Well my old beautiful 02 LS that was sold to my mother-in-law has overheated maybe for the last time. I told his son that the water pump was leaking about 2 months ago and he never did anything about it. It recently overheated twice and today it stranded my m-in-l. Her sons picked her up and she drove off and they were able to park the car where my wife works.

Well I went today to check it out and its not good but I don't know how extensive it is. I filled the radiator up with coolant (which was basically empty) and turned on the car. It struggled to turn on then once it did about 20 sec later it started to spit out all the water through the reservoir tank. I turned it off then filled it up again. Started the car then I saw that it was leaking coolant through the back of the engine. A lot of coolant was leaking. Leaking all the way to the o2 sensor.

I'm not sure if the gasket are cooked or what? There is a Pepboy's and a Firestone in walking distance but just want to know beforehand what they are getting into.

 

Could be any number of things fried gaskets,warped or cracked head, cracked block and the list goes on and on. If it was overheated bad enough I'd say it's probably a good boat anchor now. May be time to find another motor. maybe not tho I had a motor ran for about 10 minuets with no antifreeze due to a blown hose and it survived. Good luck

 

If I am correct an '02 LS has a 3400. My bet, the nylon intake gaskets as you mentioned are cooked/melted. I do NOT advise running the engine. Before you tried to start it, it would have been a good idea to change the oil, as a severe overheat will destroy the properties of the oil and it does not effectively do it's job. But what's done is done.

It's tough to advise what exactly to do at this point without being infront of the car. One option is pull the engine and outright replace it. My thoughts are if you did not hear any scraping, pinging or knocking from the engine, this may oddly be salvageable, but with some work.

Here's how I'd address it (in order):
- DO NOT CHANGE THE OIL YET! You already suspect you need to do LIM gaskets. Unless you have an itch to start the car, changing the oil is throwing money away.
- Get a loan-a-tool radiator tester. Using this, you can put pressure in the cooling system and find where it's leaking. Based on your description, I highly suspect where the LIM and the heads meet. Keep in mind, if there is 50,000 or more miles on those LIM gaskets, the coolant ports already began going to hell.
- If it is the LIM gaskets, decide now if you want to proceed. I am making the assumption it is the LIM gaskets. I would begin by draining the oil next, take a look at it. If you see metal shavings, I'm thinking this engine is done for.
- dis-assemble the car down to the LIM gaskets.
- A point of concern will be the heads and head gaskets. Odds are if the car overheated, the heads warped. You can either take them off and if they are warped, replace with junk yard heads OR have a machine shop shave the decking surface to make them flat again. What I've seen the cost of heads at a pull-it-yourself yard, I'd probably get a new-to-you set of heads that appear in good shape (of course if you do, bring a straight edge to check for warping at the yard). Personally, if I don't suspect the head gaskets being damaged, I would just verify all head bolts are still properly torqued in (this way it forces the head to tighten up to the block again if it's not already).
- During re-assembly, make sure to use aluminum LIM gaskets. They have a much longer life and cost maybe $20 more (if that).
- Once you are re-assembled, re-connect the pressure tester. You mentioned the water pump failed, hopefully that is the ONLY leak you find.
- Next, change the oil, get all that crap out of there.
- With fresh oil and making sure the car has coolant, start the car. Yes, we have not yet changed the water pump. The idea here is to hear how the engine sounds, perhaps take it for a quick ride around the block before spending more money. Any knocking, pinging, scraping, anything abnormal? If not, you may be lucky. Change the water pump then.
- Drive the car about 500-1000K miles and CHANGE the oil. The idea is that there is still crap in that oil from the overheat and other crap like coolant from the LIM change.

Again, this is a recommendation without seeing the car. I've dealt with a car that overheated and seized on me once. Luckily, fix the coolant problem (and the melted coolant sensor), fresh oil and it sounded fine and ran fine. But, the following issues may have resulted for the immense heat that seized the engine (alternator failed, water pump leaked, changed the tstat and had a bolt bust off in the tstat housing, and lastly, despite the belts being lined up right and everything looking straight, it was flipping the alternator belt about every 1-2 months).

Beware and be careful. I hope everything turns out for the better.