with the radiator. that is a HUGE task to get that out.
you got lucky on the coolant tank not exploding... good job. no need to replace the pulley either unless its bad.
While you have the plenum off, do the starter instead of the radiator.
there are some parts you want to go genuine and you can save some $ going with OEM stuff but not Porsche boxed. Check out Uropa PArts and also gaudian. don't be afraid to call the local dealership for you and ask if they can get you a deal on these parts as well. i have had better success with deals on proper parts this way. Put it this way, i did a $2,300 parts list for the coolant system and the timing chian for about $800 with proper parts.
food for thought.
rock auto has a genuine REMAN Bosch starter for $250.
you might want to check the divination on bank 1 and 2 for the timing chain. its about the mileage that they tend to be at the end of life.
09-06-2022, 06:13 AM
#4
Thanks guys, lots of good info there
I just ran my fan test again, this time with a sheet of plastic blocking the grill to allow me to test at higher temps. Once it got to 101c, the fan sped up to 1800rpm so I guess I do have variable speed and that it must be working ok. I'm still surprised that there's absolutely no fan action at all until 96c. I'd normally want the fan running sooner than that, but I'm used to older engines I guess.
Maybe it is just the thermostat. I might start out leaving the radiator and fan, which were the expensive items anyway and sounds like a lot of work to swap. Pump, t-stat, expansion tank and hoses only for now.
Is the air line under the plenum a common failure? I hadn't really planned on taking the intake off this go around.
I might look at cam deviations, but the motor runs great and I'm *trying* to avoid too much scope creep. Definitely hadn't planned on pulling the timing chain off!
I just ran my fan test again, this time with a sheet of plastic blocking the grill to allow me to test at higher temps. Once it got to 101c, the fan sped up to 1800rpm so I guess I do have variable speed and that it must be working ok. I'm still surprised that there's absolutely no fan action at all until 96c. I'd normally want the fan running sooner than that, but I'm used to older engines I guess.
Maybe it is just the thermostat. I might start out leaving the radiator and fan, which were the expensive items anyway and sounds like a lot of work to swap. Pump, t-stat, expansion tank and hoses only for now.
Is the air line under the plenum a common failure? I hadn't really planned on taking the intake off this go around.
I might look at cam deviations, but the motor runs great and I'm *trying* to avoid too much scope creep. Definitely hadn't planned on pulling the timing chain off!
09-06-2022, 09:06 PM
#5
Food for thought and im not sure how realistic or factual this is but the plastic that the "exploding coolant tank issue" is made of is the same as all the other fittings and parts including the radiator are. My cayenne had the radiator done fairly recently before i got it so i left it alone but once the tank exploded on me i made it the mission to replace ALL coolant pipes and fittings and orings. I found that MANY origional orings were leaking and MANY of the plastic pieces showed stressed issues visually and only one was leaking (from the alternator)
I made it my mission to replace ALL plastic and rubber parts.
use oring lube.
the plastic hose under the plenum on the turbos are CRITICAL HITS and many threads here about a mystery leak and this being the issue.
So if you want to replace the radiator its not a BAD idea to, just that those are not as common to fail. Be aware that the replacements often (even OEM) have additional ports on them with rubber caps that do not last as long.
"OEM" aka "toyota coolant" as in the PORSCHE coolant is only garanteed at 80K miles or 2 years of life..... where as the Zerek is basically 150K or 5 years of life.
There are about a dozzen hoses behind the wheel well i mentioned and also the aux pump for the climate control. i left those alone and will do those next time i service the coolant... aka 3 years or 100K... whatever comes first.
as for the timing chain, its worth a glance with durametric but otherwise just start planning on the job some time. my cayenne had a +7 bank 1 and a -14 on bank 2 (spec is 8 total between them) and it still ran just fine with nothing more than a code indicating it was time.
i would also mention that as preventative that you change the transfer case and differential fluids with every other oil change. oil for them is cheap but the service for them is terrible and its been a notorious issue for them to fail from fluids that do not last as long as they should due to many issues such as vent placement and broken / cracked vent hoses.
One more thing you want to address with the coolant is to check the EVAP drain and clean it and the cabin air filter. not really part of the coolant but the heater core is and is a 10 minute job.
the coolant pump is easily done when the timing chain is done but not necessary to be done. i just know that these cars have a (everything needs work at 100k to 150K miles)
I made it my mission to replace ALL plastic and rubber parts.
use oring lube.
the plastic hose under the plenum on the turbos are CRITICAL HITS and many threads here about a mystery leak and this being the issue.
So if you want to replace the radiator its not a BAD idea to, just that those are not as common to fail. Be aware that the replacements often (even OEM) have additional ports on them with rubber caps that do not last as long.
"OEM" aka "toyota coolant" as in the PORSCHE coolant is only garanteed at 80K miles or 2 years of life..... where as the Zerek is basically 150K or 5 years of life.
There are about a dozzen hoses behind the wheel well i mentioned and also the aux pump for the climate control. i left those alone and will do those next time i service the coolant... aka 3 years or 100K... whatever comes first.
as for the timing chain, its worth a glance with durametric but otherwise just start planning on the job some time. my cayenne had a +7 bank 1 and a -14 on bank 2 (spec is 8 total between them) and it still ran just fine with nothing more than a code indicating it was time.
i would also mention that as preventative that you change the transfer case and differential fluids with every other oil change. oil for them is cheap but the service for them is terrible and its been a notorious issue for them to fail from fluids that do not last as long as they should due to many issues such as vent placement and broken / cracked vent hoses.
One more thing you want to address with the coolant is to check the EVAP drain and clean it and the cabin air filter. not really part of the coolant but the heater core is and is a 10 minute job.
the coolant pump is easily done when the timing chain is done but not necessary to be done. i just know that these cars have a (everything needs work at 100k to 150K miles)
09-11-2022, 05:23 AM
#6
on my 957 GTS I realised the temp is actually real like what the dash says vs real unlike many other cars where half way can be 110c
in winter my GTS never gets above 60c on the highway with 20c outside temp, the oil gets to about 80c
in summer sits right on half way and never gets over unless going up steep mountain passes or doing some climbing and never seen it at more than 105c and I live in Queensland so it's pretty damn hot here in summer
this should be a reference for you I guess, the GTS has shorter gearing so revs will be higher than a Cayenne S, I think the cooling systems on Cayennes is pretty good, can only compared them to Range Rovers.
If you do the cooling upgrade I suggest you take the intake off and pin the barbs behind the head and the one in the front near the stat since you're there.
I did not see the cylinder head plastic breeders on your list, replace those if you're there, they aren't expensive and are probably toast or will break if you even look at them wrong let alone touch them
in winter my GTS never gets above 60c on the highway with 20c outside temp, the oil gets to about 80c
in summer sits right on half way and never gets over unless going up steep mountain passes or doing some climbing and never seen it at more than 105c and I live in Queensland so it's pretty damn hot here in summer
this should be a reference for you I guess, the GTS has shorter gearing so revs will be higher than a Cayenne S, I think the cooling systems on Cayennes is pretty good, can only compared them to Range Rovers.
If you do the cooling upgrade I suggest you take the intake off and pin the barbs behind the head and the one in the front near the stat since you're there.
I did not see the cylinder head plastic breeders on your list, replace those if you're there, they aren't expensive and are probably toast or will break if you even look at them wrong let alone touch them
09-11-2022, 09:40 AM
#7
RL Community Team
Rennlist Member
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on my 957 GTS I realised the temp is actually real like what the dash says vs real unlike many other cars where half way can be 110c
in winter my GTS never gets above 60c on the highway with 20c outside temp, the oil gets to about 80c
in summer sits right on half way and never gets over unless going up steep mountain passes or doing some climbing and never seen it at more than 105c and I live in Queensland so it's pretty damn hot here in summer
this should be a reference for you I guess, the GTS has shorter gearing so revs will be higher than a Cayenne S, I think the cooling systems on Cayennes is pretty good, can only compared them to Range Rovers.
If you do the cooling upgrade I suggest you take the intake off and pin the barbs behind the head and the one in the front near the stat since you're there.
I did not see the cylinder head plastic breeders on your list, replace those if you're there, they aren't expensive and are probably toast or will break if you even look at them wrong let alone touch them
in winter my GTS never gets above 60c on the highway with 20c outside temp, the oil gets to about 80c
in summer sits right on half way and never gets over unless going up steep mountain passes or doing some climbing and never seen it at more than 105c and I live in Queensland so it's pretty damn hot here in summer
this should be a reference for you I guess, the GTS has shorter gearing so revs will be higher than a Cayenne S, I think the cooling systems on Cayennes is pretty good, can only compared them to Range Rovers.
If you do the cooling upgrade I suggest you take the intake off and pin the barbs behind the head and the one in the front near the stat since you're there.
I did not see the cylinder head plastic breeders on your list, replace those if you're there, they aren't expensive and are probably toast or will break if you even look at them wrong let alone touch them
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11-07-2022, 05:30 PM
#8
Well I went a bit silly on FCP Euro last night. I think I ordered every coolant hose they sell, along with water pump, pulley, thermostat, expansion tank, lots of o rings, intake gaskets, tensioners, idlers, air filters. Got the 3 way coolant hose from rock auto which apparently already comes with a metal T.
I figure while it's apart I'll do everything I can. Got flexible hose clamp pliers and vacuum bleeder coming from ebay.
Still undecided about whether to do the radiator or not.
Have a fairly small window of available vehicle and personal downtime so hopefully everything goes smoothly with no extra breakages.
Nearly started ordering all the vacuum hoses too but where do you draw the line?
I figure while it's apart I'll do everything I can. Got flexible hose clamp pliers and vacuum bleeder coming from ebay.
Still undecided about whether to do the radiator or not.
Have a fairly small window of available vehicle and personal downtime so hopefully everything goes smoothly with no extra breakages.
Nearly started ordering all the vacuum hoses too but where do you draw the line?
08-14-2023, 05:58 PM
#9
So after all that work the temp needle still starts climbing if you go too slow for too long. Basically anything under 40km/h and on the throttle for more than 5 mins. Only ever happens when I'm off road. Even in low ambient temperatures. If I keep the revs down by using a higher gear, say under 2000rpm, it's better.
If I stop and idle, go over 40km/h, or coast down hill off-throttle, it comes down fairly quickly. It's definitely engine load with low airflow that triggers it.
On our big trip earlier this year we did a ~30 min steep, technical climb, in a hurry, to get to the top before sunset. It got to the 3/4 mark on the gauge and when we got out at the top she smelled hot. Unfortunately stopping earlier wasn't really an option.
Just this weekend, very mild winter offroading, it got between 1/2 and 3/4 in just a few mins.
With new water pump, thermostat, hoses, coolant I feel it should be better than this. I'm thinking the radiator might be partially blocked internally? Knew I should have changed it while I had everything apart
If I stop and idle, go over 40km/h, or coast down hill off-throttle, it comes down fairly quickly. It's definitely engine load with low airflow that triggers it.
On our big trip earlier this year we did a ~30 min steep, technical climb, in a hurry, to get to the top before sunset. It got to the 3/4 mark on the gauge and when we got out at the top she smelled hot. Unfortunately stopping earlier wasn't really an option.
Just this weekend, very mild winter offroading, it got between 1/2 and 3/4 in just a few mins.
With new water pump, thermostat, hoses, coolant I feel it should be better than this. I'm thinking the radiator might be partially blocked internally? Knew I should have changed it while I had everything apart
08-14-2023, 06:02 PM
#10
RL Community Team
Rennlist Member
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Can you run with an OBD2 scan tool that displays your actual coolant temp. I've seen mine go as high as 220 F without moving on the needle and it never goes higher than that because the cooling fans have come on by then, but it normally runs between 178-185 under normal use (but I'm not slow off-roading mine either).