Prosecutor

I see many threads where people, who I assume have stock cooling systems, state that their cars stay at temperatures like 187 - 190 F during normal driving in the summer. My car (2003 A4 Coupe with 95+K miles) has never been that cool in the summer. My normal temperature cruising on the highway at 75 - 80 mph is 201 - 207. It creeps up to 225 F with extended sitting; however, usually does not get much above 212 - 219 in traffic.

I know that there are some variations...e.g., radiators blocked by debris over time...but again, my car never ran that cool when new.

Any thoughts? Do cars just have different personalities based on manufacturing, etc...

BowTieRocket

Hi! My stock 1999 Coupe ran in the 220 range last summer, when the ambient temperature was around 100F. Got as high as 235F in traffic. I don't have the manual open, but I think the fans are programmed to turn on about 228F, so running warm is normal. In fact, the stock thermostat is 195F or so.

I did a few upgrades and added the DiabloSport Predator performance tune, and the car runs about 195F most of the time now. Haven't driven it in traffic, but I'd expect it to run a little warmer then.

These things are designed to run hot, to help with emissions. I have a 1984 WS6 Trans Am, and it runs 220 or so in the summer, even with the 165F thermostat in it. The fans just don't kick on. It will run more in the 200F range on the road, but once it's been driven a little in town, it doesn't cool down too fast. Given the cast iron block, that's expected. My 1994 GMC Jimmy runs about the same, as does my wife's 2004 Grand Prix.

So I have been cautious about going to a much cooler t-stat. I'd like cooler runnings, but the PCM is programmed for a specific range, and if I change that, I'll probably need a custom tune. So it will wait until I get the modification bug again. But the Predator or equivalent will cool it down some.

Y2Kvert4me

When mine was stock, in hot weather it usually ran 195-200 moving (ie: freeway), a little warmer, 200-215 in city driving, and would peak at 230 when idling for long periods of time.

With 160 Tstat and fans reprogrammed, it now runs 175-178 when moving, and maxes out at 200 idling.

Point & Shoot

My range of operating temps - 194 to 226 or so when the fan kicks on............no worries here & HOT in Tampa in the summer idling in traffic

Blown 346

My car also has the stock cooling system and runs between 215 to 220.

electra

If it bugs you; change the thermostat and reset the fan on/off temps. Takes about 30 minutes to do the 160 stat and another 5 minutes to reset the fans with HPTuners. My car runs 175 on the highway in 100 degree weather and 185 in traffic. Just remember there is no free lunch. In the winter my car never gets above 160 on the highway which is too cold to boil out the moisture form the oil so I either change oil more often or reset the fans. Regardless of what you have been told, heat is the enemy for your moving parts. GM made the LS1 to operate @ the temps set from the factory for emmissions purposes not for performance. Within reason; a cooler engine runs stronger and lasts longer.

leadfoot4

I did the "shim" modification to my OE '01 thermostat several years ago. I took a rather lenghty drive this past Sunday in 75-80 degree weather. My water temp was 186-187 on the DIC.

MattB

Don't be too bothered about what other people are saying what their temps are, unless you know what the ambient temp, humidity, altitude and driving style are when they get those temps and how that relates to where you are and the ambient temp, humidity, altitude and how you drive.

There may be good reasons to get your fans re-programmed, but your temps look normal to me.

When you say that your car has never been that cool, do you mean in the passenger compartment? There are other cures for that, and they do help. A good tunnel plate and wrapping some of the exhaust as well as insulation will all help in that regard.

kevin40zx

You're not alone.

Tigershark3

The temps on my '99 run about the same as what others have posted. October 2006 issue of Corvette Enthusiast had an interesting article on cooling w/ Water Wetter. 50/50 water/antifreeze mix - temps for them was 228 degrees. After adding water wetter the temps dropped to 220 degrees. Looks like this stuff works at least to a degree anyhow. (no pun intended). $.02

alini

Something else you can do too is clean out the front of the radiator. I jacked mine up and cleaned the radiator fins with compressed air from the backside, kind of like a reverse flush. Car runs about 10* cooler now from where it was, which says alot out here in the 100+s of Vegas

BowTieRocket

Absolutely right! The Sixties muscle cars ran much cooler. I worry about my 428CJ when it gets over 210F, and prefer it in the 190F range. Thinking about something in the 180F range for a replacement tstat for the Vette - trying to balance between never really warming up half the year, and running too hot the other half. But Electra hit the nail on the head - it's all about emissions. The hotter they run, the less NoX they emit. To the point that, in the mid 1970s, to smog a car in the People's Republic of California, you had to disable the vacuum advance and set the timing back several degrees on the 1960s car. The Shelby has a coveted "SMOG EXEMPT" sticker on the windshield, since it was limited production and ram air, but they charged you $25 or so to put a plug on the carb vacuum inlet and vacuum advance nipple, set the timing back to the point where the car always overheated, and put a sticker on the speedo telling you not to exceed 55 MPH ever to avoid engine damage due to overheating.

I brushed mine when I installed the Vararam, and got a lot of road debris - foxtails, grass clippings, light stuff that got snarfed up - out. I like the compressed air idea. Used a pressure washer on my 1994 Jimmy, and dropped the temps about 5-10 degrees most days.

fdxpilot

The stock thermostat is nominally a 195 deg part. Obviously, there are production variations, not only in the thermostat, but in the Temp sensor. My 02 never runs cooler than 194 once it has warmed up. Your thermostat/temp sensor is on the high end, giving you 201. The rest of the temp range sounds normal, as the fans come on low speed (if the AC is off) at 226, so what you are seeing is normal. As mentioned, if you can't stand the stock temps, you can get a lower temp thermostat and reprogram your fans. Without reprogramming, the temps during extended sitting will still get up to 225, since there is no airflow through the radiator. Another hint, which seems counter-intuitive, is to turn on your AC. If the AC is on, once the car slows below 30mph, the fans come on, as long the coolant temp is over 165 deg. So, unlike old style cars, running your AC can keep your car running cooler, unless outside air temps are extremely hot.

Mr. Jones

when my car was stock temps were just like yours-no problem.
I now run a 180 deg. stat with fans adjusted. it runs around 195 deg.
I had a 160 stat it ran around 178-185 in the summer with fans adjusted, winter temps were lower.

cool air - hot (190+) motor thats was my goal. oil temps are around 204. alum. engines and old cast iron motors are two totally dif. animals. the alum. engine does not retain heat like the cast. hot spots in the cylinders are less likely in alum.
try to keep a 50/50 mix of water and anti. to much anti will also run hotter.

'00FRC

I had my car into my buddy who does tuning. He reprogrammed the fans (and added a few more parameters like disengaging a/c at 80% throttle or above) to come on sooner because they will let the motor run a little hotter before the primary and secondary fans will come on.

nb8822

How do you reprogram the fan temperature?

Vetteman Jack

Closing this 10 year old thread down.

nb8822 - post up your question in the C5 Tech section.