As many of you may or may not already know, I've been having some cooling problems with my '89 IROC after a rebuild. It's to the point now that the temp gague will read at about 180 degrees as long as the car is moving at highway speeds or higher. In the city (i.e. 35MPH or lower with stop lights), it will run higher than 220. In stop-and-go traffic, the gague will continually pull up and even enter the redline if I'm in traffic for long enough (makes you *really* nervous in traffic where you really don't know when you'll be able to get the car moving).

I've done a lot of troubleshooting already, and I know both fans are working. However, I have noticed that the antifreeze is an opaque brown/orange instead of a bright, semi-translucent green. I know it's due to the crap/rust that sitting at the bottom of the block, and my dad thinks that it will never completely go away.

Would really dirty coolant harm the heat transfer of the cooling system (thus causing the engine to run hotter)?

Thanks (and forgive me if I've already asked this before--I can't remember if I did or not )

 

wouldn't hurt to change it, does wear out over time, but your numbers don't sound that far off for stock set up. make sure radatior is clear. molding in place

 

ede: It's normal for the temp to redline if the car is not moving?

I'm not sure if it's fair to compare a V6 engine of less than half the displacement with a 350 V8, but my bone-stock '88 Camaro with the 2.8L V6 keeps cool sitting still <b>much</b> better than my IROC. I recently did a "test" with my '88 Camaro where I drove it around to get it to operating temperature and then parked it on my driveway. Once it was parked, the temperature was at about 200 degees. I left it running for about 15 minutes while paying special attention to the temp gague on the dash. The temp would pull up past 220 degrees to probably about 225, and then it would pull back down to about 200. Then it would pull back to 225, and then back to 200. It never pulled past 225 or so because the fan would cycle on (and it only has one fan).

The IROC, on the other hand, will continue to slowly pull up into the redline even with both fans on. What I'd really like to see is my IROC behave more like my V6 camaro, if possible. At least that way, I wouldn't feel like I'm going to ruin my engine if I'm stuck in traffic.