Topping off Coolant

I noticed the other day that my coolant was under the low/minimum mark on the reservoir. I can not find any leaks to save my life, and I have not had any issues overheating. The truck seems to be running fine. I have OEM SLLC pink stuff (50/50 diluted) and was planning just to add more. However, I am not 100%, sure that the previous owner used OEM pink stuff, the coolant in the reservoir seems to have the same color. Could I get away with just adding more or do I need to drain and refill?

Thanks.

 

Never checked if there were any aftermarket coolants that are pink. Should be fine to top off, but if the mileage is unknown on the coolant it might be a better idea just to do a drain and refill in the system. Best practice is to drain and refill the system after 100k / 5 years and then every 50k / 3 years after that. It doesn't take long to swap out but you'll need to pick up 2 gal of coolant and a coolant funnel for the service.

 

I would argue that if you’re just missing like half a cup just to use water. You’re not going to dilute it enough to affect the freezing point.

 

Toyota SLLC = Pentosin Pentafrost A4 = Zerex G40
all of them are 50:50 mix and are pink

 

Yes, you can just top it off.

 

You might get a new radiator cap.

 

My fluid was dropping slightly over time and a new rad cap fixed it. Old cap was 14 yrs old.