Answer
Jul 20, 2025 - 09:43 AM
If the coolant reservoir on your 92A Cayenne isn’t holding pressure, it usually means there’s a leak somewhere or the cap’s not sealing properly.
Here’s what you might want to check:
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Coolant cap – Easiest culprit. If the rubber seal inside is worn or it’s not rated for the right pressure (usually around 1.5 bar), it’ll let pressure escape. Try replacing it first — cheap fix.
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Cracked reservoir – These plastic tanks can develop hairline cracks over time, especially near the seams or around the hose necks.
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Leaky hose connection – Check the small return hose and main lines for any signs of seepage or corrosion around clamps.
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Pressure relief valve (if equipped) – Some Cayennes have pressure-venting caps or valves that can fail.
Luckily, this repair manual will walk you through pressure testing the cooling system and replacing the tank or cap if needed. Definitely worth pressure testing the system to spot where it’s bleeding off.
