Bizarre '94 T-Bird 4.6L temp problems

[Darkwriter77]

Sooooo, the TurdBird is being ... well, a turd, lately. Ever since I bought the thing, it's had a tendency to run a little warm for my liking, especially any time I run the A/C (which I just charged and is holding up just great). After swapping in a 180* T-stat (drilled 1/8" hole to bleed out air pockets) and fabricating an air dam for it, both which helped significantly, now it has a tendency to run either wayyyyy cool or wayyyyy hot - usually the former, for the first 10 minutes, and the latter for the rest of the time.

Today, I darn near overheated the sucker in the same traffic conditions, same temps that I've been driving in for the past few weeks. Ambient temps were 110+*, smooth-flowing traffic (around 45 MPH consistent), and the A/C rockin' = 4/5 of the way towards the evil "H" on the right of the gauge. I get it out on the Loop 202 and cruise up to 70 MPH, roll down the windows, crank the heat full blast (sort of using the heater core as an auxillary cooler), and the temp drops back down to the middle where it should be, although still a hair warmer than where it should be. I get off the 202 and onto Roosevelt about 15 minutes later, and within three blocks (WITHOUT the A/C going) the temp shoots back up to where it was, wayyyyy too close to overheating for my comfort.

Here's what's weird. The fan's blowing just fine. There isn't a leak anywhere to be found anywhere at all (not even a hint of coolant smell anywhere underhood), no white smoke, no coolant in the oil or vice-versa, and the coolant level is staying steady. WTF? As hot as the temp gauge was reading, I expected to see/hear the thing boiling over, but there was no such craziness going on underhood. No telltale signs of leakage under the water pump or anywhere else on the front/side/top/back of the motor, the coolant level has remained steadfast for the past couple weeks (and so has the oil), and gas mileage has been pretty good at 25 MPG average mostly highway with the A/C running.

Only theories I have so far:
- Radiator is plugged up with sediment and not working efficiently enough at low speeds;
- Defective thermostat;
- The fan might be a designed to run at two speeds, and it's only running at the lower speed due to a faulty relay or coolant temp switch (although it does certainly seem to be putting out plenty of air);
- Temperature sending unit is totally exaggerating how cool or hot it is at any given time (although it does seem to give consistent readings as per driving conditions, strangely).

Any other suggestions/ideas? I was already considering ditching this car beforehand, but if I can't solve this little riddle, I'm just gonna sell the thing for a different DD and let it become someone else's headache pretty soon...

 

[timeless2]

My thoughts (before reading your suppositions).....

Blockage somewhere (coupled with poor coolant mixture).
Sending unit and/or associated wiring to and from the gauge. Those things never were all that accurate.
How are the radiator fins (clean, laden with dirt--given your location)?

 

[Gearbanger 101]

May sound like a stupid question, but are you sure you put the thermostat in the right way up? Putting it in upside down will certainly throw a wrench into the mix. You also may want to have the system pressure tested. It could be the beginnings of a bad head gasket. Even if you're not noticing a significant drop in coolant, it may be enough to create hot spots on the engine.

There's also a cooling mod that can be performed to the rear of the drivers side head if you feel like doing it. It really helps out with hot spots in the back of the head where the coolant isn't able to freely flow through. If you’re unfamiliar with the mod, let me know and I’ll dig up a link.

 

[Darkwriter77]

Well, I'm totally positive the T-stat is in the correct way - spring side goes down, as the thermostat housing really isn't deep enough to allow you to put it in backwards. I'm still kinda suspecting that the T-stat might just be defective, though, because it worked perfectly well for at least a couple of weeks after I first installed it; now, it's almost acting like the thing is stuck open or closed (or maybe halfway?).

The internal blockage idea is kinda scary. I dunno what the prior owner might've dumped in there at some previous point to band-aid a minor leak, and it might've collected in a spot and formed a blocking booger somewhere. If that's the case ... ugh.

Didn't think to look to see if maybe the radiator fins are clogged with crap. I guess I could crawl under there and see if there's a bunch of road gunk gathered between the A/C condenser and the radiator (leaves, tumbleweeds, small animals, etc.).

The more this thing starts to look like a major expense, the more I'm inclined to just bail on it, post it on Craigslist, and let it be someone else's headache. I'm too broke to afford even a pair of head gaskets, let alone the headache of changing one or two of those out on an OHC motor...

 

[Darkwriter77]

Okay, so after farting around with it for about an hour or so, today, I've found the following:

1. A rather mild but not unusual collection of bugs, dead plant life, and (now THIS is weird) animal hair gathered in the front part of the radiator between it and the A/C condenser, but hardly anything on the A/C condensor, itself ... like it magically passes through that thing and sticks into the radiator. Weird. Gonna blow out the crap that I can tomorrow morning and see if that helps at all;
2. The fan works just fine. I've verified through TCCOA.com posts that it does, in fact, have two speeds, but I can't really tell if mine is kicking into high speed or not. It doesn't SOUND or FEEL any different, really, as far as I can tell - might have to have someone switch on the A/C while I'm standing by it to see if I can feel a difference then. It runs from a cold start at idle, and it seems to run the same with the A/C switched on (it's to my understanding that A/C on = high speed). It's not some insane amount of air output coming from the thing, of course, but I haven't felt anything other than a Mark VIII fan or aftermarket unit ever really put out a LOT of air from an electric fan, so I dunno... ;
3. There's not a single white stain, funky smell of coolant leakage, wet spot, or loss of coolant anywhere to be found underhood, still;
4. As hot as it claims to be getting, two things are weird about it: A. The coolant never boils, and B. The "Check Gauges" light never comes on, which it SHOULD do whenever temps rise above the 3/4 point. Again, I suspect a bad sending unit ... but it's weird that getting it on the highway and cranking the heat brings the temp level down, but driving in city traffic makes it heat up in a jiffy.

So, assuming that the sensors are good, I'm still not sure what to think of the deal. I mean, since highway speeds seem to result in better cooling, then that tells me the radiator is doing its job, which should mean that the radiator fan is shot, right? When I blew a fuse to the electric fan on my Fox, it acted the same way - cool/normal on the highway, but hot in city traffic. BUT ... in this instance, the fan does appear to be working just fine. Soooooo ... WTF?

So, to recap, here's the weird points that stick out:
1. Runs VERY cool for the first 10 to 15 minutes, heats up gradually. Runs normal to slightly above normal on highway (mostly warmer after it's already been getting hot), but gets WAY hot in city traffic.
2. Having the A/C off does not help.
3. Fan works, thermostat is new, no fuses blown.
4. No loss of coolant, anywhere.
4. Coolant never boils, "Check Gauges" or "Check Engine" lights never come on.

 

[timeless2]

How's the water pump doing? Any bearing noise, belt slippage (sorry, assuming the Bird uses a serpentine driven pump here)? Check the belt for scoring (visual inspection). Another thing to do would be to remove the serpentine and manually turn the pulley to see if there is resistance or play in the impeller's driveshaft.

 

[Darkwriter77]

Hmmm ... didn't think to try it that way, but it does make sense. I always just figured the water pump's only telltale sign was when it starts seeping coolant from one of those little holes over or under the middle. Might be clogged up with stuff, I dunno. Gonna try giving it a hand-spin when I flush out the leaves n' crap, soon, and see if that reveals anything.

I do notice a weird squeaking/squalling noise coming from the front-end, but it sounds more like it's coming from the electric fan. I kinda wonder if perhaps the bearings to that are going bad, but it seems to turn freely enough by hand, sooooo ...

 

[timeless2]

How did the pump feel?

 

[Darkwriter77]

Just got done cleaning the radiator just now. Oh ... my ... GAWD. I swear, there was so much hair on the front of the thing, it looked like someone had shaved Chewbacca from head to toe, swept the hair up into a pile, and driven my car right through it. This is just what I pulled out of the Shop-Van hose, as it was so thick that it clogged the thing. I had to put the opposite end of the hose on the blower side of the vacuum to dislodge it from within the hose, and THIS thing came shooting out across the driveway...

View attachment 377703

Now, picture a whole layer of that about 1/4" thick spread out the entire lower 3/4 of the radiator (the part I couldn't readily see from above until I loosened the thing from its mounts and pushed it back). I dunno if this will cure my problems, but it sure as hell won't hurt to no longer be carrying half of a Wookie on the front of my car!

(Just for good measure, I did check the pump. Spins perfectly free and fine by hand. Ditto for the electric fan motor, doesn't feel like it's binding up or squeaking at all - maybe the squeaking is coming from the A/C compressor, as it sounds to be from that general area down there...)

 

[Darkwriter77]

UPDATE: Removing Chewbacca from my radiator helped only marginally. Still gets too hot for comfort in city traffic. But get this - put 'er on the highway, and with or without the A/C on, it runs perfectly normal temps. Pull off to a sidestreet, and POOF! The temps magickally roll back up to 3/4 or more.

Sooooo ... I'm thinking the ECT sensor isn't working, as it's not telling the ECM to kick the fan onto its high speed (which would explain why it gets cool on the highway but not at low speeds), not triggering the "Check Gauges" idiot light, and not shutting off the A/C. However, it still doesn't explain why the coolant isn't boiling over ... not that I WANT it to, of course. Maybe I've just got some damned good antifreeze in there...?

BAH! Poop on it all. It goes up for sale as soon as I pull my stereo junk outta there (probably tomorrow)...

 

[timeless2]

Dang, that's one nasty hairball!

 

[Darkwriter77]

If I had taken the time completely remove the radiator from the car, the hair would have likely come off in one solid sheet, like lint from a clothes dryer screen. Naaaaastyyyyyy.

I still don't have a clue what animal these hairs come from. They look ... almost ... human...

 

[Darkwriter77]

UPDATE: Bought an ECT sensor today at Autozone. Haven't put it in yet, but now suddenly I notice that my radiator fan isn't kicking on AT ALL. Sooooo, either I have both the high- and a low-speed relays crapped out on me, or my radiator motor was somehow gradually failing on me. I'm going to run direct 12v power to it tomorrow morning and see if it kicks on at all to rule out the motor - it still turns freely by hand, so I dunno. I'm just afraid it might be that super-expensive relay behind the passenger-side headlight ... although I doubt that, seeing as it controls the A/C, also, and that works just fine, so far.

 

[cjones]

the CCRM has several relays in it. one going out normally won't bother the others.

does your fan come on when the A/C compressor is engaged??

 

[Darkwriter77]

Strangely, it used to about a week ago ... and now it doesn't come on with the A/C on or off.

Sticky relay, I guess? I dunno. Again, gonna hafta see if the motor, itself, is okay first. If it is, that'll be a huge relief, and I'll just pick up a relay or two to see if that does the trick. I haven't ruled out the ECT sensor entirely as being an issue in the matter, being that it never tripped the "Check Gauges" light, nor did it shut off the A/C when it got hot. Hell, maybe it's ALL bad? Bah, screw it! Replace everything!

I'm at a point right now where I get to decide whether to just say, "Screw it, let someone else deal with this," and add it to the short "things that need to be fixed" list on a for-sale ad, or just say, "Screw it, what's the use," and just fix what needs fixin', keep the damned thing, and find some other way to trim my monthly expenses other than gas mileage...

 

[cjones]

after you check the fan...

make sure you have power on the BK/O (Pins 3 & 4) wire on the CCRM.

with A/C on check for power at the BR/O wire (Pins 6 & 7).

also, if you say "Screw it, let someone else deal with this," and you can come out to Avondale during the week, WE can take a look at it.

 

[Darkwriter77]

ANOTHER UPDATE: Okay, so I've verified with a multimeter that I've been getting sufficient power TO the fan, so the relays are working. The temp sensor (ECT) is apparently still kosher, because there's no trouble codes (a failed ECT will trip the CEL and tell the fan to go to high speed at all times). Here's where the silliness begins.

I ran direct power to the fan. There's three terminals - a ground, a high-speed, and a low-speed. From ground to low-speed, I get nuttin'; from ground to high-speed, I get somethin', but not a lot. I plug the sucker back in, turn on the motor and switch on the A/C. No spinning fan. BUT ... if I give the fan a nudge at that point, it WILL spin ... but very slowly. Sooooo ... time for a new fan motor, right?

I march my happy arse downtown to the hub store of Autozone, blow $106 or so on a motor, three bolts, lock nuts/washers, and two jugs o' antifreeze (since I have to disconnect the top radiator hose to pull the fan shroud assembly out, and everything comes gushing out like mad). I grind/drill the rivets out of the old motor, bolt up the new one, and plug 'er in. Everything seems good n' happy, right? I crank the motor, switch on the A/C, and lo and behold, the fan does spin on high speed ... BUT ... with the addition of a horrible KKKRRRRRRRKKRKKKK!! sound as the fan proceeds to try to destroy the shroud.

This is funked up. The thing spins perfectly freely by hand when it's not mounted, but when it's bolted into place, it hits the shroud on a spot or two and puts a little damper on the motor's abilities (and makes a horrible noise, to boot). I'm sure this probably helped kill the original fan motor off, as well. Sooooo, I'm guessing I just need to figure out exactly where it's rubbing, get crazy on it with a grinder, and hope that nothing else fails anytime thereafter, because I'm completely friggin' tapped out of money, now... ...but at least I'm certain that this stupid thing will run cooler, now.

And, being that I've crossed the line between breaking even and taking a loss on the thing by selling it, I've decided to keep the TurdBird. That, and after just one day of going back to driving in 111* degree heat in downtown Phoenix on a Monsoon-season summer day, I can no longer lie to myself about the fact that A/C is a beautiful, beautiful thing when you've got it ... so why give it up?

Many, many thanks for the advice, guys.

 

[timeless2]

Glad you have eventually come to a solution.





Thanks to all that have participated in this thread and this forum.

 

[FrankenStang]

ANOTHER UPDATE: Okay, so I've verified with a multimeter that I've been getting sufficient power TO the fan, so the relays are working. The temp sensor (ECT) is apparently still kosher, because there's no trouble codes (a failed ECT will trip the CEL and tell the fan to go to high speed at all times). Here's where the silliness begins.

I ran direct power to the fan. There's three terminals - a ground, a high-speed, and a low-speed. From ground to low-speed, I get nuttin'; from ground to high-speed, I get somethin', but not a lot. I plug the sucker back in, turn on the motor and switch on the A/C. No spinning fan. BUT ... if I give the fan a nudge at that point, it WILL spin ... but very slowly. Sooooo ... time for a new fan motor, right?

I march my happy arse downtown to the hub store of Autozone, blow $106 or so on a motor, three bolts, lock nuts/washers, and two jugs o' antifreeze (since I have to disconnect the top radiator hose to pull the fan shroud assembly out, and everything comes gushing out like mad). I grind/drill the rivets out of the old motor, bolt up the new one, and plug 'er in. Everything seems good n' happy, right? I crank the motor, switch on the A/C, and lo and behold, the fan does spin on high speed ... BUT ... with the addition of a horrible KKKRRRRRRRKKRKKKK!! sound as the fan proceeds to try to destroy the shroud.

This is funked up. The thing spins perfectly freely by hand when it's not mounted, but when it's bolted into place, it hits the shroud on a spot or two and puts a little damper on the motor's abilities (and makes a horrible noise, to boot). I'm sure this probably helped kill the original fan motor off, as well. Sooooo, I'm guessing I just need to figure out exactly where it's rubbing, get crazy on it with a grinder, and hope that nothing else fails anytime thereafter, because I'm completely friggin' tapped out of money, now... ...but at least I'm certain that this stupid thing will run cooler, now.

And, being that I've crossed the line between breaking even and taking a loss on the thing by selling it, I've decided to keep the TurdBird. That, and after just one day of going back to driving in 111* degree heat in downtown Phoenix on a Monsoon-season summer day, I can no longer lie to myself about the fact that A/C is a beautiful, beautiful thing when you've got it ... so why give it up?

Many, many thanks for the advice, guys.

Now you understand why I'm so reluctant to sell my '04.

 

[Darkwriter77]

Sorta ... but then again, I don't dish out $500 a month for the luxury of A/C.