Cars was standing for a couple of months while I was away.
Checking the oil before starting I noticed that one side of the dipstick was the reassuring honey-colour of clean oil, but the other was dark grey.
The tissue I wiped the dipstick on has a faintly yellow-gold damp patch that I associate with clean oil, but also a slate-grey "skidmark",wiped off the dipstick, that looks metallic.
I guess there were fine metallic wear particles suspended in the oil, and the long stand has allowed them to settle out. Since the dipstick is at an angle, (i.e. not vertical) it can have an upper and a lower side. I wasn't paying enough attention to know if the upper side was the one with the sediment, though thats what I'd expect.
Is this normal (on a very old car: 1986 Daihatsu Skywing)? Havn't seen it before, but I suppose this combination of circumstances might not have occured/been noticed.
I'd have thought suspended metal would visibly discolor the oil, but I suppose the oil film on a dipstick is rather thin.
I suppose I'd better drain the oil, and maybe drop the sump and look for debris. It had an oil and filter change (Mobil Delvac MX 15/40) about 6 months ago. EDIT but had omly done about 300 miles since then. ENDEDIT) Thats a recent spec oil and, from reading, may not have enough zinc for my flat tappets
There was an intermittant tick when I first bought the car but it went away after I [censored] about with water-cleaning the cylinders, so I was tempted to call it pre-ignition. Maybe something loose just got ground away and/or lodged somewhere.
Checking the oil before starting I noticed that one side of the dipstick was the reassuring honey-colour of clean oil, but the other was dark grey.
The tissue I wiped the dipstick on has a faintly yellow-gold damp patch that I associate with clean oil, but also a slate-grey "skidmark",wiped off the dipstick, that looks metallic.
I guess there were fine metallic wear particles suspended in the oil, and the long stand has allowed them to settle out. Since the dipstick is at an angle, (i.e. not vertical) it can have an upper and a lower side. I wasn't paying enough attention to know if the upper side was the one with the sediment, though thats what I'd expect.
Is this normal (on a very old car: 1986 Daihatsu Skywing)? Havn't seen it before, but I suppose this combination of circumstances might not have occured/been noticed.
I'd have thought suspended metal would visibly discolor the oil, but I suppose the oil film on a dipstick is rather thin.
I suppose I'd better drain the oil, and maybe drop the sump and look for debris. It had an oil and filter change (Mobil Delvac MX 15/40) about 6 months ago. EDIT but had omly done about 300 miles since then. ENDEDIT) Thats a recent spec oil and, from reading, may not have enough zinc for my flat tappets
There was an intermittant tick when I first bought the car but it went away after I [censored] about with water-cleaning the cylinders, so I was tempted to call it pre-ignition. Maybe something loose just got ground away and/or lodged somewhere.
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