Ok I sked this question before but no answer:
I bought a 2000 Lesabre Limited with 25k miles and it is mint...Under is as clean as a 2011 car. Heres my ? With 25 k on it ho long before I can expect UIM problems ? And should I change/plug it now or will it probably last a while ?? I think my Park Ave one failed after 120k Whacha think

You should be fine for a while. But it'* hard to say when it will fail. If it was me I would simply pull the UIM and plug the ports, but that'* me and I can do it with my eye closed.

isnt it usually around 50 or 60 k they fail for the most part ??

Also the coolant looks like Dex cool but it looks really clean, should I leave it alone of chg it with the Prestone mixes with all ??/
Thx Dan

You should be good to 100k. If you don't know how old the coolant is, then change it out. You can refill with Dex or any color, your choice.

yea i know the car only has 25k on it and the dex looks clean in the overflow tank....would it still be good with just this little miles ??

If it'* over 5 years old, change it regardless of miles.

i just dont know if maybe he had it chgd already, he took it to the dealer every 3k miles for service, I wonder if they had it do it at 5 yrs and again at 10 yrs etc /....any way to test it to see if its still good ?
I just hate to dumo it if its still as good as it looks..

If it looks clean, it may have been changed. But I'm a believer in, if I don't know, I change it. New coolant is cheep.

should I do the tsat too or probablly not right ?

If it'* working then no need.