Interesting Cooling Issue :confused: Long... AGAIN!

[SC4LIFE]

Now this has me baffled...

I've replaced my rad thanks to Ryan Harris and the car had been working great for about 2 weeks, then I noticed it started getting a little hot and so I checked for codes and got 118, so I replaced it and it ran fine. Now just a week ago I noticed it started running hot again but it never got to the point where it was critical until last week when the check engine light came on and coolant started bubbling out the overflow tank. While I had the hood up at the time I could hear a slight hissing sound comming from the rad so I tapped the rad cap and the coolant stopped bubbling out and started to suck back into the rad, at this time I squeezed the upper hose and summarized that there was no coolant flowing in it. After about an hour sitting in a parking lot I got her started again and managed to make it home (gently to try keep the temp down) and heard it bubbling again soon as I got home but not to the point where it was boiling out the overflow bottle. Now here's the thing, is it possible that the ECT sensor has gone bad again (I plan only buying the FORD one this time) since I did buy it from CTC and it was PLASTIC as oppposed to the metal one that I had taken out? ALSO!!! a few days ago I let it run and it got hot again, this time the CE light came on and the fan infront the condensor fired up but not the rad fan, but as soon as I tapped the throttle it came on for a about 5 seconds and shut off, I did this a few times and it kept doing it. I decided to hold the throttle down to about 1300 rpms so the fan would turn on, it did, the temps went right down to the N and I then let off, sure enough the fan shut off! I'm lost as to why it does this. When ever I used the code reader to run codes it triggers the relays for the fans, both fans turn on but when the engine gets hot the rad fan won't turn on causing it to overheat?... Any ideas ladies and gents? Rad cap maybe? In any case, I plan to replace both the ECT sensor and rad cap but just wanted to know if anyone may know if it could be something else?!

Cheers,
Luke

[Fordz Coupe]

Luke, I just chased a similar problem in my '94. Changed both temp sensors, 1 by the T/stat (feeds gauge) & 1 on the passenger side (feeds IRCM), no fix.
Low speed fan would only come on if I touched the throttle. My problem was potentially more serious as the pusher fan is inop. Was assuming IRCM going bad.
Turns out swapped in another low speed fan & everything is now normal so fan may be going bad.
Change the Rad Cap & T-Stat asap for cheap insurance, Steve

[Paul93SC]

While I had the hood up at the time I could hear a slight hissing sound comming from the rad so I tapped the rad cap and the coolant stopped bubbling out and started to suck back into the rad, at this time I squeezed the upper hose and summarized that there was no coolant flowing in it.In order for the cooling system to work properly, you need a good rad cap. By your description it sounds like one problem is a weak cap (not building pressure). My suggestion is to get a FORD cap, not a NAPA/PartSource/"what-ever" brand.

Also, keep in mind it takes several days (or more) for all the air pockets to work out of the system, and in the meantime you will experience some pretty wild temp gauge fluctuations.

One other thing I'd like to mention: our lo-speed fan doesn't kick in until 220f. On my gauge this is the "M" in the word "NORM". While it seems like it's on the way to overheating, it's really not.

Re: ECT- ...since I did buy it from CTC and it was PLASTIC as oppposed to the metal one that I had taken out?Again, when it comes to sensors, I would suggest buying the FORD part. These are not hi-cost items and aftermarket stuff is of lower quality. Plastic? ewww... :(

[SC4LIFE]

Thanks Guys, i'm going to go out today and grab a new Rad cap and ECT sensor from Ford. I'll keep an eye on the temp guage and if I feel it is still getting too hot i'll look to replace the fan motor.

Cheers,
Luke