normal temperatures?

[justacar]

What are the normal operating temperatues for a 1999 coupe? I should mention that I just passed 118,000 miles. My temperatures have been all over the map in the last week: cruising varies from 190 to 220. During a time in a traffic jam in the heat, the temp got to 250 before I had to turn on the heater and that brought the temps down fast. The problem only seems to come up when the A/C is running. Fans? They seem to be working, but I have yet to check that both are operating. One of them is hard to get at. Which fuses should I look at? Water/coolant mix? I did have the coolant drained and refilled last fall and this is the first time for higher temps in Cleveland this year. Any suggestions?

 

[rrhayden]

That seems a bit hot, check between the radiator and ac condenser. Corvette's collect trash there and it will block air flow through the radiator. I had a similar problem and found the total front of the RADIATOR COVERED IN GRASS, PAPER, AND STUFF I COULD NOT RECOGNISE. After cleaning, 20 degrees cooler

 

[justacar]

Thanks, I'll check tonight

 

[rrhayden]

I was shocked at how much stuff was there. On my 92, you have to peak through a small opening on the pasengers side of the radiartor shroud where the AC lines pass through. To clean it I removed the radiator and pressure washed it. There are a couple of threads here that explain how to do it. It is not difficult at all, just time consuming.

All the best

 

[fhturner]

I see you already have some tips and replies, justacar, but I'll throw in my experience as well. I haven't noticed any excessive temps on my 98 Coupe like you're seeing (250 deg.). My normal range for coolant temps seems to be between 194F and 216F, or thereabouts. The oil temp seems to hold pretty consistently at about 220F once the engine has warmed up. Hope this helps! Good luck!

 

[IGOFAST]

When you had the coolant drained and refilled, did they "burp" your cooling system to get all of the air bubbles out? If not, that could be part of your problem.

 

[jorge33265]

I have a similar problem on my 97 but my temps only go to 234. 250 is way to hot your going to bow a head gasket if you dont get that checked out. I wonder if there is a relay for the highspeed fans. well im sure it is but i wonder if it gives a trouble code if its bad. I've never like a hot running car and ive had 4 vettes and they all run hot. Well not the 69. C4-C5s run hot. I know that C4 you have to let the air out im not sure about C5 they dont have a bleed screw on the termostat. You can reprogram youre computer to turn the fans on faster or you can install an automatic fan switch from pep boys for like $60 that will keep the temps down. But given that youre at 250 there is definatly something else wrong.

 

[johnl]

To clean it I removed the radiator and pressure washed it. There are a couple of threads here that explain how to do it

I have searched and searched and can't seem to find the thread. Can anyone assist in finding it?
Thanks
John

 

[AmosF16]

I'm for checking the easy things first--I'd check the fuze for the fan to make sure it's still good before doing anything else. Happened to me in another car--it's an easy thing to fix. Your owner's manual should have a list of fuzes and locations. Cheers, Andy

 

[rrhayden]

Here is the artical I used to referance my radiator cleaning.

The only things I found that were not covered were as follows.

1) I had to remove the air pump located in the front drivers side next to the radiator. This was to remove one small screw holding the upper and lower shroud together.

2) I also had to figure out how to wiggle the upper shroud to get it past the AC plumming. I found that by lifting the drivers side streight uo and to the passengers side I could slip it off.

Hope this helps !
Ron
http://www.batee.com/corvette/dcrg/...iscuss_sim3.htm[/URL]

 

[johnl]

Perfect.
Thanks for the link...looks like I have a new weekend project to look forward to. With 138,000 mi, it's probably about time.
J

 

[justacar]

Wow: 138,000? I though I was doing good wih 118,000 on my '99. Of course, living in CA, you don't put up with al the winderful weather we have here in the winter. I do drive it all winter, and you'd be surprised how good it is in less than ideal conditions. Is there anything a long mileage guy like me can learn from a fellow long mileage guy? Anything to watch for in the next 20,000?

 

[vettegirl]

When you had the coolant drained and refilled, did they "burp" your cooling system to get all of the air bubbles out? If not, that could be part of your problem.

I just drained my coolant and replaced it after having to put plain water in in a pinch (car overheated while on road trip). I have noticed it is running a little hotter than normal...how do you "burp" the cooling system?

Thanks!
Lauren

 

[hawaii-5-lo]

hey everyone,
if i remember the high speed fans dont kick on until 235*,but with the a/c running it would only get that hot in extreme conditions.
did your spoiler fall off.its one thing to pick the large rubbish from radiator and condensor,i clean mine with industrial strengh coil cleaner,the cooling fins get clogged with dust.when you fill the cooling system,make sure the t-stat opens(leave cap off of fill)then turn on heater for a minute and top off if necessary.is your water pump origanal?one last thing,you must go 50/50 with dex-cool and distilled water,no substitutes.good luck,later,Todd.

 

[vettegirl]

Thanks Todd!

The car had been running fine since the Daytona thing, but this Saturday in heavy traffic it seemed to get too hot (it did not overheat, and only got to 220, but that was enough to freak me out!).

Anyway, while reading through the owner's manual trying to figure out when the fans were supposed to come on, I saw you were supposed to dilute the coolant. When I had replaced it after Daytona I put the coolant in full strength since the bottle said "Pre-diluted" (that will teach me to read the instructions first!!). Anyway, I drained the radiator again and did 50/50..

I need to just relax and enjoy the car...this obsessive guage-watching is getting old!!

Lauren

 

[hawaii-5-lo]

hey Lauren,
mine will(would) get to 235*in heavy traffic,so i did the t-stat mod and made it a 180* and got a fan switch to turn on at 185 and off at 165*.car does not get over 195* in heavy traffic.later,Todd.

 

[jorge33265]

Just out of curiousity whay kind of fan switch did you buy? Mine does run at 235 in heavy traffic with 90 deg weather. My car is lowered so that doesnt help matters. Was the install easy?

 

[hawaii-5-lo]

i have a Vinci swith/harness.easy to install,plug and play,some are adjustable,some come with the probe recalibrated.how low is your car?i lowered mine 2 1/2 inchs,heres a crappy pic.

polished and painted everything myself,lots left to do.

 

[jorge33265]

Its looks as low as yours. I feel speed bumps on the bottom of the car. I cut the bushings in the front and dropped it as low as it would go. Then I adjusted the back to be even with longer screws. Ride didnt change much. Actually I think i used your instructions you posted some time ago. Thanks by the way. : ) took like 1 hour. How much did the fan switch kit cost?

 

[IGOFAST]

I just drained my coolant and replaced it after having to put plain water in in a pinch (car overheated while on road trip). I have noticed it is running a little hotter than normal...how do you "burp" the cooling system?

Thanks!
Lauren

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 fowl.
4. Allow the system to drain completely.
5. Inspect the engine coolant:
o Discolored -- follow the flush procedure below.
o Normal in appearance -- Continue with the next step.
6. Close the radiator drain fowl.

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.