Thermostat and cooling tech questions. I need your help - Ford Mustang Forum
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post #1 of 5 (permalink) Old 08-26-2004 Thread Starter
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65 Fastaback's Avatar
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Location: Grand Rapids
Posts: 146
Thermostat and cooling tech questions. I need your help

Another 2 evening project for my 65 Fastback with the 200 inline 6. I removed the heater hoses,
back and forward flushed the motor and radiator, bought all new reproduction radiator and heater hoses and tower clamps. I thought it would be a good idea to replace the heater core at the same time.
Holy moley, the housing that surrounds the heater core was full of twigs, leaves, you name it.
I degreased the engine and compartment and will install everything tomorrow.
I have some "need to know" questions. Which direction does the thermostat go?
The spring with copper end twords the radiator or motor? When installing the gasket,
do you put the thermostat into the water outlet first, followed by the gasket?
Does the gasket adhere to the water inlet or the block?
The previous owner did a lot of wierd things and I just want to do it right.
He used the Permatex gasket and not the Felpro that I bought with the thermostat.
Any preferences? Use both? Best way to apply? The wierd things I'm most concerned about
is that there are two inlets to the block for the heater hoses to go to.
He has what appears to be a galvinized pipe coming off both sides of the block,
with a 90 degree elbow which, tapers down to a threaded end to receive the heater hose.
Both the elbows had a blockage. I managed to clear them. This may have occurred during the flush,
but I'm not sure. A considerable amount of rusty scale is evident from what I can see looking into the threaded end of elbow. The heater core was bleeding out reddish orange water after it was removed.
I'm glad about removing it. How in the world do I, should I, attempt to remove the elbows.
I'm so afraid of attempting to break loose (or literally breaking) either the straight pipe or the elbow.
If its caked with rust, how soon will it plug again? What did go into the block where this galvinized pipe comes out? Any suggestions? Can the heater core be bypassed? Could it affect the
cooling of the motor? I realize, there would be no heat inside. Its not an air car.


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post #2 of 5 (permalink) Old 08-26-2004
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What was probably in the engine instead of the "creative plumbing", was a straight pipe nipple with the proper size hose nipple at the other end. Since the heater core and corresponding hoses are clean, I'd check the radiator and bottom hose to see how much crud is in them. The thermostat housing on the small blocks has a small machined area where the t-stat fits in. The spring side should go in the block as this is where the heat is to change it to open. I use RTV to seal BOTH sides of the gasket and t-stat.(please refrain from globbing it on, smooting with a finger works good)I've seen alot of engines that would look so nice but the assembler put this stuff on so thick it's squeezed out from every gasket area.Looks bad. The elbows are a crap shoot. You might spin 'em right off with a pipe wrench! .....or they may crumble as soon as you put a wrench on 'em. Either way if you do remove them use teflon tape for reassembly.Best o' luck

Old and in the way.
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post #3 of 5 (permalink) Old 08-26-2004
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Hello.The spring end of the thermostat goes into the motor.The upper hose is the return hose to the radiator so if you put the thermostat in the other way the coolant flow will be trying to push the thermostat closed.Put a very thin coating of sealer on the gasket surface of the thermostat housing,then put the thermostat in, then the gasket,then a very thin coat of sealer and then install the assembly.Don't over tighten the bolts.It can warp the housing a little,causing it to leak.One of those little pipes should be sticking out of the side of the water pump.It should come out without too much trouble with a small pipe wrench.Without having seen it myself,I'd have to say that your probably better off not messing with the the other one.That sounds as if it could turn into an adventure pretty easily.It wouldn't make much sense to me to bypass a brand new heater core.How that's done is to have one hose going from one of those pipes to the other,or to plug both of them.Either way,they are both still in the system.Hope that helps.
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post #4 of 5 (permalink) Old 08-27-2004 Thread Starter
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Location: Grand Rapids
Posts: 146
Re: Coolant and thermostat

Thanks Rod Bender and Veronica.
I have a few more questions.

What degree thermostat should I have for my motor?
Its a1965 Inline six, three speed trans with no air.

I removed the battery cables from the motor and forgot which one goes where.
Which battery cable goes from the starter to the battery?

Please don't take this the wrong way but are you a guy or a girl?
If your a girl, you sure seem to know your Mustang's.
Where did you gain your wealth of experience?

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post #5 of 5 (permalink) Old 08-27-2004
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Location: Houston
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Hi again.I think that I'd run a 180 thermostat in your car since the air flow is great in the 6cyl cars and oil doesn't really lubricate properly until it hits about 180.The positive battery cable goes to the closest side post of the starter solenoid and the negative bolts to the engine block below the alternater.And no,I don't take that the wrong way.I hear it(read it?) all the time.It used to bother me when people said some variant of "you're pretty smart for a girl",but I finally realized that what they mean is "I am unaccustomed to seeing girls that understand how cars do the things that they do",so it really isn't a big deal anymore.Good luck on your car.
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