sand8

Wonder why Porsche is not using electric water pump instead? Is the Cayenne hybrid using the same system or using electric water pump? Or, the battery pack cooling system has separated cooling system?

synrgy350

Does anybody know if a check engine light will appear if you just unplug the vacuum line and cap it off?

chassis

Before CEL is questioned, the first question is what state the vacuum-actuated shroud will be in, if the vacuum line is disconnected.

synrgy350

Shroud is retracted without vacuum, the solenoid connected to the vacuum line is actuated during warm up to facilitate the engine warming process.

You can see it in action here:
Next time I change the oil I'll try capping the vacuum line and seeing if anything pops up on the cluster.

chassis

Good idea. Shroud retracted with no vacuum means max pump output with no vacuum which is what you want.

Is there a shroud position sensor? That would complicate things if the ECU can see shroud position and determines it is in the “wrong” position for the current operating state.

The vacuum command valve should not be affected by the downstream line being plugged. The valve is nearly 100% likely to be seen by the ECU.

synrgy350

The only thing I could see happening that would trigger a CEL is that the engine warm up time is prolonged which may trigger an error. The water pump itself is purely mechanical and has no position sensor.

Hoping for no CEL, that way the entire vacuum system doesn't have to be replaced when the pump starts to fail.

chassis

The coolant shutoff valve on the left/driver LHD side also plays a role. I haven’t read enough in detail to know if an unrestricted pump, by unplugging vacuum, would have no effect because the coolant shutoff valve is closed during warmup.

95_993

During my last oil change (at 40k miles), I noticed my coolant was a little below min. I don’t know how long it’s been low and know visible leaks anywhere. I topped it off to see if the level drops again.

additional info: Blackstone oil analysis came back good, with no issues.

PorscheACC

Bad Porsche vehicle part/system designs are not caused by government regulations or in the name of fuel economy and emissions..

If Porsche knows that they have a defective part(s) design that needs to be changed preemptively to avoid $9,000+ large engine repairs/issues, they need to issue a TSB to deal with it, and with the defective part changed earlier in mileage, and not wait for the owners to get screwed by it and charge owners full Ca$h-Cow Porsche price repair costs.

chassis

In the past several months there have been several NHTSA "manufacturer's communication" documents for the vacuum valve ("change over valve") and water pump.

Porsche knows there are problems with this system and are nibbling around the edges with partial solutions.

The change over valve can fail via intermittent sticking, causing overheating. Sounds like a candidate for preemptive replacement in the 75k mile range.

Low coolant can result from "normal" seal leakage at the water pump.

So far I haven't found anything addressing failure of internal water pump seals which allow coolant ingestion into the vacuum system.

Seems like water pump replacement in the 50k-75k miles range would be good practice. Fairly involved job from a cursory look at diagrams, photos and videos. Water pump price seems not too bad at less than $300.

Ironman88

Any guesstimate on the number of hours to do the work?

chassis

A rough guess is not more than 8 hours for a dealer. The pump itself does not look difficult to remove. Gaining access is the time consuming part. This is from reviewing photos on eBay of salvage engines for sale.

I am speaking about the V6 water pump which is belt/pulley driven. The V8 water pump is gear-driven and I don’t know what differences are involved.

V999

This is a technical thread, which is great. But I have a very basic non-technical question about the Cayenne cooling, which is this... what is the normal operating temp range for water and oil in the '24 Cayenne S? I've been seeing mostly between 200F to 215F for oil temps (about 93C to 102C). But I got it in October and it still isn't all that hot where I live quite yet. So not sure what to expect when ambient temps get into the 90s.

bluonek1k

Since 3k miles my TTC has been low on coolant (about an 1.5 inches below "MIN") before every service interval (~10k miles). Dealer says it's due to "venting" which is "normal." While I doubt my Cayenne has this particular issue (yet), there could be an issue with the coolant cap over "venting" as there's residue on the top of the cap.

I'm curious if this thread's issue will come up in conversation during my upcoming 40k service. Highly doubtful - the dealer/corporate relationship isn't designed for preventative corrections. If it ain't broke (like all the way broken with full evidence) then corporate won't pay the bill.

95_993

I agree with you and I am highly doubtful there is an issue. In my instance, if coolant was making its way into my induction system, traces would have shown up in my oil analysis. Over venting may be an issue as you noted