Coolant in my oil! Help!!

Discussion in ''Da Nailhead' started by Robin Cook, Jul 30, 2021.

  1. Robin Cook

    Robin Cook 70 GS350(455Tribute) 65 gran sport

    I have a 401 that was sitting on my engine stand for 15+ years, freshly professionally built back then. I’ve run it numerous times on an engine run stand with radiator etc. over the years with no issues whatsoever. Finally got it installed in my grand sport, and I’m finding antifreeze in my oil. I’ve started with the timing chain removal and inspection it’s brand new, resealed it and pulled the oil pan, was able to sneak it out by lifting the engine. I then pressure tested the cooling system, and finding coolant is coming through the oil passages! So I pulled a main, sure enough coolant is pushing through into the oil system. I have not pulled heads yet but that’s about all that’s left. Before I did that I thought I would ask you folks if you’ve seen this before and what I could possibly be expecting. And all suggestions most welcome! As you can appreciate it’s been very frustrating, I’m on this car for 20 years and it’s Road ready before I came across this issue. On a note, I’ve seen excellent workmanship throughout the engine on my dissassembly, everything brand new even see Grease dabs from fingers on rockers and timing chain area.
     
  2. TrunkMonkey

    TrunkMonkey Well-Known Member

    Pull the valve covers and mop them dry (in the event coolant in the oil is up there) then pressurize the cooling system again and see if you get coolant on top.

    And do a compression test.

    I'm hoping it's a head gasket.
     
  3. Robin Cook

    Robin Cook 70 GS350(455Tribute) 65 gran sport

    Thanks for that trunk monkey, valve covers are off and there’s a pool of mixed oil and antifreeze milky in the valleys. Pressure testing the cooling system did not make any difference. Valley covers off no evidence of coolant movement leakage there. When I pull the oil pan lots of dripping antifreeze from the Crankshaft. So. Pulled a main cap and clearly see coolant from oil gallery to bearing. ive never seen anything like it.
     
  4. TrunkMonkey

    TrunkMonkey Well-Known Member

    Once in the oil, it's gonna be everywhere.

    It's a problem with bearings if you run it and get it hot, as it becomes corrosive and also can turn to steam mess up oil's ability to live and col journals.

    Since you have not run it long enough to do any harm, you have time to see if it's a gasket issue.

    If that's it, when you put it back together,
    clean up at this stage is drain, replace filter, new "cheap" oil run a few minutes, drain, replace filter, good oil and go.
     
  5. telriv

    telriv Founders Club Member

    Also you will need to take the lifters apart & get the water out of them or buy new lifters.

    Tom T.
     
    TrunkMonkey likes this.

Share This Page