I'm seeing a good bit of 7+ year old BMW's come in with cooling systems (plastic reservoirs, radiators) that are cracking/leaking. Is their plastic just that bad or is this an indication of not changing the coolant every couple years? I have about come to the conclusion that it is not if they start leaking but when.

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Jim

Not only frequency of changing coolant. Correct coolant even more important as using one that is not compatible with the plastic will result in the plastic breaking down. Similar thing with MB top tanks on 300D 123.

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Grumpy Old Diesel Owners Club group

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1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
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1968 Ford F750 truck. 6-354 diesel conversion.
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a friend of mine bought a used 540 and soon after the coolant expansion tank went..turns out it is a common problem. Coolant tank cracked.. - 5 Series Forums

Yeah the BMW guys I know say that at 7-10 years drop a G note and replace all the plastic before it starts to fail.

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