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Im not Sure were to go, with this. Car seems to still get Hot. Must tell you guys that a have a new shrould and radiator now thermo is 180, but I'm putting an 160 in. Is it just because on this heat that its running 225- 235? I have an flex fan. I have checked my timing, its set at 6 deg. So I pretty much don't know where to go from here. If you can help that would be great. Im also using Waterwetter. Thanks Herb. P.s. sorry for any miss spelled words.
:(
 

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If it's hot at idle, but goes down when you are at speed, then your fan is inefective. If it's hot idle and moving, then it may be a clogged radiator, non-flowing water pump or other internal problems. 220 -230 isn't overheating, just hot, and already addressed in other threads.
 

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You can do a flow check by disconnecting the upper radiator hose while cold, starting the motor and watching to see when water begins to flow. Thermostat should open at 180 and flow should be good. The results might tell you something about your water pump and the flow within the motor channels. If you have a new radiator, that's the next place I would look (motor/pump).

Most of the posts I have read, criticize the flex fans, you might want to consider a solid or the electric fans.
 

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loose the flex fan, check the fan blade to radiator clearance,make sure your water pump plates are in good shape, buy a GOOD radiator. Eric:cheers
 

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I agree with Eric, make sure the diverter plate is installed. Also, make sure you have a good quality water pump, it may be bad flow. Also, you can install an electric fan with a thermostat switch to turn on at a certain temp, 190-above the stat temp to keep amp draw low. Radiator may be clogged and need replacing.
Just keep at it and I'm sure you will find your demon.
 

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are the belt(s) tight enough or glazed? flex fan may be causing water pump pulley to slip while at speed. i know its basic, just a thought though. good luck.:cheers
 

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I found a factory GM flex fan off a '69 Cadillac 472 V8. It's big, has a deep pitch, and pulls a lot of air at low speeds. Took care of my hot weather vapor- lock- in- traffic problem. That, and I have a fan shroud and the factory 4-row radiator. Worked for me.The original style clutch fan never did well.
 

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Could be your carb jets are too small.

Could be a cheap stamped impeller in your water pump - need a full cast iron impeller.

Or your water pump divider plate is not clearanced properly and/or bent/missing.

I'd also lift the front end and "burp" the engine for any air pocket.
 

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Try playing around with your timing. Advance it as much as you can, as 6 seems alittle low. My 455 runs way hot with retarded timing.I bought a water pump from summitt racing that runs 50% more under 3500 rpm( I forget name brand).It helped my cooling alot. Also check your carb. Lean mixture will cause heat too. As mentioned above, the clearance of the divider plate is crucial. I forget what the spec is,but it needs to be very close to the impellers. Hope this helps,
Scott.
 

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Just went thru this with my 68 yesterday and replaced the radiator cap thermostat. Next I was advised of burping and divider plate clearance of which I read a great article on the web. I decided to pull the pump and take it in and talk to another guy I know who is a pontiac head and he has read the article himself and had first hand experience with this stuff.
The new rebuilts are pressed on and have no lip etc where as the one I took off we decided to experiment with.

When we set the divider plate on the pump motor there was a good 1/4 inch gap between the teeth and plate so he put a puller on it and pulled the teeth out and now when I put the divider plate on it is almost touching but by the time I put two gaskets on should be good to go.

I plan on finishing this project up between today and tomorrow and will let you know the outcome. Another thing you can do if you dont have the lip to put a puller on is beat the divider plate closer very carefully but I would suggest using some heat.

We pulled out three different water pumps from the parts place he works at and what amazed me was every one of them had different clearances and none were even close to what they should be but this is something that will definantly make a difference in flow. Cannot remember where I read this article but is was very informative of this problem. Im sure someone else knows where its at Im pretty new here and only reason I piped in was just went thru this yesterday and spent the night researching things after I tried flushing the radiator puttin new cap and thermo stat in.
 

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Overheating Issues

This:cheers:cheers:cheers:cheers:cheers is what helped me. Once I adjusted this divider plate to impeller clearence my temperature went from 230 - 235 to 190 max. This is in 95 to 98 degree weather here in New Orleans.
 

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Good deal My car did about the same Im running between 195 and 203 now and I think when I put a shroud on it it will be good to go definantly helped my problem though.
 
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