Winter hibernation seems to last a long time here in Pa.But as I have plenty of time to waste, I can spend it tinkering on my car.
My cooling system works just fine. New rad., fan, clutch,etc, etc. I have also made an opening in the center of the front bumper, and directed that airflow through the horizontal plate on which the horns and coil used to be located, to the upper part of the radiator.( Look at old thread from 2011- XJS- aerodynamics.)
Back to this Winter. Thanks mainly to Jonas in Lithuania, I added a temp. sender to “B” bank, which meant moving the ejector pressure hose (for the air bleed system) over to “A” bank.
I added an overheat sender to the “B” bank thermo. housing lid.
Finally, I have placed a pressure switch in the “B” bank top hose.I’m calling it the CCL (Catastrophic Coolant Loss) warning.
I may describe things more fully, once everything has been thoroughly tested.
The cooling system had to then be filled, and bled, which brings me to the point of this story.
I have an H.E., with two radiator caps.I also like to use clear vinyl hose for my overflow.
When I started my engine, I saw that a mixture of coolant and air was flowing through my clear hose to the overflow tank. Engine had not run long enough to start to warm up. That seemed strange, so I shut things down, and removed the cap on the header tank. On the bottom of the rad. cap is a small disc, which should be lightly spring-loaded. It allows the coolant recovery scheme to work. The disc on my cap was no longer spring-loaded, meaning that my car’s cooling system was not being pressurized.
Not too important now, but I would have had a really bad event once things warm up, and I’m out for a blast, with the A/C going full tilt.
I would not have stumbled on this, had I not had overflow hose I could see through.
Moral? Check your perfectly fine-looking radiator cap, before it bites you!
Photo is included for general amusement.
The Trident ballistic missile uses a device called an “aerospike” which is basically a small flat disc held out front of the missile:
When the air hits it it is deflected around the missile, significantly lowering the drag. Because the aerospike is retracted prior to use and extended once in flight, it also reduces the overall stored length of the missile – critically important for a weapon that is stored right-side-up inside a nuclear submarine.
Anyhow, I have pondered whether the flat front surface of the XJ-S front bumper acts as an aerospike deflecting oncoming air around the front grilles rather than into them. If that’s the case, one solution would be to cut an opening through the bumper as DavetheLimey has done. Another idea would be to round the front surface of that bumper, perhaps by attaching something with a semicircular cross section, thereby helping the oncoming air to simply flow around the bumper and into the grilles rather than being deflected around them.
The advantage of that second idea is that it should be pretty easy to test. If you are familiar at all with the temps your XJ-S runs, you can just fab up something smooth and rounded to bolt to the front bumper using the holes for attaching a front license tag. Drive the car with and without this attachment and report back on whether the car tends to run cooler with it. I’d expect it to only make any difference at cruise speeds; it certainly won’t make any difference when you’re stuck in traffic.
Whoops! The old site is XJ-S aerodynamics, not XJS. Got to be SO careful!