i drained and refilled my radiator and recovery tank earlier this Spring in my 00 coupe with 46k, with fresh Dexcool in the correct mixture with water and brought the level to full.

Big diffeence in operating temps. When i took possesion of the c5 last September, didnt have the oppurtunity to drive it in real hot weather,as it was nearly October here in CT.

But a couple of trips were taken at outside temps at 80-85 degrees.

My coolant temp on the dic ran between 218-226 jumping up several times to 230, before the fans kicked in and dropped the temp down to 215 or so, which is normal temps for these c5's as most of you already know.

No radiator obstructions or road junk are present, but now in normal summer driving ambient temp at 80-85 my coolant temps usually stay at about 196-203. Yesterday was the big test. Temps hit record high here in CT. 103!

driving with the ac on i was monitoring the coolant temps on the dic.

mostly rural and secondary road driving, the highest reading that i got was 217. with the average temp running 203-206 or so.

I have noticed throughout this year though, normal driving, at temps from 60-85 degrees my coolant temps stayed right at 196 for the most part. So doing a coolant change, and keeping the coolant level topped off does indeed make a diference in operating temps. Ken

 

i just cleaned my radiator last night..before in traffic i would get to 130 and the fans would bring it down to 215 or so..and once i got moving it would drop to 205 to 215...which was not good enough for me..i used compressed air and cleaned out my rad..and now on the hwy i am at 185 and around town to 205...its a world of difference.

 

If you hard wire or use a switch run a hot wire to the Pass. side fan your car will run at 195 all of the time, except for pulling very long hills it will go to 200.

I have mine switched so I can shut the fan off in cool weather or when I run the interstate, I added the switch where the power port in the center glove box was, just remove the socket and put the switch there out of the way and out of sight.

At 101 with the air on or off my vert kept it's cool, I would rather buy a fan when I need one then need to replace an engine.

I didn't have to constantly monitor the heat at long traffic lights, or run the the a/c to activate the fans hoping the traffic would move soon.

It made summer driving a little more for 10 bucks.

 

If you still had the original coolant in your '00 (not sure if you did or not), I would say the new coolant would do a better job of keeping the car cool. Your temps seem about right now.

 

i would highly recommend one of the water additives like WATER WETTER and there are a dozen others that work as well. i have seen a 10-15% reduction in temp in the 3 c5's i have used it in.

its like $10, you pour it in the rad and worst case you lost $10, best case you save a blown head gasket, cheap insurance to me.

 

I don't live in a real high heat area so I dont really see the temps out of control on my Z. I do plan on changing the fluid this weekend. The car has 25K so I figure its do. I will be using a 50/50 Dex-cool and distilled water. I am more concerned with corrosion and seal life in my water pump.

 

If I'm reading correctly, you still have what you had before. You said before when the fans kicked on the temp would drop to 215 and now with the air on the temp is 217. The fans stay on when the air is on, so that seems like a 2 degree difference when in the same state of circumstances. Try it with the air off and see if it doesn't still run up to 226 and then the fan kicks on.

 

No, 217 was the highest temp on the dic when the outside temps were at a record breaking 103 degress this past Friday.

Before the coolant change, I would hit 227 in 80 degree weather and the fans dropped it to about 215.

Really though, not bad considering many members on earlier posts were running as high as 240. And my temps seem to fall within what GM enginneered the ls1 engine to run at, if not a bit lower. Ken

 

Thanks Steve o. I have heard others mention good results with water wetter. Ken

 

You have a vivid imagination.

 

But the fans were on already in the 103 degree drive. The fans kicked on and lowered it to 215 in the 80 degree drive. It doesn't really matter. The important thing is, it is lower to you and you feel like it helped. And in that way, it did.

 

My car ran hot like that(factory setup for emissions and gas mileage) when I bought it. I put in a 180* thermostat and reset the fans and the care ran a respectable 190* with 192* sitting in a drive through or traffic light. Last weekend I figured I'd replace the 180* with a 160*($33.99 at Autozone) and reset the fans. The car ran 172* to 174*. I'm trying for an optimal 180* and I keep playing with the fan settings but can't get it there. Today was low 90's and the car still runs 172*. I also flushed out the system and added a bottle of a water wetter type product from Walmart that only cost $6.88 when I swapped stats.

And to really upset people I refilled my car with green stuff since I hate Dexcool. Oddly the owners manual says if you do that change the fluid out every 30,000 miles or 24 months, yet Prestone says 150,000 or 5 years. The manual claims Dexcool is good for 5 years or 150,000 miles. The manual claims the use of Dexcool is to prevent corrosion of the engine, radiator, and heater core. The green stuff is also safe to use in aluminum engines. I figured since I don't run any recommended fluid in any location I may as well use what I like in the cooling system as well. The only factory recommended fluid I use in my car is Premium fuel. :-)