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

high-lead solder. Results of industry standard tests of the new Toyota extended-life coolant now
show a substantial weight loss (corrosion), both in a 50-50 mix and in a 33% coolant mixture
(solder corrosion is much greater in this more diluted solution). If you have to change a radiator
or heater core, use aluminum. Or, if it's an older car and the owner wants the lowest-cost
radiator, you might procure a soldered-together copper-brass unit. Conventional American
coolant should provide better protection against solder corrosion, which can result in radiator
tube restrictions and leaks. But no coolant provides perfect protection.
[Ywan Mason] Dex-Cool, according to a GM service bulletin only gives the extended life when it
was used as the first and only coolant in the car. Residual amounts of conventional coolants left
in the system even after careful draining require that the Dex-Cool be changed at the same
interval as any other coolant, every two years. [Chris Herbst] Dexcool can cause problems if
installed in a leaky system, or if it is used in a system run low on coolant. Also, it finds leaks
where typically there may not be any (or one might not see any).
Zerex G-05. This is Valvoline's new Zerex coolant, known as Extreme G-05. From their
website: Extreme G-05 is a low-silicate, low-pH, phosphate-free, formula that is designed to
protect diesel engine cylinder liners from cavitation. Extreme G05 is safe for both gasoline and
diesel engines and is approved by DaimlerChrysler for worldwide MTU applications. Utilizes
hybrid organic acid technology to minimize inhibitor depletion; Low-silicate, low-pH and
phosphate-free formula; Protects all cooling system metals, including aluminum
Makeup Water. [Tip from Prestone's Info Line] We would consider the order of preference for
water to be as follows:
1. 1st choice: Type IV water- Both demineralized & Deionized.
2. Next choice: Distilled water
3. Next choice: Bottled water (like the type at a grocery store)
4. Last choice: Tap water
Draining Engine Coolant.
Which Coolant to Use? See the discussion on Coolant Recommendations .
Block Drain Plugs Location.
B230F. [Inquiry:] B230F - I want to flush the cooling system, but the only block drain I see is a
threaded male plug on the RH side of the block (kinda high) below exhaust manifold runners 1
and 2. Is that all there is? [Response: Randy] Look for the block drain on the passenger's side
of the block, #4 cylinder back just above the oil pan and in front of the transmission bellhousing.
13mm wrench will loosen, continue to turn counterclockwise and the coolant will flow out. You
can attach a hose and run it into a container with about a 2 gallon capacity. If it hasn't been
used in some time you may have to clean it out to get a good flow. You can also unscrew the
entire drain. Open the reservoir cap to increase flow. You will not be able to remove all the
coolant: it always seems as though about two quarts remains in the system. On the 940Turbo: