My 2002 Ranger XLT with 2.3L has just turned 418k. When heated, bubbling is coming through the coolant reservoir and I have been adding small amount of coolant almost on a daily basis. I am assuming this is caused by head gasket leak. No water/oil mix or sign of leak through exhaust system. Body and suspension is in good shape so I am considering purchasing a completely rebuilt engine as I use truck in my job. Any thoughts or recommendations?

 

I would check with local machine shops to see turn around time for local rebuild.
Local means any warranty issue is "local".

Head may be fine, just needs cleaning and new cam bearings, and new gasket
New bearings and rings in block and new oil pump


Blown head gasket, or cracked head, will start to bubble as soon as engine starts.
The pressure in the blown cylinder is 150+psi when cranking and 900+psi when cylinder fires, rad cap is rated at 14psi, so..................cold or warm wouldn't matter, pressure leak would be there regardless.

You can do the Glove Test, it is free
Cold engine
Remove rad cap and overflow hose
Seal overflow hose outlet, vacuum cap or short hose with bolt in it, even chewing gum or putty :)

Put a latex glove over rad cap opening and seal it with rubber band, or use a balloon instead of glove, even a condom works.

Pull spark plug wires or pull Fuel Pump relay you want a NO START.
Now crank engine and watch glove

If glove bounces you have a cylinder leak, blown head gasket
If it just lays there then you don't

If it does bounce you can remove 1 spark plug at a time and crank the engine
When glove stops bouncing the last spark plug removed was from the leaking cylinder, reinstall it to confirm.

 

Thanks Ron. I will try this as soon as I can.