Tuesday, 19 May 2009 15:14

Hey Toby 13---High Voltage Wires, Sealing Foam, Prius Coolant, and Radiators

Written by Toby Chess

Hey Toby—I thought that all high voltage wires on hybrids are orange, but an adjuster told me that there are other colors. Are there more that one color for high voltage wires?
    —Dan from Fresno

Hey Dan—Thanks again for hosting the I-CAR classes at your shop. As to your question, yes, there are several color wires for high voltage. You can have blue wires (Some GM products) that carry 36 volts, Yellow (Toyota and Lexus) that carry up to 48 volts and orange for over 100 volts.


Dan, I would recommend that you and your staff take the ALT 02 from I-CAR. Give me a call and I will set it up.

Hey Toby—I liked your info on air conditioning. Got any more helpful hints?
—Bob from the Valley of the Sun, AZ

Hey Bob—Move to some place cool during the summer. Just Kidding! I put together a series of scenarios using the manifold gauges and center vent temperature. Here are a couple that may help you.

 Problem 1
Low Side (blue) is low, High side (red) is low and center temperature is warm—Most likely the system is low on freon. Also check for restriction in the high portion of the system,

Problem 2
Low side is high, High side is High and center vent temperature is warm. One more check reveals that the high pressure hoses are extremely hot. Most likely the condenser is not working properly. Another problem could be an overcharge of refrigerant.

Problem 3
Low side is normal, high side is normal, and center vent is warm. Air and /or moisture is in the system.

Problem 4
Low side is low and High side is High and center vent temperature is slightly cool. Upon further inspection the expansion valve is found to be frosted or sweating. The expansion valve is most likely stuck open

Problem 5
Low side reads high and high side reads low and temperature at the center vent is warm. The culprit is in the compressor system. If the compressor is no noisy there may be a worn or loose compressor drive belt.

Hey Toby—I recently received an A/M radiator and it was missing the foam on the top and bottom (See photos).

Question—What is the foam used for? —Sam from Los Angeles

Hey Sam—The foam is used to seal off the condenser. The hood will sit on the foam and direct the air so that it goes thru the condenser and not over the top. You need to transfer the foam and it is not included item on the estimate.

Hey Toby—Do you need any special tools to bleed a radiator on a Toyota Prius?
—Jill in Sacramento, CA

Hey Jill—You will need a scan tool to open the coolant control valve, which begins the bleeding procedure. Any air trapped in the system can ruin the inverter/converter unit and that could be very costly. You will also need to use straight coolant from Toyota (do not mix with water). I-CAR has a great video clip on this procedure in their ALT 02 class.

Hey Toby—Our shop had a Toyota Prius towed into in with front end damage. There is a tank mounted to the left rail (see picture). It is slightly damaged. I have 2 questions. First, what is it used for, and second, does it need to be replaced?
—Henry from San Diego

Hey Henry—Great questions and thanks for the picture. It is a storage tank for the coolant. It is designed to keep the engine coolant warm for up to 3 days. The engine will run more efficiently when it is warm. It will also produce less emissions when it is warm. To your second question, Toyota states that any damage to the unit, including broken brackets will require replacement. For a more detailed discussion, again I would recommend that you and your staff take I-CAR’s ALT 02 .

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