Hello everyone. It's been a while since I have posted here. Life has been crazy this past year.
For the past year or so, I have noticed that the coolant level in the overflow reservoir has been going down. I have been topping it off every now and then. I would say maybe a half cup or every 1000 miles or so. It could be more or less as I have really not measured it precisely.
Some background info on the vehicle. The car has 293k miles on it. It is 2008 V6 and I bought it in 2019 with 206k miles. For the first 40 or 50k the coolant never went low. I never had to add any. Around 255k or so, I noticed the coolant going down with no visible leaks. With the help of this forum, I was able to figure out that the radiator was leaking. I replaced that and all was well.
Around 275k or so, I started noticing loss again. The issue still exists but I believe I am loosing more coolant now and I would like to fix it if possible. There are no visible leaks anywhere. The only thing I could find is a tiny crust spot near the thermostat housing. See image below.
Any thoughts on what to check or replace?
Should I pull the spark plugs and check those?
Do I just replace the water pump since I have no information on when it was changed?
I want to do another road trip but am hesitant this time around.
Appreciate the help as always!