Hi guys new here......this one's got me stumped. My wifes friend dropped off her 02' Montero Sport Automatic/3.0L for me to look at. It's been using oil the last couple weeks on her.

Here's where I'm at.
1) The overflow catch for the radiator has notable oil mixed in with the antifreeze...I pulled the radiator cap and it's loaded with the mix.
2) There's no notable exhaust steam and th tail pipes clean as a whistle first thought was she popped a headgasket)
3) The motor seems to run fine and has good power...according to her no noticeable differences in power and or gas mileage
4) I drained the oil and it's clean...no noticeable mix of antifreeze in the ol whatsoever...the underside of the fill cap is spotless!!


My first thought.... that it might have an internal engine oil cooler in the radiator leaking...I can find no such thing on the truck

This project seems like it's going to go deeper into the block/heads...(not sure I want to go there...will if I have to though). Does anyone know if there is any notable gasket failures on this 3.0L motor?...Headgaskets, intake etc....?

I've never seen a engine mix oil with antifreeze/cooling systemand not mix the antifreeze in with the oil in the engine!!!

Any help or thoughts no matter how far out there are greatly appreciated...didn't think I'd be spending my Sunday on this..seearching theengines or parts online for the motor...seems they don't come very cheap anywhere!!!


Thank you in advance
Tom

 

Another thought....

On the head gasket....is there a water jacket that runs next to an oil gallery? Thinking that the gasket failed between the two ports and having the oil pressure be much greater than the water pressure...therefore the oil overpowers the water and mixes with the water and not allowing the water to mix with the oil???

Stretching here.....I've already disconnected most of the plenum...so I'm going for one of the heads having a fialed gasket....hope I chose wisely...

Any thoughts though.....please offer'em before I scream!! Help!

 

If there is no oil cooler I would look into a blown head gasket between the oil return and water jacket holes like you said.

 

Yeah...that's where I'm headed. Hopefully everything unbolts and nothing snaps....thats a whole nuter problem....



Thanx

Tom

 

Just going out on a limb because it has happened to me. Make sure that she (or someone else) did not put oil in the overflow or radiator. It sounds bad but thats what happened to me. I noticed oil in the coolant of the wifes carbut no coolant in the oil, flushed the coolant system, that was years ago and still no more oil in coolant. Till this day i have no idea how oil got into the coolant.

 

I have to admit, Thats an excellent thought idea! Me...being a technician by trade...I'velearned to keep everything to the K.I.S.S method first and to not assume anything....I didn't do that here.....just assumed she popped a gasket inside the block.

She did tellme that the trucks used oil ever since she bought it years ao...she knows nothing about anything under the hodd, so I wouldn't put it past her. It's been running for about a 1 or so with no oil in the sntifreeze at all.....and to be honest I didn't see anythig wrong with the head gaskets when I pulled it apart...so your suggestion makes more since than ANYTHING AT THIS POINT!!!

thanx for sharing that thought!

Tom