Press the "gauges" button until the DIGITAL display shows coolant temperature -- this digital gauge is MUCH more accurate than the useless analog gauge you are referring to. Generally people recommend to ignore the analog gauge.

So please get the temperature reading on the digital gauge and post it here.

 

 

Well crap I forgot the L98 models didn't have some of the digital dash features of the LT1 cars. I thought they had very similar information displayed in similar ways. Sorry about my mistake.
In which case I suggest renting/borrowing a laser thermometer to determine what temperature your engine is actually running. Point it at the cylinder head, don't get too close to the exhaust. AIso I think you can connect some sort of digital gauge (ohmmeter) to the coolant temperature sensor and get an accurate reading, or perhaps there's an ALDL connector that will show more information. Hope this helps you.

 

 

 

 

dgxr's advice was good - but I'd recommend getting a IR temp "gun" and pointing it at the thermostat housing - the upper rad hose, and the rad inlet. Those should all be about the same temp , and should correspond with the temp gauge. If they don't - you've just found your problem (Inaccurate temp gauge). If that is the case - try replacing the temp gauge sender first - that is the normal issue. These IR guns typically cost around $20 - $30 and are available thru Amazon, some of the big box hardware stores and better stocked hardware stores. Those IR guns are useful for a number of other tests as well....

Another worthwhile test to be performed with one of those IR "guns" is to look at the radiator inlet temp and the outlet temp when the fans are running - you should see a good 20 degree drop. Much less than that and your rad isn't doing as good a job as it should....

Just one question - when you did the "coolant flush" - did you just drain the rad - or did you pull the block drains as well ??? This is more of an issue on the LT1./LT4 cars that use the reverse flow cooling system - but doing a full drain and refill is a good idea when experiencing cooling system issues .

 

 

That is probably a correct readout of the temperature. My L98 runs between 195-235 depending on how long I sit in traffic no matter what the temperature is unless it is really, really cold outside. That looks like 230-235 on the analog gauge to me. If the fans come on when it gets hot, it has new coolant, a working thermostat and runs OK I would let it alone. According to my research, the L98 in these cars was designed to balance performance with emissions and fuel economy. The higher engine temperature allowed for slightly higher compression, better fuel economy, and cleaner emissions.

The journey with my car ended up leaving me to embracing what the engineers intended. My C4 was riddled with all of these "improvements" like IAT relocation, a lower thermostat, fans on all the time, etc. As I experimented with putting it back to the original configuration, I found that the car runs much better and gets better fuel economy which is important for a daily driver. I suppose if one was racing some of these changes would be beneficial to some degree although how much improvement they would provide is up for debate.

 

Hot to the touch could be almost anything from 160 - 250... Generally speaking most people can't hold something that's at 150 or so on their fingertips for more than 5 - 6 seconds....Most household hot water heaters are set below 140...

Spend the $$$ and get to IR gun, or borrow one and that will tell you what you're dealing with...

And even though the dealer charged you $450 - that does not mean they did the full cooling system drain / flush. It's rather rare that a dealership mechanic will pull the block drains - it normally creates a big mess - as coolant goes darn near everywhere. Very difficult to catch the coolant as it runs down lots of different things.

 

Clean the Aluminum fins with "Coil Cleaner" available at Home Depot for cleaning the aluminum fins on your Home A/C system. This stuff removes the corrosion that accumulates on aluminum outdoors, it will make the radiator transfer more heat if the coils are clean. You spray the coil cleaner on and wait a few minutes and spray it off, just don't use pressure or the water will bend the fins on your radiator, I use open hose and get it all off the car.

Check your Coolant mixture, too much anti-freeze actually works against you. I have seen cars that were having problems simply because they ran pure anti-freeze in their coolant system. I could not tell where you live so I will tell you that here in Northern Virginia we don't see deep freezes very often. I run 30% A/F and 70% Distilled Water with a bottle of "Water Wetter" in it to help even more. Water is way better than A/F at transferring the heat....

{On my C3 I use Evans NPG coolant and my big block really likes that stuff. It has a boiling point of over 375* but the coolant is expensive, when you need 4-5 gallons of it then you hurt financially. Literally the first time I used this expensive coolant on the highway a road rock jumped up, hit my fan blade and punched a hole in my radiator, that was painful as I could hear it running out on the way home. Now I keep silicone plugs in the car for such an event.}

Check your Radiator's pressure cap, if it is over five years old pitch it and buy a new one of the correct pressure for your particular car. The "standard" cooling system will work better with pressure in it, the pressure raises the boiling point of your coolant.

Check your engine's timing to be sure that is not adding to your car's troubles. I keep mine set at the factory settings as I have a stock L98.

Check to be sure that your front spoiler is all there and functional, this is critical on a Corvette.

Never, ever trust your temperature gauge to be accurate unless you made it so or have verified that it is. Your temperature gauge certainly looked like it was reading hot for a 84 degree ambient day.

I hope that this might help you keep your Corvette cool (er). Good Luck!

 

 

I was able to get a lot of the debris from the radiator area without removing the shroud. I used a back scratcher stick, inserted through the hole in the upper-right area of the shroud. This loosened up a lot of the junk and then I put a vacuum hose long extension down the hole and sucked most of it out. Worked pretty good. If you take this approach, be very careful to avoid bending the cooling fins on the radiator.