Different coolant, different temperature?

[Palut]

I had my water pump replaced a few weeks ago, and ever since I've noticed that my car runs just a little hotter than usual. The cooling fan comes on more often than it used to, and the temperature gauge has gone above the normal mark a couple of times, which is very unusual. The only time it EVER did that before now was due to idling in 100° traffic with the A/C on for an hour. The weather has been a bit warmer lately, but hasn't gotten above the mid 70's, and it's never behaved quite like this before.

I also noticed that for a week after the change, the coolant would expand quite a lot in the expansion tank. Now it doesn't expand hardly at all.

Can different coolants have different amounts of heat transfer? Different amounts of expansion for a given temperature change? Does new coolant behave differently than old coolant?

 

[Vilan]

All coolants are (in the concentrated version) around 95% ethylene glycol. Only 5% is in the remaining additives and proprietary whatevers. So there shouldn't be any big difference between brands.

Are you using the same concentration now as before? If you were 50/50 before and 40/60 now, that might have an effect. Maybe.

 

[Ray H]

I'd also suspect air wasn't completely purged from the sytem. (or, is still getting into the system)