I've been reading up on the AC system in '87 but have reached a few stops in my mission.
First off I know i need a new compressor (when it goes you might as well get an accumulator (~80 - 100 bucks) and a new orifice tube (~4 - 9 bucks).
Anyway, by "take out whole AC system" i guess you mean all the componenets of the system (not counting the controls for it in the dash).
well you'd have to remove compressor (easy enough), condenser (behind the radiator... should be a li ttle harder than the compressor but not that hard).. of course the condensor is a good what.. $150 buck from a regular parts store.. then the evaporator (inside the firewall) might be a pain to get out but not impossible. thats another $150 give or take.
Oh and the compressor should run you at least $180 bucks...
Thats assuming your hoses are all good and your pressure switches are fine too (switches should be.. your hoses you'd have to check to see if you had "black death" go down in there and its mucked up.. which you'd need at least a new liquid line i believe which should be 50 -80 bucks?)
That comes to a total of about $618.00 U.*. .. maybe you can find parts cheaper but i dont know. most of those prices are from advance auto parts (i worked there.. dont any more I AM NOT ADVERTISING haha) those prices don't include core charges so that 618.00 is how much it should be after you turn in your old compressor (should be only part with a core charge).
Then if you wanna do the refill of the system yourself:
Anyways tack on that a can or two of ester oil for about 8 bucks... and 3 - 4 *12 oz* cans (say 4 to be sure but i think 3 should do it) of R134A.... $30 bucks for a conversion kit (30 bucks oughta get you one that comes with refill hose, adapters for your R12 system and even some cans of charge... )
And the total is ~650.00....
Then let'* hope you have an evacuation machine that can pull the necessary vacuum... if you have a normal air compressor there are add-ons that can make it pull vacuum for about 15 bucks.. (assuming you have an air compressor already... else a compressor is like 150-200 for a descent one)
Tack on that some flushing solution (~20 bucks?) and of course a manifold guage set for (30 bucks?) and you're up to around $710.00 (assuming you have an air compressor)...
All in all i'd say its best to see which ones of your components you can salvage..
your evaporator should be ok, your condensor has a good shot of being ok... if you had black death it might have a clogged passage you might never know about which could cause pre-mature failure..
that why i never got around to doing mine... i got a new compressor and accumulator and orifice tube.. but some dumb a$$ mechanic never gave my parents 2 of the hoses (including the cut off switch on it) and I don't have any equipment for evacuation and refill so i'd hate to put in so much money into it and not do it... i gotta think about it for a while... in any event i guess i'd get a shop to flush, evacuate and refill the system if i did get the new hoses but oh well...
Good luck ! Don't 'not do it' cuz of my down view of it... there'* nothing i'd want more than cold air for summer driving in my bonne but i just couldn't make the ends meet, if you know some good shops and got some nice prices you should be able to do it at far below the estimated 700 bucks i mentioned... maybe your hoses are fine and all you need is a new compressor and accumulator! in that case ~250 to 300 (compressor+accumulator) + evac / flush / refill is all it would take!
sorry for long post
'87 Pontiac Bonneville