First time poster here. I have an ‘86 FJ60 with 166K miles, strictly my weekend ride. At each oil change (which I limit to ~500 miles) I send a sample off to Blackstone Labs for testing, all of which have come back positive for coolant in oil. By appearance, the used oil does not appear milky. The underside of the oil filler cap shows some “milky cream” but what appears to be a normal amount.
I have performed the following diagnostic tests and maintenance procedures:
1) Cooling system leak down test-negative result.
2) Combustion test-negative result.
3) Compression test-numbers look great, all within range.
4) Replaced the oil cooler, positive for coolant in oil afterwards.
I have yet to pull the head, inspect it and replace the head gasket (not sure I want to tackle that project myself) but I understand that represents the proper path forward.
Could it be that one or more of the Welch plugs under the valve cover are the cause? If it is the head gasket, why do the above test results look good?
I have performed the following diagnostic tests and maintenance procedures:
1) Cooling system leak down test-negative result.
2) Combustion test-negative result.
3) Compression test-numbers look great, all within range.
4) Replaced the oil cooler, positive for coolant in oil afterwards.
I have yet to pull the head, inspect it and replace the head gasket (not sure I want to tackle that project myself) but I understand that represents the proper path forward.
Could it be that one or more of the Welch plugs under the valve cover are the cause? If it is the head gasket, why do the above test results look good?