Coolant dye in oil.

  • #1

    Coolant dye in oil.

    88T 5 sp.

    Every time I drove this car 10 miles or more, steam came out from under the hood when I shut it off. The oil and coolant looked ok but it failed the block test so I replaced the head gaskets.
    After that it passed the block test but it still steamed.The steam came from the driver’s side, but I was never able to pinpoint it with certainty, although once it seemed to be coming out the oil dipstick hole.
    I added fluorescent dye to the coolant to find possible leaks, found a few minor ones, and fixed them all but it still steamed. It never overheated; the temp gauge always stayed right in the middle, and the coolant level did not drop.
    Then I discovered the coolant dye in my oil, even though I never found coolant in the oil or the mayonnaise-like appearance of coolant on the oil filler cap or oil in the coolant. I performed compression and leak-down tests.
    All the plugs were dry and looked fine when I removed them. Compression was 130-140 psi cold in all cylinders and no sign of significant leakage on the leak-down test.
    All cylinders measured above 94% and no bubbles came up through the coolant filler reservoir with 90 psi. So the coolant dye in the oil and the steaming indicate coolant in my oil but all my tests failed to find the location where they are mixing. I also replaced the intake manifold gaskets, but that still did not prevent the coolant dye from showing up in the oil. Where could the leak be that it doesn’t show up on the block, compression, or leak-down tests?
    Last edited by Z_Karma; 10-23-2016, 10:14 PM. Reason: wall of text into paragraph format,
  • #2
    Did you have the heads crack tested while they were off?
    Straya, +61
  • #3
    As I think about this hypothetically it should be the other way around.

    You should be looking for oil in the coolant.

    At idle you should have in the ball park of 20 psi oil pressure and this will increase with rpm.

    Your stock radiator cap vents at 13 psi no matter what.

    so while its running you should be pushing at least 7 psi of oil into your coolant until you shut the motor down then your gonna shove 13 psi of coolant back into the oil for a few seconds.
    Life's short
    Go fast
    Have a blast
    Leave a good looking corpse
  • #4
    Yes, the heads were checked for cracks and resurfaced at a trusted shop while they were off for the HG job.
    I should also add the exhaust does not blow any visible smoke once the engine is warm, and the turbo boosts fine. It always starts, idles smoothly, and runs great. I feel like I am chasing a ghost, but that dye had to get into the oil somehow.
  • #5
    Sorry old post, but was this ever Resolved? The oil could be mixing with coolant inside the turbo housing.