I have a 170 CI slant six rebuilt less that 2K miles ago. Car is not a daily driver. I now notice that the coolant is becoming dirty and air bubbles show in the coolant when the car is running. I believe it must be the head gasket. Oil is clean and clear. Before I go to the trouble of pulling the head, would appreciate confirmation of my suspicions or other possibilities of the problem. Thanks
Sounds like it. Run a compression check (or better yet a leak down test if you have the equipment), one or two holes should be showing a loss of compression. Sounds like it isn't too bad yet, so run it with the engine cool (head gasket clamp "should" be a little looser then).
If the compression test is OK look for loose hose clamps or cracks in the lower radiator hose. It might be sucking air.
I guess it would depend on how big the hole is in the head gasket but when I had a blown head gasket it looked like a geyser not just bubbles!
Bubbles in the water while the engine is running is a sure sign of a leaking headgasket. Pull it now before it gets worse - its one of those issues that will never get better and will only deteriorate as time goes by. Looose clamps should show leaking water and the radiator/cooling system will not hold pressure as the leaks allow the pressure to escape. Does the radiator system overly pressureise/ Its a sure sign that the air is getting pumped in through the leak point annd will replace the coolant with air and you loose your cooling ability
If compression looks good, then do a block test. This would show exhaust gases in coolant. Another thing to check is the oil filler cap. If it looks milky on the inside of cap, then you have exhaust in coolant. In the radiator, it looks like rusty mud when this happens too.
Put a pressure tester in the place of the radiator cap after the engine is already warm. Once the coolant has expanded from heat to operating temp. it should not continue to rapidly build pressure, rapid pressure build at this point indicates head gasket or crack.
another thing is find out what type of head gasket the rebuilder put on it and then find out if its one that needs to be retorqued after it warms up/broke in , as those old style gaskets are out there and it will do the same thing if the retorquing is not done . not all gaskets are permatorques
Agree, head gasket.. Maybe the head been planed too much and now the head bolts are bottoming out in the block, not allowing the right pressure on the gasket??
Make sure your wife didn't pour it full of cheap champagne because it was running hot. It happens a lot, I've read about it in several of the car magazines. Happens all the time.
My sister's Falcon 170 [about 10 yrs old at the time] had oil getting into the coolant and then overheating. I made up a jumper line to bypass the a/t cooler in the radiator, flushed the cooling system and nursed the car back home [close to 200 mi] - no fix but eliminated one possibility. Pulled the head a couple times with no evidence of gasket or cracks in deck or head surface issues, new gasket and flushed each time. Oil always remaining good, no water getting into it. Drove me nuts until I got a deal [$75, it was about 40 yrs ago] on a good 'yard engine and stabbed that in, no more problem. Only thing I could figure was there was a small crack in the block or head between the internal oil galley that fed the top end and water jacket which allowed oil to go one way only when the engine was running and oil pressure greater than water but not back the other way when shut down. I'll be interested to hear what you wind up discovering. Ed
Guessing game. ....... any rad shop that is worth anything will have an exhaust sniffer. Tell them your problem. Have them test it. Takes 30 seconds. Then you know.
Y'all have answered my question. Your responses pretty well confirm my suspicions as well as other items to check. i.e., head bolts too long after cutting the head. Thanks to all and I'll let you know what I find when I get into it.
Use a block tester, if the fluid in the tester changes color, you have combustion gasses in the cooling system. blown head gasket, or cracked head etc. These testers do not cost a lot and work very well to determine if there is combustion gas entering the cooling system.
Your most basic and first step is to Run the block test to check for combustion gasses in the coolant. Now since you can't tell with obvious certainty- I'd guess its a small leak and this stuff works fantastic on those small leaks. http://www.amazon.com/BlueDevil-Head-Gasket-Sealer-ounce/dp/B000NOO798
Finally ran compression check. High is 140 psi low is 130 psi and other cylinders fall between those numbers. If it is a head gasket, it must be a small leak and maybe the Blue Devil sealer would work or would I just be playing with my a**? Not familiar with a block tester and where do you find one? Thanks
I got my block tester from Snapon, years ago. You can probably find them on ebay, maybe Napa, Rockauto etc.
http://m.advanceautoparts.com/mt/sh...w-combustion-leak-tester-uvu560000/22981757-P First google hit.
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