When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Ok, this first screenshot is at engine cold, ignition on.
Next is engine cold right after engine start up,
Next is after the fast idle has settled completely down.
These next pictures are at various points on the dash gauge.
All the these measurements were taken on a stone cold engine that has sat overnight. They were also taken with the engine naturally warming up, not forced, not driven, not heat soaked.
Hopefully this helps, I thought Celsius would be better for you. I'm American and we use a different measurement system then the rest of the world does. If you need any other information let me know.
Hopefully this helps, I thought Celsius would be better for you. I'm American and we use a different measurement system then the rest of the world does. If you need any other information let me know.
Doug you are a legend thank you very much for doing this for me. I need to digest and compare once I am off work but I can immediately see is that the readings when cold are consistent with mine. I think the key is when the thermostat opens (when that value changes). I am assuming yours changed from 97% once the car reached operating temp. This indicates the percentage activation measurement is the same as percentage closed (not open as I had interpreted).
Anyone know if there is any type of gasket or seal where this connects? (Area circled on thermostat housing)? I think I may have a minor leak in this location.
If I remember correctly, there is on opening on each side (your red circle) which is sealed by an o-ring. Between the housing and the head. Take a look at the parts diagram. The diagram only shows one side and one o-ring but you will actually need to order two. One for each side.
The o-ring in the lower hose is easy to replace without removing the expansion tank, and can be replaced with a generic black 3mm thick, 16mm ID, 22mm OD o-ring. If you siphon out the tank, you lose very little coolant as well.
Most every Cayenne I've seen at this point in time leak to some degree from this joint, but I haven't seen a tank actually leak because it's cracked or something.
You're killing it Garrett! Always making the lives of your fellow members easier.
OK my analysis of data comparing my subject vehicle (with Coolant Display Defective dash error) and Doug's reference vehicle (no issues reported).
This sure has helped me and hopefully can assist others. This is a strange fault with no codes logged in ECU. Thanks Doug for your assistance. I have enough evidence to satisfy me that the Thermostat is defective in my vehicle despite being replaced by an Indy when I purchased the vehicle 3 years ago (only 30K klms). I will embark on Thermo replacement, vent line, engine temp sensor and seriously considering a carbon clean.
I have also learned that a MAP activated thermostat has a heating element to heat the wax pellet (when activated under certain conditions - e.g. sport mode) to ensure the thermostat can be fully open rapidly despite coolant temperatures being lower. After observing the data I have concluded the 'MAP Thermostat Activation' value in the ECU is telling you how much additional induced activation is required at a given temperature to achieve full open status.
I have been looking to purchase a coolant vacuum fill tool in prep for this job. I notice the expansion tank filler has an inner neck and outer neck with small overflow hole in between. How do you insert and vacuum seal the system with that little hole on the outside of the filler neck? The lip on the outer neck looks too shallow to allow a seal above the hole. Hope this makes sense.
I don't remember doing anything special when I vacuum filled my car. I used the schwaben fill tool. Maybe the tool I used didn't need to do anything special. I can get you the part number for the tool I used. What sucks about the tool I have is that I can't use it for anything else,
Doug looks like I might have finally ended this saga after replacing a sub standard (Euro Parts) failed TSTAT (after less than 10k miles) with a genuine TSTAT. It looks like the Euro Parts one either failed partially open or a rubber/plastic seal from the plate valve came off and disappeared. All I can say is I am glad I opted for genuine on the replacement. Photos here: https://rennlist.com/forums/cayenne-...l#post19651875
For those that are interested and on a related topic, I did my first vacuum fill and with the Airlift II. It took a bit of practice as the design doesn’t give much clearance on either side but worked in the end. Whilst the tool quality is good, the design is not ideal for the cayenne as the hose connections are on the body level with cone rather than being up and out of the way.
I decided to flush the old coolant to replace its with Nulon Pink Long Life which meets Porsche spec. We can’t get Zerex in Australia. I ended up running 30 litres of distilled water through on seperate warmup cycles including a good drive with heater on in sports mode to circulate everything.
I found that if you pop the bottom radiator hose with cap removed and service valve open you drop about 4ltrs of coolant. If you also pop off the LHS coolant hose from the water/oil heat exchanger you drop around another 4-5ltrs so combined that is about half of the engines coolant capacity. That second hose I mentioned is tough to get off the first time (down near the crankshaft pulley) but then it is easy on/off.
Once the fluid was pretty well clear (after about 3-4 refills, warm-up and draining) I vacuum pulled ~9ltrs of concentrate into the system to mix with what was already in there (distilled water) so 50/50 in the end.
It sounds like a bit of mucking around but once that bottom heat exchanger hose came off, with the right tools I had the hoses disconnected and reconnected in no time, including removing and refitting the fan which is as cinch with the upper and lower radiator hoses disconnected. It literally slides straight up and out.
11-29-2023, 06:39 PM
