Dave wrote:
>I recall some time back you posted info about the pressure cap for the
>cooling system recovery tank. Looked for that e-mail, but couldn't find
>it.
Actually the 7# cap is original.
If the radiator has been recored with a modern core, it can withstand
a 15 psi cap. The later caps, for the 1970 Datsuns (240z, 510, etc are
all 14 psi... and work fine).
Yep, heater hose is metric. 1/2" sounds correct.
I like to buy the heater hose from an INDUSTRIAL SUPPLIER. Someplace
that sells it for Kenworth or 18 wheelers. There is a GOODYEAR silicone
hose that runs $3 to $4 a foot. Cheap insurance as it really does
have a 20 year life. It pays to make sure the hose is Goodyear, Gates,
anything quality.
Avoid the hose from "discount auto supply" or what ever. About 50c/foot
but horrible quality.
>
>I had experienced a problem of running hotter than normal and a loss of
>coolant. Finally identified the leak to be a "pin hole leak" in the
>metal line, attached to the carb heat shield, which supplies the
>heater. It appears to be very badly corroded, so I decided, "Why not
>run a hose from the head connection, bypassing the intake manifold,
>(past that "always frozen" manual bypass valve), connected directly to
>the heater supply, and do the return to the water pump in a similar
>manner? I suppose I would lose some "preheat" of the intake manifold
>(if that's why it's plumbed that way), but figure that would be
>inconsequential.
With that pipe I really doubt it would do much to preheat the carbs. Just
an easier way to run it.
>
>As a temporary measure I've bypassed the whole mess by connecting the
>return hose to the water pump directly to the outlet from the head.
>(Actually, in Hawaii, this could be the final solution, since all I use
>the heater for is VERY occasional "demisting").
NO! I would NOT recommend doing this. Reason is the coolant normally passes
through the heater, which is really a small radiator. The coolant is usually
cooler returning back to the engine.
You are better off just capping off the heater tubes in this case. This prevents
hot water from bypassing the radiator.
>
>BUT, with that bypass in place and the old (14# ?) cap in place, I'm
>still running hot. The system is tight, now--no coolant loss. I just
>used a Prestone flush for the cooling system, following their
>directions. I had been running hotter than usual coming up the
>mountain, for quite a while before the leak developed. A lot of the
>cooling fins on the radiator front face have flaked off.
Remove that "bypass".
Good time to do a full tune up. Adjust valves, mixture, and timing. Make
sure all the basics are covered first.
You do not have one of those "thermostatic" fan clutches, do you? Fan
should be locked to the water pump.
>BTW, I enjoyed your Bavarian "Mist" Wagon joke!
You're welcome. Caution: do NOT tell that one to a Bavarian... but if
your host is from Baden-Wurtemburg you can. Oh, the other meaning of
"BMW" is "Break My Window" Sigh.
Cheers,
Tom Walter '68 2000
Austin, TX.
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