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OK, since last fall I thought I had a pinhole in the heater core, since I could smell antifreeze faintly, and the windshield very slowly developed a fog pattern that would not clear on a 40-mile ride. Engine temperature since I did the head gasket a year ago has always been between the warm and 1/3 marks. Antifreeze loss was about 4 oz or so every week or two - 400 to 800 miles. Nothing on the ground, nothing loose.
Last week I found a pinhole in the overflow jug and fixed it with a patched spare from my 92 (it leaked at Carlisle in 2006, from the bolt flange). Replacing the jug stopped the coolant loss and smell completely. Great, heater core must be fine.
However, now the temp gauge goes up to the halfway mark, or a hair beyond, when idling in traffic. Stays in the normal range on the highway. I bled the system by parking uphill, and the coolant level has been stable all week.
Last night I looked underhood with the engine idling after a 40-mile ride home, and the jug level was normal, no change. I touched the top radiator hose - hot, normal. I touched the radiator cap - cold. COLD. I put my hand across the top of the radiator core. Very warm at the hose inlet, with a temperature gradient down to body temp or less at the cap. I could keep my hand on it indefinitely.
I know there should be a slight gradient, because the radiator has to shed heat in the path between the top and bottom hoses. However, this is not normal. Thoughts? Clogging radiator? The fins are all intact.
Last week I found a pinhole in the overflow jug and fixed it with a patched spare from my 92 (it leaked at Carlisle in 2006, from the bolt flange). Replacing the jug stopped the coolant loss and smell completely. Great, heater core must be fine.
However, now the temp gauge goes up to the halfway mark, or a hair beyond, when idling in traffic. Stays in the normal range on the highway. I bled the system by parking uphill, and the coolant level has been stable all week.
Last night I looked underhood with the engine idling after a 40-mile ride home, and the jug level was normal, no change. I touched the top radiator hose - hot, normal. I touched the radiator cap - cold. COLD. I put my hand across the top of the radiator core. Very warm at the hose inlet, with a temperature gradient down to body temp or less at the cap. I could keep my hand on it indefinitely.
I know there should be a slight gradient, because the radiator has to shed heat in the path between the top and bottom hoses. However, this is not normal. Thoughts? Clogging radiator? The fins are all intact.