Still running hot

[architecthec]

Hey guys,
I thought my over heating problems were solved when I changed the thermostat (195*) last weekend. Temp gauge has been staying about mid range until I got on the freeway yesterday and the needle got on the L in NORMAL again. When I got off the freeway and stopped at a traffic light the gauge went back to mid range. Go figure, now it heats up at high speed and cools down while waiting on a light. I bled the air at the bypass tube until it no longer needed water and checked it again after it ran hot.
I think I hear the water pump making some noise, but nothing big. Just a slight little raw grinding noise but it could be coming from something other than the water pump. I'm suspicious of the fan as well. It does not come on until needle is on the M or a little past the M.
Any and all help is appreciated.
Thanks,
Hec

 

[thomas91169]

sounds normal to me. needle should be in the 12 to 1 oclock position during operation.

 

[Twistedoffpurp]

I'd say that either the t-stat is not operating properly or it could be the pump on it's way out.

 

[architecthec]

Thanks.
I'll just keep an eye on the temp and see waht happens.
I've had a few 289's and 302's but this is my first 4.6.
What is the deal with "getting a tune"? Do you have to buy a $300 tuner and then figure out how to use it? The Cobra I bought does not have a lot of mods but the guy I bought it from said it could use a "tune" and suggested a Diablo.

 

[Kilgore Trout]

What is the deal with "getting a tune"? Do you have to buy a $300 tuner and then figure out how to use it? The Cobra I bought does not have a lot of mods but the guy I bought it from said it could use a "tune" and suggested a Diablo.

Well, you can have a professional tuner hook your car up to a computer dyno with a wideband air to fuel ratio meter and tune your car to operate optimally throughout the entire power band.

Or you can order a Diablo Predator/SCT XCal and connect it to the ODBII port and load up a pre-made tune yourself.

Obviously a real dyno tune is going to be better than a best guess tune from Diablo or SCT.

However, with the Diablo or SCT you can also read trouble codes, datalog, monitor engine parameters, and if you have an automatic transmission you can manipulate and monitor it as well.

 

[architecthec]

Kilgore Trout,
Thanks for info. There is a shop in the Austin area that will do a TUNE for $75.00 /hour. Since I do not plan to do any mods am I safe in thinking I will not need another tune. If so, sims like taking it to the shop is more cost effective.
Thanks for the help,
Hec

 

[SVT32VDOHC]

My 96 Cobra always ran in the L in NORMAL. It did this before the supecharger. During the install of the Vortec supercharger, I also installed a custom built 3 core aluminum radiator. Cost me 330 dollars, but it was the best modification I have ever done. My car stays at the N or O while normal driving. If I get on it a bit here and there it only gets to the R. And that is on hot days too..80-95* days...thats hot for Michigan.

 

[architecthec]

Thanks to everyone for the input.
I am leaning towards replacing the waterpump. $50 for a new (not rebuilt) one from O'Reilly AP and it looks fairly easy to get to.
BTW I rounded out the 1/4" square inset on the by-pass tube plug. The Ford dealer says no one makes a replacement. I was thinking of welding a nut to the top of the plug. I had to use vice grips to get the plug off and on last time.

SVT32VDOHC,That is an awesome looking engine.

Thanks again.

 

[architecthec]

Overheating problem solved

I replced the thermostat one more time. This time with a Motorcraft and I followed the refill instructions in the Cobra owners manual. I also rocked the car to help get the air out of the by-pass tube. The car runs around the O and R in NORMAL. Anybody know how the letters correspond to degrees? I fugure A is around 195*. What would the temp be with the needle on the right side of the L?
Thanks to all for the help

 

[hotpony]

That's probably about 225-230 degrees or so. My Cobra was having some issues with overheating and so we put an Evans waterpump in, Steeda 4 core and with the Superchips 1725 tuner we set the fan to come on at 180 degrees. It does heat up a tiny bit going up hills about 90 (pretty steep here in Hawaii) but not much, maybe runs about 180-190 all the time. I guess it's pretty hereditary with these 4V's, I'm guessing it's in the cooling system design. Only thing you can do is replace the components, such as the radiator/water pump to higher volumes and get a chip to turn the fan on sooner.

Good luck