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I own a 1988 Volvo 240 DL & have two problems that my local mechanic can't seem to figure out. The car has started to overheat. The mechanic has replaced the radiator, the thermostat & the hoses & it's still happening. The coolant in the reservoir is hot. It doesn't happen all the time, but when it does, it can happen right away or when the car is running for a while. It doesn't seem to matter if it's cold or hot outside. Secondly, now the car doesn't start when it rains. As soon as it's dry out again, it starts right up. Any thoughts? I'm starting to get fed up with it.
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Could you give me a bit more information? Does the car change at all when it overheats? A loss of power, stumbling idle, surging? How do you know it is overheating? Are you taking readings from your temperature gauge, or have you confirmed that the water will physically boil over when you let it run? I ask because sometimes the gauges themselves malfunction and give incorrect readings, essentially telling you an overheat is in progress when in fact, you are doing just fine. Give me a bit more info about what happens to the car during this process. Can it happen during idle, or only when running?
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We first noticed the car overheating only by the temperature gauge. The car doesn't seem any different at all when the temperature gauge reads hot. It happens at different times. It might happen when it's idling or local driving or on the highway, but not always. The last time the temperature gauge read hot, my daughter opened the hood & turned the cap of the coolant reservoir a little & it hissed like the sound steam would make. We had thought maybe it was just the gauge, but should the coolant in the reservoir be hot?
Answer -
It is normal for the coolant in the reservoir to be very hot (about 180 degrees). To me that is a good sign, because it indicates the coolant is circulating properly while the car is running. It is also normal for pressure to escape when you take the cap off the reservoir, because coolant expands when it gets warmer, so there will be an increase in pressure until you release it or the coolant cools down. That pressure indicates you have a nicely sealed coolant system, again to me that is good news. What would be bad would be if while the engine was running and overheating, you were to open the reservoir and see actual steam come out consistently, or if you saw bubbles coming up through the reservoir. Generally when an engine begins to over heat, there are physical symtoms, like stumbling rough running. Check for some of these other indicators to determine if the car is actually overheating.
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Thank you. Because of the car not having physical symptoms, I think you must be right & it must be that the gauge is faulty. My second question was about the car not starting lately when it rains & then starting right up again when it's not raining. Is this something you're familiar with about older Volvo's?
AnswerI warn you to still be careful about the overheating, just in case we are wrong and the engine really does have an issue. If you drive it too hot, you can destroy your engine, so keep an eye on it. As for the wetness issue, I would suspect it might be the same wiring issue that is causing the gauge to work improperly. When it gets moist outside, that can help conduct electricity in a short and make an electrical problem worse. If when it is wet your engine will turn over but not start, I would check to make sure you are getting a spark at your spark plug. Also, inspect all wiring under the hood and look for frayed or bare wires that might short out.
