Maybe There’s No Overheating
Question: We have had an overheating problem on our 1988 Toyota Camry LE from the start. This car heats up when driving up inclines or in hot weather. The Toyota dealer has not been able to find out what is causing this. On a recent trip to Las Vegas, we had to stop three times each way and wait for the temperature needle to return to normal.--J.B.
Answer: You may be among the many motorists who mistakenly fear their car is overheating simply because the temperature gauge shows the engine is operating hotter in high-load situations.
You do not mention whether the cooling system actually boiled over. Rather, you have become alarmed because the temperature needle has swung over to the hot side of the gauge.
It is acceptable for the temperature needle to move into the yellow portion of the gauge. It is not until it moves into the red zone that the engine is about to overheat.
No engine’s cooling system is able to maintain a stable internal temperature under all operating conditions. On hot days or when running up a steep hill, engines inevitably run hotter.
The Camry is designed to climb a difficult mountain pass in hot weather without overheating. At its normal temperature, the engine coolant is supposed to be 190 degrees to 208 degrees at a pressure of 14 pounds per square inch.
The coolant, however, can get significantly hotter without the engine overheating. At 220 degrees, a sensor in the engine will automatically turn off the air conditioning and relieve the engine of that additional load.
The engine coolant does not boil over until it reaches about 240 degrees, assuming that you are using the correct radiator mixture of 50% water and 50% glycol antifreeze.
Next time, keep a close eye on the gauge. If after a trip through the desert you have not lost any coolant, the system is probably fine. Otherwise, you should have the radiator checked for blockage and the thermostat changed.
Q: I have a 1990 Ford Taurus GL with a 3.8-liter engine. The engine smells like sulfur or rotten eggs. The catalytic converter was replaced, but the stink persists. Most of my trips are relatively short. How do I get rid of the smell?
-- S.K.
A: The stench comes from the gas hydrogen sulfide, a byproduct of combustion. The engine is not supposed to generate the gas if it is correctly tuned.
The condition is most often associated with an improper fuel-air ratio, typically an over-rich mixture. But knowing the cause does not provide a solution.
Ford issued a number of technical service bulletins in 1986 and 1987 to assist mechanics in addressing the problem. They described a procedure in which the mechanic would run an engine control module check (a computerized diagnostic system) to determine if there is a specific problem.
If the diagnostic turns up a glitch, it is likely to be covered under your 50,000-mile warranty on the car’s emission system.
With or without diagnostic checks, mechanics often can correct the problem on 3.8-liter engines by adjusting idle stops on the fuel injection system’s throttle body.
The throttle body is the portion of the injection system that regulates the flow of air into the engine. By reducing the air flow, the engine will get a richer mixture. By increasing the air flow, the engine gets a leaner mixture.
In addition, a leaky fuel injector can also allow too much fuel into the cylinder, resulting in hydrogen sulfide gas. A good mechanic should be able to eliminate the stink and possibly improve the performance of the engine.
