2000 Ford Explorer Bubbles in coolant reservoir when running

Hi, I have a 2000 Ford Explorer XLT 4.0 OHV and my coolant in gone every 200 miles from reservoir. Also I found out the bubble in reservoir when running . Couple weeks ago was running bad like 5 cil and the check engine was on. I change the wires and the spask plugs and is running better but still like 5 cil when is cold. My mechanic told me is the head gasket and is about $1500. At this point the truck have 185000 miles and is not worth the repair. I found out on the net about some head gasket repair solution{steel seal,bar, etc.}.Have you use one of those sealer?
Thank you
Livio

1500? come on, for an ohv engine unless is a o mile engine,. buy one on a junkyard for 300 and ready to go,. aslo, that engine is easy to repair,. 1500 is a steal.

why is easy, the camshaft is inside the engine, no need to setup the timming, just new gaskets and head bolts, and take the head to a machine shop and ready to go.

I would be more inclined to look into the intake manifold gaskets, they are a known porblem on this motor.

but none the less, if it were me and everything else was already out of the way, I'd do the head gaskets while I was at it, why do the same job twice, ya know.

But, as stated, if you can't do it yourself, $1500 out the door is a fair deal.