Now, I have a question: I just bought a 1989 Mercury Tracer Sta. Wgn. It is overheating. On the open highway, it does not so much. But in town it slowly reaches boiling point.
A new water pump was put it just two years ago, so I doubt that this is the problem. The fans are all functioning properly. I just put a brand new thermostat in itâ€“still kept overheating. It has a brand new, correct radiator cap. Coolant is at the right mixture. A shop just installed a new timing belt last year, so I donâ€™t think it is jump timing.) I just got through retiming it, placing the timing at the manufacturers recommended mark, degree. (Seems the engine idles faster at this correct mark though.) I read the work order for the timing belt and the mechanic who replaced the timing belt suggested that the radiator may need rodded out. But it was left undone, I suppose because the previous owner did not want to sink more money into it. I did flush it out well, but still over heats. (The way I self tested to see if perhaps the radiator fins were clogged was this: 1. I drained the radiator 2. then I left the bottom drain valve wide open 3. I placed our garden hose in the radiator cap snout and turned it on full blast. A good pressurised stream of water issued from the wide open drain cock below, so I assume that the radiator fins are open and clear. But, perhaps not all of them are? If there are some open, then the pressurized hose water could possibly be diverted into the open rather than the shut ones? Does it sound like the radiator may be clogged? I would sure appreciate mutual help as diagnosing a car is the hardest part, the repairs being the easiest part.
When the car has warmed up touch the radiator at different spots. If it is not uniformally warm and some areas are cooler than others then you could have a cloged radiator.