I have a 1968 Firebird 350 - 2 speed convertible. The car continually gets hotter as you drive. Pulled a small grade today and it hit 235 degrees!!!

Here is what I have done to keep this thing cool:

$700 Super Radiator, dual electric fans @ 180 degrees (eBay)
Closed divider plate gap
Oil Cooler w/ remote filter (removed because it didn't help)
180 degree Thermostat replaced (right side up)
19" 7 blade fan w/ clutch (now removed)
Coolant Wetter
50/50 mix
Engine is Rebuilt w/50 miles since rebuild
Tried 8 bolt water pump and timing cover (now removed)
Tried a 4 core radiator with shroud spaced 50/50 (now removed)
Timing is set 12 degrees BTDC
All filler panels, baffles, and inserts are there
Headers removed
Tried 3 different water pumps

I am at my wits end. The car has ALWAYS run hot and everything I have done hasn't cooled the car by ONE single degree. The car has a 2 brl carb (Rochester), therefor I am not racing it and driving it pretty easy.

I just ordered a Meziere electric water pump. It is supposed to pump 35 - 40 GPM. Has anyone ever tried one of these water pumps? Did it help cool the car?

Thanks.

New engines can run a little warmer until they are fully broken in, but it does sound like you are higher than the comfort zone. Have you made sure there are no air pockets? Squeeze the upper radiator hose, it should be firm when the thermostat is open.

Also check to be sure the lower hose isn't collapsing. Original style hoses had an internal spring coil to prevent collapse. Many years ago I had a car that would idle cool with no issues but got hot when driving. It took a while to find that the hose was collapsing when the pump sped up. The car had a numerically high rear axle ratio and the water pump pulley was a small diameter, making the problem worse.

If you want to sell that 19" clutch fan, let me know. Radiator and shroud too if they are like new.

Upper hose is nice and firm. I replaced the lower hose today. The old hose had the spring inside. The new hose is a "flex hose" and the spring is built into the hose itself.

I plan to keep all the parts due to the numbers matching aspect. Even though the current set-up isn't numbers matching I can always put it back. I have 5 water pumps for the car... I guess I'll have 6 when the electric pump gets here.

I just want to be able to drive the car. It is a beautiful car and I love driving it. I'd love to be able to put the top down and drive it across the country.

Carb running too lean?

Have you double checked your temp gauge reading? Where is the sensor located?

I've done most of the changes that cool down these V-8's in a run hot condition. All but the masticated fillers and the divider plate clearance (.060). Most would think my convertible runs hot at 210° - 235° peaking at 245°. But it runs just fine on a hot day, in a slow rolling parking lot (Woodward Cruise).

I think you're chasing the dragon that haunts us all. Unless your experiencing boil over, I wouldn't throw anymore money at it.

I am using both ports (one on each side of the thermostat) on the intake manifold. The driver side port has the temp gauge sender and passenger side has the thermocouple that activates the electric fans.

If using the 180 degree thermocouple as a guide then the temp gauge is close. The first time I saw the fans kick on the temp gauge said 190. But then as the car sat there idleing the gauge seemed to read more accurate. By that I mean the fans would bring the temp down to where they turn off, then heat would build and they would turn on. I could see all that on the gauge.

I agree that this is a phantom dragon. After I try this electric water pump I am out of ideas. I have adjusted the carb. Maybe I should get the original AC spark plugs?

The idiot light equipped Firebirds don't even trigger the lamp until 245 or so. 50/50 coolant under pressure won't boil until about 265.

You're technically not overheating, but running hotter than you desire.

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