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View Full Version : Alright. Big Question on Cooling System.


Z_Drifter_87
01-26-2009, 06:00 PM
First of all, I have a 97 Cobra Convertible. I drive for a while and the water temp likes to stay on the M in NORMAL while i'm driving 45mph plus. when i'm at idle, it gets on the A in NORMAL. Now i already flushed out the system and removed the thermostat and running two gallons of antifreeze and the rest water. Now i dont know if there is air in the system and not finding the bleed valve or something or if my water pump is going out. Now it it helps, when i remove the cap from the resovoir, there is alot of pressure let out When the car is cold. So any help??? Thanks

ca01cobra
01-27-2009, 03:45 AM
It sounds like there may be air in the cooling system. On my '01, the water temp sending unit is located in the coolant pipe assembly on top of the motor, near the alternator. I would think the air would accumulate near the top of the closed system, and that may lead to higher temper readings.

Probably best to put a new thermostat back in and refill everything. Then run the car through a few heat cycles, and check the water level each time when the motor is cold. Also, run the heater as well, maybe some air is trapped in the heater core. The cooling system may need to 'burp' out the air.

Larry95
01-27-2009, 10:35 AM
I have some experience on the '94/'95s with temp gauge issues. Don't know if the later models are the same. First the FCM (fan control module) could be the problem. It controls the two speed fan, and if it doesn't go into high speed then you can have the problem like you have. Also, the factory temp gauge is next to useless. It is not accurate at all. I had a GT that stayed on the high side of the normal and after replacing the gauge it never left the low side ever again.

pacificgreensvt
01-27-2009, 01:32 PM
Take the plug out of your coolant cross over tube, let it run for a while, let it get hot, its that easy, it should burp its self, Your owners manual should have the step by step directions. One time I left the plug out over night & the bubble worked its way to the top on its own. OR you could have a bad switch are your fans comming on?

VenomSVT
01-28-2009, 01:00 AM
I would definately check the crossover tube and make sure it is full. If it is empty (air bubble) the coolant system will not circulate.

Z_Drifter_87
01-28-2009, 01:02 PM
Well thanks for all your advice. As far as the fans turning on, yes but only the high speed because i had to bypass it with a relay cause i think the controller went out. also as far as the crossover tube, on the plug, the fitting fo the 1/4 in drive is stripped and is very hard for me to take off. i have to use a monkey wrench. i've tried to go to the dealer and order it but they said that they dont make them anymore, "discontinued" was the word, just my luck. So i'll try the burp thing and new thermostat thing. thanks. will update when i'm done. thanks again:)

VenomSVT
01-28-2009, 07:01 PM
Expensive but here's where you can buy a plug for the crossover tube.:thumbsup:

http://www.latemodelrestoration.com/iwwida.pvx?;item?item_no=LRS-8500AA%20%20%20%20%201&comp=LRS

brkntrxn
01-29-2009, 01:06 PM
Just use a pipe plug. You don't have to replace it with the stock big, flat top looking plug.

puzzle13
01-29-2009, 07:25 PM
You can buy a very nice plug at most high performance parts places and they even come in colors. Won't be the exact same, but all you need is the same threading. Once you get this open, use a funnel turned into the crossover opening with some water in it. You need to run the engine until the thermostat opens and then as it runs the bubbles will come out. Keep some water in the funnel at all times! When you open the crossover tube it will be empty! Usually these years are very easy to do ... the 03 & 04's are really a lot harder. Using distilled water instead of tap water will also lower the temps a few degrees!

brkntrxn
01-30-2009, 11:59 AM
You can buy a very nice plug at most high performance parts places and they even come in colors. Won't be the exact same, but all you need is the same threading. Once you get this open, use a funnel turned into the crossover opening with some water in it. You need to run the engine until the thermostat opens and then as it runs the bubbles will come out. Keep some water in the funnel at all times! When you open the crossover tube it will be empty! Usually these years are very easy to do ... the 03 & 04's are really a lot harder. Using distilled water instead of tap water will also lower the temps a few degrees!

Yep, I generally drive the front tires up on a couple of boards or I jack up the front end. That will ensure that the crossover pipe is the highest point in the system. In addition to what Michael said, fill the system via the overflow/degass bottle until it is half full. Then close that off and continue filling the system from the crossover plug. Once full, run the engine with the heater on until up to operating temp. Let it cool, fill it again and heat cycle it again. Cap it off, run it for a day and check it again. You will be amazed at the air bubbles that will sometimes be found in the DOHC cooling system.

I run distilled water, water wetter and just enough antifreeze to make me comfortable that it won't freeze.

Kevin

Z_Drifter_87
02-05-2009, 03:24 PM
Thanks guys, problem solved. There was some air in the system and needed a new radiator cap. Thanks alot. :D