Seems to be getting worse, anything in excess of 40mph. There is no
obvious evidence of overheating, just that the temp gauge needle pegs,
and if you stop the car for a minute or two, it goes all the way down
to normal. Someone suggested I flush the system, but I also suspect it
could be tranny related (clogged filter?). Fluid level is fine, but I
have noticed over the years that when I haven't run it for a while (~1+
year) the fluid would drip out, and I'd let it idle for a while, fluid
would rush into the overflow bottle after a while. When I replenished
the tranny fluid, it would be fine.
Bob Urz - 26 Nov 2006 00:50 GMT
> Seems to be getting worse, anything in excess of 40mph. There is no
> obvious evidence of overheating, just that the temp gauge needle pegs,
[quoted text clipped - 5 lines]
> would rush into the overflow bottle after a while. When I replenished
> the tranny fluid, it would be fine.
Does it have a fan clutch? Have you changed it?
Bob
hls - 26 Nov 2006 05:02 GMT
>> Seems to be getting worse, anything in excess of 40mph. There is no
>> obvious evidence of overheating, just that the temp gauge needle pegs,
[quoted text clipped - 7 lines]
>
> Does it have a fan clutch? Have you changed it?
Bad fan clutch doesnt normally cause vehicles to overheat at speed. At low
speed or idling in traffic,yes.
Overheating at highway speed is usually a restriction in coolant flow or
blocked air path to radiator.
I think he needs to find out first if it is really overheating or is getting
a false indication.
I dont see the transmission being a likely problem, but stranger things have
happened.
Bob Urz - 26 Nov 2006 05:41 GMT
>>>Seems to be getting worse, anything in excess of 40mph. There is no
>>>obvious evidence of overheating, just that the temp gauge needle pegs,
[quoted text clipped - 18 lines]
> I dont see the transmission being a likely problem, but stranger things have
> happened.
I had the fan clutch degrade on my S10. I would go out on the Hi-way for
awhile and it would run hotter but still run. Then, i would come back
into town and the temp would shoot way up and during a hot day the truck
would actually miss and quit running. I felt the fan clutch and did not
think the clutch was bad. My brother in law felt it and said otherwise.
I changed mine and the problem went away.
There has been some cases of water pump impellers degrading on some cars
though i have not heard of that happening on a GM truck. Might
be worth it to take the pump off and change the thermostat
Bob
maxwedge - 26 Nov 2006 00:50 GMT
How did trans fluid get into the overflow jar? Maybe I misunderstood
what you are trying to say?

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Chris - 26 Nov 2006 01:48 GMT
the fan spins rest assured. I only brought up the part about the
overflow bottle filling (after starting it up after a year or more) if
in fact my overheating problem is not related to the coolant system,
but the tranny possibly overheating (?).
Question is if I flush and refill the system (it's got pure water
right now, and no thermostat), and that doesn't do the trick, what
then? I do suppose I should just get to it, but I had to put off a trip
today, and it made me anxious.
Brent P - 26 Nov 2006 02:04 GMT
> Question is if I flush and refill the system (it's got pure water
> right now, and no thermostat), and that doesn't do the trick, what
> then? I do suppose I should just get to it, but I had to put off a trip
> today, and it made me anxious.
Having plain water and no thermostat might be your problem. In any case
restoring it to the way it should be, with a thermostat and the proper
coolant can't hurt and could only help in figuring out what is wrong with
the system if the problems persist.
Antifreeze not only lowers the freezing point but increases the boiling
point. Removing the thermostat has changed the way the coolant flows
through the system.
Kevin Bottorff - 26 Nov 2006 02:08 GMT
"Chris" <chrism3667@yahoo.com> wrote in news:1164505720.870677.240950
@l39g2000cwd.googlegroups.com:
> Question is if I flush and refill the system (it's got pure water
I think you need to find out if it is really overheating, sounds like it
may just be a sender or gauge problem. KB

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Noozer - 26 Nov 2006 05:49 GMT
> the fan spins rest assured. I only brought up the part about the
> overflow bottle filling (after starting it up after a year or more) if
[quoted text clipped - 4 lines]
> then? I do suppose I should just get to it, but I had to put off a trip
> today, and it made me anxious.
Pull what you can at a wrecking yard and start swapping stuff piece by
piece, easiest to hardest. If you still can't find the problem, then it'll
be in the engine block.
Come to think of it, it could be timing related. If I remember correctly, if
the timing is too retarded the engine will run hot - something that would be
more exaggerated at high RPM. You might have messed up weights in your
distributor.
Rodan - 26 Nov 2006 02:16 GMT
"Chris" wrote: 82 Chev G10
Overheats at highway speed - anything over 40mph.
Temp gauge needle pegs but if you stop for a few
minutes it goes back down to normal.
I suspect it could be tranny related (clogged filter?).
Fluid level is fine, but I notice that when I haven't run it
for a long time (over a year) the fluid would drip out,
and I'd let it idle for a while, fluid would rush into the
overflow bottle after a while. When I replenished the
tranny fluid, it would be fine.
_______________________________________________
In order of highest probability:
Thermostat failed partially open.
Deposits built up inside radiator.
Leaves or trash blocking outside radiator.
Fan belt slipping.
Water pump impeller slipping or eroded.
Exhaust mainfold too hot (burned valves)
Trans fluid too hot.
Anything else.
Good luck.
Rodan.
Ashton Crusher - 26 Nov 2006 06:34 GMT
>Seems to be getting worse, anything in excess of 40mph. There is no
>obvious evidence of overheating, just that the temp gauge needle pegs,
[quoted text clipped - 5 lines]
>would rush into the overflow bottle after a while. When I replenished
>the tranny fluid, it would be fine.
Put antifreeze (50/50 mix) and a thermostat in it and a new radiator
cap. (only about $20 total) With plain water if anyplace in the
engine gets the water over 230 or so (assuming the cap holds pressure)
it will boil and the steam messes up the whole cooling system function
leading to rapid additional temperature rise. If your cap is bad it
just makes things worse.
Chris - 27 Nov 2006 01:32 GMT
seems to be some very useful stuph here. Thanks guys, I'll check it out
;)