Hello,

I recently purchased a 1999 SC400. I noticed that while driving on side streets, or in stop and go traffic, the temp gauge would go a bit above normal. I didn't think much about it as I was going to do the timing belt replacement and put in a new thermostat. I finally did the timing and put in the new thermostat and noticed that the temp gauge is now sitting right above the third tick more often. The gauge will still go down to the normal position, but not as often.

Attached is a picture that shows what I mean.

Should I worry about this considering how minimal the position difference is? It's only a few millimeters above normal. My last car was a bomb that I was fixing all the time, so I might just be a bit paranoid from that.

 

You could try to bleed your coolant system with your heater on, but I think that's fine. If it were going to the next white tick, i would be letting the car cool down.

 

Thanks, I should've mentioned in the original post that the needle never goes above where it shows in the picture. I've let the SC sit for a while while running, I've driven it hard on the highway, and it won't go above there, so no overheating issues.

 

thats normal.

 

I feel like the second one is normal and the first one is low. you should be fine as long as it doesn't go above either of those marks.

 

What color was the coolant that you drained and what color coolant did you put in?

I noticed something similar when I first bought my SC and it turns out it was because it was originally a Florida car and the original owner was using a higher water concentration + Toyota Red than what I needed for Chicago. I put in a 50/50 Red mix and I noticed temps looked more like your 2nd pic when they used to be the first.

I had basically the same experience with my IS300 but opposite. The brother of the original owner had his auto dealership service the car with green coolant, and when I got the car I switched to Toyota Pink and I immediately saw operating temps drop on the gauge and OBD2 port.

 

I knew i wasn't the only paranoid SC owner That's normal. From the many SC400's I have owned, each one varies in temp. Stay vigilant , however. We are driving heirlooms.