Honda 1991 Prelude Owner's Manual page 93

Cooling System (cont'd)
Thermostat
The thermostat in the cooling system does not need to be changed
for summer or winter operation. However, for extremely cold
climates, an optional thermostat is available from your Honda dealer.
Replacing Coolant
Replace coolant at 36 months or 45,000 miles (72,000 km), which-
ever comes first. Thereafter, replace every 2 years or 30,000 miles
(48,000 krn), whichever comes first.
RADIATOR COOLANT
REFILL CAPACITY:
(Including reserve tank)
6.15 l (1.625 US gal, 1.353 Imp gal)
1. Set the heater temperature lever to maximum heat.
2. Remove the radiator cap and loosen the drain plug when the
radiator is cool, and drain the radiator.
RADIATOR
CAP
DRAIN
PLUG
3. Remove the drain bolt from the front side of the cylinder block,
and drain the engine and heater.
4. Apply non-hardening sealant to the drain bolt threads, then rein-
stall the bolt and tighten it securely.
5. Tighten the radiator drain plug securely.
0.75 l (0.198 US gal ,0.165 Imp gal)
BLEED BOLT
DRAIN BOLT