Canada - HVAC - Optimum Cabin Interior Temperature

Bulletin
0706

Issue Date
1999-12-23

Reference
EM-98-006

Model
ALL

Year Range
1985 ~ 2002

Market
Canada

Component
EM

Subject:
SERVICE HINT ~ OPTIMUM CABIN INTERIOR TEMPERATURE (ALL MODELS).

The following Service Hint has been published as a quick reference guide.

1. Optimum cabin interior temperature (All Models).
- The addition of Genuine Toyota Long Life Coolant (LLC) to water in the engine's cooling system, provides corrosion protection to all engine cooling system components. However, the addition of LLC also lowers the freezing point of water.
- For best heater performance, it is recommended that the LLC concentration be adjusted to between 50 ~ 60% using an optical-type coolant tester; (see Fig. 1).
- DO NOT EXCEED 60% CONCENTRATION as cabin interior heating efficiency will be reduced; (see Fig. 2).





- For manual-type heater controls, check air-mix damper control cable operation. For rotary dial-type temperature selector operation an audible 'thump' should be heard when selecting from any position to max. hot position. If not, it may be necessary to adjust the control cable. Also when using temperature selector controls, the lever should be placed in either the recirculation or fresh air position; placing the lever in the midposition will result in ventilation losses.





NOTE:
A 60% LLC concentration provides freeze protection to a temperature of approximately -50�C.

NOTE:
As you can see, for a too viscous LLC concentration (65%), the output temperature drops rapidly. In fact you can expect a 20�C temperature drop in a period of just 1 minute (measured at heater outlet, foot level). This condition arises from an increase of LLC circulation resistance in the cooling system. At 55% LLC concentration, the heater outlet temperature is relatively stable.

CAUTION:
When replacing engine thermostats, please be aware that thermostat, pt. no. 90916-03110 is intended for use on Paseo and Tercel only.

NOTE:
Issue of this Technical Service Bulletin is to ensure that proper repair information is available. IT DOES NOT CONSTITUTE AN AUTHORIZATION FOR REPAIR. Normal provisions of the formal warranty policy, as applicable, will apply.