C5 Temp goes to 240*

[c5havin]

Hello Everyone. My 2001 Vette coupe (stock LS1)has a cooling issue, and thought that you guys may be able to help shine some light on it for me. While driving, even at freeway speeds in clean air, coolant temps get up to 235, and no lower. In the city, it gets close to 245, and doesn't come down lower than 235. Temp climbs slowly and steady at a stop light. Both fans are working, no codes, and have blown through the radiator, and no trash bags in front of the radiator. Coolant level is full, haven't had to add any. Water pump was changed 25k miles ago. Car idles smooth, no misses, and otherwise runs normally. How should I proceed to solve this issue? Thanks in advance for everyone's input.
A bit more info: I just went out and started the car. No leaks found, nothing dripping. The 2 heater hosed coming off of the water pump are moving hot water. Well, they seem to be as warm as the a/f is. The lower radiator hose is MUCH cooler than the 2 heater hoses. Actually, the lower half is a bit cooler to the touch as the top of the hose is. So, am I circulating water? Thermostat not opening? The engine got up to 225* before I shut it off. At idle, it took approx 15 mins to reach that temp. I hope this helps to gain some understanding of what may be going on.

[ZO6_Vette]

I would at this point change the thermostat.
You can test the old one with a pot of hot water and a thermometer.
Just to confirm it opens at about 192 degrees.

[c5havin]

Originally Posted by ZO6_Vette

I would at this point change the thermostat.
You can test the old one with a pot of hot water and a thermometer.
Just to confirm it opens at about 192 degrees.

Thank You for your reply. I have one on the way. I guess it kind of makes sense, and the cheapest place to start. Thanks again. Respectfully, Mark

[motorman]

Originally Posted by c5havin

Hello Everyone. My 2001 Vette coupe (stock LS1)has a cooling issue, and thought that you guys may be able to help shine some light on it for me. While driving, even at freeway speeds in clean air, coolant temps get up to 235, and no lower. In the city, it gets close to 245, and doesn't come down lower than 235. Temp climbs slowly and steady at a stop light. Both fans are working, no codes, and have blown through the radiator, and no trash bags in front of the radiator. Coolant level is full, haven't had to add any. Water pump was changed 25k miles ago. Car idles smooth, no misses, and otherwise runs normally. How should I proceed to solve this issue? Thanks in advance for everyone's input.
A bit more info: I just went out and started the car. No leaks found, nothing dripping. The 2 heater hosed coming off of the water pump are moving hot water. Well, they seem to be as warm as the a/f is. The lower radiator hose is MUCH cooler than the 2 heater hoses. Actually, the lower half is a bit cooler to the touch as the top of the hose is. So, am I circulating water? Thermostat not opening? The engine got up to 225* before I shut it off. At idle, it took approx 15 mins to reach that temp. I hope this helps to gain some understanding of what may be going on.

get a IR temp checker before tearing into anything to make sure the corvettes temp sensor is not correct.

[c5havin]

Originally Posted by motorman

get a IR temp checker before tearing into anything to make sure the corvettes temp sensor is not correct.

Another great idea! At 230* on the fwy yesterday, I got on it, and there wasn't a ping to be heard. I drove it easy when it was at 240*, still no ping. Maybe my mechanic buddy can loan me his. Thanks for your reply. Respectfully, Mark

[LLC5]

Originally Posted by c5havin

Hello Everyone. My 2001 Vette coupe (stock LS1)has a cooling issue, and thought that you guys may be able to help shine some light on it for me. While driving, even at freeway speeds in clean air, coolant temps get up to 235, and no lower. In the city, it gets close to 245, and doesn't come down lower than 235. Temp climbs slowly and steady at a stop light. Both fans are working, no codes, and have blown through the radiator, and no trash bags in front of the radiator. Coolant level is full, haven't had to add any. Water pump was changed 25k miles ago. Car idles smooth, no misses, and otherwise runs normally. How should I proceed to solve this issue? Thanks in advance for everyone's input.
A bit more info: I just went out and started the car. No leaks found, nothing dripping. The 2 heater hosed coming off of the water pump are moving hot water. Well, they seem to be as warm as the a/f is. The lower radiator hose is MUCH cooler than the 2 heater hoses. Actually, the lower half is a bit cooler to the touch as the top of the hose is. So, am I circulating water? Thermostat not opening? The engine got up to 225* before I shut it off. At idle, it took approx 15 mins to reach that temp. I hope this helps to gain some understanding of what may be going on.

Make sure that the radiator and condensor are free of debris that gets caught in the cooling fins of both. The plastic radiator/condensor cover will have to come off, then clean out the area with compressed air or water with a long hose or special tool designed to do so. Good luck with it.

[c5havin]

Originally Posted by LLC5

Make sure that the radiator and condensor are free of debris that gets caught in the cooling fins of both. The plastic radiator/condensor cover will have to come off, then clean out the area with compressed air or water with a long hose or special tool designed to do so. Good luck with it.

Hey LL....That is the first thing that I did. I was hoping at first it was just a bag or a flattened paper cup. Blowing through the 2 units had always worked in the past. But this time my temps were much more extreme. Thanks for the reply. Respectfully, Mark

[ToolGuy]

These cars are set for a certain engine temp and it's in the high side.

That said, I've seen the temps you have BUT only when idling in August while at a cruise. Not while drving.

So it's def worth investigating.

Thermostat and coolant change would be my first looks, that is if you've never replaced both before. Although your pump was changed, the tech should have done a change then too.

[LLC5]

Originally Posted by c5havin

Hey LL....That is the first thing that I did. I was hoping at first it was just a bag or a flattened paper cup. Blowing through the 2 units had always worked in the past. But this time my temps were much more extreme. Thanks for the reply. Respectfully, Mark

Did this happen all at once, suddenly?

[c5havin]

Originally Posted by ToolGuy

These cars are set for a caertain engine temp and it's in the high side.

That said, I've seen the temps you have BUT only when idling in August while at a cruise. Not while drving.

So it's def worth investigating.

Thermostat and coolant change would be my first looks, that is if you've never replaced both before. Although your pump was changed, the tech should have done a change then too.

Thanks TG! That is what is on the agenda for the day. The thermostat and the fluid were changed along with the water pump, but parts wear out. I'm praying that no damage was done if the thermostat was the original problem.

And LL......This came on all at once. As I said, summertime here in the central valley of CA, the days get pretty warm. Usually triple digits for a few months. I notice at that time of year I need to blow the debris out of the condenser and radiator. Most always causes a 10-15 degree temp drop in the operating temp. Thank you for your replies TG and LL !!!!!!!!