View Full Version : ausie

09-20-2004, 05:45 PM
having a similar problem to what you had or have... basically at work today, i was going to lunch, noticed i had a radiator light (orange service center light). I had gotten lunch, came back, poped the hood and noticed radiator fluid had been coming out from the cap ? not so familiar with this car nor radiator systems? think it's a bad cap? thermostat? i know you had a similar problem, but any suggestions on what to do? anyone.

09-20-2004, 08:26 PM
I think I would goto auto zone and have them test it for free or buy a new cap theey are pretty cheap. I missed gingerman raceway due to a cracked thermostat housing due to the former owner.

09-22-2004, 06:20 AM
Thats a first, never had my username as a topic :)

Casey, it does sound similar, however I never noticed an indicator light on the dash. As for the Check Engine light, I have had that come on for other reasons other than coolant. If you have a scanner get the codes read (if you have not done that already).

Over time, and also design related, the high temperature nylon tends to become warped at the neck of the resivior if an aftermarket cap is used and if overtightened. One reason the factory cap had a ratchet or torque slip was to reduce the tension on the plastic threads. That just did not provide a good seal for a presurized coolant system. Aftermarket caps only come in a 16psi rating (at which I thought the factory was 22 psi). If I did not say this earlier, I had coolant overflow since the 01 Cobra was new, especially when the AC was used. Since I clean the engine bay as well as the rest of the car I am always inspecting things and have not noticed coolant levels dropping below the required level in the resivior, that is before changing it.

This past month was the second time the coolant was changed along with a new thermostat with a lower temperature (188F) than stock (195F). It only overflowed twice since then (during the burping process, and for the first test drive after topping off the coolant after burping - removal of trapped air). It has yet to dump any coolant since then. It may be premature to change the thermostat at 30k miles but perhaps it is not.

Sure, more than likely the overflow issue is related to loss of pressure from the CAP or any trapped air that may be in the system. I also have noticed some gray soapy clumps in the coolant prior to changing it but that may be associated with the contaminants from the tap water. This time I used the pre-mixed coolant which is 50/50 glycol and distilled water and so far I have not noticed any strange floaters in the coolant.

What comes to mind is how many times the stock motor detonated (not just your average ping, but RPM stopping bangs where the motor completely shuts down). That probably occured perhaps three times too many. The cause was the BBK CAI kit which found a new home in a box in my basement inside a garbage can full of things waiting to be trashed. My only concern is if the head gaskets are still intact. I will have to get the coolant tested for hydrocarbons as well as having the compression tested before I install any forced induction.

The cooling system is not that much different than your traditional type with the exception that it does not have an overflow resivior. The actual level of the coolant in the resivior is the level in the radiator. Not exactly compatible with the rules of drag racing since they require you to have a catch can to prevent coolant on the track. One reason I am considering making some changes back to a conventional system if it is available.

For starters, it is best to aviod the use of tap water when mixing coolant since some chemicals or minerals will leave deposits and possibly change the boiling point of the coolant. In my case I have to deal with bleach, flouride, along with metals from the old pipes (galvanized steel) which are in my 100yr old home. With that in mind sort of diminishes the heat transfer properties of the coolant if added to the resivior.

Secondly, if your vehicle has more than 30k miles on it, you should either test the coolant or flush it out. You may as well replace the thermostat since they do fail over time (note, you will need a new "o" ring too). Also note when changing the coolant, you will have to burp the system since the 4.6L motors like to trap air (usually in the heater hoses so run the heat while bleeding out the air).

Coolant change: start with the engine cold, if you are replacing the thermostat (probably should), you can opt to ignore the pep-cock on the radiator and just open the thermostat housing (small metal housing with three hoses connected to it). Also you will need to remove the plug that is on the coolant cross member (it will be tight so a small ratchet may or may not work, I had to use a channel lock plyers to loosen it). Install new thermostat and O ring (o ring goes in last) after all of the coolant flows out and assemble the housing. Get a clean funnel and add coolant to the resivior (leave the plug open at this point). When the resivior becomes full, you can add coolant to the plug port (put the resivior cap back on to prevent coolant spilling out). When you get to the point where you cannot add any more coolant, put the plug back in and tighten it. Open the resivior cap again, but this time leave it off. Trick: carefully squeeze some of the hoses (especially the one on the passenger side) which will get some air out. Some coolant will spill out. Top it off and start up the engine and let idle. Turn the heater on (fan speed does not matter but you must have the right most switch in an active position. At this point, you need to wait until the fan kicks in which will be the same time the thermostat opens. The coolant level will begin to drop. Put the cap back on and turn off the motor. when it cools down, add more coolant if needed and repeat the process again.

Also, if you want more efficient cooling, there are products you can add to the coolant such as Redline "water wetter" or Royal Purple "purple ice" which is supposed to reduce the vapor barrier created by the hot surfaces in the heads and block. I used the purple ice when I recently replaced the stat.

More than likely the problem you may be having are related to the seal on the resivior cap. Since this is a closed system under pressure, you will get some coolant to overflow when it gets hot due to fluid expansion. If you note the hump on the resivior (towards the passenger side), that is there to serve as an air pocket to allow for fluid expansion as the coolant gets heated up. The resivior cap is designed to allow pressure release above 16 to 22 psi, too bad Ford did not provide a catch can in the design to prevent coolant loss. The fact that you may be experiencing coolant loss from the cap could be an indication you should replace the cap. Also, some bimetals change their characteristics over time and may eventually open at a higher temperature, or worst case the spring may become weak and the stat will stay open which could lead to overheating.

Oh well. looks like another novel.

09-22-2004, 10:34 AM
all that information was great indeed... thank you very much.

09-23-2004, 06:18 AM
Changing the coolant and stat will help keep the temperatures down a bit. The lowest temp stat that you can use without re-flashing the chip is 180F. You will have to order it to get one. Most if not all parts shops do not carry replacement thermostats for the newer 99+ mustangs. If they do it will be the 195F stock OEM replacement. Some parts stores may have the 160F stat but that cannot be used unless you buy the programmer/chip for your car.

A colder stat should aid in preventing pinging but it will not stop it if there is any carbon deposits on the pistons or cylinders. Sometimes the EGR valve pulses can sound like pinging. It sounds similar but different. Since I have replaced it I now hear it open up when it becomes activated.

Keep it cool, keep it longer.