That hard gray paste in older cars' oil pans, heads, etc.
That hard gray paste in older cars' oil pans, heads, etc.
(OP)
The stuff that takes a scraper to remove from corners and low spots. Comes off in chunks sometimes.
There are plenty of stories about what that gray stuff is, and isn't.
Like zinc from ZDDP, or the final result of moisture from combustion byproducts the non-detergent oils couldn't handle, and so on.
My favorite is lead from "leaded" gas.
1 - Does anyone know what it really is?
2 - Does anyone know A simple inexpensive chemical test to differentiate lead from zinc. Anything from color change to Class O G pyrotechnics is fine.
thanks
Dan T
There are plenty of stories about what that gray stuff is, and isn't.
Like zinc from ZDDP, or the final result of moisture from combustion byproducts the non-detergent oils couldn't handle, and so on.
My favorite is lead from "leaded" gas.
1 - Does anyone know what it really is?
2 - Does anyone know A simple inexpensive chemical test to differentiate lead from zinc. Anything from color change to Class O G pyrotechnics is fine.
thanks
Dan T





RE: That hard gray paste in older cars' oil pans, heads, etc.
Mike Halloran
Pembroke Pines, FL, USA
RE: That hard gray paste in older cars' oil pans, heads, etc.
I do love Home Depot/Lowe's/NAPA/McMaster solutions.
Almost as much as "found on the side of the road on trash day" solutions.
RE: That hard gray paste in older cars' oil pans, heads, etc.
I've always assumed the gray stuff was lead. The last engine I found it in was a 390 Ford that had gone 100,000 miles at ~10 mpg on premium gasoline. I loved that car.
Mike Halloran
Pembroke Pines, FL, USA
RE: That hard gray paste in older cars' oil pans, heads, etc.
It will be a while for me, but I promptly sent the link for the 3M test kit to an old car forum to stir up some trouble.
regards,
Dan T
RE: That hard gray paste in older cars' oil pans, heads, etc.
A lot of the old guys still swear by non-detergent oil. See the results below.
RE: That hard gray paste in older cars' oil pans, heads, etc.