Thermo King T-500R Maintenance Manual page 142

Normal crankcase pressures with a new air cleaner are shown below:
The vacuum will increase as the air cleaner gets dirty and becomes more restrictive. Remove the breather cover and the baffle
plate and check to make sure nothing is plugged or damaged.
See the TK270, TK370, and TK376 Engine Overhaul Manual (TK 53163) for the procedure to check the crankcase pressure.
If your readings are significantly more positive than 0 to 11 in. (0 to 279 mm) H
the rings. A compression check should be performed to confirm this.
The following items can effect the crankcase pressure readings.
3
1. Breather Cover
2. O-ring
3. Baffle
4. Baffle Plate
Crankcase Breather Components
Unit/Speed in. (mm) H 2 O of vacuum
Truck/Low 0 to 8 in. (0 to 203 mm)
Truck/High 2 to 11 in. (51 to 279 mm)
TriPac 0 to 8 in. (0 to 203 mm)
Crankcase
Pressure Effect
Increase Piston Rings Stuck or Worn
Increase
Decrease Air Cleaner Dirty or Plugged
Engine Maintenance
1
2
4
O of vacuum, you may have excess blowby past
2
Typical Cause
Restrictor Plugged
9-4