Just to let you guys know, my temp gauge still drops periodically from the halfway point to the bottom of "normal". It will then slowly climb back up to the halfway mark. It also seems that when the temp gauge drops, all of the pressure in the cooling system is lost. I wait for it to drop, then i feel the upper rad hose and it is hot but soft. Then i take the cap off the bottle and there is no pressure at all.
I'm pretty sure the Vulcan is the simplest cooling system out of them all. Compare it to the v8 sho
, which has the reverse flow design which i don't understand at all.
In the vulcan's simplicity, i still don't understand why the bypass is needed. I think the very early '96s didn't come with a bypass. It was Fords simple idea to throw it in there and solve problems of rust clogging the small passageways in the heater core. I guess they didn't take into consideration that people up north drive these cars, and how important it is to have heat in the winter months.
Think of it this way. Some of you are telling me that the bypass is there to allow more flow for required cooling of the rear bank. Firstly, the size of the hose coming off the lower intake is only 5/8, so it can only carry so much at once. If my heater core is 100%, im pretty sure it can take the flow required for adequate cooling.
I'm really close to giving up on this issue, and just scrapping the car if the engine seizes. I will never again buy a 96+ taurus/sable with the Vulcan engine. Duratec's and sho's from now on.
Nothing is perfect. If you followed a few recent duratec threads, there has
been a hole in the oil pan with catastrophic results, and burnt valves and
Now, the SHO's are notorious for cam issues if they have not been welded
with also catastrophic results.
The bypass was an add on after early gen3's had cooling issues.
If the heater core plugged up, the coolant flow would be impaired causing
heating issues in the heads.
Your a brave guy if you took the degass cap off with the motor hot
and running. Hope you took precautions. If you found NO pressure there,
you have issues. You just need to find them. Maybe you need to get the
motor hot and stop and turn off the car. Open the hood and listen closely
for pissing or hissing sounds. Look for anything damp or wet.
Your losing pressure somewhere.
you need to step back and retrace your steps.
YOU might want to build one of my ghetto coolant pressure gages and
leave it inserted in the degass lines and try to keep an eye on the pressures.
and you are 100% sure the thermostat is a motorcraft with the jiggle
valve clocked at 12:00, and NOT in backwards?