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Discussion Starter #1
My 69 doesn't like this Texas heat and its not even hot yet. If anyone can help I sure can use it. I flushed my radiator, new water pump. I did away with the pump fan and I put two 13' electric fans in that are flush on my radiator. These fans spin around 3000 rpm. The thing I can only think of is to have it polled out.
 

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How many rows does your radiator have?

What temp thermostat?

Have you let the car run from cold to hot and watched to ensure the thermostat is opening?

When you flushed the radiator how did the flow look?
 

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I'm thinking radiator too. They get old and clogged and all the flushing in the world won't help. Nice GTO BTW.
 

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Most radiator shops up here won't consider rodding out a core anymore. Once the tanks are removed it's just as cost effective to install a new core. You can even buy complete replacement radiators pretty cheap on the web. I bought one for a 67 Camaro that looks very close to original with 3 rows for under 200 bucks SHIPPED to my door !!!
 

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When you replaced the pump, did you check the clearance between the pump impeller and the divider plate? You need to make it as close as possible. Somewhere in one of these forums is a post on what to look for , but I believe that you need to make the clearance less than an eighth of an inch. any more than that, and your pump's efficiency drops considerably. If your clearance is more than the minimum, you can gently re-shape your divider plate with a mallet.

Hope this helps.
 

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Discussion Starter #7 (Edited)
Well the theromstat is an 182 if that sounds right? Its the old Harrison radiator that has on the outside 9 grooves or rows. If that makes any sense. My car runs bout 190 avg. but on highway it can get up to 210+, just running. After I shut it off it goes to bout 230. Therom is new by the way. Bob Im not sure what you mean, the water pump plate looked ok to me, can you explain? I guess I don't know what the impeller is do you mean the fan inside the pump? The Flow of water looks good, I even ran A garden hose through one end , didn't look clogged.
 

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... Bob Im not sure what you mean, the water pump plate looked ok to me, can you explain? I guess I don't know what the impeller is do you mean the fan inside the pump? The Flow of water looks good, I even ran A garden hose through one end , didn't look clogged.
The impeller is indeed that fan-looking thing inside the pump. The divider plate goes between the impeller and the engine block. The clearance is between the blades of the impeller and the divider plate.
 

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Well the theromstat is an 182 if that sounds right? Its the old Harrison radiator that has on the outside 9 grooves or rows. If that makes any sense. My car runs bout 190 avg. but on highway it can get up to 210+, just running. After I shut it off it goes to bout 230. Therom is new by the way. Bob Im not sure what you mean, the water pump plate looked ok to me, can you explain? I guess I don't know what the impeller is do you mean the fan inside the pump? The Flow of water looks good, I even ran A garden hose through one end , didn't look clogged.
Up here in the north I run at 190 most of the time. A little higher when we get some hot summer days, 200 or maybe a little more. All motors climb after you shut them off. I'm not exactly sure how the electric fans work, but I believe you can keep them running after you shut it down until the engine reaches a certain preset cooler temp. I could be wrong, but I don't think you have that big of a problem considering you live in the scourching heat. If you were talking 240 - 260 then I would say you would have some issues. I know someone will correct if I'm way out of line.:)
 

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68GreenGoat is right on the money. My experience with Pontiac 400's (and all Pontiacs, really) is that they like to run on the warm side...especially '67's. On a 80-90 degree day, temps in the 210-220 range are pretty much the norm. I run a 160 'stat, re-cored 4-row Harrison radiator, and a 19 inch Caddillac Flex fan off a '69 472 on mine. I also run a fan shroud and just recently switched to Water Wetter. The Water Wetter helped! Here in Fresno, we have temps over 100 degrees pretty much every day from late June to late August. It was almost 90 today, and we're looking at over 100 this weekend. My '67 doesn't like it, but it doesn't overheat (much) either. Your temps sound normal to me. 230 plus: I'd start to worry.
 

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Poof

For what it's worth/reference, I live in Schertz TX (outside San Antonio) and drive 55miles round trip to work and back.

My 64 has a 400 with a 4 core (row) radiator and after market AC.

While cruising the car runs about 195 with AC on.

Gets up to 210 in stop and go IH35 traffic late afternoon (98/99 degrees).

Rick
 

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if your temp increases on the freeway your problem is airflow related. usally it is fan related, not 1/2 way into the shroud. you are running electric fans, rpm of fans is? 1st drive on the highway with the fans off. if temp does not rise or decreases you need fans that more more air or faster rpm fans. if temp continues to rise you are not getting enough flow through the radiator to cool the engine . lots of factors, engine rebore, more hp, runing lean. you then need a more effecient rad, more fins, crossflow , larger tube size, or aluminum. good luck. low speed cooling , nonfreeway is a water flow problem and you didn't metion that.
 

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new themo or not. get a 160 robertshaw design. 20 cooler than you have in there now. when they fail they fail in the open position not the closed like the standard thermostats. add water wetter like the other guy said. are you fans pullers or pushers? run it and see if a difference before changing rad or fans.
 

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My 69 doesn't like this Texas heat and its not even hot yet. If anyone can help I sure can use it. I flushed my radiator, new water pump. I did away with the pump fan and I put two 13' electric fans in that are flush on my radiator. These fans spin around 3000 rpm. The thing I can only think of is to have it polled out.
Not sure where you are in Texas. If in the Dallas/Mckinney area I can hook you up with a place that does radiator work. I had mine pulled apart, rodded and cleaned for $75. If your not sure about the radiator I would definately have it done. The other thing is the thermostat. 160 like the other guys said.

Hopefully that will get you rolling.

Jim :cheers
 

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Discussion Starter #17
Guys all great advise! I Changed the therom to 160, and add wetter. Car is running great for 4 days now. Thank you so much for all the help.
Herb.:party:
Ps. Auburn thank you for the help, I'll have to to search out that Robert Shaw stat.
 

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68GreenGoat is right on the money. My experience with Pontiac 400's (and all Pontiacs, really) is that they like to run on the warm side...especially '67's. On a 80-90 degree day, temps in the 210-220 range are pretty much the norm. I run a 160 'stat, re-cored 4-row Harrison radiator, and a 19 inch Caddillac Flex fan off a '69 472 on mine. I also run a fan shroud and just recently switched to Water Wetter. The Water Wetter helped! Here in Fresno, we have temps over 100 degrees pretty much every day from late June to late August. It was almost 90 today, and we're looking at over 100 this weekend. My '67 doesn't like it, but it doesn't overheat (much) either. Your temps sound normal to me. 230 plus: I'd start to worry.
What is Water Wetter? Additive? Or, is it a special coolant?
 

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64-67 Expert
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Watter Wetter is an additive that you put in your coolant. It breaks the surface tension of the coolant, so it dissipates heat better. It worked in my hot tempered '67. I'm going to put some in my '15 Model T also!!
 
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