Man that’s an expensive unknown! I think you need to evaluate what your goals are with this rig and if they are lining up with your finances. Nothing about owning a 30 year old suv is cheep especially if you are not doing your own work. If you pull the engine you should do the head it’s a common issue with rigs that have sub par cooling systems and especially ones that are overheated. With the engine out it’s an easy job but yes gonna cost a couple grand. Let’s say they pull it and the freeze plug is ok and the leak was from the heater lines. I feel like you need a proper diagnosis even if that means paying another shop to diagnose. I don’t see why they could not use an inspection camera or watch the engine from below and see where the leak is coming from. I have rebuilt a few engines and never had a freeze plug issue they are stainless and do not corrode. Even if the engine is overheated the head gasket goes before the plugs. I’m just trying to be objective looking from the outside. Bring it home clean the crap out of the areas mentioned and run your engine and observe. Hard to believe a shop could not see the culprit.
The first sentence in this reply is perfect. The last sentence is a close second in the race to perfection.
Yo man.
Wow this is a nuts thread. There
IS a plug in the head. Ask me how I know. I can show you many pictures of mine,
NOT in its appropriate location in the back of the cylinder head.
You can absolutely do a head gasket (head job) with the engine in the truck. Again, ask me (or countless others) how I know. Got pictures of this too, if you'd like.
This feels a lot like someone has a loaded shotgun and they are just randomly firing it into a dark room.
There are only a few places where rusty water can come from the back of the engine and "spill down across the transmission". All can be inspected with the engine in the truck.
It is somewhat straightforward to (temporarily) bypass the front and rear heaters to rule them out as culprits, which at the back of the engine only leaves like THREE things, and you say that two (PHH and Cylinder head) have already been determined as not the issue.
The heater core lines for both front and rear CAN drain in a way that would end up on your transmission, though to my mind, that should seem pretty obvious. The heater control valve fails on older trucks, it definitely drips straight down the back of the engine, and would do as you describe, though it also should be pretty obvious.
Ive dealt with two headgasket failures in recent years on two trucks, and neither dumped coolant. Not saying it cant happen, just saying it didn't. They have their own symptoms which have been documented many times over.
Dude, take a deep breath and think about this from the point of view of systems. There is nothing magic here, it's a straight six truck engine, simpler than a lot.
"Mechanics" and "Technicians" who can't diagnose the location of a coolant leak without pulling the engine frighten me.
