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View Full Version : Overheating problem again!!!!


TommyA77
08-12-2009, 12:54 AM
I just don't understand my 03 Cobra, she is as moody as a woman lol j/k.

Anyways, Took my dad for a test run, and of course it overheated again. I have no idea why it is doing it again. Ran fine all winter, all spring and the start of summer. I have had it parked for a month now.

Just curious if you guys have any ideas.

Tommy

Do head gaskets go bad on these 03's very often?

Mario95
08-12-2009, 11:39 AM
Have you search for any known TSB's Office of Defects Investigation (ODI) (http://www-odi.nhtsa.dot.gov/complaints/)

RF Cobra
08-12-2009, 12:06 PM
Tommy,

Could be lots of things including: thermostat, air bubbles, pump, clogged fins, faulty temp readings, fans not running right...

Can you tell when it is going into limp mode, whether it is before or after it shows to be overheating? If before it could be the result of another problem.

The head gaskets should last a long time, but every so often a defective one may slip through production and get shipped, or it could have been damaged during installation.

puzzle13
08-14-2009, 08:51 PM
I would try and burp the cooling system especially if yours is still in stock form. Prior to moving the thermostat, I also had a few problems after doing any work on the cooling system. If I had to drain the coolant it always seemed to get a bubble in the system around the thermostat and the thermostat would not always open resulting in an overheating issue. When you fill the coolant, add from the overflow tank and also add from the nipple on the top front of the engine. This helped, but you still have to burp using a funnel in the nipple. After relocating the thermostat with the Evans cooling system I never had a problem and I can no longer burp the system nor do I need to. There was a really good post a while ago that showed a great picture using the funnel. That is how I learned to do mine.

ausie
01-19-2010, 07:27 PM
Long ago I used to be a regualr here.... I may have been the one who recommended the funnel. I used a small bottle cut in half (believe it was from water wetter or such ). Open up the top port on the cross-over tube and screw in the bottle with the bottm cut out to make a funnel out of it. Always fill the coolant by the funnel. Of course you can add to the expansion tank as well. With the cap off of the expansion tank, add coolant to the funnel until you get overflow at the expansion tank. Close off the expansion tank at this point. Start squeezing all of the hoses slowly and you will see bubbles come out into the funnel. Add more coolant to the funnel as needed and continue massaging the hoses. Once you believe there is no air left, remove funnel and replace plug. Turn on the heat all the way, and start up the engine (do not forget to install the plug on the crossover tube otherwise you will take a shower in coolant!). Allow engine to reach operating temperature (fan should turn on at this point) then shut it off and wait for everything to cool down. Repeat the burp process again. You may have to do this at least 3 times to get all trapped air out. Once you are done, it is okay for the coolant level to be just below the fill line when cold near the top of the expansion tank. It is a messy job but it works.

I would like to look into that Evans cooling system. Anybody have a link?

puzzle13
01-19-2010, 07:52 PM
You really can't get a lot of information from the website on the Cobra stuff. You really just have to call them and talk with them and get them to send you the pamphlets. The website is www.evanscooling.com . The main ideas behind their system is removing the water to oil cooler that is mounted on the side engine and use an air to oil cooler. They have a specially designed radiator with the oil cooler on the bottom that takes care of this. The oil cooler is probably okay for street use, but not for any type of track use. There is also a kit to put an air to oil cooler in the driver side fender that tends to work very well. Some of the guys in Texas are very familiar with this. After removal of the stock oil cooler you have to relocate your oil filter to the drivers fender and this allows you to use a bigger filter which is good. Also ... they relocate the thermostat to the upper radiator hose with a very high quality thermostat with zero bypass when open. This works great and removes all problems with burping the engine! They have a different water pump, but this is not absolutely needed for the street. The other item they suggest is their coolant which uses no water and will pull more heat from your cylinder walls when under boost. This is a good thing, but the coolant is expensive, cannot be mixed with water, and you have to drain & clean the engine & heater coil prior to installing. I have used the system and will say that it does help with cooling. It is a bit expensive and if you are not having problems then you don't need it. The biggest plus is the moving of the thermostat. The stock thermostat never stops heated coolant from going back into the engine. Look at your thermostat set-up and you will understand. Their thermostat costs $100.00. but it works and no more air bubbles!!! I was not too impressed with the radiator/oil cooler combo for cost, but he oil cooler in the drivers fender works well. The oil filter move & replacement makes changing the oil much easier & cleaner. Long ago I used to be a regualr here.... I may have been the one who recommended the funnel. I used a small bottle cut in half (believe it was from water wetter or such ). Open up the top port on the cross-over tube and screw in the bottle with the bottm cut out to make a funnel out of it. Always fill the coolant by the funnel. Of course you can add to the expansion tank as well. With the cap off of the expansion tank, add coolant to the funnel until you get overflow at the expansion tank. Close off the expansion tank at this point. Start squeezing all of the hoses slowly and you will see bubbles come out into the funnel. Add more coolant to the funnel as needed and continue massaging the hoses. Once you believe there is no air left, remove funnel and replace plug. Turn on the heat all the way, and start up the engine (do not forget to install the plug on the crossover tube otherwise you will take a shower in coolant!). Allow engine to reach operating temperature (fan should turn on at this point) then shut it off and wait for everything to cool down. Repeat the burp process again. You may have to do this at least 3 times to get all trapped air out. Once you are done, it is okay for the coolant level to be just below the fill line when cold near the top of the expansion tank. It is a messy job but it works.

I would like to look into that Evans cooling system. Anybody have a link?

ausie
01-19-2010, 08:14 PM
I always thought the thermostat is used to bypass the radiator so it has a chance to cool the coolant down. When the stat is closed, circulation is completely throught the radiator, when opened, there are two loops but flow is primarily through the bypass hose which is at the bottom of the cross-over tube. The second loop is the path through the radiator but is static due to the bypass from the thermostat. I have no issues but burping the cooling system is a messy job and a PITA. I did look at their web site. Thaks for the info. :thumbsup:

puzzle13
01-20-2010, 11:02 PM
The thermostat is used to warm up the engine coolant when cold. When closed it does not allow coolant to go through the radiator and thus it heats up quicker. When the thermostat is open completely it is supposed to divert all water through the radiator to allow for optimal cooling. In the case of the 03 & 04 Cobras when the thermostat is wide open it still allows heated coolant to go back into the engine without cooling and in high heat situations this adds to the heat. The Evans Cooling thermostat is a larger unit that is completely sealed and when fully open it does not allow any heated coolant to pass into the engine.

I always thought the thermostat is used to bypass the radiator so it has a chance to cool the coolant down. When the stat is closed, circulation is completely throught the radiator, when opened, there are two loops but flow is primarily through the bypass hose which is at the bottom of the cross-over tube. The second loop is the path through the radiator but is static due to the bypass from the thermostat. I have no issues but burping the cooling system is a messy job and a PITA. I did look at their web site. Thaks for the info. :thumbsup:

Andy M
01-21-2010, 11:01 PM
I have the complete Evans cooling system on my 03 and it all works great! I run the crap out of my Terminator at road courses doing open track and I never have cooling issues. Evans makes great stuff!! :thumbsup:

ausie
01-22-2010, 01:59 AM
I just don't understand my 03 Cobra, she is as moody as a woman lol j/k.

Anyways, Took my dad for a test run, and of course it overheated again. I have no idea why it is doing it again. Ran fine all winter, all spring and the start of summer. I have had it parked for a month now.

Just curious if you guys have any ideas.

Tommy

Do head gaskets go bad on these 03's very often?
Back to the thread.... I would suggest trying to get trapped air out of the cooling system. However, there were some 03 models that were produced early on that had a casting flaw in one of the heads. To determine if you have the updated heads on your terminator there should be a blue paint dot on the valve cover or head somewhere. I do not remember the specifics and what the build dates that were affected. There is also a cooling mod that can be done at the back of the block (you need to have the transmission and bell housing removed in order to install it ). This mod will allow for a ballance in coolant flow through the heads to prevent hot spots. More than likely it could be related to trapped air, but does not explain why you were fine before and now having issues. You may have a bad thermostat.

tazzracing1
02-02-2010, 08:54 AM
The head problem was with all 03-04 they finally released a head in 05 that addressed this issue, The head cooling issue has beeb around since they started making the 4.6 32 v motor but was made worse by the addition of the supercharger.

ausie
02-19-2010, 12:39 AM
I just don't understand my 03 Cobra, she is as moody as a woman lol j/k.

Anyways, Took my dad for a test run, and of course it overheated again. I have no idea why it is doing it again. Ran fine all winter, all spring and the start of summer. I have had it parked for a month now.

Just curious if you guys have any ideas.

Tommy

Do head gaskets go bad on these 03's very often?
Recap: Air in coolant, bad water pump, thermostat faulty would be the most direct problem to look into. Of course a bad head gasket will also lead to overheating but can be ruled out by testing the cylinders or analyzing the coolant for exhaust gass, oil, fuel elements.

Another issue could be in the tune. Most of the 03/04 cobra's run a bit on the lean side at low RPM range. If your A/F ratios lean out too much or have been affected by CAI or exhaust changes that could cause overheating issues.

I would start with checking the coolant flow. When engine reaches operating temperature from a cold engine state, is the lower section of the radiator on the drivers side cold or hot? (check this with the engine turned off after warming it up). If it is still cold, there could be air trapped in the cooling system. If the radiator heats up uniformly, it could be something else.
If you get a warning light on the dash "Check Engine Light" and if the temp guage is full hot or full cold there could be an issue with the temperature sending unit. If it is overheating where the coolant is dumping out from the plastic expansion tank it could be a bad fill cap or crack in the plastic expansion tank. I had a leaky cap before which did not hold pressure at operating temperature. Also, if overheating the water pump may be the issue or the thermostat. One way to verify if the water pump is working would be to open the port on the crossover tube and crank over the engine but do not allow for it to start. If the pump is working, the coolant will spew out of the crossover tube like a garden hose on full blast. I did this by accident once so it will be messy (not really recommended).

ausie
03-04-2010, 09:14 PM
I do recall writing up something a few years ago. I did find a write up on burping the cooling system done by someone else, so I am not trying to take credit for an excellent write up by another member.