98 c5 temp running about 240 deg. on hot days with a/c on is this normal.

Thanks Bill

 

No, check radiator for debris. fine particles, small pebbles etc. check coolant level...how old is coolant/T stat?
make sure both fans are turning on...make sure you have no tiny little leaks anywhere such as the overflow tank upper hose

 

NO---- do as suggested above----Ultimately i would get a cooler thermostat---I like the 160* it won't run 160* but around 185* on a normal day--THEN if you can get it tuned set the fans like this---
#1 on at 195
off at 190
#2 on at 205
off at 196
( a stock tune is like this #1--- 226/219
# 2---- 235/227
Totally ridiculous -- Fans come on way too late and once it's that hot--it stays that way !!

 

Sounds too hot to me. Running a bone stock 2003, it has been over 100 degrees outside each day this week driving home in Houston stop & go traffic. With the AC cranked up, I haven't had any reading over 225.

 

In 100 degree temps while sitting at a light my temp will go up to 230-235 but that ks about as high as it gets.
If it gets too hot and you start to worry roll your windows down and turn your heat up to 90 with the fan on high.
That will cool the engine down some but will cook you.

 

"I don't care what you say that's funny right there " !!! ( Larry the Cable Guy)
From a racing backgroud anything above 200* is too hot-- Don't care what people say or the dealer says or the smog guy says---Running it cooler won't make the engine oil too cold---or make it NOT pass smog---It's all an old wives tale---
A cooler ECT just makes everything better---Hoses belts last longer--Everthing underhood made of plastic or rubber doesn't deteriorate as fast--- Wire doesn't peel the insulation off--Intake air temps cool down--less pinging or KR--Trand fluid cools down-- A/C lasts longer--water pump--power steeing etc etc----
These new Gen 3 engine are really bullet proof and a great platform--
They have made them so much better and people easily will keep them for 200K miles or 10-15 years--- My theory (take with a grain of salt)
is that the only way to perhaps get an engine to prematurly fail is to get it to overheat --If it's running say 225--240* all the time and say you suck a pastic bag in front of the radiator--it will spike the ECT to 260* and beyond causing a failure--they sell you a new car-and blame the failure on you-- BUT if it's running 180* all the time a plastic bag may only spike the ECT to 220*---nothing lost------LOL----

 

I read somewhere that the racing 'vettes are designed to run at 185 and basically shut down at 190 or 195!!! With my 160 t'stat, I'm usually running at 185-190 on the open road and just over 200 in town, with the reprogrammed fans running to keep her cool.

 

Interesting. Where can I read about that?

 

My car has the 160 degree stat in it. Today around 185-195 without air. Today with air, anywhere from 214 to 221. I have a inter cooler and supercharger which robs a little cooling capacity when I am on the highway. Clean between radiator and condenser. If that does not work look into a 160 degree stat and having your car's fans reprogrammed. If that does not work, consider new water pump or radiator. Take one step at a time.

Good Luck

 

i was running 220 about driving 70 i just blew out the rad also still had lots of grass particles i couldn't get out. i was running ac.

 

lol, ditto

 

in both my prior C4 and my current C5, when i had coolant temperature problems, in both cases, the culprit was either a severely dirty radiator (my C4 was 30% full of mud, and 30% clogged with mud between the cooling vanes!), or crap stuck between the air cond. condenser and the radiator..stopped the air flow over and through the bottom-feeding cooler system. Once both problems were cleaned, both cars hardly ever got above 200 degrees.
'Clean it up first before you through any money at thermostats, fans, etc. That's been my experience.

 

I like how people read somewhere but offer no link. Half the time when you read something its from a guy who dated a girl who's father worked next door to a dealership and got all of his info from the guy who washes the cars at the dealership. The washer guy tells his friends that he is the head mechanic.
90% of all corvettes never see the track and have very modest mods.. some include the hood seal and the Loyd's floor mats.
A thermostat has nothing to do with how hot a car will get, a thermostat only controls how cold the car will get. The stat opens sooner, but the heat will still rise if there isn't enough heat exchange.. the biggest culprit of an LSX running hot is debris in the condenser and the radiator.. many people think when they look up the air diffuser , that they are looking at the radiator, but in fact the radiator sits two inches behind it. A yearly external flush of both the radiator and condenser, from back to front to clean the cooling vanes will do a world of good for this condition.. if you go to an air conditioning supply house you can bu a can of condenser cleaner foam.. its aluminum friendly and will neutralize all the acid caused by the bug guts and the stickiness. let it sit 10 minutes and flush from the back and then with some compressed air..
The next urban legend is lowering the fans will help at highways speeds.. when in fact they turn off at highway speeds. The fans were also designed to cycle on and off to reach the CE approval of 180,000 cycles
Of course this has nothing to do with a highly modified track car.. the stock LSX engine does have a sweet spot that being 190F/200F coolant, 200F/ 210F oil. The clearances were designed around this sweet spot for lubricity, that's how you can get 430 HP out of this small block engine.When you think stock or slightly modified engine, you have to think hot is better than cold. One of the reasons you can get 300,000 miles out of this engine is, its not a cast iron engine, and it was tested and designed to do 200,000 miles, I have many members PM me with their 200,000 plus cars, and a few with over 300,000 miles. Cold is not your friend in an alloy aluminum engine. I just love all the 1960's thinking and urban legend found in this forum by people who making a living at anything other than automotive technology.

 

Don't really have specific info on this. I read it while researching the 160 t'stat. Mighta been on the C6R website or the engine providers.

Okay, it was a thread here on the forum: post #8

http://www.google.com/url?sa=t&sourc...tK0GNsgMmrRBLg

 

Chillbill....
I'll help you out since everyone has their own discussions going on and not any education on how the system works so you understand...


I "assume" you are talking about coolant temps, it would be helpful if you also posted your oil temps.

The C5 is cooled in two ways:

1) WHEN THE CAR IS IN MOTION:
Driving above 35 mph air moves up into the ac condenser and radiator. There are black plastic cowlings under your car and if the center piece is missing or heavily damaged the air does not get channeled up into the condenser/radiator and you experience high temperatures.

Also, there are two strips of foam on each side of the AC condenser, those keep air from going around the condenser/radiator instead of thru it. If those are pushed out or missing that can cause you to run about 10 degrees hot.

The AC condenser and Radiator also need to be kept clean, lots of sand, dirt, grass, leaves, plastic bags, etc. get sucked up there and block the movement of air. This is the most common reason a car runs hot while moving.


2) WHEN THE CAR IS STOPPED OR GOING LESS THAN 35MPH.
There are two fans that pull air through the ac condenser/radiator into the engine compartment. The fans have two speeds and there are multiple fuses for the fans in the engine compartment fuse box. You need to verify both fans are running properly, I had a fan fail and I ran about 240 degrees with one fan. If you turn on your AC it will command the fans to come on. Be very careful when you check the operation of the fans. The fans can be programmed to turn on earlier by a tuner and is the preferred way to cool your car down, vs. installing a tstat.

REVIEW:
So if your car runs 240 when you are in stop and go traffic but you see it drop down to 210 once you get up to 55 mph then you probably have a fan issue. If the car is hot all the time, it's probably an issue with air getting thru the radiator.

 

It could be: a dirty radiator. (can be cleaned with a dryer cleaner brush..dry or a low pressure hose...wet).

A stuck thermostat. They are cheap...buy a new one.

A cooling system that needs a complete system flush and a refill with a
50/50 distilled water and Dex-cool.

A collapsed hose.

The above should keep you busy. Good luck.

 

Clean the radiator out. You be surprised how much dirt, sand, grass and who know what gets stuck in the radiator fins.