yeah...they're full of crap

had the driver side ball joints on my 1st gen done for less than $200 parts and labor...
and did all my brakes (front and rear) myself for just under $60

all that flushing and cleaning crap is just how they make money....
and thermostat housing?? wtf? maybe if it was cracked i could see that being fixed for $50 at most

take your truck somewhere else...preferably NOT a chain store

go to your local parts store and ask for a reputable/honest private shop
or call around and ask for quotes

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1996 XLT 2.3T "White Lightning" 5/7 dropped, Turbo street toy
2006 FX4 Off Road, DD, work in progress
1985 XLT 2.8L 4x4 "The Black Pearl" (retired but still around)
1987 XL 2.3L 2wd R.I.P.