# 66 GTO engine runs too hot



## jerry davis (Sep 3, 2008)

Have a 66 GTO with 389 CID engine, temp too hot about 210-215 normal, at 65 MPH goes to 220-225,when idle goes to 230+.
Has a 4 core radiator with a 7 blade fan 17.5" with shroud, & fan clutch. have tried addatives, nothing i do makes any difference, temp gauge is correct i have checked with heat gun, any suggestions will be appreciated,
very very nice car, has total restrations,
Went to crusin the coast in Biloxi 2 weeks ago lots of pontiac folks said they had heating issues, must be a solution do not think they came from GM this way, again thanks


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## 05GTO (Oct 6, 2004)

I had the same problem with my 66, my fix was moving the fan closer to the radiator with a $14.00 Mr. Gasket fan spacer.


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## GTO JUDGE (May 14, 2005)

I put a 180* t-stat in mine right after I purchased it when I was changing fluids etc. Manual says it came from factory with 190*. Manual also said running hot is 230* or above. 

On hot days when driving mine will be about 190* I come to idle it will go to about 210-215* or so then when I proceed it goes back to about 190*. 

When its chilly out... in say the 40's it hangs about 180-185* when driving. I have a flex fan and it's in the shroud. I added water wetter in the summer but didn't notice a change. I plan on replacing the current T-stat with a 165* high flow over the winter. Maybe I will look into the fan spacer as well. I am hoping that will lower me.


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## grabber (Sep 23, 2009)

05GTO said:


> I had the same problem with my 66, my fix was moving the fan closer to the radiator with a $14.00 Mr. Gasket fan spacer.



Is there different thicknesses to those or is that a one standard size? Sounds like something I would like to add on mine. Thanks in advance.


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## 05GTO (Oct 6, 2004)

grabber said:


> Is there different thicknesses to those or is that a one standard size? Sounds like something I would like to add on mine. Thanks in advance.


Yes, most auto part stores sell them or you can find them online,

mr gasket fan spacer - Google Search


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## 646904GTO (Feb 10, 2008)

This may sound off base but install a 160 T-stat and have your dist. recurved to a total of 34 BTDC on the crankshaft. You may want to run 11-13 intial with this set up. If you check the stock dist. you find it probably has 40-50 degrees in it. I added a post to the tuning tips sticky about this.
I did find one engine last summer that was missing the tubes between the timing cover and water pump.


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