Hi Phillip,
I'll give a shot at some of these, and my experience with some of the
trouble areas you have outlined.
On Sat, 10 Apr 1999 10:22:13 -0500 Philip Hubbard <hubbard@idir.net>
writes:
>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.
With water coming out between the cyl head and the block, assuming you
have a non warped head, this is still a chronic trouble area on 1275s.
There is a pretty thin seal area at that point and with high engine RPM's
and a 1275 water pump, coolant is frequently pumped out the side.
Two solutions here, courtesy of my racing mini friends of many years ago.
Use a high tack adhesive on the block and head prior to putting on the
head gasket and cyl head. It gets "glued" together then. The other one
is to use the 1098 water pump on the 1275. I have done that on all 1275s
since the with no leakage ever at that point. Need also non warped block
deck and cyl head.
>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.
Remove the studs that hold down the thermstat housing and replace with
grade 8 bolts. Simple. effective cure for stuck housings.
>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.
Not likely will that be the problem but it does show that you have some
loose trash circulating in the cooling system. This car should never be
run with plain water. If you want to omit ant freeze, you MUST use an
anti rust agent with the water. Replace this by pass hose with a section
of 1/2" heater hose. Don't ever use the molded accordian hose. It's a
piece of junk and will collapse at the most inoportune time.
>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.
A "blown" head gasket is not always with a "chunk" out of it. Sometimes
it simply is a result of not being held under enough pressure because of
old worn out studs without enough stretch left in them or just getting it
too hot at one time or another. May be a result of some over heating
ages ago. Mechanical devices have a memory of sorts, and will come back
to haunt you at a much later date. The fact you have some oil leakage
now, no doubt coming from the oils delivery hole to the rocker system,
leads to the conclusion that you more likely have just a loose head,
rather than a piece missing on the gasket. I have a 1275 that wen
185,000 mile before I did a valve job on it with no head gasket leakage.
Now it has almost 300,000 mile on it and still no leakage. It's sure
getting tired though! But still no head gasket problems, and I always
"glue" the head on. with each valve job, or rebuild.
>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.
Use a good brand of antifreeze year round in the car. Using water will
lower the boiling point of the cooling system and will promote rusting of
the cast iron and corrosion of the aliminum pieces in this engine.
>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?
Looks like you are dead right on that one.
>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
Good luck on this project. You need a clean radiator, good coolant, a
little extra sealer on the head gasket and a little judicious
interpretation of the temp guage readings. Boiling on this car with even
it's low pressure system and anti freeze should be in the 245 degree
area.
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