I have a 2003 base Corvette that seems to be running hot. I would like to find out whether or not I actually do have a problem.

While driving along at normal highway speeds the engine temperature will sit rock solid at about 190 degrees F, pretty well regardless of what the outside air temperature is. However, driving in town will soon have the engine coolant temperature in the 220 F range even on days when the temperature is in the 60's. Sadly, I can't say for sure whether it has always run this hot or if the "in town" temperatures have gradually risen to what I'm seeing now! I have read other forums and understand that with the A/C off and speeds under 35 mph that both fans will turn on at the low speed at 226 F and on high speed when the engine temperature reaches 235 F. Consequently, it seems that my 220 F operating temperature is not damaging otherwise wouldn't the fans be programmed to turn on at lower temperatures?

A friend of mine who lives nearby also has a base C5 (LS1) but tells me that his engine consistently runs at about 190 F in town as well as on the highway! This spring I intend to flush the engine, radiator and heater cores, thoroughly clean the debris from the cooling fins on the A/C condenser and radiator and then refill with a 50/50 mix of DEX-COOL or an equivalent coolant. I expect to have to remove the radiator to suitably clean between the fins. I will do this whether or not the 220 F is a concern. I would also change the thermostat but doubt that it's a problem since the temperature is perfect on the highway.

In any case: 1)- Should my car normally be running around the 190 F range in town? 2)- How concerned should I be if my remedies this spring do not result in considerably cooler coolant temperatures in town?

Thanks in advance for your help with this issue.

 

On a cold day around town? Yeah, it should probably be around 190. However, temperature is not a concern unless you hit 240 F. Most likely you have a dirty radiator that is preventing good airflow at low speeds.

 

190ish is perfect and in stock form it is normal to creep up to 220-230 at idle however many don't like them to run that hot, myself included... a simple fan adjustment can keep them running at 190-200 under most conditions, no need to mess with the thermostat... the maintenance you plan on doing likely won't make a huge difference in the temps since they appear to be normal but it will ensure that everything is working to it's full potential and that is a good thing

 

Neutron. Can u post up your fans on and off temps please. Thx.

 

He may have it tuned that way. Mine stay at 190 all the time with a can tune from Diablo. My brothers 98 runs 220-229 in the same location and trips we do together.

 

Thanks everyone for all of the replies. Just to be safe I will clean the fins as well as the flush.

Neutron, I would also feel more comfortable with cooler temperatures at idle/slow speeds. How do I make the "simple fan adjustment"? What "On/Off" temperatures did you set?

 

Sounds perfectly normal to me

 

both of my fans are on at 190 and off at 182... keep in mind I have a 3" thick intercooler in front of my ac condenser, I have a dewitts full size radiator, spal fans, and it gets hot and humid in the summer so that's what it takes to keep it cool when not at speed... those settings will vary depending on your setup, climate, etc, so you might have to play around with them to get the results you want or a knowledgeable tuner would probably know where to start

you will need access to a tuning program such as hptuners or efi live to make changes to your tune, handheld tuners might be able to adjust the fans but I'm not really sure you would have to do some research on that... adjusting the fan on/off settings is common practice when you have the car tuned but if you aren't planning on any mods in the near future that would warrant a tune then you can probably have them only adjust the fan settings for a nominal fee... it will only take a few minutes to do so you might try calling some tuners in your area and see if they can take care of it

 

wont the ecm go into an open loop if the temps are to low. like using a cooler thermostat than what is supposed to be in the engine?

 

I think your fine,just do the maintenance. Sounds normal, you could have those fans kick in sooner at a lower temp if you want, that’s what I did.

 

I have a 01 Z06 and had a bad heating problem so I replaced the water pump, replaced belts, cleaned the outside of the coils of the radiator and ac cooler. put in new antifreeze and feel it is still heating up. I am not sure when the fans should come on but I have had it up to the 210 range and still no fans on. The slow speed does come on when the ac is turned on and the fans run slow and fast when I jump out the relays. Knowing when the fans are set factory to come on would be a big help. Maybe I have no problem. oh, I also looked at the temp sending unit and it seems to be working as my temp gauge and digital readout of temp are working. Any help would be appreciated. also I live in AZ in the phoenix area so it does get hot here.

thanks, Dan

 

Plenty of topics on this. No A/C, fans don't come on until 226 and don't go to high speed until 235.

 

My C5 seemed to want to get warmer than I like to see on summer days, but I'm beginning to understand that it's just the nature of the beast.
Just to feel a little better about it I installed one of these so that anytime I want to give her a cool down in traffic I just press a button and the temp gauge drops down to an acceptable level. Along with the Window Valet, it's one of the better mods that I've added to her.

https://www.saccitycorvette.com/COOLITv2.html

 

I remember the 220-230 coolant temp days back when I was stock. I now have a 160F Tstat and that along with lower temp fan setting (my tuner took care of this aspect) now my temps typically remain between 180-200F unless I'm driving hard. I'm on the stock rad still.

 

if the factory thought the stock temps were fine, does anyone know what benefit these aftermarket mods do? I’m all for mods. But why try and “fix” something that is not an issue. Is 230 that much worse for the motor than 200?

 

I'm of the same mindset as well. I think many people just think "Oh, less heat must be better" without thinking about how heat actually affects the engine.

 

high coolant temps can contribute to detonation... for guys trying to make power it can become an issue since power is directly related to heat so adding more heat on top of that is not a good thing, that's probably the main reason why people try to lower coolant temps a tad and control it the best they can... on a stock car that gets driven gingerly then I agree, it probably isn't an issue but at the same time getting it in the 190-200 range won't hurt either and could help with preventing detonation

 

The best prevention for detonation in NA cars is using the right octane fuel... FI is a whole different beast.

 

Exactly. I'm in the same mindset. I never had issues at 220-230 normal operating temps when I was stock, but going with about 100 extra HP on mods now I would be generating a lot more heat along with the extra power. That would've easily brought me to 240-250, or maybe even 260 on hard driving. Once you're at the operational range of temp, additional heat won't really be your friend. You might have reduced engine friction due to a thinner oil at higher temps, but that's about it. It's just a huge piece of mind for me to run cooler.

 

I am starting to agree with everyone that has commented on this issue. I do not drive my car hard. It is my daily driver but since I replaced the water pump, belts, flushed the system and cleaned the radiator and AC "coils" it is running fine and in the 180 range most of the time. I figure if I have to have other adjustments made to the engine management module I might get the fan settings changed but if not I am going to just leave things as they are. It does bring up two more questions... first, my outside temperature reading on the climate control is reading about 10 degrees low. Is this something that is controlled by the engine management module and can be adjusted, can it be adjusted somehow through the climate control or do I just replace the sensor? Second, the radio is suppose to stay on when the key is turned off until the door is open. Mine radio turns off for about 5 seconds after the key is turned off, comes back on and then off when the door is open. Is this a function of the engine control module or as someone else told me a malfunction happening in the switches operated by the ignition key?