The 5 Liter Ford Corporate engines were notorious for this kinda of deposit too. They had a "2-hump" oil pan in which the tie rod passed so close to the pan that the engineers put a notch in the pan.
Unfortunately, that made it really complicate to change the oil in the bump where the oil was hidden ---- so --->
THE BRIGHT ENGINEERS AT FORD put a second oil pan plug in it because turning the vehicle upside-down just to drain the oil didn't appear to be a good option - not that the customer would understand it anyway!
Sadly, quickie oil change shops didn't want to drain the engine twice, so they just ignored the second plug and the customer got 1.75 quarts of oil every time.
After doing this a few times, the unchanged oil turned into overcooked molasses and even if you stuck your finger in the drain hole, nothing came out. Usually the first symptom was a total loss of oil pressure and if the customer actually paid attention to the red light, they'd stop and get towed.
But the oil pump drive shaft by Ford was only 1/4" hex drive and it couldn't take all the pressure so it tended to wind itself up around the camshaft and then there was trouble --- bigtime!
So, you see: the top of the engine was hot, there wasn't enough oil to cool things and the deposits crystallized there, but in the pan was a whole different pudding-story!
Gawd --- I loved dem Fords!
Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money!
Unfortunately, that made it really complicate to change the oil in the bump where the oil was hidden ---- so --->
THE BRIGHT ENGINEERS AT FORD put a second oil pan plug in it because turning the vehicle upside-down just to drain the oil didn't appear to be a good option - not that the customer would understand it anyway!
Sadly, quickie oil change shops didn't want to drain the engine twice, so they just ignored the second plug and the customer got 1.75 quarts of oil every time.
After doing this a few times, the unchanged oil turned into overcooked molasses and even if you stuck your finger in the drain hole, nothing came out. Usually the first symptom was a total loss of oil pressure and if the customer actually paid attention to the red light, they'd stop and get towed.
But the oil pump drive shaft by Ford was only 1/4" hex drive and it couldn't take all the pressure so it tended to wind itself up around the camshaft and then there was trouble --- bigtime!
So, you see: the top of the engine was hot, there wasn't enough oil to cool things and the deposits crystallized there, but in the pan was a whole different pudding-story!
Gawd --- I loved dem Fords!
Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money! Mo' money!