Oil warning light on for no apparent reason

[xavier]

My 1984 323i is running nicely, but the engine oil light has come on and stays on. There is plenty of oil and the car is running fine . The oil and filter were changed about 4 months ago. I can see no evidence of an oil leak or a damaged head gasket. My next step will be to replace the sender. Anything else I should look for?

[Speedtouch]

Perhaps the oil filter you fitted doesn't have a non-return valve in it? It probably is just the sender though...