What is an "oil slinger"...and is it important? 'Cuz I forgot it.

Dear Car Talk

Dear Car Talk | Apr 01, 1996

Dear Tom and Ray:

I have a '76 Ford motor home with a 351 engine. I have replaced the timing chain and gears with new steel gears and a new chain. After I had put it back together, I realized that I had left out the "oil slinger." My questions are: What is the purpose of the oil slinger? What is likely to happen if I don't replace it? And should I worry about it? -- Harold

RAY: To answer your last question first, Harold, no, you don't have to worry about it. Every time I rebuild an engine, I have a box full of parts left over. And none of my customers has ever come back looking for any of them.

TOM: With the exception of an oil drain plug once.

RAY: The oil slinger is a thin metal disc that deflects the oil away from the crankshaft seal. The oil that lubricates the timing chain is pumped toward the crankshaft seal at high pressure and very high volume.

TOM: And that slinger sits between the timing chain and the seal and keeps a lot of the oil from pounding directly on the seal. Without it, the crankshaft seal wouldn't be able to handle all of that oil, and eventually, might let some of it leak out.

RAY: The reason it's not leaking now is because your crankshaft seal is brand-new (I assume you replaced it when you replaced the timing chain). But over time, it could start to leak.

TOM: And if and when it does, you can take it apart again, replace the seal, and re-install that old oil slinger. Just don't lose it in the meantime!

RAY: Right. You might want to make a little ornament out of it and hang it from your rear-view mirror ... unless that would be too constant and painful a reminder of the dumb mistake you made by leaving it out in the first place.

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