Volvo Maintenance Hints for 7xx/9xx - Bill Garland's Nuclear ...

Volvo Radiator Destructive Test
Radiator Replacement
Coolant Reservoir Replacement
Engine Freeze Plugs
Coolant and Maintenance:
960 B6304 Coolant Loss: Coolant Cap At
Fault
Homemade Cooling System Pressure Tester
Coolant Recommendations. See the FAQ File with more technical information about coolants.
[Editor] Folks have tried various coolants in place of the Volvo Blue-Green, which is expensive.
Your choice falls into three categories:
● Highly-silicated conventional green antifreeze (e.g., Prestone and many other brands)
● Dexcool orange with no silicates and organic acid corrosion protection (e.g., Havoline
Dexcool and Prestone Dexcool)
● Glysantin orange-yellow with low silicates and organic acid corrosion protection (e.g.,
Zerex Extreme G-05)
My own experience with Dexcool has been positive with one exception: the solder in a Nissen
brass radiator began leaking . Dexcool is known to have problems with high-lead solders, and is
also sensitive to air levels in cooling systems. If you don't keep the system topped off to the
"min" mark on the reservoir, it may cause scaling and rust precipitation. The last Glysantin
alternative is new in the US, although well-known in Europe, and may be the optimal
replacement coolant for Volvo. It has a small amount of silicates to improve corrosion protection
for lead and aluminum, but not so much as to precipitate out, and in addition uses an OAT
package.
Dexcool Coolant [From the AC-Delco site:] Neon orange in color, the coolant lasts up to five
years or 150,000 miles, whichever comes first. Conventional coolants need to be replaced every
two years/30,000 miles. DEX-COOL’s benefits include: Lower maintenance costs, due to longer
change intervals; enhanced component durability -- improved water pump seal performance and
superior heat exchanger protection over regular-life coolants; recyclability. Note: DEX-COOL’s
unique orange color acts as a reminder not to mix the new formula with conventional coolant
(usually green in color). Although it won’t damage your car’s cooling system when mixed with
other coolants, DEX-COOL will lose some of its effectiveness. (Warning: Do not use DEX-COOL
with Cooling System Seal Tabs, Radiator Fast Flush or Radiator Stop Leak.)
[Motor Magazine, Aug 2004] One of the coolant issues that may arise is the use of an
aftermarket replacement radiator or heater core made of copper-brass with lead solder. We
have in previous articles pointed out that today's coolant inhibitor packages contain a small
amount of copper-brass protection, but may provide little protection if a radiator is made with