Howdy - I fixed a coolant leak and filled the reservoir almost to the max level. Everything went fine until I drove it after I was done. The temperature kept climbing until it almost reached the red line. I shut it down and let it cool off a while. After I started it and drove it back towards home the temp stayed just a bit higher than normal. Should I be worried the temp is now higher than it was? The needle used to be just below the mid line. Now it's one mark above.
I didn't drain and flush the old coolant. I just added about a half gallon of new stuff to the old.
Thanks for any advice!

 

You don't top off aged coolant with aluminum heads and/or blocks.. Mixing formulas also causes thermal behavior changes..

You flush, put in new thermostat and 50/50 HOAT coolant($30.00 for both), and pray it's not the AC or water pump which are stuffed up in the bay with 2.3" of work space..

You can also just let "Cooling System Electrolysis Corrosion" happen by doing what you're doing or letting mechanics "good 'ol boy" it with whatever coolant they have, and pay thousands for a rebuild or transplant in about a year..

 

If you only filled at the reservoir and didn't pull the rad cap to fill the radiator directly, that is where you went wrong. If you did fill the rad directly, it's possible your thermostat is bad.

Also factors like coolant age/condition and the ratio of water to antifreeze can affect where the temperature needle stays. If it's only one tick mark above midway it's not the end of the world. But I do agree 100% that if you know your coolant is old, flush the whole system and refill only with HOAT.

 

You have a massive air pocket.

 

Thanks for the replies! I will drain, flush, and fill it this weekend. I needed to get it working again because today we bring it to the dealer for the R03 recall. Good luck!