matt33

Yes correct.. 997.1 GT3 RS

Regarding water vs oil temperature: my observation is that the water seems to heat as expected (10-15mins and we are at 175F give/take), whereas the oil temperature barely gets to 155F regardless of how long the car is running IF the outside temperature is <50ish. Early this morning I drove for 1hr and the oil temp would not get warmer than 155. Then the sun comes up/ambient temperature rises and the warning lights turn off and temperatures all normal.

It really seems like there is a circuit (thermostat/valve/something) that is stuck open that I am missing.

I dont think it can be a wiring/sensor type issue because the actual temperatures all match the gauges (this was tested). If the ambient temperature is warm everything is normal. Weird problem - the car is too efficient at cooling!

Mooty had success at Fremont Porsche. Gunter works there and knows a lot about GT cars.. so he might be my next step.

Thanks
Matty

matt33

For anyone interested.. Gunter at Fremont was able to diagnose and fix this small but annoying issue. Here is the description:

“CHECKED DTC - STORED FAULT CODE P2181, REMOVED COOLANT REGULATOR TO INSPECT SEATING SURFACE OF COOLANT REGULATOR AND FOUND ROUGH SURFACE AT HOUSING, REMOVED COOLANT REGULATOR FROM KNOWN GOOD SAME TYPE VEHICLE, NECESSARY TO SMOOTH OUT SURFACES FOR BETTER SEALING, CHECKED TRANSMISSION COOLER FUNCTIONS AND FOUND CHANGE OVER VALVE WAS STUCK CAUSING TRANSMISSION COOLER TO ALWAYS BE OPEN, REPLACED COOLANT TEMPERATURE SENSOR AS AN INTERMITTENT BIASED VALUE COULD CONTRIBUTE / CAUSE P-2181, REPAIRED THIS SYSTEM. REFIT ALL REMOVED COMPONENTS, FILLED AND BLED SYSTEM. RECHECKED COOLING SYSTEM PERFORMANCE, PERFORMED ROAD TEST - NOW TEMPERATURES ARE NORMAL.(BOTH COOLANT AND OIL) P2181 DID NOT RETURN, OK AT THIS TIME.”

mooty

^ nice. i had similar issue which gunter and team fixed.

JB911

Is there a list of part numbers? It would be good to know. So the disc valve was not the issue? Trakcar had another thread and I think he and another member had the disc valve replaced twice(?)

What the tech called a coolant regulator and the rough surface, which part is that?
The disc valve is 928.574.573.03, from the 928 cars, and turns out Mercedes also uses it under a different part number. They're pretty cheap, around $18-$22, Mercedes around $14. FVD also sells the disc valve, Pelican says it's discontinued, most P dealers also out of stock or discontinued.
I don't think I have this issue but it could be starting to happen. I had some cold days below 50 degrees and it seemed the temp took a lot longer to reach normal, probably understandable. On a hot day coolant temp takes about 10-15 mins to reach normal I think. My oil temp also reaches normal range, about 200 in S FL weather.

So if you saved receipts after the repair, please post actual part names and numbers if possible. Trakcar called it a transmission cooler valve, I see it show up as disc valve with part number 928.574.573.03, and the tech that worked on your car is referring to a coolant regulator. Pictures of the procedure would have been great
Thnx

JB911

I did find it at ecs tuning. I see it's vacuum controlled, and so checking the vacuum line is probably a good idea if it's suspicious
https://www.ecstuning.com/b-mecano-b...857457303~mec/

noro78

This is what mine looked like at ~40K. Lucky find when the car was in for clutch replacement.

JB911

Thanks for the pic. So my Durametric Enthusiast didn't show a code, but tonight I used my Torque App on Android tablet(not to be confused with the Launch X431 Torque which I might buy) I got the P2181 code. I had a CEL weeks ago and thought it might have been bad gas(there's a thread about that)

So here's the bulletin from another thread in 2011:



Technical Information
28/11 EN 3477

Mar 24, 2011

Unnecessary replacement of coolant regulator and temperature sensor (28/11)


Model year: as of 2007

Information

Vehicle Type:
911 GT3 (997)/911 GT3 RS (997)

Concerns: Disc valve on transmission

Situation: Unnecessary replacement of coolant regulator and temperature sensor With regard to the customer complaints Displayed temperature too low

Display only works sporadically
and the following fault memory entries in the DME control unitP2181 – Thermostat stuck open
P3081 – Engine coolant temperature implausible
we are getting more and more reports that the coolant regulator and/or temperature sensor is being replaced.These problems can occur independently of each other - depending on driving style and country.The main cause is a blocked disc valve; -arrow- (illustration shows the position of the disc valve on the transmission).
An indication of a defective disc valve is also if the oil temperature and coolant temperature are almost identical in the warm-up phase. As a rule, the coolant temperature should be higher than the oil temperature.

Deformation of the sealing ring can mean that the function of the disc valve can no longer be guaranteed

As a result, an additional cooling circuit is opened via transmission cooling in the warm-up phase and the engine is slow to reach operating temperature.

Action Required: In the event of a complaint, check the disc valve (visual inspection and function test) before replacing the coolant regulator and/or temperature sensor.
Only remove and check the disc valve when the engine is cold.
Part Nos.: 928.574.573.03
Disc valve


Tools: Hose clamping pliers Nr.192

Procedure: The disc valve must be removed for the test.Only carry out the following procedure when the engine is cold. 1 Removing disc valve

1.1 Remove underbody panelling,
1.2 Clamp off water supply and return hoses using hose clamping pliers ahead of the disc valve and after the transmission oil cooler.
1.3 Remove hose clamps and vacuum line between the vacuum unit (disc valve) and change-over valve and loosen screw (disc valve at sheetmetal holder).
1.4 Remove disc valve.

2 Visual inspection
When the disc valve is removed, you will be able to see during a visual inspection whether the disc valve seal is deformed and whether it is positioned in the correct groove.
2.1 Hold the disc valve against the light and look into one of the two water hose adapters.
2.2 If the seal is no longer in installation position, you will see parts of the seal at the inner wall of the adapter.
Is the seal in its original installation position?
If it is: ⇒ Step 3
If not: ⇒ Step 4

3 Function test (approx. 0.1 litres of water required for this)
3.1 Turn the removed disc valve in your hand so that the black adapter is facing upwards.
3.2 Move the disc valve over the joint rod with your hand until it is in “Closed” position and hold it closed with your hand.
3.3 Check the disc valve for leaks:
To do this, fill water into the upward-facing open adapter.
Does water come out of the opposite adapter?
If it does: ⇒ Step 4
If not: ⇒ Step 3.4
3.4 Disc valve is not leaking.
Install the disc valve in reverse order to removal.
Check the coolant level and correct it if necessary.
3.5 Work through the fault codes using “Guided Fault Finding” in PIWIS Tester II.
End of action required.


4 Replacing disc valve
4.1 Replace the defective disc valve.
Install the disc valve in reverse order to removal.
Check the coolant level and correct it if necessary
4.2 Work through the fault codes using “Guided Fault Finding” in PIWIS Tester II.
End of action required.Attached Images

JB911

So it seems maybe the car is taking too long to warm up, though I thought 10-15 minutes for coolant gauge to reach the normal warm position-Oil temp then gets normal, and I can get oil level reading as usual. Oil pressure gauge also working normally. So I'm inclined to replace the disc valve myself, or at least get under the car and do a visual inspection. If my coolant temp gauge reaches normal operating temp I would assume it's not the thermostat malfunctioning.

So here's Trakcar's work order from his thread in 2012- It states the "inner gasket for valve blade out of its slot"

JB911

So I'll get under the car tomorrow and see what it looks like-glad the Torque app revealed the code P2181 "Coolant System Performance" as it's called.
The other thread has a 2019 entry, last poster said he replaced it on his 4.0:
https://rennlist.com/forums/997-gt2-...ain-cel-3.html
I can ask a friend to use his lift I imagine that with the car on stands or ramps there's not enough room to remove and install a new one
I also need to buy clamps to shut the 2 coolant lines and I assume most parts stores have them? Searched online and found vise grips but for coolant hoses so they stay clamped while I replace the disc valve.

And here's Suncoast's page explaining the disc valve and they call it an update:
https://www.suncoastparts.com/product/SKU997GT3DV.html

atlrvr

So, also having same issue on 997.1 GT2. Did the thermostat replacement first....waste of time and money.

Now the solenoid directing coolant is being replaced.....they have done 3 test drives and so far, no issue. Picking the car up later this week so we'll see how it does after 2 weeks of DD duty.

The latest rec I accepted was described as below.....technically, the issue was without the valve redirecting coolant through transmission, then through 3rd component (i forgot what it was exactly) that the coolant never cycles through enough to register a high enough temp.

REPLACE CHANGE-OVER VALVE ON THE TRANSMISSION COOLER AND RETEST, BENCH TESTED THE TRANSMISSION CHANGE OVER VALVE AND COMPARED WITH A KNOWN GOOD PART ALSO TESTED THE DIAPHRAGM THAT USUALLY GOES BAD DUE TO AGE, LOOKS NEW AND HELD VACUUM WHEN APPLIED MANUALLY. Cost to do that out the door is 509.72


I assume this is the same diagnosis as I'm seeing above????

JB911

From what I've read, this issue started years ago with cars that were practically new. I'm at 25K miles and the car is 2011. That valve is pretty cheap, with the exception of the Suncoast link I posted. I'm gonna go see if I find it locally, it's the same valve used in 928 cars. I also inspected my vacuum lines in the engine bay this morning, cleaned elec connectors just in case.



Also found the test procedure for vacuum leak test with a hand pump, and a pic of the disc valve with another electrical connector(?)




I plan on going under the car this afternoon to look at the disc valve, elec connector and vacuum line.
If I were to tackle this myself, even with hose clamping pliers my fear is losing coolant, even if just a bit, and air in the system. From reading what a complete system bleed with special vacuum tool(I don't have one) a complete bleed is a major endeavor. But I seem to recall in motorsports they had a bleed system for rapid bleed in the pits after component changes, can't remember details.

But if just a bit of air gets in after replacing the disc valve will the system purge itself since it stays mostly full?

Thanks
JB

JB911

I'm also reading on a post where the problem turned out to be the change-over valve on Porsche Club Great Britain:
https://www.porscheclubgb.com/forum/...969310&mpage=2


FIXED!!!

Test drive yesterday looks very much like this issue is now fixed. Took the car for a drive yesterday and noticeable differences. Car now warms up much quicker, does not cool down when engine is under load, does not cool down when coasting down a hill, oil temperature higher and of course, no annoying warnings!

So, to reiterate, the "System Fault" warning appeared on the dash (with the red "!" warning light), the temp gauge stops working and the red temp warning light flashed at the right end of the temp gauge. When I connected up the OBD I got fault codes P2181 ("Cooling System Performance") and P3081 ("Manufacture Specific" which in the case of a 997 means "Engine coolant temperature implausible"). On occasion the fault would clear itself and the temp gauge would then read spot on 80 degrees. After clearing and before the fault appeared again, the temperature would always go down before (I guess) it reached a tolerance limit and the fault occurred again. The problem was under-heating as opposed to over-heating.

As the car was under-heating, the obvious place to check was the thermostat which sends water to the radiators (or not), so I changed this first based on various advice found during a quick Google. I am glad I did this as it required me to drain the coolant, which obviously had been mixed during it's life and needed replacing. This work however did not solve the problem.

I next read this thread which suggested the disc valve, at which point another cooling circuit came to my attention, that which cools the gearbox oil. The disc valve opens up the channel to a heat exchanger / radiator which cools the oil and this is located under the car where it gets a lot of air, so it's very efficient. What became clear was that this circuit was stuck open i.e. the cooling was permanently on. This equates to the disc valve being in its "rest" position (it's spring loaded), which is as it is when the car is not running. As soon as the car starts (from cold), this valve should close to aid warming of the engine and as obviously the gearbox oil does not need cooling at that point. The way it works is that an electrical circuit (I assume triggered by the oil temp sensor) opens the change-over valve (next to the disc valve), that in turn directs vacuum to the disc valve. The disc valve then closes as a result of this vacuum thereby closing the coolant circuit and stopping the oil cooling.

I could have done better in my investigation here (I should have checked vacuum first) but my next step was to change the disc valve, to no avail. I then checked that I had vacuum into the change-over valve (which I did, lots of it!) after which I changed the change-over valve. NOTE: YOU NEED TO CLEAR THE FAULT CODES BEFORE THE DISC VALVE WILL WORK PROPERLY AGAIN! At first I thought it still wasn't fixed but clearing the fault did the trick. I started the car and saw the disc valve closed for the first time.

So there you have it. If you get these fault codes and the same symptoms as described above, I suggest you first check whether the disc valve changes position when you start the engine from cold (you can do this with the car in the air without even removing the under tray; there is a convenient hole to inspect through). If not, this is your problem. It may not be the exact same fault as on mine but at least you know where to begin your investigation. Happy to answer questions on the procedure if anyone has any. Wasn't easy with the restricted space but then again, what is?!

Thanks so much to Jeff for the moral support; couldn't have done it without you!

Jules in France

JB911

FCP Euro also has the disc valve, $17.89:
https://www.fcpeuro.com/products/por...et-92857457303


I'll search for change-over valve just in case. Apparently 991 cars have various change-over valve issues, many replaced under warranty. So if it's not the disc valve it could be vacuum and change-over valve problems-

* I’m doing more reading and some call it control-over valve, others change-over valve. There’s a few of them, and the 991 has 8(!)

JB911

So I'm also gonna test the change over valves, they are activated by 12 volts- from a renntech post:- remove the valve from the engine bay

- Connect the wires coming out from A and B to the electric change over valve's connection

- If you've got a working valve, you will hear a click sound when the valve triggers.

- Now, also blow from one pipe (after wiping it with an alcohol wipe!).

- you will be able to blow thru/NOT blow thru as the valve opens/closes as you connect/disconnect the 12v supply wires.
This is a pic of the valve, they're about $16-$22 depending on vendor:

JB911

I realize I've overwhelmed this thread with info, but I'm trying to see which of these might be the problem. The disc valve or change-over valve(one or more). There are quite a few change-over valves-left side of the engine bay #4, two of them:



There's one next to the disc valve itself by the transmission:


So as mentioned, even the 991 cars are plagued by change-over valve failures-I'll start testing these today, and go under the car to see the disc valve as well-
Part # is 996 605 123 01, or 722280020 on some vendors.