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J
Free Member
Send PMMAPLE, Canada
Joined: 3/9/2008
Posts: 164
Vette(s): 70 VETTE 350/300HP, AUTOMATIC, ALL STOCK EXCEPT FOR MILD CAM,LAGUNA GREY, 3:55 POSI GEARS
DO THESE PUMPS REALLY MAKE A DIFFERENCE, WE CHECKED EVERYTHING ON THE CAR AND IT STILL HITS AROUND 230 AT HIGH SPEEDS OR HARD DRIVING. DID A COMPRESSION TEST AND IT WAS FINE, WONDERING IF I PUT A HIGH FLOW WATER PUMP WILL MAKE A DIFFERENCE. THE TEMP STAYS AT 195 AT IDLE, BUT ONCE I HIT HIGH SPEED OR RUN IT HARD IT HITS 230. I HAVE A NEW RAD, FLUSHED BLOCK,160 THERM WITH 4 BYPASS HOLES, ALUMINUM WATER PUMP, ALL SEALS ,SPOILER AND FAN SHROUD ARE THERE, NEW 2-STAGE Q-JET CARB, NGK SPARK PLUGS AND ADDED WET WETTER TO COOLANT. ANY IDEAS!
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K
Hey JC,
Just an idea;
Is it possible that your heater core is partially clogged or are the heater hoses old and soft? Or are they kinked anywhere?
Keep in mind that I ask more questions than answer around here.
Just a thought, though.
Good luck with it!
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r
I still think a hose is collapsing during high rpms. I have seen these same symptoms numerous times, change everything but the hoses and it still runs hot. Two of my Vettes did the same thing and it was the lower hose both times.
Scott
Scott
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Free Member
Send PMFrederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
I agree with the hose collapsing under vacuum...classic symptoms. Check your lower radiator hose in particular and make sure it has the coil spring inside it. It needs that to keep from collapsing.
Be careful of high flow water pumps. Some can actually pump coolant too fast and the coolant doesn't stay in the radiator long enough to adequately shed heat. You could also have air pockets in the cooling system that need to be bled out.
Also...check the timing and make sure it's not too far advanced or too retarded.
One more thing...is the engine built up? More power = more heat. If this is the case and everything else checks out normally, you may have to consider electric fans.
Be careful of high flow water pumps. Some can actually pump coolant too fast and the coolant doesn't stay in the radiator long enough to adequately shed heat. You could also have air pockets in the cooling system that need to be bled out.
Also...check the timing and make sure it's not too far advanced or too retarded.
One more thing...is the engine built up? More power = more heat. If this is the case and everything else checks out normally, you may have to consider electric fans.
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J
Free Member
Send PMMAPLE, Canada
Joined: 3/9/2008
Posts: 164
Vette(s): 70 VETTE 350/300HP, AUTOMATIC, ALL STOCK EXCEPT FOR MILD CAM,LAGUNA GREY, 3:55 POSI GEARS
BOTTOM HOSE HAS A SPRING, TIMING HAS BEEN CHECKED, STOCK 350/300HP MOTOR.
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I don't think 230 is a problem especally if it's only when it's working hard.
Mine (with the stock engine) ran 220-230 all day long without a problem.
The stock electric fan was set to come on at 238. If it runs at 195 at normal driving I don't think you have a problem.
Dave
Lifetime Member #116
Dave's '82 
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r
Do you have the right temp. sending unit and is it in the right location?
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J
Free Member
Send PMMAPLE, Canada
Joined: 3/9/2008
Posts: 164
Vette(s): 70 VETTE 350/300HP, AUTOMATIC, ALL STOCK EXCEPT FOR MILD CAM,LAGUNA GREY, 3:55 POSI GEARS
MINE IS LOCATED FRONT LEFT OF MOTOR, NEAR ALTERNATOR.
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I understand you would like it to be lower, but it really is not a problem at that temp.
However you may need to look not at the cooling system itself, but the duct work, seals, and the lower spoiler in front of the car. The airflow makes a HUGE difference.
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V
Former Member
Send PMMounds View, MN - USA
Joined: 5/24/2007
Posts: 1034
Vette(s): 70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe
Two thoughts. First is to verify the accuracy of the temp gauge. If it has a 160 thermostat and the gauge shows 195, maybe it is off. If you can borrow an infrared temp sensor, point it at the intake right next to the sender and compare to the car's gauge.
You mentioned a new carb. Possibly it is too lean at higher load, which can cause a lot of heat. I have seen air/fuel meters that clip to the tailpipe, or you can have it run on a chassis dyno. All the other suggestions about air dams, seals, etc are great ideas, too. While you will probably not do any harm running at 230, that is not normal and should be curable.
Larry
You mentioned a new carb. Possibly it is too lean at higher load, which can cause a lot of heat. I have seen air/fuel meters that clip to the tailpipe, or you can have it run on a chassis dyno. All the other suggestions about air dams, seals, etc are great ideas, too. While you will probably not do any harm running at 230, that is not normal and should be curable.
Larry
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in Forum: C3 HVAC, Fuel, Emissions, and Exhaust
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