OGCLK320

I replaced my radiator with OEM BEHR after finding a small hairline crack in the original one. Now it is super hot here around 90˚-105˚F and the car is running fine no leaks or anything. But the temperature seems to be varying a lot more than it used to. When cruising on the highway AC on its about 85˚C and with the AC off it's about a needle above the middle line 82˚C or so. Now when stopped at a light or driving slow without much air in these high temperatures it has been climbing to 90˚C to almost 100˚C it did not get to the 100 about a needle or two below, but it has me worried about so much fluctuation. I have been reading threads all night about it and they say thats normal, but I never remember my temperature fluctuating so much even in these temps. I filled my radiator with Zerex G05 50% 1 Gallon and another Gallon of Tap water. NOT distilled water. Would this make the huge difference? I plan to flush and switch to distilled because I don't want to cause any damage. the PH was around 8.5 almost 9. I know it should be PH7. I also have the Cold Air Intake and had to shorten the end intake pipe that the filter connects to because the filter was rubbing on the frame behind the headlights and caused my last filter to develop a hole in it. Sorry for rambling on just hope someone can help. New thermostat maybe? Distilled water? Now my CAI is breathing hotter air? Any help is appreciated!

mint

Don't think tap vs distilled would make a difference in terms of running temp -- only reason you'd want to use distilled is to avoid mineral build up or corrosion in the lines or radiator; so definitely do this sooner rather than later and probably never do this again or risk having to replace all radiator parts/lines.

I searched high and low on operating temps because lately it seemed like my car was starting to run a lot hotter than it used to. I've had the coolant flushed and thermostat replaced, no leaks so I'm thinking my range is normal from what I've extensively searched. If I'm on the freeway moving at ~40mph+ then I'm around 82-85 no matter the ambient temp. If I'm idling or in city traffic, with full AC and it's 90+ ambient then I'll be a couple mm or so below the 100 mark but never over. If I'm idling or in city traffic and it's less than 90 ambient then I'll usually be anywhere from 85-95. Basically, as long as you make sure your coolant level is good, thermostat isn't stuck and don't have leaks and don't run above 100 you're probably good.

You may also want to check that your auxiliary fan system is functioning properly via a visual check and the AC diagnostic menu. As the car runs warmer, value #20 (current for aux fan) should read higher, meaning the fan is increasing speed respectively with the operating temp.

OGCLK320

Thanks twinsin, the tap water has been in a couple days now but will change it right away. I should have just put in the distilled from the get go. stupid. How do I pull up the aux fan read out? The fan was running good today it seemed like it was on high when the AC was on and car was at idle. The car cooled down a lot when the fan stayed on high for a bit today, it did not rise above 85 with AC on at slow speeds with the fans on high. I held both Auto buttons down on the AC and I think it manually turns on the fans, I think I read this somewhere? Have you heard this?

mint

Re: distilled vs. tap. I'm sure short-term there isn't a high risk of damage assuming your tap water doesn't have an extreme pH but still...a gallon of distilled is like, $1 so better safe than sorry. I mean, there's no downside to using distilled other than you can't buy a cheeseburger from McDonald's


And on the AC diag menu: pffft, LMGTFY From Marcus' webpage (seriously, all 208 owners should have his page bookmarked in their browswers): http://www.marcusfitzhugh.com/CLK/DIY/acdiag.html

OGCLK320

Thanks for your help twinsin!

Ruination Fan

Im pretty sure you did, but gotta ask....did you "burp" the system after the repairs? You may have had an air pocket in the system.