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67 gs 400 cooling issues

Ryan474

Active Member
Just did a full rebuild on my motor and its running over 200 degrees at 60 mph. Ambient temps 80. I had bought a brand new OEM style radiator that is brass/ copper and i feel like it should be cooling better than this. We had put a better water pump from TA performance and thought this would be successful but still hotter than normal temps. Running a 160 degree thermostat... anyone have a better solution? Aluminum radiator? Modifications?

Ryan


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My car is a/c and 4spd. I had a "Desert Cooler" which didn't do the job. I went to a 2x1" aluminum original look rad. It's pretty good, but I am going to go to the Griffin 2x1.25" original look aluminum rad. With the one I am now running I would not have your heating problems. However, if it is 90+ and I am stuck in big city traffic, it can warm up (with a/c). If I am climbing a long summit on a hot summer day with the a/c on, it will warm up. I can get across the summit, but I would probably be leaning on 210. I am hoping the Griffin will make the difference.

Changing the thermostat doesn't help. I would go back to the 180. I would also stick to an original style clutch fan. For the GS, they offered 3 clutches. Make sure you are not running the standard one. My a/c car has a 7 blade fan, maybe if you don't have one you can find one. It also has a small shroud.

Cruising at 60, neither the fan or the shroud will make a difference, the system should be working on natural air flow.
 

Ryan474

Active Member
Thanks for the info! I do have a 7 blade fan on it. I saw that TA performance does sell an aluminum rad with or without tranny cooler. Runs a bit expensive at almost 800 bucks! Wonder if anyone has experience with one... ill look up the griffin one you suggested. Found a champion aluminum radiator that we got for under 300 that we are going to try just to see if it will make any difference. My car is non a/c so at Least i dont have to contend with that.


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Ryan474

Active Member
Well aluminum rad lowered temp on Highway down to 175/180. Still had some higher temps at idle so installed a 12” maradyne fan in front of rad and that did the trick. Fan hides behind grill and didnt break the bank.. 250 for fan And wiring harness.


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schwemf

New Member
Ryan,
I believe there were two different water pumps in 1967 (which I know was true in later years), depending on whether your car has heavy duty/Air Conditioning or not. Different diameter pulleys and different number of blade fans (7-blade with fan thermo clutch verses 4-blade fan ) were used for each application. I believe you'll have the overheating problem that you're seeing if you use the heavy duty water pump (again, the only one available new today) with the non-heavy duty pulleys and 4-blade fan.

Check out the Buick Performance Group's web site, as I believe they have an article that addresses this.

-mike
 
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LARRY70GS

Active Member
Ignition timing also plays a role in high temperatures at idle and low speed. The 1968 400 engine had a distributor(Part # 1111285)with 30-34* of mechanical advance. Initial timing was 0* (TDC). The vacuum advance should be connected to manifold vacuum so that you have it at idle. Running ported vacuum will result in the engine idling at 0, and that retarded ignition timing will heat the engine up all by itself.
 

Ryan474

Active Member
Thanks for the info guys. I’ll look into this And get back with you.


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