The Scenario:
Just finishing up a total engine rebuild of the 77B. Learned that the
DPO had installed the wrong radiator. Moss has 'em on sale - get it. Get a new
fan thermal switch to go along with the new second fan that you've installed.
Install the new radiator with the proper support bars.
Fill up the radiator, look for leaks, see none. Good. Start up the engine.
Look for leaks, see none. Great. Close the bonnet. Take the car for a short
spin around the block to warm it so that you can get back to tuning it up.
Upon returning and pulling into driveway notice that temperature gauge is
heading toward the red. Not good. Where is the electric fan noise? Grab
bonnet release. Frozen solid. Very not good. Quick - open garage door and get
car inside off of cold, wet driveway. Turn off engine while observing
temperature gauge nudging red. Regret having procrastinated on hooking up
emergency bonnet release cable. Eventually find long enough rod to push through
screen and release bonnet catch. No steam, but might warm. Expected to find
that the new fan switch had popped out of the radiator. Surprise - it's still
in place. Why didn't the fans come on? They did with the old radiator.
Must be the new thermal switch is NFG (Not Functioning Good). Short across
it and expect to see the fans come on. No way, Jose'. Check for 12 volts at
the switch's green wire. Nope. Remember the inline fuse. Check it. It's
blown. Ah Ha. Key off. Replace the fuse. Key on. Still no fans. Check fuse.
Yep, it's blown. Dang it -- it must be that the new fan motor is drawing too
much current. Unplug the new, second, fan. Replace the fuse -- old fan spins
like it's supposed to. Unplug the old and plug in the new one. Short across
the fan switch -- hear a clank, but no spinning fan blade!
Remember the new radiator support bar that I mentioned earlier? Guess what
is positioned by the bolt that holds the support bar in place? It's the hidden
clamp that holds the bonnet release cable in its proper position. If you're not
careful, when you tighten down the bolt the clockwise rotation can skew the
bonnet release cable so that it will be contacted by the next fan blade to come
by. This will bind up the fan motor and cause the fuse to blow. It can also
put the bonnet release cable at an angle that will not allow it move.
So there you are - an engine about to overheat and a frozen bonnet
release. Ah, the joys of LBC'ing. BTW, I installed the emergency bonnet
release wire before I left the garage.
--
Bud Krueger
http://home.ici.net/~bkrueger/
52TD
77MGB
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