Ok, so I finally got to the repairs I think I needed to solve my
intermittent overheating problem taking the advice of the good folks
present in the PUDDLJMPR chat room the other night.
Short background:
The '74 never overheated all last summer. Ran a bit warm on one or two
occaisions going up very long, steep hills, but after the summit the temp
went back to normal. About a month ago I took a little 200 mile round trip
to look at a '65 Sprite I didn't buy. Overheated in a major way - coolant
boiling out between the head and block etc. Got that cooled down enough to
make it home and now about every 2-3 days it starts to overheat. As long
as I don't have to sit in traffic, it's ok. If so, it starts to climb
dangerously close to the "too hot" range. No signs of coolant leak, but
definite sign of leaking oil at the front of the head/block join opposite
the spark plugs.
Progress so far:
Tore down the engine enough to pull the head off and replace head gasket.
Didn't look obviously broken, but maybe it's extra compressed in the
affected area? Anyway, new gasket in place. Also put in a new summer
rated thermostat. Today I need to finish up by bolting the manifolds and
carbs back on, adjusting the valves, timing the little guy and tuning the
carbs. Then just fill the radiator back up and drive and pray. :)
Observation:
Man, do those thermo housings rust on their solid or what?! Took me 45
minutes of applying Liquid Wrench, tapping, prying, repeat ad nauseum to
get the dang thing off. I replaced that too.
Questions if you stuck it out this far:
My little by pass hose was plugged solid with crytalized gunk (coolant?)
and so was the inlet opening going to the water pump. Could this be a big
part of my problem? Would this cause the car to overheat only when
stressed? By stressed I mean a hot engine sitting still in traffic - not
going 65 down the highway.
If a head gasket is "blown", is it always evident (i.e., a chunk blown
away) or can it just be compressed more in one area? I'm hoping that I
don't have a warped head or something drastic. But if that were the case
seems like I'd overheat more consistently.
Any advantage of filling with anti-freeze in the summer? I was thinking of
going pretty much straight water through the hotter months and then getting
the system drained, flushed and filled in the fall in prep for winter.
I'm trying to figure out what one piece is connected to the engine block.
It's at the front on the spark plug side. It's attachec to a metal wire
looking deal with a spring-like wrap around it. Can't find it in my
manuals, but tracing it quickly it looks like it might be the temp guage
sensor. Am I close?
Well, thanks again to everyone on the list - to the people in the chat room
who gave me some pointers on head gasket replacement to go with my manual
studying and to everyone here for past, present and future help.
Philip
1974 Damask Midget - Arioch, Lord of Chaos
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