Okay, I have an rb25det engine and there is a little oil and water mix and a bunch of smoke coming out of the oil filler and breather hoses (I want to say it's white smoke but I don't want to rule out blue smoke). The exhaust SEEMS fine. Very little smoke so I think its normal. A LITTLE water is collecting in the exhaust. I did a compression test and cylinders 5 and 6 have way low compression. I just recently changed the radiator fluid and it is now dark brown. It really doesn't smell like anything in my opinion. Is this a blown head gasket? Or could it be rings or valves? I feel like it's a head gasket since its two cylinders right next to each other having problems, but i'm no mechanic. Also there is oil on the side of the engine on the exhaust side right underneath #5 and #6. Should I do a leak down test? Should I put a little oil in the cylinder and try the compression test again? How much oil should i use? Thanks so much, any help is a big help.Do I have a blown head gasket?5 and #6 low compression readings on an inline 6 points to a faulty head gasket. Try this. Open the radiator cap and then crank the engine. If coolant sprays up like a fountain from the radiator, it's a head gasket problem. This test only work sometimes depending on how bad the problem is.Do I have a blown head gasket?Water doesn't always spray out of the radiator cap opening if you have a leaking head gasket. With the radiator cap removed and the coolant level full, start and let the engine run for a while. If you notice bubbles coming out of the radiator filler neck this can also indicate a bad head gasket. Has the engine been extremely hot recently? Another possibility is that you could have a cracked cylinder head or a crack in the cylinder block between cylinders 5 and 6. If you get to the point where you coolant leaking into one of the cylinders and you attempt to start the engine the water in the cylinder will not compress the way the air fuel mixture does. I have known plenty of people who had cases where water entered the actual cylinder and when they went to start the vehicle the water would not compress and it ended up bending a piston connecting rod and eventually breaking a piston.Do I have a blown head gasket?Change gaskets,if it has oil in the water it's gone.Do I have a blown head gasket?Loss of compression in adjacent cylinders is usually a head gasket. It is possible to have a head gasket blow only between the oil and coolant passages and not be blown bad around the cylinders, meaning you would have oil and water mixing but no smoke. Dark brown radiator fluid would be enough to convince me its a blown head gasket. Is the oil a chocolate milky color?
Bad rings would most likely cause blue smoke. Bad/burnt/dirty/sticky valves could cause your compression problem, but wouldnt cause the brown coolant. If you want to do a compression test, use about a teaspoon to a tablespoon of oil in the spark plug hole and see if the compression rises significantly.
