I noticed that the coolant in my radiator was brown (2 year old 350 GM crate engine), so I reversed flushed it and repalced the antifreeze. Now a month later it's brown again. What's up?

Check the type of coolant you are using. Some coolants are designed only for alloy engines. May not be working well...as in causing corrosion...in the cast iron 350.

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Regards,
Leigh
76 Trans Am
70 Camaro RS/SS
Sydney, Australia
TA76400@hotmail.com

<font face="Arial,Verdana" size="2">Originally posted by LeighP:
Check the type of coolant you are using. Some coolants are designed only for alloy engines. May not be working well...as in causing corrosion...in the cast iron 350.

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Yeah, some newer coolants (pink) are made just for newer engines. You have never used stop leak to try to fix a radiator leak, have you. That could also cause that problem.

If you have an auto trans, maybe it's tranny oil from the cooler?? Or, how about an internal oil leak?? You didn't say if it was oily or not.

How old is the radiator? Did it sit empty for a while during your engine replacement? What mixture of coolant/water are you using or have been using? If you have a lot of rust build up in the radiator itself, it'll keep coming loose and turn the coolant mixture brown.

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Fawn
73 Camaro RS 350 (the love of my life)

Thanks for the suggestions. I used the regular green Prestone. I don't have an automatic but I'll check for oil in the water (although I haven't seen any water in the oil). The car only sat for about 2 weeks during the engine swap and I had the radiator boiled out. I'm wondering if the guy who installed it for me didn't put in enough antifreeze. I think I'll try to flush it again.