have u flushed it yet.

 

Your heater core could be all calcified and crapped up inside. If that's the case, you would want to look at the radiator as well, it might not be flowing/cooling like it should. Flushing the system as crabapple suggested would be a good idea.

 

Not to hijack, but what is the best / easiest way to flush the coolant on these LT1s?

Back in the day, when I had my '64 Nova SS with a 327 and glide, I just got one of those Prestone Coolant Flush kits and installed it in the hot water inlet hose for the heater core. Hooked up the garden hose and let her run for about 15 minutes until only clear water came out.

I am guessing that it is a little more involved on these motors?

 

I was thinking the heater too, 69. When I Impala started having the problem (before anything became apparent) one mechanic told me the same thing.

Will do Craby. Hopefully it's as simple as that. It's alright GrandpasWagon, I actually wanted to know how to do it. If it's simple enough might do it myself. If not I'll have to take it to the shop.

Here's something I found

http://consumerguideauto.howstuffwor...t-camaro-2.htm

 

My 97 is doing the exact same thing yours is doing. I've had it for about 3 years, and the temp gauge needle never went above the halfway mark, ever. But about 2 months ago, I had a coolant leak. Turned out to be the water pump gaskets, they were pretty much gone. I fixed that, and refilled it and made sure I got all the air out , using the bleed srews with the front end jacked up a bit. But now when I'm sitting at a light or drive thru or something, the needle inches up to almost the 3rd mark, then the fans kick in and it goes back down to about halfway. Seems like it's working the way it should, with the fans coming on at about the right temp, but something has changed because it never did that in the previous 2 1/2 years. I'm going to flush the radiator next week, but I doubt that will do much, if anything. And I've just ordered the SLP fan switch so I can make the fans cut on earlier. That will probably help, but again it really worries me that it just started doing it. Since the air rushing thru the radiator when I'm driving, or the radiator fans themselves cool it down like it should, could it be the radiator itself may be too plugged and I need a new one? And one thing I should point out is that when I first saw the leak, I couldn't get to it right away, and put a bottle of the heavy duty stop leak in it. Could that have plugged the radiator up enough that it no longer functions as it should?

 

I started driving the car again, after changing the damn Duralast trans mount (which lasted exactly 10 days...lol) with the Energy Suspension unit, and I just remembered I still have this overheating issue.

I haven't flushed it yet. But the shop that hooks me up with this stuff is 50 miles away from my house so before I go there I need to know what other things should I try that may fix the issue? Could this be caused by a faulty water pump? How would I know? There are no visible new leaks to speak of.

As for reprogramming it I have a DTC 16 as Solomon from LT1PCMtuning.com found out. It still runs fine, but if I intend to tune the PCM, do I HAVE to change the opti? Speaking of that, how did I manage to get a DTC 16 only 10k after changing the opti?

Edit: I found out DTC 16 maybe caused by a loose wire to the distributor. Also I found this:

http://cdntechnologies.com/camaro/co...c16_1_of_2.pdf

 

if the radiator is plugged then the crossover pipe on the back of the heads is most likely pluged as well. that could cause the air to be stuck in the head and lead to a slow buildup to overheating.