Ok i am at the point where I want to just get rid of my truck. I've had this same dam problem for a year now and no fix has been helpfull at all. It all started when I had those 10 min. oil change places flush my system. A few weeks later I noticed that the temp guage would never rise properly then my truck would over heat. If I turned the motor off, i'de hear a pop sometimes and the coolant would go down and I'de have heat. Mechanic flushed the system again, replaced tstat, cleaned out radiator to no avail. Took it to ford, cause mechanic said it could be headgasket. Ford replaces the waterpump, kinda helped but still had problem, just not as often. Then the spring and summer come, NO PROBLEMS AT ALL. Not once did I ever had a problem. Untill, the first cold day 2 weeks ago. Driving to work, hit every red light, temp never would go up. Give it gas, go up. hit red light, temp go down. Eventually it would goto normal and I'de have heat. Then on last thursday, im reving the engine from the tb and notice the resevoir starts to rise. To the point of overflow. I shut off the engine and hear the coolant rush back. I start the truck and drive to my mechanic. I tell him whats going on again. At first he and another guy said it could be the blend door actuator since sometimes the temp would be normal but I'de have no heat. But then when I leave it overheats, take it back. Says it has to be the tstat again.
Now, monday have it flushed, new tstat, synthetic ford coolant added. Seemed to help, heat seemed to be hotter, no problems till yesterday night. Temp took longer to warm up, and had barely any heat. Tonight, no problems after work. Nothing till i decided to go out. Drive around for a bit, temp was not at cold after sitting. Started to warm up, then i started to loose my heat but not to the point of cold. Kinda cool, had to keep it revved at around 1500rpms to get it hot again. The whole time the temp guage is at normal. This happened twice. The second time it kinda was luke warm. The heat very gradually came back and stayed. I've run out of idea's, options and money.

What the hell is wrong with my truck?

 

Shoot it and put it out of its misery. JUst kidding sorry no idea im in here trying to find my own heating problems.

 

Hi 97flairside,

Seems like you have an electrical bypass device incorporated in the cooling system somewhere that is not activated by how warm is outside and is by the coolness!
On the same note:
Is this happening when you are demanding heat and flipping on the switch?
Electrical Diagnostics can be a real pain in the nads!
I know what it's like troubleshooting problems!
________________________________________________
‘90 Ranger XLT: 2.3L, EEC-IV, EFI, DIS, 2wd, Mazda 5sp

 

the problem im having has nothing to do with the electronics. Its the cooling system itself. I developed the problem i've been having for the last year again. truck overheats only in the cold fall and winter months. Thats when i loose heat.

 

Didja check the heater core? Sometimes they can get plugged up and cause problems similar to the ones you are experiencing. It's a simple job on an '87, don't know about a '97 though.

 

the 2 things people are saying are the heater core or headgasket. How can I check the heater core?

 

Just my 2 cents..seems to me a bad head gasket is pressurizing the cooling system. Im not sure, but it may slow down or increase the flow of the coolant...buddy of mine had that problem on his escort, and his radiator hose blew right up and puked all over....have a leak down done and get rid of your headaches.....later

 

after your truck has warmed up, feel the heater hoses going into the firewall...they both should be hot..one going in..and one coming out...if they arent both hot,,,your heater core is plugged or bad...take it out(after it cools)and try flushing it out....later

 

both the inlet and outlet hoses are hot. I've checked those before.

Whats a leakdown test? How does it work?

 

http://web.ask.com/redir?bpg=http%3a...akdown.htm&o=0

 

click on "ask" then the vfaq one. check your rad cap too. if its not holding pressure, your coolant will puke into your resevior, then you have air in your system..........later

 

I asked my friend who just graduated tech school about the test. Sounds complicated on these modular engines.

I originally thougt it was the pressure cap. I replaced it once and it went away then it came back. Replaced it again and it went away for 5 months.

 

Is it possible when they did the 10 minute oil and flush job they disconnected the heater hoses and switched them when they went back on? Maybe theres some crud in the core that with normal flow is ok but since the flow is reversed it intermittently blocks flow when you put the heater on in cool months?
Just grasping at straws but I've wondered before if it was possible.

 

what do you mean put hoses on wrong? I've since had my hoses replaced so thats out of the question. I also think ford would've seen that when they did the waterpump.

 

I just mean putting what was the inlet hose to the heater core on the outlet instead. It would put the flow through the core backwards to what it was originally. Might have dislodged some debris inside the core, if it was old.