SEPT 16/96, SONIC PMTN ADDITION FOR SECTION 1.3 OF ALL PMTN'S

Cooling Systems

It is very important to keep the cooling system in good condition. This PMTN addition is
addressing rad caps and radiators in all years of the Toyota A body. 

Clutch fans should be replaced after 150,000 miles or anytime there is any sign of
excessive oil and dirt build up at the seals by the input shaft. Genuine Toyota rad caps and
thermostats should only be used, they are much better than any of the aftermarket
brands. When installing new thermostats be sure to check for correct placement of small
check valve on thermostat, it should be at 12 o clock at the top.

You should also remove the radiator on high mileage cars to check for weeds and foreign
material between the engine radiator and AC condenser. It is very common to see large
amounts of foreign material trapped in there, this material will restrict air flow to the
radiator causing cooling problems.

Depending on what year Supra you have there are 2 types of radiator designs. 1982 to
1985 MA-67's use a copper radiator. All copper radiators use the same style of rad cap.
The 1986.5 to 96 Supras use a plastic & alloy radiator design. The plastic & alloy
radiators use two different types of rad caps.

There are 3 styles of rad caps used on Supras, all three are unique in design and can not
be mixed and matched. One of the designs is better than the others. You will have to use
the correct cap for your type of radiator. I  recently ran into a 1987 Supra Turbo with a
rad from a 1990 or newer. The owner was trying to use the cap from the 87 and was
driving the car with no pressure in the radiator.

Style 1. Pn# 16401-36011 Rad Cap is the large round one used on all years MA-67's,
it is also used on most older Toyota cars, trucks & fork lifts. This one is the best of all
the types and will last much longer than the other two styles. They are used on all copper
radiators only.

Style 2. Pn# 16401-83010 Rad Cap is a small diameter cap used on 86.5 to 90
MA-70's, it has very small seal areas and is prone to early failure. My 1990 V6 4
runner is now on its 3rd one in 120,000 miles. I replace them every 24 months or
50,000 miles. If you have a 87 to 90 Supra and don't know if you have changed your rad
cap, you need one, go and buy one today!

Style 3. Pn# 16401-72090 Rad Cap is also a small diameter cap it is used on 1990 to
1996 Toyota Supras. This cap looks very much like style 2 but has redesigned seals, this
style will last longer than style 2 but not as long as style 1. I would recommend changing
it at the same intervals as the style 2 cap just to be safe.

Many people seem to change the original factory pinch style rad hose clamps for the
more common screw type hose clamps. Always use the factory Toyota rad hose clamps
that come with the Supra when it was new. If you tossed them out buy yourself a new set
or get some from the junk yard. This clamp will allow for expansion in the rad hoses,
your hoses will last much longer with them. They are by far the best clamp to use in this
location, that is why Toyota put them there.

END OF FILE

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{SONIC} Supra Owners Network In Canada
FROM THE HOME OF THE SUPRA GTE
Information provided is given free of charge in good faith without prejudice.
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