Sunsation

Well—darn; here we go again. Those of you that are aware of my previous issues (previous long thread) with this ‘overheating’ message—that occurs randomly in several temperature environments; some as low as 36F and engine temps displayed as low as 135F— the dealer replaced all sorts of hardware, etc. to ‘resolve’; but it didn’t stay resolved. Back to the dealer today for diagnosis and HOPEFULLY permanent resolution. The warning appears quite frequently and totally randomly, and during what I would consider non engine stressed periods. For a vehicle that I would consider to have a cooling system capable of dealing with pretty heavy engine loads and sustained high throttle use—this warning should NOT happen. It’s not like I am coming down the back straight of LeMans at full chat!

So, question: Have any of you guys ever had this warning come up before? Under any circumstances?

And—what are your normal running engine oil temperatures displayed? And how high have you ever had an oil temperature? My water temp has never displayed over 194F (according to Mr. Schnave, that’s all it will EVER display—and it’s lying), it’s the oil temp that has been anywhere from 210-250F—when climbing a big hill at highway speed; not towing or anything.

Little help, guys?

icemang

I think the water temp will jump up when it starts to approach overheating, the 194 reading is a big plateau but I believe there's higher more accurate readings above it. Maybe I'm just hoping, though. This seems like a sensor or computer error rather than a hardware problem considering the various scenarios you present. Good luck.

toma nova

What is the TPMS warning light? My Boxster threw many false warnings and lights when the battery was on it’s way out - did the dealer look at that?

dasams

Buy an OBD reader so that you can get confirmation on the temps.

Schnave

I think you may have a wiring or connector issue. You have multiple coolant temperature sensors, with a separate sensor for the water temp gauge. That could explain the warning triggered by one sensor while the temperature gauge indicates correctly. It could also explain the randomness of your warning lights.

I would rule out oil temperature sensor problems, as this would first trigger a separate yellow “Oil temp high” caution advisory, rather than the red “Engine temp high” warning which could mean either oil or water temperature. Coolant temp does not have a separate yellow caution advisory.

Your engine oil temp of 250°F is within the upper normal range. The oil cooler on the EA 839 V-6 begins opening at 230°F and doesn’t open fully until 257°F. I could find no reference of the temperature at which the warning is triggered.

The 194°F water temperature indication, as icemang pointed out, will plateau (lie to you) until the temperature rises above 221°F. It will then jump up to an accurate reading.

A bad sensor would trigger a CEL and would have been a quick and easy fix last time it was in the shop. It is unclear if a corroded connector or shorted wire would trigger a CEL. Additionally, if the mechanics previously changed all the sensors, that would not necessarily fix a corroded connector or intermittent shorted wire.

You may wish to ask your mechanic to do a “wiggle test” on the G62 and G82 sensor connectors and the associated wiring to the ECU.

Sunsation

Mechanic pulled the codes and did tests that indicated “engine block coolant switching valve stuck closed”. He (she?) removed/replaced the valve and no overheating warnings have appeared since.

Hopefully—this issue is resolved PERMANENTLY. Why didn’t they pull these codes and discover/ resolve the problem the first time I brought the vehicle in for the exact same warning?

Rhetorical question, I know….

Safou

hi I have the same problem on my Porshe

it says that my cooling water temp is too hot
i changed my waterpump and a valve on the passenger side is there still something Else that I need to get fixed

i hope you can help me

ck54

I got this code in my 2020 Cayenne Turbo last week.
Shut the car off and it reset, code went away.
The next day got a code that said the coolant pump is faulty.
Had it towed to the dealer. A week later and it still there being fixed to the tune of $9K. It is 4 month out of warranty.
I lived through the coolant tube problems with the first generation Cayenne. That cost a ton of money to resolve.
I've been a long time Porsche guy but I'm done with Cayenne's. They a fine as long as it's in warranty but after that dump it!

luv2sleep

This reminds of Audis and BMWs back in the day. The ultimate maintenance nightmares!

Sunsation

To Mr. Safou: not sure this will help, but below is the fix my dealer finally arrived at to resolve my 2019 Cayenne S overheating problem. It has worked for the past two years despite me towing 7,500 pounds (3,400 kilos) of boat during 110 degrees (43 Celsius) degree heat ( I love in Arizona; pretty close to Hell in the summer!). Good Luck!!

PS: my wife was born in Amersfoort….

chassis

Looks like V8 water pump and coolant switching valve are weak points.

Notice in the invoice above the tech checked for signs of water in the vacuum system. Porsche knows this is a problem - failed water pump vacuum actuated active impeller shroud.

Theoretically not impossible to diy these two items but the space available in the front of the engine seems like a challenge from a time and disassembly point of view.

The switching valve would be less cost for parts and labor to preemptively diy replace, the question is access via-a-vis other parts that need to be removed to gain access.

On_Your_Left

Cooling seems to be VAG's current headache with their engines. The V8 has issues over in Audi land too. I had this cooling TSB issue hit me a few months ago on my '22 SQ7. Thankfully done under warranty, as changing the t-stat is gobs of labor; half of the freaking car has to be disassembled to get at it.

chassis

I have seen water pump failure posts on EA888 2.0 4-cylinder engines in other applications.

Agree VAG seems to have a corporate problem with cooling systems, specifically water pump and valving.

So far EA839 2.9TTV6 doesn’t seem to have cooling problems in Audi and Porsche installations.

On_Your_Left

Found my service invoice. Lots of hours wrapped in there! I would haven't been surprised if they had to remove the sunroof based on the rest of it