Brad-Vette

My car gets super hot (250 degrees) when im at a stop light. if im driving its around 195.

What's the best way to start troubleshooting what it could be? When do the fans kick in, im not even sure they are working.

Sorry for the newbie questions.

Cliff Harris

Take the top off the radiator shroud and clean out all the trash between the AC condenser and the radiator.

Just BOB

Assuming your AC works, turn it on. If the fans turn on, you have just verified that the fans have power (no blown fuses) and that the fan relays are good, AND are responding to the PCM call for fan activation. The PCM turns on both fans at 228°F.

If the fans don't come on, the simplest thing to check, AND the most likely failure item is the fuse (which also powers your smog pump).

Pulling the radiator shroud is a lot of work and unnecessary. The is plenty of room to eyeball the front of the radiator by looking through the opening on the upper passenger side of the shroud where the AC lines pass through to the AC condenser. These cars are bad about vacuuming up plastic bags, fast food wrappers, etc, and if you have a dog that sleeps in the garage, it will even suck up dog hair off the floor. I tied a plastic pot scrub brush to a wooden dowl and raked two big coffee cans worth of dog hair off the front of mine, just by reaching through the afore mentioned opening on the passenger side of the shroud. Since you are running 195°F at speed, your radiator probably isn't fouled too bad, but cleaning is is a good maintenance item to keep up with.

bogus

what year?

Also check:

1. Rad cap. Is it holding pressure?
2. Hoses. Any leaks?
3. Overflow tank. Cap, hose in, tank itself. Any leaks?
4. 1991+, surge tank. Leaks around the rad cap?

The thing with these cars, air flow is at a premium, if the system has even the most minor leak, they will start puking coolant and running hot. Just this weekend, I found a small leak on the hose into the overflow tank... puking half a gallon of coolant every 100 miles, and not holding pressure. Instead of coolant being sucked in, air was. Instead of coolant being stored, it was being sprayed out onto the highway. And it ran REAL hot.

A few years ago, the rad cap boss on the surge tank decided to take a crap on me... that was not pretty. I sorta fixed it with some epoxy, but that didn't last long. It failed as I was leaving for FL one March. I had to order the surge tank whilst driving to FL! That was after puking nearly a gallon of fluid on the first day. I ended up keeping 3 gallons of water with me at all times... And buying distilled on the interstates isn't easy, so I was refilling with tap at gas stations. Shiver. I finally got down there, the tank arrived, swapped same. But due to a lack of tools and resources, I was stuck with the nasty coolant until I got home. I topped off with good antifreeze and flushed it out after I returned.

In short, something small that can cause any loss of system pressure will cause all sorts of havoc.

Finally, if you have an L98 and the mileage is hitting 70k, there is a strong chance that the head gaskets are failing.

hooked073

it honestly sounds like your fans are not truning on considering your temps seem normal going down the rd. I agree try the ac and see if they come on then let it idel while watching the temp with the ac off if the fans do not kick on at 240 give or take some you know they are not working when they are suppose to

Tom400CFI

Open hood, stand and watch fans/temp gauge as it idles and heats up.

You said, "the fans kick in, im not even sure they are working"
...open the hood and find out!

Tommycourt

I live in Arizona where the ambient temps can go as 118 and we have had days @122 which will affect your cars temp. Your fans should kick on regardless of temp when the A/C is engaged. Normally the fan will kick on when your temp. hits 226-228. I run a 195 thermostat. First of all make sure there is no air trapped in your system. There is a thread on here that will explain how to "burp" you engine. Secondly you have a low coolant sensor (on 88's) that is located behind the oil dip stick which will read "low coolant" when the water level is not adequate. It can be replaced for approx. $15. As others have mentioned, you have to keep the intake vent, below the radiator clean. This is a MUST! Check all your hoses and water pump for any leaks first of all. Make sure that your anti-freeze is fresh and clean including your overflow tank. Clean anti-freeze can affect water temp. There is also a product called "Water Wetter" which can be added to the coolant tank to help aid in lowering temps: about $9.00 per bottle and you should need only one. The L-98 engine is made to run hot. The other day our ambient temp was 117 degrees and my heat ran up to 237 degrees according to my gauge. I have a buddy who has had his temp gauge go to 245 degrees. If yours start to run around 235-240 shut the A/C off and run it until it cools down to around 215-220 and you will be fine. Do not be alarmed if the temp reads 235 as you are still ok to drive. Make sure you have the correct radiator cap on which should be 16 lbs. I wish my car ran @195 however out here that isn't possible in the summer. If you see ANY leaks, shut the car off and repair immediately. I hope this will help you and wish you the best of luck. Others on here may have some good ideas also.
Tommy

Tommycourt

I should ad the following: running a 50/50 mix of anti-freeze and distilled water is a good mix. I run about 60/40 (60% anti-freeze) and the rest distilled water. 70/30 will work and raise the boiling point of coolant to about 270 degrees but if you are in a cold climate, your heater will not put out enough heat to keep you warm. 50/50 is probably the best to run.
Tommy