POST 1 / ORIGINAL POSTEROriginal post
have a 03 C4S,coolant level goes down slowly,cant see any leaks,had a good indy do a pressure test and he cant see anything,no sign of water in oil,any ideas?/ Thanks Albert
8 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
Discussion summary
YOUR RESEARCH2003 C4S coolant loss ??
1 matching discussions were examined; no attributable action/outcome evidence was detected. No consensus or repair conclusion is claimed.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Read captured repliesInsufficient extracted evidence does not mean there is no answer in the original discussions.
1 matching discussions · 8 captured posts examined · 0 partial discussions
Coverage and how to read this overview
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
8 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
- Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
2 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
New cap solved it.
No unique explicit quoted action; no causal link assigned
Generation: 20261026T052503Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
POST 2Original post
How long does it take and how much are you losing over that period. I have the same issue... I lose about 200 ml every 30 to 45 days. There is no evidence of any loss visually. I am of the opinion that perhaps the heater core is leaking. There is an occasional whiff of coolant when I turn on the A/C after the car has not been driven in a couple of days.
POST 3Original post
Your coolant tank or cap is often the culprit especially if your tank has yellowed, it can develop tiny cracks that can be hard to detect. My tank was leaking for awhile before I replaced it. My Porsche is a MY99 so it's 4 years older than yours. GL
POST 4Original post
Update coolant cap. The newest version ends with "04."
POST 5Original post
If I fill mine up to the max it will always go back down below min and stay there. If I fill it to min it will go back down to where it was prior and stay there. It's stayed there for 2 or more years so I think the min/max marks are way off.
POST 6 / ORIGINAL POSTEROriginal post
probably loss a quart after 3000-4000 miles,i updated the cap,i guess i will just keep a eye on it and see what happens
POST 7Original post
It is your cap. I had the exact same issue on my 997. New cap solved it.
POST 8Original post
Stevens Creek found the same problem with my cap. They pressure tested it and said it was fine but that the cap was leaking. Actually, there was crusted coolant around the edge of the cap when I got it. I had a replacement in hand when the car arrived. I'm hoping that it solved the problem. -Eric
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