# overheating



## Topkat (Sep 9, 2010)

Howdy all. While on our way to the big city to stock up on good sippin' Bourbon.....I saw my temp gage go from slightly below 1/2 and go to 3/4 hot. We stopped to eat and continued our journey......a dozen more miles into our freeway ride at 60-70, and going up and down some gradual miles long ups and down, the needle was just about pegged full when we pulled into a rest area..... after 1/2 hour it had cooled off a tad and we turned around for home.....all the way home, like 30 miles, it ran 2/3 to 3/4 hot.....
In the past it has never really rose above 1/2 way?
Im thinking thermostat? 
The fluid was and is fine... 
thanks as always 
Tk
(pours a round of Elijah Craig for all)
:cheers


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## trues607 (Dec 15, 2012)

I agree. It sounds like the thermostat is stuck open.

Sent from AutoGuide.com Free App


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## jetstang (Nov 5, 2008)

Thermostat is stuck almost closed, reducing flow through it. I had a failsafe that failed, I will never use those again. Replace the stat and see if it's cured.


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## Rukee (Feb 8, 2007)

:agree


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## geeteeohguy (Feb 2, 2008)

Elijah Craig? Crap, now I'm gonna have to google _that _one, too. Yes, verify that it is, in fact, running warmer. Borrow a pyrometer or buy one at Harbor Freight and see what your actual temp is. I had a '66 GTO that 'overheated' for ten years. Found out that when I fixed the bad ground to the dash cluster, the needle went right back down to 185. These old gauges ain't always reliable. Have you tried Bookers? That one will burn the hair off your chest!


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## Topkat (Sep 9, 2010)

Havn't tried Bookers....yet..........but walking by the car after we stopped ya could feel the heat bigtime........thanks folks!


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## chuckha62 (Apr 5, 2010)

When I was questioning my gauge accuracy, I bought an infrared thermometer. Whenever I was concerned, I got out, opened the hood and checked the inlet of the radiator. BTW, those infrared thermometers work best if pointed at a black object.


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## Rukee (Feb 8, 2007)

Never had an issue with overheating in like 18 years of owning mine....until today. Just a few blocks from home and the temp light comes on. hit the thermostat housing with the Lazar temp gun and *231. Just ordered a *180 thermostat and gasket.


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## gjones (Oct 8, 2012)

*heat*

I thought that the light didn't come on until it got to like 240+? If that's the case, I'm going to hook my light back up, seeing as how I never boil over. I can't stand looking at that gauge, anymore!


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## Rukee (Feb 8, 2007)

LOL, so I get the parts and wait for it to cool off, and then find out it's a gal and a half low on coolant. Whoops, should have checked it.


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## geeteeohguy (Feb 2, 2008)

#$*%# _Mechanics_!! (same thing happened to me a few years ago, Ruk in my '67.....it was low on coolant.......these non-recovery systems will sneak up on ya!)


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## kjk990 (Sep 1, 2010)

Whats too hot? Last summer I drove home, about 20 miles, in 104 degree weather. When I pulled into the driveway I was at 235. But it never boiled over.

Our normal summer temps in SF Bay area, California run 70-90 degrees outside most of the time. I run 185 on lower outside temp days, but add 20 degree outside temps and I go up to 220 or so. I am constantly watching the temp gauge and worrying, but my cap has never popped. Am I worrying for nothing? I have heard these engines run hot.

What is everyone running on a 90 degree day?


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## gjones (Oct 8, 2012)

*Hotter-n-a-$2 pistol*

Mine has never boiled over either, but has run hot in its' earlier days. I still am threatening to hook that idiot light back up, just so I don't have to look at that lousy temp gauge ever again! I'm gonna do it! Yes, I will! Mark my words! :lol:


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## Griff (Nov 13, 2011)

OK, sorry for the off topic remark but there was some discussion of bourbon, try Blantons.


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## olde-goat (Feb 1, 2009)

*Overheating*

I upgraded to an actual temp gauge on my 65 tripower non Rally gauge car. My manifold had an extra hole cast in the manifold. It is currently sealed of with a pipe plug. I am now thinking that I will remove the pipe plug and screw in the original temp sender and reconnect to the idiot light. My thinking is that the light would or should catch my attention quicker to an overheat problem problem and save me from having to constantly look down and over to the gauges mounted under the radio.


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## geeteeohguy (Feb 2, 2008)

Thanks for getting us back on the important stuff, Griff! Here's my take, driving these cars ( a bunch of them) for the past 35 years (gets up on soapbox): These cars don't really run 'hot', but they don't run as 'cool' as some other makes/models. All the ones I've owned with a temp light and no gauges 'never' ran hot unless it was low on coolant through neglect, and 'all' of my rally gauge cars have run 'hot' according to the gauge if you consider 210 hot. Here's the thing: gauges can vary in accuracy, and the new sending units are generic and incorrectly calibrated. Pete Serio referred me to Lectric Limited for a sending unit for my '65, and now it runs at 185-195 even in 100 degree weather. Before, it was over 200. Keep in mind that new cars run at 220-240 degrees all the time, because hotter is more efficient. I have fan shrouds, clearanced water pump plates, good stock 4 row radiators, and good fans in both of my current GTO's (that I've had 30+ years now). All is good. Summary: if you don't want to worry, go back to a light, if you have rally gauges, they need the right sender and need to be verified. 225-230 is getting up there, but not really overheating. If it starts to boil over, then yes, there is a problem.


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## gjones (Oct 8, 2012)

That about settles it for me, gt! Aren't the original senders calibrated to around 240+, though? (A little too high?).


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## geeteeohguy (Feb 2, 2008)

Senders are different for gauge or light. Not interchangable The light type are calibrated to come on at about 235-240, which is, indeed, HOT. I had a generic NAPA sender in my gauge car ('65) and it was about 200 ohms different than the correct, LectricLimited sourced unit. It was good for a 20 degree drop on the gauge, which made me happy. These engines can and have been operated at 200+ degree temps for decades with no harm done.


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## Eric Animal (Oct 28, 2007)

That is a lot of needle movement...I'd check coolant level, ground on sender and/or gauge.....AND try a infra red thermo gun on it. Good old Jim Beam for me....unless there is some Maker's Mark that needs to be drank!!:cheers


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## geeteeohguy (Feb 2, 2008)

:cheers:cheers:cheersGood to have you back on board, Eric, and to see that you have your priorities absolutely ironed out.


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## Purple Haze (Feb 27, 2011)

Very similar story with our 65! Ran 185-ish for 3,000 miles.... then overheated. Changed the t-stat and voila, back to normal. Brought the old stat in the house, stuck it in a pot of boiling water and......it would not open!!!!!!!! Then after 5 min, only slightly!!! All is good. Never thought to try the new one!!! Might have been a good idea!!

Another good tip for the T-stat issue is...... when ours overheated I was a block from home. Pulled into my garage, opened the hood and could not touch the rad!! DUH!! But...I could actually grab to top rad hose!! Another indication that there was no flow!!


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## Topkat (Sep 9, 2010)

Hi gang, I finally got to take the Goat for a short drive after replacing the thermostat. Im not sure the heat ranges avsil, but I had the lowest one in (165?) But replaced it with the next higher one...anyway, on my drive the temp gage stayed at 2/3 and MAYBE a tad below that.
This wasnt on the long uphill that prompted changing it, but 2/3 still seems high(?)
Hithertofore.........lol.........it consistantly ran at 1/2 hot.
Could my fan clutch be hosed? It's new but I realise that means nothing
Am i needlessly worrying?
That long uphill is 40 miles away and would seem to be the ultimate test.........
I have heard that sometimes people drill holes in the therm? Is that a bad idea?
Take care and hope all is well my brothers........


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## Rukee (Feb 8, 2007)

Dill a hole in what? The thermostat?? 
If you have driven it already I would say the air trapped already is gone. Do you have one of those laser thermal guns so you can tell the exact temp? If not maybe you could borrow one from a local parts store and shoot it under the thermostat to see what temp it's running at.


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## Topkat (Sep 9, 2010)

I once heard some folks drilled holes in the T to get more water flow...........guess that aint possible..........shruggs.


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## geeteeohguy (Feb 2, 2008)

I've been known to drill ONE small hole (1/16") in T-stats simply to allow air to burp to allow easy fill up. Drilling multiple holes to enhance operation would negate the purpose of the 'stat. I agree with Rukee. Verify the temps with a heat gun. I once had a '66 GTO that 'overheated' for years.....until I fixed the bad dash ground which returned the gauge reading to normal....


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