SERIES 60 ON-HIGHWAY ENGINE OPERATOR'S GUIDE See Figure 26 for inhibited propylene glycol-base (IPG) coolant concentration versus freezing and boiling temperatures. antifreeze/water mixture are correct by using a POWER Trac ® 3–Way Coolant Test Strip. If chemical analysis is used, elements in the coolant must fall within the limits listed in Table 17. Always verify that the freeze point and nitrite concentration of the Figure 26 Coolant Temperatures vs IPG Concentration (Sea Level) All information subject to change without notice. 93 DDC-SVC-MAN-0039 Copyright © 2009 DETROIT DIESEL CORPORATION