I have a Triton v10 engine in my vehicle

I have oil in my coolant but no coolant in the oil.

What could be the problem?

  • sounds like a blown head gasket. Apr 26 '16 at 3:35
  • Funny, everybody says that, and I've seen a whole lot of cars and trucks with this issue. Never ever is it a head gasket. Normally it's either a cracked head or a cracked block, usually caused by cold weather with improper antifreeze or by running the vehicle without proper amount of coolant or engine cooling fan issues. Has anybody on this forum ever seen a "blown head gasket"? And oil in coolant but no coolant in the oil just means that at the leak, the oil is at a higher pressure than the coolant.
    – zipzit
    Apr 26 '16 at 4:21
  • One other note.. Its quite possible the leak is at a heat exchanger inside the radiator... I don't know that vehicle very well, I didn't think they have an engine oil cooler in the radiator. I'm pretty sure there is a transmission cooler in there though. Are you sure it's not transmission fluid in the coolant? (Hint: what color is the "oil"?)
    – zipzit
    Apr 26 '16 at 4:28
  • @zipzit - Most of the blown head gaskets I've seen have the coolant blowing out the exhaust. I cannot specifically point out a vehicle which I've worked on which has had oil in the coolant due to a blown head gasket. I've seen plenty which have had coolant leaks into the oil, though. If an aluminum head warps, this is what you'll find most often. This is due to coolant getting out of it's hole, past the head gasket, and into the valley. Most OHV heads don't have an oil galley through the head, I'd bet. They have oil through the lifter/push rod to lubricate the top end. OHC is another case. Apr 26 '16 at 13:33
  • I've seen a badly over heated vortec 4.3 with a presumably bad headgasket and engine oil in the coolant owner opted to junk the car so it was never torn down to verify.
    – Ben
    Apr 26 '16 at 17:52

If it has an engine oil cooler, that is most likely the problem, a faulty oil cooler, some are made into the radiator, others have heater hoses running to a remote oil cooler, and a few I have seen are where the oil filter screws on, the oil cooler has a leak into the coolant side. The reason no coolant is in the oil is because it is a high pressure leak, oil pressure is always higher than coolant pressure when running, so if the leak only happens at 20-25psi or above, coolant will never get into the oil.

Other than that it could be a head gasket as suggested but is rare.

If the oil cooler is in the Radiator, obvious because it has big oil lines running into one of the end tanks, pull it and have it leak tested at a radiator shop.

  • 1
    I love cowardly down votes, thanks. My answer is from 35 years experience in repair shops, and automotive machine shops has been the cause on every oil in the coolant issue I have repaired with one exception early Ford FE truck blocks had an oil passage in the block that fed the rocker arms in the head, the passage in the block would crack, I fixed this by drilling out the passage and press a modified (cut to length) push rod into the properly sized hole, saving the block.
    – Moab
    Apr 26 '16 at 22:37
  • I don't know who downvoted you, but I threw my +1 in because it is a reasonable answer, and more than likely could be correct. It's fairly easy to tell if it has an oil cooler if you know what you're looking for, which I think you explained. Apr 27 '16 at 0:13
  • Thanks but Someone down voted again, cowards. There is no way to be 100% correct when you don't have the vehicle in your shop, sometimes even when it is. All I can do is post my 40 years of experience repairing cars in this situation.
    – Moab
    Apr 27 '16 at 0:58
  • I've quit worrying about the downvotes ... you always get the neighsayers ... still stings a little, but not much you can do about it. Apr 27 '16 at 1:02

You will rarely see water leaking through a small hole as will oil. Water has surface tension and does not “wet” metal as oil does. Early attempts to use pure ethylene glycol as a high-boiling point coolant were very troublesome due to such leaking. Smaller amounts in predominately water work fine.

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