Coolant in my oil, possible causes?

[Seth_O]

1993 FZJ80. I did a full head job 5 yrs/47k miles ago, following the FSM exactly. I used OEM gaskets.

Hunting for a coolant loss in my truck (using UV dye) i discovered a small amount of dye in my oil.

Praying that it was from my oil cooler i did a pressure test and got 160-170 (dry) across 5 of my 6 cylinders. #3 cylinder however was 140.

Thinking that maybe a head bolt or two had loosened since the head job 5 years ago, I pulled the valve cover and cams. All my head bolt paint marks are still pointing directly to the rear of the truck.

It doesnt seem like I should have a bad HG after so little time and miles. Is there any other possible cause that could explain the symptoms? I wouldnt expect a cracked block or head, this thing has just been a grocery getter for the last 5 yrs.

Help please?

 

[BILT4ME]

1993 FZJ80. I did a full head job 5 yrs/47k miles ago, following the FSM exactly. I used OEM gaskets.

Hunting for a coolant loss in my truck (using UV dye) i discovered a small amount of dye in my oil.

Praying that it was from my oil cooler i did a pressure test and got 160-170 (dry) across 5 of my 6 cylinders. #3 cylinder however was 140.

Thinking that maybe a head bolt or two had loosened since the head job 5 years ago, I pulled the valve cover and cams. All my head bolt paint marks are still pointing directly to the rear of the truck.

It doesnt seem like I should have a bad HG after so little time and miles. Is there any other possible cause that could explain the symptoms? I wouldnt expect a cracked block or head, this thing has just been a grocery getter for the last 5 yrs.

Help please?

Unfortunately, there are only a few places coolant can get into the engine oil.

Head gasket
Hole in oil cooler
Crack in head
Crack in cylinder wall.

If all I was looking for is a leak, I would consider a pressure tester and pump up the cooling system accordingly.
My bets on a hard to find external leak are:
3 O-Rings on bypass pipe above thermostat
PHH
Front heater core
Rear heater core.

 

[Seth_O]

Unfortunately, there are only a few places coolant can get into the engine oil.

Head gasket
Hole in oil cooler
Crack in head
Crack in cylinder wall.

If all I was looking for is a leak, I would consider a pressure tester and pump up the cooling system accordingly.
My bets on a hard to find external leak are:
3 O-Rings on bypass pipe above thermostat
PHH
Front heater core
Rear heater core.

Tks for taking the time to respond. Although not what i was hoping for, it is what i expected.

Time for another HG i guess.

 

[John Mc]

Did it turn out to be the HG again? I'm dealing with the same disappearing coolant, and small amount of coolant in oil. I think it might be the oil cooler, just can't find any threads where this was the cause. I replaced the HG 200,000 miles ago with no issues since. I'm anticipating another HG or cracked head. I'm just looking for some hope at this point.

 

[HuyFZJ80]

Did it turn out to be the HG again? I'm dealing with the same disappearing coolant, and small amount of coolant in oil. I think it might be the oil cooler, just can't find any threads where this was the cause. I replaced the HG 200,000 miles ago with no issues since. I'm anticipating another HG or cracked head. I'm just looking for some hope at this point.

I’m dealing with the same issue as you. Sent my oil to Blackstone and there’s a very small amount of coolant in the oil sample (0.32%). She drives well, though smokes a bit until fully warmed up. I assume it’s a head gasket…

 

[John Mc]

I’m dealing with the same issue as you. Sent my oil to Blackstone and there’s a very small amount of coolant in the oil sample (0.32%). She drives well, though smokes a bit until fully warmed up. I assume it’s a head gasket…

I'm just living with it. I put some head gaskets snake oil in and it seems to have slowed it down. I did the oil cooler gasket and it made no difference. The engine has over 460,000, drivers good and I just add a little coolant everything couple of weeks. I've probably put 20,000ish miles since. I can't see it in the oil anymore I think it must be evaporating fast enough to not be noticable. I can say I'm proud of my decision but it's what I'm doing. I'm working on fixing up a 94 for my son and I think it also has a small head gasket leak. So I'll probably be replacing his soon.

 

[HuyFZJ80]

I’m in the process of gathering all the parts needed for the HG job, as well as the “while you’re in there” stuff. I’m planning ok keeping her for a while, and would like the peace of mind knowing it’s ok