superbee_68

iTrader: (3)

I searched the threads and no one has had this exact problem.

I had a coolant boil over problem when I bought the car a little over a month ago. The water pump had just been replaced along with the radiator and the coolant was changed to green stuff, so I changed the thermostat and flushed the coolant system. I put red dexcool back in the car because thats what it originally came with it.

Then I took it out for a spin, the temp was fine, then all of a sudden the temp gauged droped to zero and the idle started surging. I freaked out and pulled over as the car died. Turns out the temp sensor plug fell off the sensor. I pluged it back in and all was fine.

The car has been doing great for the past couple of weeks, but then...

I was out at texas motorspeedway and decided to be stupid and do some donuts. I did donuts for about three or four minutes until I looked down and saw the temp gauge climbing fast to 260. I shut it down immediately, and coolant boiled over out of the overflow reservoir for a little while. Topped it back off after a cool off, and went on my way.

The car would only stay cool if the A/C was on. The fans only come on with the A/C on now.

Thanks for reading this far, so I think if I figure out the fan problem, then I can finally be done with this dang cooling problem.

Any ideas on what to do next to get the fans to work? I'm trying to avoid a leak down test or litmus paper test because I don't want to change a blown head gasket, and for a while the car has been dong just fine, so I don't think its a head gasket.

1 FMF

iTrader: (1)

how hot out was it when you were doing donuts?

i would say the good news is that if whenever you turn the AC on the fans come on, that proves the computer can turn them on, and the fan relays work, and the fans work.

If I remember correctly, oem computer settings for fans to turn on low speed are 216 or 222F and for high speed it's 228 or 232 or 236 F. I would first suggest, because it's free and rather easy, drive the car to warm it up then park it and let it idle. Make sure the AC is turned OFF before you ever started the car. Don't have any heat or AC on. After a few minutes of idle your fans should come on automatically on low speed, and possibly cycle to high speed depending on the outside temp. If they don't then all i can think of at this point is it's a computer problem.
Is the car stock? Did anybody ever mess with PCM settings? You can change the radiator fan on/off settings, if you have a handheld scanner or autotap I think you can bring up those values to check what they're set at.

superbee_68

iTrader: (3)

The temp outside was in the low sixties, and I had just left the track when I saw the opportunity to finish off my tires, I work as discount tire so I get a hefty discount. I had to keep the a/c on to keep the car from getting hot at the track which confirms your theory.

So my buddy has efi live and a 98 ta just like me so we plugged in his laptop and checked the settings. They were all stock, so then we manually switched on the low then the high fans speeds with his laptop. They work just fine. So we redid the program for the fan settings. Lowered the low speed fan kick on to a slightly lower temp and the high setting was lowered to. Its about to be summer and i live in texas so its gets well over 90 and some times in the 100's for most of the summer and i want a cool car.

Also we set the fans to stay on high after the car is turned off for two and a half minutes if the temp is above 235 or something like that for quick cooling after I make a pass at the track.

So far it seems to be fixed, I see a slight dim in the radio display when the fans turn on so I know they are working, and the temp stays low. I'll just have to see if the new program works for when its 110 degrees outside!

Thanks for the help.

1 FMF

iTrader: (1)

fyi, whenever the AC (or compressor) is engaged and that includes turning on the defogger not just AC, the reason the computer turns on the radiator fans is because of AC compressor line pressure. And, if you are below 30 mph then the PCM automatically kicks the fans on low speed if the compressor is running- I have a fan switch with led lights so I know whenever the fans come on low or high speed. Was going to say, turning on the AC to get the fans to come on isn't the best way to keep coolant temps down because you're dumping the heat from the AC radiator into the engine radiator, but if it works it works.

wssix99

iTrader: (5)

Are you sure your fans weren't on when you were overheating before? The stock setup would be engineered to assume air flow over the radiator at high RPM. The stock fans will just get you through idling on a hot day.

Maybe the high RPMs and little forward movement were enough to test the limits of the stock set up?

BTW - If you were doing donuts on the TMS racing surface - I'm jealous.

superbee_68

iTrader: (3)

When i stopped the fans were not on and on the way to the gas station to get some water they weren't kicking on. It's really weird.

Today it was hot outside and the car never got hot. The fans are kicking on now with no problems.

I'll keep you updated.

BTW- I wasn't on the track, I was out in the ginormous parking lot, but I have driven on the track before