Hello I'm new here so I hope I'm in the right spot.
I've recently taken ownership of a 96 SVT Cobra. Everything is pretty much stock with the exception of some minor suspension upgrades, etc.
I recently had the air conditioner serviced and all was well. Since I'm in Phoenix the temp out here is starting to hit the 110+ range. I was noticing that when the Air conditioner was running the temp was reading abot 2/3 in the normal (right between the M-A in normal). So I figured what the heck and put in a high performance water pump.
Now since the new water pump has been put in things have gone from bad to worse. The temp now steadily runs between the A-L on the NORMAL indicator.
Let me give you the readers digest version of what happened and maybe someone can give me a clue.
I drained the coolant from the radiator, then from the drivers side engine block (removed plug and got a nice coolant bath all over me). I know there is also a plug on the passenger side of the engine block, but I did not remove it. I then removed the waterpump and replaced it with the new one no issues on the install.
I replaced the engine plug, and filled the resevoir. Ran the car to heat it up to engage the thermostat so I could fill more. I let the car heat up and shut it off. It was at this point I learned I needed to remove the crossover plug (on top of the engine) and fill that with coolant (to fill the block I imagine). I did this and heated the car back up. At around mid temp the resevoir began to overflow. I let the excess spill over and waited. I began to think the thermostat may have become defective and I replaced that as well. There are no leaks and everything seems to be functioning; however it is still running hotter then it was before.
Another thing that concerns me is that I seem to have drained more coolant then I was able to put back in. It did take what I was able to drain into a container, but I'm sure I dumped about a gallon's worth that I had the pleasure of soaking up in towels.
So any ideals? I burped the hoses saw no air, top and bottom hose do get hot when running.
It just seems to me that the thermostat is not opening and pulling any fluid from the resevoir. Do I need to take it in and have the good ole machine pump it dry and then re-fill it?
Also is there any way for me to verify that the waterpump is working properly? Again I have no leaks from any hoses or fittings (no fluid anywhere on the ground).
Any help is appreciated.
Thanks

 

wow man sounds like your having fun. hate to ask it sounds like you know what your doing but the thermostat is installed properly right? have you replaced the radiator cap? you said it dumps coolant into the resevior but it doesent suck it back into the engine and radiator. it could be a defective cap. if evrything is new and installed properly thats the only thing i could think of. hope it help and please keep the forum informed on what you do and what happens.

 

My friend just got a 96 Mystic Cobra, and it was reading high as well.We replaced the Tstat and the coolant temp sensor, flushed the rad, and now its good. Try the Coolant temp sensor, or try posting this thread in the 4.6 Modular section.(Sometimes guys who know answers dont come into the General Tech section)

 

Hey man.....98 Cobra....same problem

If we put out heads together on this one we can come up with somthing. I'm getting sick of the "did you wipe your *** after you ****?" responses so let's solve this together.

I have only replaced the thremostat and refilled my system because I knew that the coolant was circulating because the problem only developed with my AC on. is this the case with yours??

It sounds like your high performance water pump is very effective at pumping hot water through the system. I suspect a dirty radiator OR in the case of a website I recently read, a dirty AC/Heating heat exchanger which sits in front of the radiator. I would try the heat exchanger first. Iknow I would if I had a place to do it!

Get back with some updates!!

 

Ok I did install the thermostat properly as far as I know. It only goes in one way and has an o-ring type seal on it. As for the radiator cap no I havent replaced it but the only thing that would do if defective would be to leak pressure or not allow the excess to drain. I havent seen anything to lead me to the cap. I know the 96 cobra seems to have a history of running warmer then most would like. While still in the "Normal" range when you run almost out of that on a pretty consistent basis it makes you feel like at any second something could go wrong. Like I said it ran pretty much in the center of the temp range, unless the AC was running. Even then it would only bump up to about 2/3 of the way. Since I messed with the coolant and pump its just not happy. I'm going to be out of town for the week so I wont get any chance to play with this. I'm going to hit up a few of my buds for some ideals as well. Worse case scenario I'm going to take it to Ford when I get back and let them diagnose the issue for me. I really really dont want to chance overheating and creating more work then I already have. And because anytime I'm doing 90mph theres ALWAYS the temptaion to drop down a gear and let her rip , cooling has to be working 100%.

 

I have a 96 mystic cobra and live in ohio so i havent worried about my cooling too much. Its been high a few times but nothing like what arizona weather will do. Iveread alot about this year4.6 and ford issued a coolant upgrade kit for the 96 cobras. It was supposed to be a better radiator, fan and a/c condenserfrom the 97-98 cobras as this was fixed for those years. I spoke to the tech. department at SVT and thats what they recomended replacing. They also mentioned getting a 180 degree thermostat and having your computer recalibrated for the change since they come with a 195 degree stock. I would just recomend getting a performance radiator and fan setup with the 180 degree thermostat. The SVT tech number is 1800FORDSVT if theres anything else.