Okay, here's the thing:

Installed:
- 190 Degree Thermostat.
- No other aftermarket parts/accessories that would alter temperature.

While idling either in a parking space or at a red light, the temperature will gradually climb (2-3 degrees every 15 or so seconds) without any stop in sight. I've never let it go higher than 210 degrees, i'd hit the A/C fan and force it to cool down...

What i've done thus far:
- Flushed coolant with Air and Water.
- Replaced full coolant with 50/50 dexcool and water mix.

Possible reason for issue:
- Radiator blocked by debris etc.

Now if it isn't the radiator being blocked, what else could it possibly be??

(if anyone could tell me how to "unblock" the debris from the radiator, that'd be great too!)

Thanks in advance!

 

Charlie, the C5 cooling system is subject to some issues... while it can be typical to see engine temps rise at stop lights or when Idling... the PCM will carefully monitor your temps and turn on fans when needed.. the car can go up to 220 with absolutely no issue, this rise is usually because either the AC condenser, or the radiator are filled with bug guts, fuzzies, pussies, sand gravel, bird feathers.. but what many people do not realize is that the C5 is a bottom feeder and act like a vacuum cleaner sucking in all types of road debris found on the road surface.. this debris gets sucked up into the ac condenser and is sometimes pushed through the ac condenser into the radiator which sits directly behind it.. the only real way to clean "Both" of these to remove the top support and blow out "from the back , the radiator and the condenser.. I have a compressor and I have a Long thin blow pipe. it is important to blow the debris toward the front of the car, I do this dry, because once the vanes in the condenser or radiator are wet it cause some debris to stick.. once I throughly blow out the radiator I move forward to the condenser,,, once this is done I then use water again from back to the front of the car... Once a year I do this in the spring.. and I get almost a half cup of Guts,leaves, sand and feathers. You will see a dramatic difference in the cooling system response once this is done, but you have to do both...Many people will just get under the car and either blow all the debris toward the radiator, or vacuum the condenser thinking its the radiator
Dont worry about running in the 200/220 range..
Good Luck
Bill aka ET

 

I'm confused. If you follow the service manual for draining and flushing your system, you are supposed to hit 210 degrees anyways(so that can't be max temp....right? ). What does the car top out at temperature wise.....I have not heard anything abnormal yet.



Draining and Filling Cooling System

Caution

With a pressurized cooling system, the coolant temperature in the radiator can be considerably higher than the boiling point of the solution at atmospheric pressure. Removal of the surge tank cap, while the cooling system is hot and under high pressure, causes the solution to boil instantaneously with explosive force. This will cause the solution to spew out over the engine, the fenders, and the person removing the cap. Serious bodily injury may result.

NOTICE

When adding coolant, it is important that you use GM Goodwrench DEX-COOL® or HAVOLINE® DEX-COOL® coolant. If Coolant other than DEX-COOL® or HAVOLINE® DEX-COOL® is added to the system the engine coolant will require change sooner; at 50 000 km (30,000 mi) or 24 months.

Notice

DO NOT use cooling system seal tabs, or similar compounds, unless otherwise instructed. The use of cooling system seal tabs, or similar compounds, may restrict coolant flow through the passages of the cooling system or the engine components. Restricted coolant flow may cause engine overheating and/or damage to the cooling system or the engine components/assembly.
Drain and Fill Procedure

Important

If the procedure below is not followed a low or high coolant level condition and/or vehicle damage could result.

1. Park the vehicle on a level surface.
2. Follow the steps below to remove the radiator surge tank fill cap:
* Slowly rotate the cap counterclockwise1/4 turn and then stop. Do not press down..
* Allow any residual pressure, indicated by a hissing sound, to be relieved.
* After all hissing stops, continue turning counterclockwise to remove the cap.
* To tighten the cap, use hand tight pressure only.
3. Open the radiator drain ****.
4. Allow the system to drain completely.
5. Inspect the engine coolant:
* Discolored -- follow the flush procedure below.
* Normal in appearance -- Continue with the next step.
6. Close the radiator drain ****.

Important

When filling the cooling system use a 50 to 60 percent concentration with DEX-COOL® coolant.
7. Fill the system through the surge tank opening.
8. Fill half the capacity of the system with 100 percent DEX-COOL® coolant.
9. Slowly add clean drinkable water to the system until the level reaches to the base of the neck.
10. Start the engine.
11. Idle engine for 1 minute.
12. Install surge tank cap.
13. Cycle the RPM, idle to 3000 in 30 second intervals until engine coolant reaches 99°C (210°F).
14. Shut off the engine.
15. Refer to step 3 above to remove the surge tank cap.
16. Start the engine.
17. Idle engine for 1 minute and fill surge tank to 1/2 inch above COLD FULL mark on the radiator surge tank.
18. Install the surge tank cap.
19. Cycle the RPM, idle to 3000 in 30 second intervals until engine coolant reaches 99°C (210°F).
20. Shut off the engine.
21. Top off coolant as necessary, 1/2 inch above FULL COLD mark on the radiator surge tank.
22. Rinse away any excess coolant from the engine and the compartment.
23. Inspect the concentration of the coolant.

Flush Procedure

Important

Do not use a chemical flush.
1. Block the drive wheels.
2. Place the transmission in Park or Neutral.
3. Engage the parking brake.
4. Run the engine until the thermostat opens.
5. Stop the engine.
6. Follow the drain and fill procedure using only clean drinkable water repeat if necessary until the fluid is nearly colorless. Refer to the drain and fill procedure.
7. Fill the cooling system. Refer to the drain and fill procedure.

 

Here is what I found in mine when I did a CAI. It's good to know that it's cleaned out now even though it looked like it could have been much worse.

 

why would you install a 190* thermostat? when you could have gone with a cooler one to help your car run cooler....

 

I'm not racing her so it really doesn't matter to me, if anything, i'd run a 180* thermostat, 160 is running abit too cool for my liking.

It doesn't solve the gradual increase issue though, dnd, lucky and evil gave some great help with what to do.

 

Wow, what'd you use to clean that out? A shop vac?

 

COLDER STAT dOES nOT MAKE YOUR CAR RUN ANY6 COOLER... this isnt a home thermostat.. once the stat is open thats it.. its up to the heat trasfer rate of the cooling system to remove heat from the engine.. the stat only controls how cold your engine can get under very cold conditions.. eg if its 0 degrees then a stat at 190 will close off the circulation until the engine temp reaches 190 then it will open slightly to maintain the 190 and not allow the engine to go down to 0 degrees...
in the summer the stat opens fairly quickly.. but if the engine coolant is 220 degrees a fully opened stat will not lower that temperature.

 

ok thanks for info

 

funny how so many just can't understand that

 

My stock tune turns Fan 1 on at 226 degrees and Fan 2 at 235.

 

It will if there is proper air flow going past the radiator. The engine's temprature should run a few degrees above the thermostat temperature when the car is cruising mellow down the highway and there is plenty of air flow past the radiator.

For instance, if the car was in stop & go city driving and the coolant temp was at 220 F before getting on the highway, then a few miles of driving at 60+ mph should bring the coolant temp down close to the thermostat temperature. Of coures at idle and car not moving, there is not enough air flow past the radiator from the fans to bring the temp back down to the thermostat temperture - plus the fans are programmed to turn off well above the thermaostat temperature.

Sounds like the OP isn't letting his fans come on to keep the car cool during idle periods. Obvoulsly, if there is no air flow across the radiator the coolant temp will increase until the fans come on as controlled by the computer. Once the fans come on, the temp will cool until the fans go off, then heat up again until the fans kick back on ... all normal operation.

 

I hope you are not trying to explain the C5 cooling system to me...or cloud the issues with your input...( You quoted my post and tried to teach me something buy giving conditions that had no bearing on the OP's problems, there was No mention of cruising down the highway at 60 mph )

First of all the fans do not run after the car reaches 35 mph... so all you have is air temps at ground level to cool the system... if the system is partially block by all the debris I mention then you will have exactly the conditions mentioned..and very little heat transfer
if the guy is in stop and go driving and stopping at traffic lights, he is not cruising the highway at 60 mph.... why do so many people want to post contradictory or misleading post to the advice I am giving the original poster...""??? you certainly cant teach me anything about a C5 cooling system....ZeeOSix;1563719199 I didn't ask you for any help so please dont give me any.

For the original poster's information:
Depending on model year
01-04
The low speed cooling fans are commanded on when the coolant temperature reaches 108°C (226°F). They are turned off if the coolant temperature lowers to 104°C (219°F). The high speed cooling fans are commanded on when the coolant temperature reaches 113°C (235°F). they are turned off if the coolant temperature lowers to 108°C (226°F). When the A/C is on and the coolant temperature reaches 85°C (185°F), the low speed cooling fans will be turned on at vehicle speeds less than 56 kPh (35 mph).

For early model years:97-00
Low speed fans come on at 219,high speed fans come on at 228,low speed with a/c on...
Both fans have high and low speed capabilities

I hope this helps the original poster.
also Be careful who you listen too on this forum


Good Luck
Bill aka ET

 

As I said before, the OP is not letting the fans come on natually at their normal turn on points. You could have no thermostat in your engine and the coolant temperature will always rise when there is zero airflow through the radiator. Let the coolant temp go past the 210 degree point and make sure your fans kick in and keep the coolant below around 230~235 degrees.

And ET ... you are getting excited over nothing, as my post you seem to be getting all upset over is just elaborating the function of the cooling system. Take a chill pill.

 

Let's play nice guys - if you can't let me know, and I'll shut this down.

 

Thanks again.. This is much better than the alternative.

 

Okay...let me address a few things:

First, Moderator, thank you very much for not abruptly closing this thread, i'm using this as a learning experience...the person who was in my life (up until recently) who was helping me hands on learn the Vette and it's mechanical parts is no longer around, so I have to rely on this forum for answers...while I do what I can to make fixes.

Evil - You're right on cue, thank you for all of your input and keeping things on track for me, you've answered my questions perfectly, and I thank you very much for your help and time!

Zee - You moved away a little bit, but you came back and pointed out what I mentioned, that I won't let the car get too hot...this is because i've driven "Non-Sports" cars in the past...the temperature always stayed at one point and never went away from it, even when stopped at a light...i'm not used to it increasing slowly when stopped...it scares me, even to this moment....I get scared to see the car get to 225*+ and would rather it never go there....maybe it's something I should get used to?

Thank you all for your help! I desperately need this education, let's play nice, I don't think I can afford for fights to take this learning experience away from me

 

Didn't mean to confuse the issue, but what I said earlier was to show that the only time the coolant temperature is going to be anywhere near the thermostat temperature is when the car is or has been moving down the road for some time. That is good to know to verify that the thermostat is actually working correctly. If you were cruising down the highway for many mile (at mellow speeds) and the coolant temp was way above the thermostat temp, then either the thermostat is defective or the radiator is lacking air flow big time.

Every water cooled vehicle will have the coolant temperature slowly increase if it's sitting still for a little while and idling ... that's because you need air flow across the radiator to keep the coolant temperature from climbing. That's why there are fans on the radiator ... to flow air through the radiator when sitting still, otherwise the engine would over heat in a short time.

As others have said, part of the issue could be debris in the radiator ... actually it will mostly be in the A/C condenser, but it still blocks air flow to the radiator. If you let the fans come on and the temperature goes above about 230 F and the fans never go off, then the radiator is definitely lacking enough air flow.

Anyway, let the fans come on and make note of the max coolant temps seen, and go from there.

 

The fans are free to run anytime coolant temp dictates. There is no speed limiter for that.







Of course if the fans do run while moving, it certainly indicates a problem...but as far as the PCM programming is concerned, the fans can run at ANY mph. The 35mph turn-off value applies to the turn-off point while a/c is in operation.

 

I've cleaned the rocks and etc from the condensor a couple of times in the life of my '99. I purchased a long air-wand with a bend from Harbor Freight for $4.95 and hooked it up to the compressor. Worked just fine and I had quite a pile of rocks come out of there. This last time I did it, I couldn't find the wand thanks to a move and a tiny garage where its lost somewhere inside. I fabricated a copper tube to a garden hose connector and used it with the same results. Worked just fine.