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75 coolant problem

Old Apr 20, 2003 | 11:28 AM
  #1  
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68350hp
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From: Canton Ohio
Default 75 coolant problem

The coolant in my dads 1975 L-48 coupe has been disappearing since he got it back on the road last year. He has had to put over one gallon of 50-50 mix of prestone and water in about 600 miles. There is no leakage from the radiator. The hoses (brand new) are not leaking. The water pump is dry around the seal and there is no dirt residue around it. The oil level has not increased and the is no frothing or any apparent impurities in the oil. He is going to get a pressure test on the system in the near future. Any ideas or suggestions. The car is running great with no seeming ill effects other than a spike in the coolant temp when it gets low.
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Old Apr 20, 2003 | 11:38 AM
  #2  
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SanDiegoPaul
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Default Re: 75 coolant problem (68350hp)

Have the radiator sniffed for excessive hydrocarbons first. With good coolant there WILL be some HC's but it should read very minimal on a machine. Tailpipes dry?
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Old Apr 20, 2003 | 11:42 AM
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Default Re: 75 coolant problem (68350hp)

Have you checked the heater hose connections?

What kind of radiator cap do you have?
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Old Apr 20, 2003 | 11:51 AM
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Default Re: 75 coolant problem (68350hp)

The pressure test should show if the system has a leak. But you could also check the freeze plugs on the side of the block for evidence of leakage. I've seen instances on SBC's were the freezplugs had corrosion and developed a pinhole. You could use an inspection mirror for the tight accesses.
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