My Dad's 99 Taurus seems to have been having the same clogged heater core problems that have been reported by numerous posters here. He had the system flushed by his regular mechanic at the start of last winter, which helped somewhat but did not return the heat to full operation. With the onset of cold weather in November, it was obvious that the heater performance had declined again, so he had his mechanic do another flush, this time with a special "high pressure" flush system the garage had just gotten. The heater performance remains very poor. I discussed the problem with the mechanic, who mentioned that the heater core had a bypass tube, which, if clamped shut, improved the heater performance. He was a little confused because he had apparently never seen a bypass straight across the heater core like this.
From what I have read of others comments here, it seems that the problem is relatively easily solved by doing a thorough backflush, and that the poor results other posters (and my dad as well, probably) have got from having mechanics do the flush is that they don't seem to persist until the core is completely cleared (which may take 3-4 flushes). My questions are:
1) From some posts, I get the impression that the bypass was put on the heater core as part of a recall fix. Can anyone tell me the problem that was being fixed, and why/how the bypass fixes it? 2) Since the heater performace improves substantially with the bypass clamped shut, is there any damage likely to be created by just leaving it clamped shut until I can get around to doing a thorough backflush? (Morning temps are less than 10 F the last few days...)thanks in advance,
Paul