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Mustang Cobra Member
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Discussion Starter #1
Okay all you techy Mustang Cobra guys, put on your thinking caps.
A few months ago I posted a problem with my 97 Cobra running on the hot side of normal on the temp gauge. It also has a 'CHECK ENGINE' light that comes on for no discernable perticular reason. This Cobra is equipped with a Vortech V-1 supercharger. Short of changing out MAF's, TB's, etc. (all additional hardware) I have been observing and testing situations to see what makes the temps go up. Even with the thermostat removed, the temp goes way up. The radiator fan doesn't come on until the temp is way up.
While I can accept running toward 'H' in bumper-to-bumper traffic on a 90+ degree day, I can't accept the gauge going to the 'L' in 'NORMAL' when the ambient temp is 60 degrees and the A/C is off.
I finally got my hands on a code scanner over the weekend. Along with a few sordid comments about the computer (it is altered with the Vortech chip), the scanner did indicate that the "ECT" (engine coolant temperature) circuit was high, with a value given as 4.75 volts. Technical info extracted from the scanner indicates that normal ECT is in the 0.4 to 0.7 volt range. The scanner also reported that technicians have found poor ground connections for the two smaller ground wires at the battery's negative terminal. I cleaned the terminal connectors, solder the joints and used an electrical joint compound in the bolted joints to the body, all to assure good grounding in this area. The temps still run up and the light still comes on whenever it wants. Based on the 4.75 volt reading I'm leaning toward a bad ground somewhere else in the car, maybe near the computer.
So, before I dig into the right kickpanel, if there is anyone out there who has solved a similar situation and/or can shed some light on a solution, I'd be appreciative.
 

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Did you try posting this over on the Corral.net 's modular forum yet? The guys on that board know their stuff...sorry I can't offer any further help. Goodluck
 

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It might be the thermastate it self or run a ECU dia and see if you get any number. Check the radiater or intercoolers they could be clogged with trash
 

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Mustang Cobra Member
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Discussion Starter #5
Well now, after nearly two and a half years, and a multitude of minor fixes and modifications, I am back (actually just stumble across the old message!) to report that during the winter '03'-'04 standdown I installed a two-core radiator. As of this date I have not taken to the road for a complete full temperature rise test drive. That could come as early as this weekend as all of our snow will have melted and dried off, and the ambient temps are forecast to be in the 60F range.
More later, hopefully in something less than 2&1/2 years!
 

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How did it go? I know that it has been warm in PA recently. Yes i know you got snow just a few weeks back, but hell it should be warm there now. :p
 

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Mustang Cobra Member
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Discussion Starter #7
LunaticSVT said:
How did it go? I know that it has been warm in PA recently. Yes i know you got snow just a few weeks back, but hell it should be warm there now. :p
It went VERY WELL, VERY WELL INDEED! Worth every penny for that radiator.

In the AM with ambient temps at about 55F, the temp gauge kind of jumped (by my previous experience having a modified t-stat installed) to the 'A' and kinda hovered between 'M' and 'A' as the new "180 -degree"(wink-wink) t-stat opened and closed. My fan override was set for much lower (like 'R' to 'M') so it was on continuously, which, when the t-stat opened, made the guage drop like a rock.

On the way home with the ambient temp around 74, with the top down and the A/C on full normal, the temp gauge stuck at 'A' with the fan running continuously.

The 'wink-wink' above is my feeling that the latest 180-degree t-stat I got is really a 195-degree because it was by the same manufacturer, in the same box, and carried the same part number as the replacement I bought from NAPA more than a year ago which was represented as a 195-degree exact replacement for the stock unit. I modified that one by drilling (4) 1/4" holes in the main valve disc to allow some continual bypass flow. This slowed warmup and kept things cooler under mid-ambient, no A/C conditions, but did nothing with high ambients and A/C on.

Ergo, the 2-core radiator. I pronounce the radiator changeout a resounding success.

As for the temp still jumping to 'A' and hanging around there, I blame it on a not-so 180-degree thermostat. Possibly somebody is playing a game with t-stats. I won't name names, now anyway. Doesn't matter as I've got a lead on 160-degree 'certified' t-stats. I know this car runs much better when the temp gauge is hovering around straight up. and that's where it's going to be when I get done. Adjusting the fan override to that is a snap! ANd then watch out for the stampede of Mustang ponies.
In a couple of days I'll know more about the 160-degree t-stat and I'll keep all posted here for my ability to purchase it, and then how it works.
 

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Discussion Starter #9
VENOMUS said:
It went VERY WELL, VERY WELL INDEED! Worth every penny for that radiator.

In the AM with ambient temps at about 55F, the temp gauge kind of jumped (by my previous experience having a modified t-stat installed) to the 'A' and kinda hovered between 'M' and 'A' as the new "180 -degree"(wink-wink) t-stat opened and closed. My fan override was set for much lower (like 'R' to 'M') so it was on continuously, which, when the t-stat opened, made the guage drop like a rock.

On the way home with the ambient temp around 74, with the top down and the A/C on full normal, the temp gauge stuck at 'A' with the fan running continuously.

The 'wink-wink' above is my feeling that the latest 180-degree t-stat I got is really a 195-degree because it was by the same manufacturer, in the same box, and carried the same part number as the replacement I bought from NAPA more than a year ago which was represented as a 195-degree exact replacement for the stock unit. I modified that one by drilling (4) 1/4" holes in the main valve disc to allow some continual bypass flow. This slowed warmup and kept things cooler under mid-ambient, no A/C conditions, but did nothing with high ambients and A/C on.

Ergo, the 2-core radiator. I pronounce the radiator changeout a resounding success.

As for the temp still jumping to 'A' and hanging around there, I blame it on a not-so 180-degree thermostat. Possibly somebody is playing a game with t-stats. I won't name names, now anyway. Doesn't matter as I've got a lead on 160-degree 'certified' t-stats. I know this car runs much better when the temp gauge is hovering around straight up. and that's where it's going to be when I get done. Adjusting the fan override to that is a snap! ANd then watch out for the stampede of Mustang ponies.
In a couple of days I'll know more about the 160-degree t-stat and I'll keep all posted here for my ability to purchase it, and then how it works.
UPDATE TIME!

Okay, the lead on the 160-degree 'certified' t-stat turned out to be a bit bogus because the vendor didn't really have any. But what he reportedly had was a 180-degree, and it was the 2-stage type as comes stock with the Cobra.

When it arrived I stuck it in a pot of hot water with the stock Ford t-stat and the NAPA #109 that NAPA sells as a replacement 192-195 degree t-stat. No doubt about it, the 'certified' 180-degree unit opened before either the stock Ford or its replacement equivalent NAPA #109 were even thinking about opening. I tried to control the water temperature by removing the pot from the heat and by adding crushed ice to lower the water temps just a bit for effect. I was pleased with the results, but the real test was to be in comparison to the t-stat (yet another NAPA #109 peddled as a 180-degree unit by one of the Mustang parts purveyors we may all know!) that was still in the Cobra. I did not mess with pots and hot water. I put the 'certified' 180-degree unit into the car and ran it.

The results: just great! With the cooler ambient temps (50 F) of the A.M. drive-to-work hours, the temp gage moved up quickly and hovered low-to-mid 'M'. With the higher ambient temps of the return trip (85 F) the gage hovered mid-to-high 'M' with or without the A/C on!, at a bumper-to-bumper 20 MPH or at 75+ MPH in the hammer lane. No more 'A' and 'L'!

CONCLUSIONS: 1) the 2-core radiator lowered operating temperatures, period!
2) the fan override can lower those temps even more
3) the 'certified' 180-degree t-stat lowered the mean
operating temperature.

So, if anyone tries to sell you a NAPA #109 t-stat as a 180-degree 2-stage unit for your Cobra, look elsewhere. They are either ignorant of the true properties of the NAPA #109, or they have a bridge they might be willing to sell you too! As an aside, from what I have seen through all of this, it looks to me like the 180-degree stock t-stat for the GT (a 1-stage unit) is the start for the 2-stage unit for the Cobra, with the second stage part simply added. Looks to me like the second stage of a 192-195 degree unit (as in Ford's stock unit for the Cobra) could be extracted from it and plugged into the GT's 180-degree unit to produce a 2-stage 180-degree unit for the Cobra.

As for the 'certified' 180-degree t-stat, I found it on Kenne Bell's website under 'ACCESSORIES' for $8.95 plus S & H. It came in a plastic bag, no manufacture's box. The constructuction and markings are nearly identical to the Ford and NAPA units, right down the lettering fonts and the little numbers and letters up there on the bottom of the expansion chamber. Essentially, there are no distinguishing marks.

No more turning off the A/C when the gage goes beyond the 'L'. No more lost horsepower as was noticable when operating at and above the 'A'. And an overall cooler operating situation all the way around.

Not bad for a 2-1/2 year effort!
Oh yeah, DRIVE COOL!
 
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