'79 Thermostat

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JohnO - 30 Dec 2006 23:00 GMT

I helped my son replace the thermostat in his Mustang today, assuming
that his 'no heat' problem was typical. We bought a 'stat from Autozone
that claimed to be original equipment.

The first thing we did when we got home was drop the "bad" 'stat in a
pot of water with the good one, and fire up the stove. They both opened
up at about 190-200, but the new one opened up a lot farther.

I'm thinking that's too high...any idea what the temp of the 171ci
(2.8) 6-cyl engine is supposd to be?

-John O

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Big Al - 31 Dec 2006 06:49 GMT

> I helped my son replace the thermostat in his Mustang today, assuming
> that his 'no heat' problem was typical. We bought a 'stat from Autozone
[quoted text clipped - 8 lines]
>
> -John O

195

Al

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JohnO - 01 Jan 2007 00:18 GMT

> > I helped my son replace the thermostat in his Mustang today, assuming
> > that his 'no heat' problem was typical. We bought a 'stat from Autozone
[quoted text clipped - 10 lines]
>
> 195

Thanks, Al. The son reports that the heat now works well enough.

-John O

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Backyard Mechanic - 01 Jan 2007 21:41 GMT

>> > I helped my son replace the thermostat in his Mustang today,
>> > assuming that his 'no heat' problem was typical. We bought a 'stat
[quoted text clipped - 9 lines]
>> >
>> > -John O

Judging from what you say, and what you saw and making some suppositions,
the problem wasnt the stat at all... but probably low coolant level. A
typical problem.
What you SHOULD have looked for is that it fully closed

OPENING temp of the thermostat has little to do with heater; except the
lower the stat temp, the lower the air temp from heater.

Signature

Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!

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JohnO - 02 Jan 2007 00:43 GMT

> Judging from what you say, and what you saw and making some suppositions,
> the problem wasnt the stat at all... but probably low coolant level. A
[quoted text clipped - 3 lines]
> OPENING temp of the thermostat has little to do with heater; except the
> lower the stat temp, the lower the air temp from heater.

Ya know, you're probably right. Oh well. :-) Fortunately we didn't
spend a lot on this, and the kid gets some experience and a fresh load
of coolant.

-John O

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elaich - 02 Jan 2007 15:10 GMT

> OPENING temp of the thermostat has little to do with heater; except the
> lower the stat temp, the lower the air temp from heater.

EXCEPT on the 2.8, where the thermostat also closes off the heater bypass
when it is open.

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elaich - 02 Jan 2007 00:54 GMT

"JohnO" <t696asm@yahoo.com> wrote in news:1167519651.940051.43690
@i12g2000cwa.googlegroups.com:

> They both opened
> up at about 190-200, but the new one opened up a lot farther.

That was the whole problem. The 2.8 thermostat does double duty by closing
off the heater bypass when fully open. Only partially open meant that the
bypass was still open.

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JohnO - 02 Jan 2007 01:51 GMT

> "JohnO" <t696asm@yahoo.com> wrote in news:1167519651.940051.43690
> @i12g2000cwa.googlegroups.com:
[quoted text clipped - 5 lines]
> off the heater bypass when fully open. Only partially open meant that the
> bypass was still open.

Hey! All things considered, I like your answer better than BM's...but
only because it means there really was a mechanical problem and not a
maintenance problem. :-)

But either way...

-John O

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