trying to decide if i can mix Peak Blue "European" OET coolant in with the factory coolant for my 2012 Volvo S60, which i think might be pentofrost nf.  the first has

ethylene glycol
diethylene glycol
water
sodium benzoate
denatonium benzoate

and the second has:

ethylene glycol
2,2'-oxybisethanol
disodium tetraborate pentahydrate

any negative interactions that will mess up my car?

I dont see generally a problem. The main compounds of both coolants are the same. But I would test first a small amount in a beaker to see there is no precipitation. To mix borate with benzoate  is maybe a problem.

Edited January 14, 20214 yr by chenbeier

On 1/14/2021 at 12:20 AM, chenbeier said:

To mix borate with benzoate  is maybe a problem.

those are the two that I was most concerned about