Hi. I have a 2003 Corvette. I have noticed that the past 2 or 3 weeks. Where I live we have had temperatures recently as high as 104. My Vette temp can sometimes reach up between 232-239 (but will not go higher than 239) . My friend said they shouldn't run that high. He said his used to run between 210 and 220/225. He suggested I take it to the shop. Which I am tomorrow. He said I should get a 180 thermostat and have them flush and refill the coolant. I have not done that since I had the car (which has been like 2 years) my fan works. So I am not sure why at times the temp runs that high.

He also told me to ask the shop to check for cracks. Which I asked the shop to, when I called and made an appt. Will changing the thermostat and draining and refilling the coolant, solve the problem? I spoke to the shop and scheduled an appointment for tomorrow. He said he has a 160 temp if ibeant it, but said he would have to send the car to the programmer (is this true?)

This will be my first time using the shop and I'm not trying to get ripped off. He said to put in a 180 thermostat and drain and refill my coolant would be 200 bucks, does that sound reasonable? I did buy the car used, but have had no issues until now. Runs fine, it's just the temp has started to climb at times. Should I go with a 180 thermostat or a 160? What are the cons of going to a 160?

I hope after he changes the thermostat and coolant it will run it's normal temperature. Thanks for reading and any advice is great! I am a newbie, when it comes to Corvettes. Thanks in advance!

 

Clean the radiator!

Compressed air, back to front. A handful of dirt can cause temperatures to go up 20F. Two handfuls can put you into overheating. I've been there. I got like 35F lower temps from a good clean.

After it's cleaned, then think about spending money. New coolant? Yeah, probably. New thermostat? Not a ton of benefit for a stock, street setup. 160F thermostat? Absolutely not, for a stock-ish street setup. Remember, a thermostat doesn't really help you much if your temperatures are high; by the time you're hitting 220F, it's fully open, and whether it opens earlier or later won't stop your temps from going up past 220F tomorrow if they're going up past 220F today.

(Until you clean the thing.)

People always jump into thermostats when the real answer, almost always, is just cleaning the bloody thing.

Do the regular maintenance while you're there: new coolant and pressure test the coolant system. Can always add one of those 18 psi caps, if you want.



Edit: You blow the air from the back towards the front. Sorry for the brain fart.

 

my 180 stat car NEVER sees temps above 208 !!!!!!!!!!!!!!!!!!!!

 

gimp's response is one of the better I've seen on the forum and what I always expunge.

When I bought my car the first thing I did was remove the radiator, clean in completely front to back and in & out, replaced upper and lower radiator hoses (they're rubber, and they expand and contract with engine temp), and flushed and filled with fresh Dex. In addition to cleaning I think people frequently overlook coolant service. The OEM Dex-Cool is listed as not having a service life, but realistically a 2003 year model car should of had coolant service done at the latest back in 2013. I'm certain there are people with 20 year old C5s that have never serviced the coolant. People will also say don't go with Dex because it can cause issues, but what I believe REALLY causes issues is people draining the Dex, performing what they **think** is a coolant flush when it's really not, then mixing in standard coolant without realizing there's still a ton of residual Dex in the system, which then wreaks havoc.

I've never seen temps above 205-210 F and I drive in an area that frequently sees 110 F + ambient.

 

Go to Advance Auto and get a 186dg thermostat and especially get a NEW A C Delco Radiator Cap 18psi. All less than 25 dollars. By the way you can get Dex Cool by Prestone, gallon is 14 dollars and change at Wal Mart. My vette was always running at 220 and in traffic it was going much higher in temp. When I did the above my normal open road temp is 195 and even around town it rarely goes over 205. YOU WILL GET ripped off at the dealership.

 

Gimp knows what he is talking about......just do it.!

 

I was going to say,, "Your friend cost you some unnecessary cash".

ALWAYS start with cleaning the cooling air opening at the front of the car under the bumper/Facia, AC condenser, Radiator and the 1" space between the AC condenser & Radiator.

Get the max air flow out of what you have. You will be amazed at what comes out of the fins with just back spraying with a garden hose.

YES, up grade to the 18 lb cap.

Bill

Bill

 

Always hot down here...Ft Lauderdale. My 2000 usually runs under 200 degrees. Clean the radiator, check the hoses, use a mixture of 50% DexCool and 50% distilled water. Change to a new pressure cap ....for starters.

 

Follow Bill Curlee`s suggestions. He is without doubt one of the most knowledgeable members on the forum.

 

The shop claimed they cleaned my radiator. They also put on a new thermostat 180, replaced my cracked coolant reservoir and refilled my coolant. I go to pick it up today and the guy drives it around, to make sure everything is fine. He comes back, there is steam coming from my hood. He opens it up and the coolant is bubbling out from underneath the cap. Which resulted in all the coolant drained out. Which has NEVER happened. He refilled it. I ask him why was my coolant bubbling out through the sides if the caps. He said he didnt know and then started checking things out again and told me, my fan was only coming on at low speed. So he tells me that I will need the fan replaced and it will solve my temp problem. He says when the AC is turned on both fans come in high. So he tells me to drive home with the AC. Which I do. I drive home going know faster than 30mph. The temp didnt get any higher than 224 on my drive home. So I'm feeling good. I pull into my garage and pop my hood....and here comes the steam again. After letting my car sit in the garage turned off and not running, I go out to the garage about 20 minutes later and there is coolant all over the place, and no coolant is left in my coolant reservoir. I feel the shop has no idea what the hell they are doing. I will admit I am not mechanically inclined and am at my wits end and will probably take it to the dealer any ideas as to why the coolant reservoir is bubbling and draining through the sides of the cap? He claims its cause the temp was high when he drove it (he claimed 234 temp) I drive it home and my temp was 222 and I still got the steam and bubbling out of the coolant.

 

By the way, thanks to all of you who replied. I just feel like I am getting ripped off...and my problem isnt getting fixed.

 

The fan is supposed to only come on at low speed. At high speed, the airflow from your ground speed will cool your radiator; fans would get in the way.

Edit: let me add a quote.

Go to a different mechanic. Tell them, very specifically, to clean the rad by blasting compressed air through the fins, from underneath, back to front.

Also get a new 18 PSI radiator cap.

 

When I bought my 99 not too long ago, I ran into the same problem. After much research and great guidance from this forum, I went to Tractor supply, purchased an 18" wand for my air compressor and then bent the end to 90 degrees and cut it off to where it was only about 1/2" long. I then took the top cover off of the radiator and AC condenser and started spraying air forward into the condenser and backwards into the radiator. I just started at the top left and worked my way to the bottom right and you wouldn't believe the pile of dirt I had under my car once I was done. I then had a tune done ($250) that turned on the fans at a few degrees lower than the factory settings. I also did a coolant change and new hoses while swapping it out. I never see above 200 degrees anymore. It mostly runs at 194 when on the road and 198 in traffic. I actually drove it to Raleigh today and sat in downtown traffic around 1pm. It was 92 degrees there today and muggy and the highest it got was 198.

I believe they refer to the C5 as a bottom feeder so now I'm very careful not to run over grass clipping that are in the road as they will start to collect between the condenser and the radiator.

 

you could have air trapped in the system, there is a specific method for adding coolant !!!
COOLING SYSTEM BLEEDING

1. Fill system through radiator surge tank opening up to base of fill neck. Start engine and idle

for one minute. Install radiator surge tank cap. Cycle RPM from idle to 3000 in 30 second

intervals until engine coolant reaches 210°F (99°C). Shut off engine.

2. Loosen radiator surge tank cap. After all hissing stops, remove cap. Start engine. Idle engine

for one minute and fill surge tank to between FULL COLD and FULL HOT. Install radiator

surge tank cap. Cycle RPM from idle to 3000 in 30 second intervals until engine coolant

reaches 210°F (99°C). Shut off engine. Top off coolant as necessary.