Dear Tom,
Help! My ’07 Chevy Impala with a V5 engine overheats and all the cheap fixes have not worked. It has a new temperature gauge, I flushed the radiator, replaced the temp sending unit and bled the system for air lock (it even failed the "sniffer" test for the cracked head). I've heard others with this make and year have had this problem. Were there any recalls? What else do you think I should check?
Barb from South Wales, N.Y.
Barb,
I am not sure of what you refer to when you mention the "sniffer test." Perhaps a four-gas analyzer? This will only reveal if there are excessive tailpipe emissions, not water in the exhaust. Try having a "Block Test" performed. The tech will draw a vial of a coolant from the radiator and then mix it with a special chemical to see if it turns color. If it does, that means there is exhaust gas in the cooling system and thus a blown head gasket. Another way to track down a blown head gasket is to perform a cylinder leak-down test. Finally, a compression test will reveal if there's a leaking head gasket. These are the only ways I know to track down a leaking head gasket. There are no other ways of repairing an internal leak short of disassembling the engine and inspecting for a blown head gasket and/or a cracked cylinder head. Good luck.
Tom
Tom Torbjornsen is an automotive expert of 37 years. An automotive journalist in good standing with the IMPA (International Motor Press Association) and MPG (Motor Press Guild), Torbjornsen is the Repair and Maintenance Editor for AOL Autos, At Home Portals and many other websites. Hear his radio show. America’s Car Show, on the SSI Radio Network Saturdays at 8 a.m. Listen to the show on the live stream during regular show times at www.americascarshow.com. Send your car questions to his website at www.americascarshow.com. You can also find Tom’s book, “How To Make Your Car Last Forever,” in local Barnes & Nobel booksellers, or order online at Amazon.com.
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