ISituation: ts 20 degrees C outside, I was driving in rush hour traffic, pull up to a light and some guy starts pointing at my front end. I got out and there was cooland everywhere.

I shut off the car, the stock temp gauge was in the red and the coolant was leaking from the plastic overflow in front of the passenger tire.

I have a scoot vented hood, fmic, big *** rad, Aluminum ast and the fan mod, so this should not have happened.

I got some coolant filled up the car and it ran fine afterward at 84-88deg C, my normal operating temp.

I checked on the laptop after I had turned off the car initially and it read 98 deg C, but this was several minutes after I had stopped. I am guessing the temp must have been close to 110 deg C (230f).

There was a trail of coolant down the street and a large puddle under the car. The only place I could see that it can from was a small hole on the top of the over flow container. Should there be a hole there?
I have a tube running from my ast to the over flow. When I felt the ast right after I stopped it felt as if the coolant was boiling inside.

The only thing I could think of is that the T-stat malfunctioned. I drove the car most of last summer in alot warmer weather and never had a problem.

What do you guys think?

 

you shouldn't have immediately shut off the car. it completely 'shocks the block/motor. letting it idle why you check would've been fine.

t-state could be one of the problems. always wanna check it.

 

Since you have done the "fan mod" you can easily check to see if BOTH fans are operating (hell, if any are operating at all).

Any car will overheat in stop & go traffic without fans, no matter how big your rad is.

Yea, there is a hole in the top of the coolant tank. Keeps you from overfilling it.

 

yeah the fans are working fine, I'll replace the t-stat just to be safe.

d0 luck: yeah your right I should have let the car idle a bit, I was just shocked when I saw how much coolant was on the ground.

Would it matter if I had a higher mixture of anti-freeze to water? I still haven't changed it from the winter when I added alot of extra anti-freeze to keep the block from freezing.

 

Some coolant gets spit out from the overflow tank if you overfill the cooling system or if you really heat up the engine. Could also be that your cooling system in not holding pressure or something.

 

change caps, thermostat and convert to evans npg+

 

If you change your mix add more water not antifreeze. The antifreeze acts like hot syrup and holds more heat but also has less ability to shed that heat at the exchanger(ie radiator). Sounds like a stuck thermostat or air pocket to me. Replace the thermostat and when you fill 'er back up, take off the TB coolant line to bleed any air in the rear housing up and out that line(it will help). Good luck.
BTW, I have used Evans NPG and if high temps scare you, that's not the way to go. Evans has a super high boiling point but your temps will run hotter, you'll also need to run no thermostat which I still have done and it SUCKS! Try ProBlend's 40 below product. I've used it now for over 5 years on a track car that see's 105degreesF in the summer with a front mount IC and my track temps stay below 230!
Art

 

My car used to do that when the coolant o-rings were failing. Exhaust gasses escaped into the coolant system which pressurized it to the point where it barfed all the coolant into the overflow tank. My theory is that when the coolant system isn't totally pressurized the exhaust gasses in the coolant would still be allowed to escape through overflow tank. When the coolant system reached a certain pressure the pressure cap wouldn't let the gasses escape so the system would build up 11+ lbs of pressure and then blow coolant out to the overflow tank. I hate to be a doomsayer but it's something you should consider and do the champagne test and the o-ring failure tests.

 

The hole in the overflow tank is there for a reason. Its to let out pressure if it builds too high. If you didnt have that hole you would of had something going BOOM from too much pressure build up..... hey its better to lose coolant than to have a blown up upgraded radiator right.

 

go more water than anti-freeze for the summer

 

I changed the coolant today, went approx 70-80% water, I also added water wetter.

Changed the plugs for the hell of it and the oil and the car ran fine all day in stop and go traffic. Temps never went above 86C.

I am also going to seal the area between my fans and the rad, there is a gap at the top and the bottom.

What is the best thing to use?
The gap is about a quarter of an inch all along the top and bottom.

Also those of you using a FMIC and who can't use there stock belly pan, did you just fabricate a new one from aluminum or run without?

 

That does sound like symptoms of exhaust pressurizing the coolant. Or as was stated bad pressure cap allows coolant to boil and overfill the overflow. I just rebuilt a Supra for that symptom, headgasket blown. I guess its not winterpeg right now!? Take care and hope for the best!

 

I modified my belly pan to work with my greddy 2 row fmic. Not running with a belly pan can cause overheating when you're not moving since the radiator fans will simply recirculate the hot air.