User Manual

HOW-TO SECTION
Coolant Extender Inhibitor
Additive for “OAT” Coolant
The inhibitors in OAT coolant must
also be maintained, but less often
than traditional SCA-type coolants.
A po rtab le test is available to test the
levels of OAT inhibito rs in coolant.
Where this is not u sed, fleet testing
has determined that a OAT coolant
extender package should be added to
the coolant at 300,000 miles (480,000
km), two (2) years, or 5,000 hours,
whichever comes first. The proper
maintenance dosages for all OAT
coolants are listed in Table 26 ,
reflecting 0.6% by volume extender.
This dosage should be added t o the
water-only and the glycol systems at
thesameinterval.
The pro per application of extender to
OAT coolan t will p rov ide:
□ pH Control
□ Restored inhibitor levels to prevent
corrosion
□ Cavitation p rotection to protect
wet sleeve cylinder liners
NOTE:
Do not use tra dition al SCAs in
OAT coolant, and do not use
OAT extender in traditional coolant.
OAT Coo la n t Drain Interval —
A properly maintained OAT-inhibited
coolant will last 600,000 miles
(960,000 km), four (4) years, or
10,000 operating hours, whichever
comes first. At this time th e coolant
should be drained, an d th e cooling
system should be thoroughly cleaned,
flushed, and filled with new, properly
inhibited OAT coolant.
Chronic Coolant System
Problems
The most commonly seen coolant
system problems result from
maintenance and formulation factors
such as:
□ Hard water
□ Dilution of the coolant by the
addition of u ntreated water
□ Over dosage or under dosage of
corrosion inhibitors
□ Improper corrosion inhibitor (most
often phosphated)
□ Mixing SCAs
□ Improper testing
110 All information subject to change without notice. (Rev. 01/04)
DDC-SVC-MAN-0058 Copyright © 2004 DETROIT DIESEL CORPORATION