Quote:
Originally Posted by firemediceric
rrgrassi,
given the car's symptoms, how do you suggest I proceed? Especially if a UMO analysis may not show coolant in the oil even if the head is cracked? The car, after it warms up, runs great. I hate to go looking for problems.
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Do the oil analysis, as instructed, because even if there is no mixing, vapors do condense and can leave a tell tale residue the anaylsis can pick up. It possible to have mixing, but not enough to give the oil a "milk shake" look to it, like Brian Carlton said. Also do a compression and leak down test on the cylinders. You can also check for bubbles coming in to the coolant tank, with the cap off, and engine running. Take the cap off while cold, start the engine and let it idle until it reaches it's normal operating temp. Look for bubbles while the car warms up. When the engine is cold, it is possible for the cracks to seal due to the contraction of the metal, and then open a bit as the heat causes the metal to expand. I had a gasser Datsun F-10 do that. Started running hot, and losing coolant. The radiator showed bubbles when the engine ran. The Datsun also had some water on the #3 piston. Turned out to be a head gasket, and that was only seen after disassembly. Also repaired a Ford 460 that blew a head gasket. Only way to tell on this one was the water drooling out between the head and the block on the front of the engine. No visible oil/water mixing in either case. So do all the testing you can before throwing money at repairs.