Well yet again here is another FD3S Coolant issue. Here are my symptoms. The Filler neck is each time after I drive the Car is completley empty. When I open the AST relief tank there is Coolant in there but the level is very low. So what I have done to troubleshoot here is i have removed the Cap off of both the Filler neck and the AST tank andbegin filling the Air Seperation Tank until it reaches right up to the top, then Cap it. Once the AST gets full i can see coolant in the bottom of the Filler Neck. I begin pouring in the Filler Neck until its topped right up. I begin squeezing the Rad Hose right under neath the Filler Neck and alternate with the hose running from the Air Seperation Tank to Filler Neck to push out any Air Pockets, I have even removed the Coolant Hose from behined the throttle body to completley bleed the system. I keep squeezing the Hoses till i notice that the Level at the Neck is ready to spill over and the level doesnt drop. I decide to leave the cap off, and to my suprise not even 10 minutes the level has dropped at the Filler Neck substancially! where is the Coolant going? I look beneath the Car for any leaks nothing. The over flow tank is always full. I have even left the Cap off the filler neck for 30 minutes and the Level at the Neck will drop right to the bottom of the Neck this is without starting the car at all. I have been wrestling this issue for a while now. I get the Coolant Buzzer before i even start the car each morning. When the car warms up the buzzer comes on and goes off intermittently as the Coolant Expands which makes sense. I have an aftermarket Temp Gauge and it will read a steady 180 F to 210 F even when the car is pushed to its limits. The funky thing is the Stock Gauge will start moving right to the white line with the buzzer going then will drop back down to its normal linear position! When the stock gauge moves to the white line the After Market Temp Gauge drops from 180F to 150 F. When the stock gauge comes back down from the White Marker within seconds the Aftermarket Guage will jump up to 195 F to
210F then drop back down to 180F and remain steady. I have the after market Fan Mod done by removing the AC Fuse so i just hit the AC button and the Fans will run all day long. What you guys think? Coolant Seal Failure? Or leaky hoses? I thought i mention also that after i drive i get a drop of coolant from the overflow hit the pavement but i do see What looks like Coolant/Water spraying the inner wheel which leads me to believe that the coolant is overflowing from the overflow while i am driving. When the car is shutoff and left over night unlike the filler neck and AST which need coolant everytime after i have driven, the coolant in the overflow remains full consistently but after a few days will require a little to get it full again.

 

Possible problems/things to fix, in this order:

1. Replace both coolant caps. Be sure you get the correct cap for AST & filler neck.

2. Possible leak. Pressure check for leaks.

3. Probable coolant seal leak. Live with it as long as you can. Rebuild engine

 

Thanks for helping Adam. I have replaced both Caps. anybody else?

 

Can a bad coolant Seal suck Coolant from the Filler Neck without running the engine? that is where i am not quite convinced that it may be a Coolant Seal but rather an External Leak that is drawing air into the system. Unless of course the Broken Coolant Seal is allowing air from the Combustion chamber to seap into the cooling system when off and is bringing the level down. Your guys thoughts on that. Af far as performance is concerned the car rips hard, puts 12 pounds boost in second and third gear on stock twins engine runs really good.

 

Coolant heats up, and expands. When it cools off, it should draw back into your cooling system. If you have a bad seal (or leak) air will get into the system. That may be why you don't have full coolant when it is cold.

Are you sure you have the correct cap on the AST and filler neck? The AST cap should have a pressure rating of .9 bar. The filler cap seals the filler neck. It is not a rated spring cap.

 

You would think that leaving the car off all day and removing the Filler neck cap and the Air Seperation Tank Cap you would get all the air out of the system. When i refill i squeeze the lower Rad hose and hose running to the AST aswell as removing the rear Coolant hose behined the throttle body to disperse air out of the system and then replug once coolant comes out. I have the correct caps adam i replaced both. The .09bar cap for the AST is correct. Funny thing this morning was after a day of not starting the car refilling the system at the AST and Filler Neck, The coolant has gone done in both the AST and Filler Neck again substancially! where the F*** is it going? not on the ground thats for sure.

 

Sorry if I missed it but does the car smoke on cold startup? If you are losing coolant that fast it should be too hard to track. On a cold engine it isnt uncommon for the coolant to seap into the engine when there is a bad coolant seal, but the way you describe it I would imagine you would be seeing a lot of smoke.

If you have replaced the caps and the hoses leading to the overflow tank, dont see any major leaks or smell any leaks when the car is running in the engine bay, then you are really left with one harsh reality.

It sounds like you are losing it at a very fast pace, I wouldnt recommend driving it very far. Look on the brightside, this engine failure is the cheapest to rebuild. You dont have to worry about damaged rotors or housings during the rebuild.

Good Luck.

 

well i am getting strong coolant smell to the right of the Air Intake Box right where the overflow bottle is after i have driven the car. I can see the Spray of Coolant in the inside wheel wel. Which tells me that coolant is over flowing from the bottle while i am driving. I dont see coolant on the ground after i have parked after driving.

 

One other thing to check is the hardline to the turbos. Due to thermal cycling they will leak. I fixed mine by running that powdery aluminum flakes coolant sealer (the dry kind) but only 1/2 a bottle. That fixed it for me.

 

Do you have a pick to see where i can see the Coolant Hardline to the Turbos bro? are you referring to the Blockweld Copper Seal job to fix that leak?

 

Don't have a picture off hand but if you take off the intake pipes, you'll see an inverted u-shaped metal pipe going into the turbos. My guess is that it's the crush washers that would need replacing.

 

This might help. Is your ast level with your filler neck? If it sits lower then the neck, It will pour coolant out of the overflow hose. I had the same problem. Raised the ast and no issues anymore.

 

I question this. I'm a noob, so I may be completely wrong. Stock, the AST sits lower than the Filler neck opening. The only time that the AST should fill the overflow hose is when the system pressure goes over .9 bar. The intake for the AST is below the overflow hose with the pressure cap in between.

Now, if you had switched the fill cap with the AST pressure cap, then you could have that situation that you describe and raising the AST would keep the overflow hose from filling. The other problem could be a worn AST cap whose spring was shot. Likewise, if the AST cap didn't seal it would do the same thing. But if everything was setup as it should be and working, there is no way the AST would drain coolant into the overflow tank without the system being over .9 bar.