I've replaced the radiator, water pump, thermostat, coolant reserve tank, and pressure cap (18) and the car is still running hot. On the highway it's running 220, when I drive in stop and go it goes up to 240-245. The fans are cycling. Nothing stuck in the radiator. I don't know what else to look for. Could one of the Corvette savants on here help me.


P.S. On another note...What does the A-6 SCM B2860H code mean? I looked at the code list but couldn't find it.

 

Did you put in a 160 degree stat?

 

Make sure your ac condenser is clean also, if it is restricted it will block air to radiator. Not sure why a 160 thermostat will help with temps over 220? Not saying it won't help just have not seen a explanation as to why, do they flow better?

 

There is a plethora of info on stats... depending on where you live and what ambient temps you are dealing with... the 160 degree stat will help your car run in the sweet spot during the summer months... you can switch it back if your driving during the winter months and need warmer temps...180 to 200 is where you want the temps to be... with the 160 stat our car stays right at 181 to 187...
during this summer... it might need the 180 stat this winter to keep it at those operating temps...

 

Yes, I burped it. I put back the original temp. stat. I may go with the 160 to see if it helps. I replaced the radiator and cleaned up the AC also. I did everything I've read and even had it at my buddy's shop. We're both confused.

 

I would try adjusting the fan settings first before doing a 160 stat... 230-240 is normal for a stock cooling system at idle but when cruising on the highway it should go down considerably less than the 220 degrees you are seeing... to me that sounds like air in the system or clogged ac condenser fins but you said that was checked... are you positive that both fans are coming on?... I had an issue recently where my driver side fan would cut off when it switched to high speed and was causing my car to run warmer than usual

 

I'll try the pressure thing, can't hurt. I'll also double check the fans.

 

I don't know about the center air dam. I hadn't even thought of it until I read about it in another post. Would you happen to have a diagram of how the air dam is supposed to look ? Other wise I'm just staring at space

 

Had similar problems going through the burp method multiple times with no luck. Stumbled upon the bleeding method I describe at the end of this post https://www.corvetteforum.com/forums...ing-now-2.html . I've had the system open a few times since and this method has never failed me in getting all of the air out.

Good luck!

 

I would try this simple procedure to make SURE that the air has been bled from the heads and that the air bleed system is clear. It requires a visit to the hardware store for some simple parts.

On the passenger side top of the radiator there are two hose connections, the one closest to the center of the car is the air bleed hose, about 1/4" inside diameter. On a stock car, this hose goes to the throttle body and then out of the throttle body to the air bled pipe assembly, a silver colored pipe about 5/16" in diameter connected to the front of both heads.

With the system cool, cut the air bleed hose at a convenient place between the radiator and the throttle body and using small hose clamps, insert a barbed 1/4" brass connector with a hardware store 1/4" valve on it and a clear plastic hose downstream of the valve leading to a clean container on the floor by the right front fender. Temporarily plug the radiator side of the cut air bleed hose with a small metal plug and small hose clamp.

With the coolant system full and cap on, run the car until cooling system pressure starts to build. Open the 1/4" hardware store valve and watch the clear hose for coolant flow and air bubbles into the clean container. After a coolant change, I have found that it may require a flow of a quart or more to get all the air out. Don't let the surge tank get too low. Shut down, depressurize and refill if necessary.

Once the bubbles stop, shut down and carefully depressurize the cooling system and reconnect the air bleed hose using the aforementioned barbed connector and small hose clamps, but first make sure that the remaining hose leading to the radiator is clear by blowing through it with the surge tank cap off.

With some care, the above can be done losing only a small amount of coolant.

This test tells you two things, whether the air bleed system is clear and working and tells you when you have gotten all the air out of the heads. If coolant does not come out, then the air bleed pipe, air bleed hose, throttle body or ports in the heads may be plugged.

 

Not to beat a dead horse but I have asked for a explanation of this 160 suggestion before. Maybe I'm dense but I still can't see how a 180 stat is going to run hotter then 160 stat if motor is over 220? Would both stats not be wide open, does a 160 stat open further at 220 or flow more?
I really don't see it, I'm not being sarcastic, just have not seen a explanation that makes sense, cooling capacity is cooling capacity if both are wide open, but maybe I'm missing something.
Thanks

 

LOL... I know I had a hard time swallowing this pill myself... but, I have seen it on the forum too many times and experienced it myself... the 160 stat reduces operating temps...
If you have thick skin and can stand a little heat in the kitchen... you can PM Evil Twin and ask him to explain it to you... he's a VERY smart man.

 

It must flow more at same temps otherwise once engine is up to temp...past opening temps they would be the same. Starting early will help for a little while but sooner or later the heat load will surpass capacity! Gotta increase capacity to keep up, no way around that. It's all btu's
thats my best guess, just never read it anywhere

 

I didn't mean to confuse anyone with my statement... aside from everything else on topic, I was saying I would adjust the fan settings before trying a 160 stat... you can achieve operating temps close to if not the same as what a 160 stat will do just by adjusting the fan settings... also a 160 stat will not do anything about your idle temps, they will still shoot up if you do not adjust the fan settings to go along with the new thermostat... you will notice the difference with a 160 thermostat when cruising which is not the issue most people have... assuming everything else in the cooling system is working properly it's almost always high idle temps with the ac on that people have problems with... a 160 will also make your car take longer to reach operating temp, run too cool in the winter, and can also reduce your heater temps which is all no good in my opinion... switching the thermostat out every other season may be fine for some people but not me, I am not removing my blower just to change the thermostat unless I have to... I'm just not a fan of them, I live in some of the nastiest summer months in the u.s. so if I can get by without one where I'm at then surely most others could as well

 

What do you have for radiator/fans? You are FI aren't you? My sc 383, with a4 runs hot in Florida without ac on at highway speeds ....Getting dewitts with oil cooler, spal fans and seperate trans cooler, soon , I don't think a 160* stat will help me without this other stuff.

 

dewitts full size radiator with no cooler and dual spal fans, 180 thermostat, and yes the car is supercharged... if it were me I would opt for the dewitts with no cooler, they don't work as well as an external cooler and you are sacrificing some cooling capacity... if you do need a cooler I would run an external one... my opinion, I don't think the 160 stat will really help you period

 

I was going to get a radiator with no coolers, and just run a seperate trans cooler, but dewitts told my mechanic the radiator with B/I cooler will run oil 20* cooler. Trans will be seperate ...it gets hot also. I don't think the stat will help me here either. Frankly ...I think the B/I oil cooler will be a wash.

I will let you know in a few weeks
Thanks

 

I had the same problem. Did you change your tstat at all? That ended up being my issue. From my understanding these closed systems work different from the old school way.

 

[QUOTE=soondg;1590362143]I've replaced the radiator, water pump, thermostat, coolant reserve tank, and pressure cap (18) and the car is still running hot. On the highway it's running 220, when I drive in stop and go it goes up to 240-245. The fans are cycling. Nothing stuck in the radiator. I don't know what else to look for. Could one of the Corvette savants on here help me.

I based my reply on this post... based on what I've seen on the forum and what I experienced... the change to a 160 stat will more than likely reduce your operating temps...it's a pretty cheap and easy thing to try...If it doesn't help you, come back and post that it was a waste of time and money

 

I've had a little bit of trouble like this before and like I said, my issue was the thermostat but since you have replaced yours obviously it's something else.
1. There was a thread in here that someone posted regarding the o-rings in the coolant crossovers on the top of the heads. They claimed that the o-rings were leaking at high temps and sucking in air making the car overheat. I would look for this thread and see if that is a problem you are having.

2. You might want to go to a shop that has a vacuum system to bleed the coolant system. It's possible that you are just not bleeding it right.

3. Make sure you dont have milky oil, a leak in your heads will spill coolant into your motor creating milky colored oil and take away coolant from your system causing it to overheat.

Good luck