Foamy Residue

R

Robert Legner

Member
I have a 1950 Ford with an 8BA stock engine. I run Rotella 15-40 detergent oil with a small amount of MM oil added. When I drive the car, 10 or more miles, the oil filler tube cap shows a foamy yellowish residue. The foam feels oily with the moisture droplets showing The same residue drips off the draft tube also after the drive. Any ideas about the reason for this, is it the oil? Are the moisture droplets simply the moisture accumulated inside the engine? If I drove the car farther would the foam/moisture burn out? Thanks in advance for your thoughts.

Ford Ranger
 
A bit of blowby maybe. Seems kinda normal. The more you drive it, probably less you're gonna see. Jack E/NJ
 
I'm thinking you're not getting it up to proper operating temperature for a long enough period of time....
 
Yes, the engine has thermostats, the operating temperature runs in the normal range. I would think 10 miles of driving would dry out an engine, maybe I need to drive it 50 miles and then check it.
 
What are you calling "normal" range, or are you just reading the original temp gauge? If so you might want to try a hand held IR temp meter. Very hand to have and not very expensive.
 
have you added any water/antifreeze to engine lately?, smell any antifreeze at the tailpipe? any sparkplug show signs of water? or maybe just different from the others? these are things I would check on. but you definitly have a moisture problem. road draft tube not blocked, fill cap not plugged up with dirt. drive the engine with a piece of cardboard in front of radiator to raise temp a little, not a big, just maybe 8" square
 
If you look at the cap is it all rusty and crappy looking inside too? sounds like you need to run it at temperature for longer. Condensation is happening.
 
Just to be sure there is not a serious coolant leak into the oil, - Does the oil on the dipstick look normal? Not a little creamy?
 
Check the crankcase vent system. Could be a blocked draft tube or a clogged mesh in the oil filler cap.
Ken
 
There is no smell of anti-freeze from the tail pipes, the oil on the dipstick is clear, yesterday I soaked the oil filler cap, seemed to be dirty, possibly was not vented if it was too dirty. Thank you for your responses
 
I ran the car today, did not drive it, just warmed it up in the shop, and inspected the moisture coming out of the tail pipes. The moisture was clear, no antifreeze odor. And, the oil fill breather seems to be clear now, blow-by fumes escape there and are dissipated by the fan stream of air. Will drive the car quite a few miles to see if the foam disappears.
 
In my last post I failed to mention the oil is clean, no moisture on the dip stick, and there are no bubbles in the radiator when the car is running. I do not think there is an antifreeze leak into the firing chambers. Does the draft tube and the oil filler tube vent blow-by from the the same parts of the engine? It would seem the draft tube would vent the upper part where the tappets are, and the oil filler tube would vent the lower part where the pan and crankshaft operate. Or are then somehow connected?
 
Might get that thermal heat reading gun so you know what temp your up to for your test run. They can be found for very little cost.
 
Robert Legner said:
Does the draft tube and the oil filler tube vent blow-by from the the same parts of the engine? It would seem the draft tube would vent the upper part where the tappets are, and the oil filler tube would vent the lower part where the pan and crankshaft operate. Or are then somehow connected?
Click to expand...

The intended route for the crankcase fumes to leave the engine: The position of the draft tube provides for it to create a vacuum at speed. This vacuum pulls outside air into the lifter valley through the oil filler tube, down into the crankcase through holes in the valley, and out via the draft tube. The oil fill cap is somewhat of a filter for the air coming into the engine and must be clean for air to circulate.
 
Here is the general principle of a road draft ventilation system.
 

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Thank you guys, I think my problem was a clogged oil filler cap which did not allow for the draft tube to do it's work. I understand the system now. I have owned the car for a number of years and never cleaned the filler cap. I surely appreciate the input. Appreciated!
 
Prolly all clogged up from all that foamy residue your motor makes on those short trips. 8^) Jack E/NJ
 
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