RAM 2500 2021 Owner's Manual page 427

This vehicle has not been designed for use

with propylene glycol-based engine coolant.
Use of propylene glycol-based engine coolant
is not recommended.
Some vehicles require special tools to add

coolant properly. Failure to fill these systems
properly could lead to severe internal engine
damage. If any coolant is needed to be added
to the system please contact an authorized
dealer.
Adding Coolant
Your vehicle has been built with an improved
engine coolant (OAT coolant conforming to
MS.90032) that allows extended maintenance
intervals. This engine coolant (antifreeze) can
be used up to ten years or 150,000 miles
(240,000 km) before replacement. To prevent
reducing this extended maintenance period, it
is important that you use the same engine
coolant (OAT coolant conforming to MS.90032)
throughout the life of your vehicle.
Please review these recommendations for
using Organic Additive Technology (OAT) engine
coolant that meets the requirements of the
manufacturer Material Standard MS.90032.
When adding engine coolant:
We recommend using Mopar® Antifreeze/

Coolant 10 Year/150,000 Mile (240,000 km)
Formula OAT that meets the requirements of
the manufacturer Material Standard
MS.90032.
Mix a minimum solution of 50% OAT engine

coolant that meets the requirements of the
manufacturer Material Standard MS.90032
and distilled water. Use higher concentra-
tions (not to exceed 70%) if temperatures
below −34°F (−37°C) are anticipated.
Please contact an authorized dealer for
assistance.
Use only high purity water such as distilled or

deionized water when mixing the water/
engine coolant (antifreeze) solution. The use
of lower quality water will reduce the amount
of corrosion protection in the engine cooling
system.
NOTE:
It is the owner's responsibility to maintain the

proper level of protection against freezing
according to the temperatures occurring in
the area where the vehicle is operated.
SERVICING AND MAINTENANCE
Some vehicles require special tools to add

coolant properly. Failure to fill these systems
properly could lead to severe internal engine
damage. If any coolant is needed to be added
to the system, please contact a local autho-
rized dealer.
Mixing engine coolant types is not recom-

mended and can result in cooling system
damage. If HOAT and OAT coolant are mixed
in an emergency, have an authorized dealer
drain, flush, and refill with OAT coolant
(conforming to MS.90032) as soon as
possible.
Cooling System Pressure Cap
The cap must be fully tightened to prevent loss
of engine coolant (antifreeze), and to ensure
that engine coolant will return to the radiator
from the coolant expansion bottle/recovery
tank if so equipped.
The cap should be inspected and cleaned if
there is any accumulation of foreign material on
the sealing surfaces.
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