Red Zone Is Not Always Danger Zone

Times Staff Writer

Question: The temperature gauge on my 1983 Toyota Celica rises into the red zone and stays there for a minute or two after the car warms up before dropping back down to the normal temperature reading. This happens with every cold start without boiling over or blowing a hose. I had the thermostat and temperature sensor replaced. What sort of problems could result from such extreme temperatures?--W.D.M.

Answer: Despite what the gauge says, the car is probably not overheating. The sensor on your car (and many other models) is located at a spot on the engine where the coolant gets hot quickly from the engine manifold. This causes the temperature reading on the gauge to sometimes rise into the danger zone. Then, when the thermostat opens and allows coolant to flow from the radiator into the engine block, the temperature reading drops down to more accurately reflect the engine's operating temperature.

The only solution would be to install a thermostat calibrated to open at a cooler temperature. But then the engine might not run as hot as it should. As long as the gauge reading drops back down to the normal range soon after starting the car, you need not worry about damaging your engine.

Q: My 1980 Volkswagen Rabbit is difficult to start after it has been parked in the hot sun and often stalls once I do get it going. After I drive a half mile or so, the car runs smoothly. The car starts fine if the engine is cold. What are the possible causes of this hard starting?--T.Y.

A: Difficulty in restarting a car after it has been warmed up is a common problem for many car owners, and there are many possible reasons for the trouble. A common one at this time of year, particularly on unseasonably warm days, is that the gasoline is formulated for cold weather and is vaporizing too quickly, resulting in a form of vapor lock. Oil companies that produce gasoline blend it for either cold or warm weather, and a warm winter day can result in starting problems because the gasoline was made for cold temperatures.

Another possibility is that the fuel system isn't working properly. If your car has fuel injection, you could have a short circuit in an electrical connection that controls the flow of fuel into the combustion chamber. If you have a carburetor on your car (the 1980 Rabbit had two different types of fuel systems), the float could be sticking, allowing too much gasoline to reach the combustion chamber and flood the engine.

In most cases when the car is hard to start but runs fine once it gets going, the trouble is somewhere in the fuel system.

Q: I have a 1983 Buick Regal and have been told by my dealer that I should have the "slip spline" serviced every 5,000 miles, at a cost of $9.60 each time. What is the slip spline? Does it need servicing that often?--W.A.

A: The slip spline, more commonly called the slip joint, is a connection on the drive shaft of a car that permits the shaft to become longer or shorter when the vehicle goes over bumps in the road. If the shaft were a solid piece of steel, the front and rear suspension systems would be connected too tightly together, and the ride would be quite harsh.

The slip joint is simply a smaller shaft inside a larger tube, like a pencil stuck into a straw. To make sure the shaft turns, it has "splines" on it, which fit into grooves in the tube.

Some cars have a slip joint in the drive shaft itself, while your car has it where the drive shaft fits into the transmission. The one on your car requires no service, according to Buick officials. Go back to the dealer and find out what he is charging you $9.60 to do.

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