Engine oil dipstick

504231722 = without venting
47962399 = with ventilation

Too high pressure in the crankcase when starting at low temperature.
Closed crankcase ventilation (CCV) breather freezes at very low temperatures.
Leakage in front or rear engine crankcase seal.
Naturally condensed moisture collects in the closed crankcase ventilation (CCV) breather when the engine cools down.
At temperatures below -10 °C (14 °F), the moisture in the breather, located at the front left corner of the engine, may freeze. This temporarily increases the pressure in the engine block. When the engine warms up after starting, the ice will melt and the breather will function normally again.

In the worst case this can lead to leaks from the front and rear engine crankshaft seals.

Production:
In production, the breather has been revised and relocated to the rocker cover to prevent moisture build-up. The rocker cover was revised internally and externally to allow for revised CCV venting.
The new design of the cover seal and CCV vent was introduced into production from the following serial numbers:
T4.55 T4.65 und T4.75 ZFAH04697
T4.85 T4.95 T4.105 T4.115 ZFJT10250
T5.95 T5.105 T5.115 ZFJJ50004

Farmall55C Farmall65C Farmall75C ZFAL04712
Farmall85C Farmall95C Farmall105C Farmall 115C ZFJV10251
Farmall95U EP Farmall105U EP Farmall 115U EP ZFJK10226