Cooling question please help

[94 Eddie Bauer]

I replaced the lower intake gasket on my 94 4.0 last weekend due to a coolant leak. While I was at it I cleaned the MAF, IAC, and throttle body I also replaced the thermostat thinking that it was part of my problem. My temperature guage stays between the M and the A on the highway, and comes back down at slow speeds. I thought that maybe the fan clutch was bad, but it puts out quite a bit of air. Also, it was kind of cool last night, upper 30's so I turned the heater on on my way home from work, and the temp stayed between the N and O (where I think it should run) and when I turn it off, it jumps back up. I am confused, what needs replaced now? Any help would be greatly appriciated.

Also I have no leaks now. And it will only ping when the temp rises to between the M and A (wont do it with the heater on)

 

[94 Eddie Bauer]

13 views and no one has a guess? I would like to get this fixed asap. Please help.

 

[Redrig]

It sounds like you have a defective thermostat, also did you do a flush with new fluid? Thats all I can think of.

 

[94 Eddie Bauer]

Thanks, I will try a new T-stat and flush this weekend. I was just curious if anyone could help me rule out bad radiator, or fan clutch.
I appriciate the reply.

 

[dman726749]

from what i have heard sounds like a bad t-stat

 

[Maniak]

From that symptom, either the t-stat is bad or the radiator is plugged.

If it over heats on the freeway, but not at idle then it is more likely the radiator being plugged/bad. If it was the tstat stuck closed it would overheat at idle too (unless it is stuck partly opened, which isn't too common).

If it was the fan clutch it would get hot as you got onto the freeway, but then would cool off once you were cruising (at say about 50-60mph).

I'd still do the tstat first.. (inexpensive part).. if that doesn't do it, time to look at the radiator...

~Mark

 

[Lee S.]

I could be completely off base here and might even be dreaming this but I seem to remember reading a thread about the importance of positioning your t-stat correctly when installing. Something about lining it up correctly so it points to the 12 o'clock position or something. Like I said I may be off base but it could be that your t-stat is not installed correctly.

Maybe someone else will chime in if I'm incorrect on this.

Lee

 

[Twilightcall]

If it runs warm on the highway and it isn't incorrect ignition timing (too advanced or pinging) then it would probably be in the radiator. When the rad. is bad the temp will slowly climb and climb even when going 70. A rad. shop can rod them out for $50 or so.

 

[Twilightcall]

On the tstat can't you just feel the top rad. hose and if it is flowing it is ok or does it not work like this as in other Fords 302s and the like.

 

[MrShorty]

...If it over heats on the freeway, but not at idle then it is more likely the radiator being plugged/bad. If it was the tstat stuck closed it would overheat at idle too (unless it is stuck partly opened, which isn't too common).

If it was the fan clutch it would get hot as you got onto the freeway, but then would cool off once you were cruising (at say about 50-60mph)...

~Mark

Beg to differ with you on this, Mark. When my fan clutch went bad, it would tend to overheat even on the freeway, most notably when the highway was even slightly climbing.
Fan clutch is pretty easy to test.
1) Remove fan clutch.
2) Release thermostatic spring and rotate 90 CCW (if I remember right). This puts the fan clutch in always "on" mode.
3) Reinstall and see if your overheating problems go away. If yes, then the fan clutch needs to be replaced. If no, then look elsewhere (clogged radiator, etc. which have already been mentioned).

 

[Maniak]

I can't see how a weak fan clutch is going to over heat a vehicle (doesn't mean it can't happen and i've seen many things that just shouldn't happen).

Once your on the freeway, and just cruising 50-60 mph, if your fan clutch if working properly it loosens up and won't pull air anymore. If the radiator is workign correctly, there is more than enough air going through the radiator when your cruising down the freeway to cool.

I did the trick you suggested and that does work to get the fan to start to work, but don't expect it to stay like that.. AFter about 100 miles (all freeway) I had to turn that piece CCW. But that is a good way to test the fan clutch.

It is also possible that the radiator is clogged (externally) to the point where you just can't get enough air flow through it (whether by fan or by forward motion) which could make it overheat.

 

[have2goski]

if you are going to pull that tstat again, try boiling it to make sure it fully opens when it should.

I recently replace the tstat in my sisters old grand prix and when i first install the new tstat it was still heating up. we replaced the water pump telling ourselves, heck the tstat is new and we still aren't getting flow. well that didn't work so we pulled the new tstat out, went and boiled it. it opened fully when it should have and we let it cool then re-boiled a couple times. everything seemed to be working so i re-installed it. over heating problem solved. it seemed like the new tstat just needed to get opened up all the way once before it would work right.

luckily the water pump for her car was cheap (~$16) so we just went with it since the old one had some bearing wear you could feel turning it manually.

the symptoms you are describing seem like there still may be a problem elsewhere, but if you are gonna mess with the Tstat some more, i would suggest bringing out a pot of water and a thermometer and taking the 10 minutes to boil it.

 

[msmith65]

I did this test and found my clutch isn't working well at low speeds.

FYI, if you have a pair of 90-degree bent-nose pliers, you should be able to pluck the coil's end out and turn it without removing the fan clutch first. You will have to move the shroud (two bolts) back to reach the coil.

x-posted

 

[Texan01]

I had the same thing happen to me, running around town it ran cool, get on the highway and it would eventually overheat. replaced the water pump, t-stat, radiator cap, hoses, sending unit for the gauge, fan clutch, put an electric fan on it, you name it I did it.

Turned out to be a 70% clogged radiator, tossed a new on on there and it ran cool as it could be. Radiator shop tried to clean it out but it was too clogged to fool with. The guy even told me that I had the classic symptom of a bad radiator.

Ante up the bucks for a new/used radiator and you'll be running cool again

 

[LStoudenmire]

Lee S. is correct. The hole in the flange of the thermostat must be in the 12 o'clock position.

 

[94 Eddie Bauer]

Wow! This came back from the dead. I never did get the problem fixed, replaced everything including the radiator. I sold the Eddie Bauer and now I have a 96 XLT and it runs cool. I don't know if the people I sold it to fixed it or not, but I will find out soon enough, because I have to repo it today.

 

[emtech708]

I have a 91 XLT 4x4 with the 4.0 and it dopes the same thing, wants to fluxwat on the interstate and at idle, I have replaced the stat, and the radi. no change flush the heater core out, and installed a electric fan. You only need a fan when driveing slow or stopped, not once you start driving down the road over 30 mph, I still need assistance with mine expl