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Discussion Starter #1
Hello, newbi looking for advice.

I recently put a new radiator and thermostat in my 65, including all the hoses. I took it for a test drive on Sunday and everything looked good until I hit three stop lights in a row downtown. The car of course over heated again. Luckily I was close to home and made it after a cool down. So I figure that my options are:

1 - figure out if the thermostat is in correctly and working
2 - figure out if the water pump is working
3 - upgrade to a five blade fan w/shroud (currently no shroud)

So the question, to those who would know, is how to diagnose if this is a thermostat or pump problem? Also should I add a shroud and fan upgrade?

Thanks in advance,
Jason
 

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My 66 289 was over heating, it turned out that the distributor was installed aproximetly one tooth off, car ran ok but over heated.
 

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Is your timing set correctly, make sure it is not ATDC (above top dead center) If it is a stock 289 engine, it should be 6 degree BTDC
 

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Maybe you have air pockets in your cooling system. Try burping your system. Mine ran hot until I got all the air out.
 

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I have a 65 coupe with 289 and AT. I was having lots of overheating problems when the car was new to me - here's what I have done since, I'm happy with temp now:
1. 3 row radiator
2. Shroud
3. 160 degree thermostat (will probably go back to 180 during the cooler months of the year.)
4. Drained and flushed cooling system including removing the block plugs.
5. Filled cooling system with 25/75 mixture Antifreeze / Distilled water.
6. Installed radiator overflow tank (one of these came with the car as spare parts from the PO)
7. New radiator hoses and fan belts

Have not done, but am thinking about a 5 blade fan; radiator support-to-hood seal.

Good luck!
 

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Maybe you have air pockets in your cooling system. Try burping your system. Mine ran hot until I got all the air out.
One thing you can do is drill a small hole in the thermostat which will help to let air flow out and get rid of the air pockets, it will let a little flow through, but not enough to matter.... You'd have to remove the thermostat to do it, so that is for next time.

I'd check first for air pockets, then make sure you have good flow. To test the thermostat, take it out and put it in boiling water. Did you make sure it is in correctly (you can put them in backwards which would make you overheat). Also, make sure the lower hose isn't collapsing when you drive.
 

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I had the same problem. My radiator was old and clogged. Replaced it and all was well. But, before I replaced the radiator I did a lot of other things. If your head gaskets are on backwards they could block the water flow in the heads. If the thermostat is backwards.
 

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Discussion Starter #8
I'm learning as I go. How would one go about removing all the air from the system? Also, how do you determine the correct orientation of the thermostat?

Thanks in advance,
Jason
 

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One other thing to do is to make sure you have a lower heating hose with a spring on the inside of it. This will keep the lower hose from collapsing and causing decreased flow through the radiator.

I'd also second your testing of the timing to make sure it's accurately set.
 
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