[olderndirt]

Here's one of those 'Oh no, not again' questions. Ford saw fit to add a heater core bypass hose to the '99 Taurus. My question - what, exactly, does it accomplish. We've been having the usual 'lack of heat' problems, have flushed back and forth but the bypass hose seems to be carrying most of the hot water from the block right around to the pump. I've always thought hot water should go through the heater core and, in line with that, what would be wrong with clamping that bypass hose, allowing the hot water to do just that. I'm thinking seasonally - end of September through May.

 

[danhasenauer]

The bypass is there to make sure your engine does not overheat in case the heater core plugs up. If you have flushed yours and are still not getting adequate heat, you may have a lot of large rusty particles jammed solidly in there still. I ended up replacing one using the heater core replacement shortcut in the topic finder. No need to remove the dashboard at all!

 

[olderndirt]

After the flush, heat came back but for how long? The bypass seems to be a fix that suited Ford but didn't cure the problem. To me, the bypass is like a river changing course, eventually the old course becomes a stagnant slough. There needs to be some simple mechanical way to divert the coolant to the heater core - if overheating becomes a problem, divert it through the bypass.