Detroit 60 series Antifreeze out blowby tube

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Smellfunny, Nov 5, 2012.

  1. Smellfunny

    Smellfunny Medium Load Member

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    Got a truck at the shop Friday (14 liter Detroit) that the owner says is losing about a gallon of antifreeze or better a day. The oil fill and dipstick looked clean. The radiator cap is the same. I noticed no leaks on Friday during a look over (and he said he has seen no leaks) from hoses etc.. The truck was overhauled about a year ago and he just had a compressor put on and has had his EGR cooler replaced. He also had his cylinder head off at another shop and they said it checked out ok. I did notice some antifreeze coming out of blowby tube.

    So today, I got the truck in the shop and drained the oil and dropped the pan. Oil seemed to be free of water. I pressurized the coolant tank and saw no leaks. I let it sit for 3 hours and noticed a drop in pressure of about 1 lb. I found 2 leaking hoses (one on EGR cooler hose and one on water pump). I tighten those clamps and it seemed to stop (was closing time so I will double check that in the morning).

    Here is the thing, the antifreeze that I see in the blow by tube is pure antifreeze. No milky mix but pure green stuff. Any thoughts on how pure antifreeze can be coming out the blow by tube and not mixing? I am pretty sure most of his coolant lose was from the water pump hose and I am even wondering if some of the coolant may have blown into the blow by tube.
     
  2. snowwy

    snowwy Road Train Member

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    i'm guessing the blow by tube your talking about is actually the vent tube for the radiator. and not the actual blow by tube that connects to either a valve cover or somewhere on the side of the engine.

    if the radiator cap is bad it won't hold pressure and antifreeze leaks out that tube.

    i don't see how in the world you could actually have antifireeze leaking out of the blow by tube. specially since you say antifreeze and oil are normal.
     
  3. magoo

    magoo Bobtail Member

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    My c15 started to do the same thing a few weeks ago,noticed a small puddle of coolant under my blowby tube.I dropped the pan and pressure tested the system.Ending up plugging in the block heater to warm the block up and after 20 hours at 10 pounds of pressure i started to see antifreeze coming down the inside of the front cover.The seal on the water pump between the oil side and coolant side was leaking.My oil never showed any signs of coolant in it either.I changed the pump and cleaned out the valve covers and it has been fine since.
     
  4. Smellfunny

    Smellfunny Medium Load Member

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    It was actually the blow by or breather tube. Perfect antifreeze.
     
  5. Smellfunny

    Smellfunny Medium Load Member

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    I wanted to do that but this truck does not have a block heater.
     
  6. Smellfunny

    Smellfunny Medium Load Member

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    I found two more water leaks this morning on hose connections. Talked to the owner and he told me has already had the truck at Detroit on the dyno and with another mechanic from International dealer (side work). Has had head checked and new tubes put in.

    I found 4 leaks to their 1 so I feel like I accomplished something. He also does have pressure building in his surge tank when engine runs for a while and you rev up.

    I also found that his EGR valve is not working. He is going to try it and see what happens after I repaired the 4 leaks and try and find a used valve. He said he has already replaced the EGR valve 3 times in 2 years.
     
  7. JohnP3

    JohnP3 Road Train Member

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    Coolant will leak out of a cold engine a lot easier than a warm one. I use to first off make sure the engine, to the back of the transmission is as clean as you can get it. Leave it running at about 1200 RPM, add a gallon of ATF Dex 3, for the time it takes you to wash it. Then remove the oil pan plug and the oil preasure gauge hose and blow about 25 lbs, boost to shop air preasure, for a minute or so every couple of minutes, then back to 25 lbs air into the system, leave it on for at least twenty minutes, then punch a small hole in the oil filter and blow it out. Remove the pressure setup and the oil pan, wipe off the oil that would drip off. Remove the oil filter.
    Pressurize the cooling system and leave it sit, I have a setup that uses shop air, to pressurise the cooling system. set it at 5 lbs, slide a sheet of cardboard under the engine, and leave it sit, I have even towed it outside to cool it off. When t is cold boost the preasure to 10 lbs, wait for a couple of hours, then 15, Wait then 20. You do not want to add full pleasure to quickly, and shifting a seal, plugging a leak.
    Coolant leaks can take a lot of time, a lot less time that ripping things off that are not the problem, just so you can kick it out and get rid of the customer.You have to advise the customer it will take time, and you have to have the space to tie up a bay for a couple of days.
    Just a thought!
     
  8. Smellfunny

    Smellfunny Medium Load Member

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    Yeah, I had it for two days trying to check at various temps. I am going to call him tommorrow and see how it is going.
     
  9. country29

    country29 Medium Load Member

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    as in blowing out the overflow from radiator or around the radiator cap? if so sounds like a head gasket or air compressor putting compression in the coolant system to me, but I'm not real familiar with detroits. seen many a cat and cummins head gasket or air compressor put compression in coolant.
     
  10. Gear head

    Gear head Medium Load Member

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    could also be injector cups causing compression in cooling system. The coolant comes out of blowby hose because it boils out of the oil causing it to seperate from oil thus becoming coolant again. I have had heads checked before only once but it did happen that it checked out ok but it was the problem. I had that motor apart 3 times before we desided to replace it and no problems. Has the liner projections been checked with holdown bar at 4 corners. This would definatly explain compression in cooling system. I have had pans down and pressurised for 12 hours before it would show. GOOD LUCK.
     
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