Does a 180 degree thermostat really affect heat?

StreetDreamsGT

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Mar 6, 2003

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Dec 11, 2009

#1

• Dec 11, 2009

• #1

Guys I've been having problems with my mustang's heat lately. I started the car and let it sit for 20 minutes, the top radiator hose is hot, and the hoses going into the heater core are hot. I checked the blend switch and it's working just fine (I reached under the dash and felt the door move. The temp gauge doesn't seem to get above the L in normal, unless I drive on the parkway and do about 70 ( then it gets all the way up to the N). I didn't think the thermostat would affect my heat that much but apparently it does. I heard also that the clutch fan could affect it, is this true?

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Dec 11, 2009

#2

• Dec 11, 2009

• #2

You don't know actual temps? If you're running from one end of the gauge to the other, there's an issue.

The stat itself might be bad.

And no, the fan does not affect it. It just modifies the stat's duty cycle.

 

tannerc91gt

This last 25% is foreign territory at this point

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Dec 11, 2009

#3

• Dec 11, 2009

• #3

Go buy a $5 tstat and that should give you an answer

 

StreetDreamsGT

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Mar 6, 2003

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Dec 11, 2009

#4

• Dec 11, 2009

• #4

Well it's a brand new Mr Gasket 180* tstat, I have another new one sitting here though that I could put in. Seeing how the heater hoses are hot though shouldn't that mean it's working? After all the reading I've done I know you guys have said that even new tstats could be bad.

 

StreetDreamsGT

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Dec 11, 2009

#5

• Dec 11, 2009

• #5

So in order to test the new tstat before I put it in I can boil water to 180* and drop the tstat in it right?

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Dec 11, 2009

#6

• Dec 11, 2009

• #6

I wasn't commenting on the heat - only the huge range of movement you see in your temp gauge.

Some folks have reported issues with new stats like yours. Pull it out and see if it's stuck partially open. Then you could try boiling it and/or the new stat on the stove.

Boiling is an ok test, but a stat can test ok in the pot but not function properly in the car (the conditions in the car are much more severe than in a pot of water).

Good luck.

 

S

spoolinfusion

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Dec 12, 2009

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Dec 13, 2009

#7

• Dec 13, 2009

• #7

air pocket?

 

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

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Dec 13, 2009

#8

• Dec 13, 2009

• #8

How effective is the car's cooling system? If it's very good, then you might want to go back to the OEM 195 degree thermostat.

 

B

BYRDPE

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Dec 13, 2009

#9

• Dec 13, 2009

• #9

how old is the radiator?

 

StreetDreamsGT

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Dec 16, 2009

#10

• Dec 16, 2009

• #10

I doubt the cooling system is that good, it's all stock parts. I'll have to try and check the thermostat out or use the other one. I get luke warm air when it's fully warmed up...

 

T

THOR74

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Dec 5, 2009

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Dec 17, 2009

#11

• Dec 17, 2009

• #11

You haven't said whether or not the coolant coming from the heater core is flowing enough or "hot". Sure, you may be getting hot enough coolant flowing TO the heater core, but your core may be partially or fully plugged, and therefore the hot coolant is not flowing THROUGH your core. The fact that your blend control works is not relevant to this issue.

As well, if you ever wish to test a tstat by boiling it, don't drop it into the hot water. Rather, put the tstat in the water when it is cool and bring it to open by letting the water warm up gradually as it does when you put the stove on high. This more accurately simulates what actually happens in the car (gradual heating of coolant). I have seen tstats that will not open consistently when either gradually heated up versus dropped into hot water.

Generally, I agree that the boiling test is not perfect, but it can weed out real duds before you go through the bs of installing them and finding out the hard way.

Good luck and keep us posted.