Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: tbirdsps on April 01, 2008, 12:34:02 PM

Title: Cooling Problem
Post by: tbirdsps on April 01, 2008, 12:34:02 PM
My daughter's 86 3.8 tbird is acting strange. 

Now that it's running clean and smooth and the thermostat is new the car heats up to almost the red area and then in cools down immediately to mid-range and then repeats.

Almost like the thermostat is cycling open and closed.  It's very strange.  Or, could it be the gage?  I've never seen a car do that.:mad:
Title: Cooling Problem
Post by: cougarXLS on April 01, 2008, 12:56:41 PM
Pull the codes?
Title: Cooling Problem
Post by: Kitz Kat on April 01, 2008, 04:27:21 PM
Radiator full?
Title: Cooling Problem
Post by: Thunderhawk on April 01, 2008, 04:35:33 PM
Could be a bad thermstat, or early signs of water pump going out.
Title: Cooling Problem
Post by: Ductape91 on April 01, 2008, 04:56:35 PM
how old are your hoses?
did you properly relieve air out of the system when you changed the thermostat?
i have to ask, was the thermostat a pos junk "stant" one? :flame:
Title: Cooling Problem
Post by: jcassity on April 01, 2008, 09:23:44 PM
fan clutch
water pump
too high of a temp t-stat (or defective t-stat)

remove the t-stat and drive to see if problem is still there.
Title: Cooling Problem
Post by: tbirdsps on April 02, 2008, 09:08:05 AM
I was thinking all those things.:D I'll have some troubleshooting to do.  I didn't do the tstat myself.  It was changed as part of the emissions repair so I don't know what brand it is.

Thanks all.  I'm leaning towards the tstat and/or the fan clutch.