It finally took a poop

[Joshs93four-oh]

I had my truck in the shop to re-torque my new headers and exhaust the other day and when I went to check the oil... well, it was about 3/4" above the full mark. I pulled the drain plug and a mix of antifreeze and oil came out. About 7 years ago it developed an external head gasket leak on the driver's side head and I put Alumaseal in it and it held that long. I guess what my question is what are the chances that the heads are cracked? It has never been hot once. Also, what is the deal with having to remove the engine just to change the timing set? Thanks in advance. Josh
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Yamaha libero (g5) specifications

 

[Joshs93four-oh]

Out of 20 views no one knows about this? I know about engines but have not worked on a 4.0 before. Anyone? Josh
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TOYOTA TYPE A ENGINE HISTORY

 

[30coupe]

Well, like you, I have never worked on the 4.0, but it is possible that the head is cracked. It is also possible that the gasket let go between cylinders and the heads just need to be planed.

The timing set question, I can't answer, but if you have antifreeze in the oil, I'd pull the motor anyway and tear it down. If you ran it for any length of time with the antifreeze in the crankcase, you'd better check the mains. While you are in there, a new oil pump would be wise as well.

I don't know specifics about this motor, but that's probably how I would approach the situation. It's a heck of a lot easier to work on them outside the truck, and since you will have to pull the wires and hoses anyway, you might just as well pull the motor out and make life easier.