buying an used volvo
 

I have a 1993 volvo 850 with 137k on it. I got it 15 years ago at 84k m. I put in around 2k for repair this year, the radiator is leaking and my mechanic told not to fix it anymore and just go get another one. The idea is to get one that is as close to the 850 as possible. Someone was trying to sell me a 2006 v70, saying it's the same as 850, another lot told me that a S60 before 2010 is also the same car but a sedan. He has a S40 on his lot, 2009 with low miles, and told me S40 is just like S60 but smaller. I read online that someone with a S40 had engine problems. So I come to the site want to know:
1. is before 2010 V70 and S60 just like my 850 ( of course there are some changes but in general)
2. Does S40 (2009) has a general engine problem or it's just an isolated issue and how does it compare with S60 the same year
3. any suggestions for someone who has a 850 for 15 years and would like to get a replacement close to it with fewer miles/years.
my budget is around 10k, give or take. I don't drive much and want to get it right so I'll keep it for a while and not have much maintenance troubles if possible.
thank you in advance for helping,

After market parts are pretty easy to find for 850s from quality suppliers like Nissens. Not sure where you are located but I did a quick look at Eeuroparts.com and they price a Nissens radiator at $105. Check out Tascaparts.com if you want to go Genuine Volvo at $209. Don't waste your time going with used or something that is not designed for your model/year.