I've had my car for approx. 1 1/2 yrs so far. Its a 04 GTP(No mods..all stock) For the first 6 months, everything seemed to be running fine. Every since then it seems like 1 problem after the other but I'm working through them.
About 1 yr ago one of the coolant elbows exploded on the highway. I had just replaced my radiator earlier that day and I was watching the temp gauge while I was driving. The temp gauge started to climb in the the red and before I could come to a complete stop on the shoulder, the elbow exploded. Since then I've read up and learned a lot about our cooling systems. The car had 100k miles at this point and I'm not sure what the previous owner did with regarding to the cooling system. The coolant was like rusty mud. My engine compartment is still a nice orange thanks to the coolant. After changing the elbows, I flushed the system and I thought I did a thorough job with the flush but my radiator cap still gets a brownish sludge on it(not as bad as it was before). I followed one of the write-ups on here on how to do the flush. I took the thermostat out and put the garden hose into the radiator(by disconnecting the upper hose) and let the water run through for nearly 10 minutes. Ever since then, I have still been having fluctuating temps. A lot of times in the summer, when getting off the highway, my temp would get up around 225. I was thinking it was high but when it was 90+ outside I figured it wasn't too bad.
My real concern and question is yesterday when driving home, I was doing a steady 30-40 mph on the highway for about 15 minutes and the temp was getting up to 220-225. It wasn't stop and go. Everyone was doing just a steady cruise and the outside temp was 48F. Wouldn't the outside temp alone be enough to keep the car pretty cool? What am I missing that might still be causing my car to run so hot? Before the coolant elbow problem, I don't think the temp ever went above half way on the temp gauge.
I know the stock temp gauge isn't that accurate but I know my other 2 cars never get above halfway on the temp gauge, even in the middle of the summer. If I also remember correctly, my GTP never went that high until the radiator and elbow issues. I also just got my car back on the road after swapping the trans and I'd like to keep the car from running too hot so that it doesn't contribute to getting the trans to run too hot. I'm not sure how much one affects the other but I really don't feel like replacing my trans again.
