I've been pondering this question for some years, and never really asked.

I have a '92, F-150, I-6 300, with 114,000 miles....
Where does your temp Gauge needle run about in "NORMAL" while driving between 60 and 70 mph with A/C on and Ambient air temp around 80-95 F?

I have replaced water pump, clutch fan, thermostat, rad. hoses, had A/C checked and charged. When I run the A/C either normal or recycled, I always watch the needle move into the "L" of NORMAL. I cannot remember what it used to run @ before I had numerous problems with the temp problem. But it all started about 3 years ago with the Fender mounted relay and has been borderline negotiable ever since. Also have checked Coolant mix and is at least 50/50 or 40/60 (coolant/water) mix, The only thing I can remember is that I after changing the water pump, I can remember the needle would go up and then down really fast, after the t-stat opened, and it was all cool then, but it never really does that anymore.

Another thing I remember is that after a cold winter morning, COLD! -25 below wiht wind chill, I said ok, cool, lets put a piece of cardbord in front of the rad, which I did and helpedout great, but one day after thing had warmed up and it was pushing 45-50 outside, I hard squalling form the fron with increased speed, 1st time and I nodded, 2nd time it did it later, I quickly turned off the truck, and inspected everything and just pulled the cardboard for safe measure and it never did it again.

I have also replaced everything with Ford parts, except the Fan clutch, which is Hayden, but I can also spin it freely, it does have a bit of friction behind it, but spins easier than I believe it should when hot, but I cannot tell if it's locking up when it reaches 170 F. It's a lot harder to spin when it's cold, which is normal. I have digital temp gauges also installed and when it's @ the "L" in NORMAL, it's about 225 F.

Any thoughts? Maybe I messed up the bearing in the water pump housing, but both the upper rad and lower rad are hot, with the upper being hotter, so I feel comfortable there since even when I change the coolant, I can see flow.

Thanks again for looking! Any thougths and ideas are welcome!

 

When I run the a/c in my '88 it seems like it gets up to the "M". That always catches my attention as she normally runs at or below the "N". I know my system is in perfect running condition so i just watch and keep on going.

Sounds to me as though you've done about all you can do. Are you using a 180 degree thermostat?

Tim

 

Did you flush out the engine and radiator when you put in the new pump and tstat?

 

Hey, thanks for the replies guys.

Yes, I did flush the system and have 2 twice since then. I know that there is an electrical problem sometime with the gauges sicne whenever I put the system under heavy electric load, the gauges actually go up, so I give myself some credit knowing that it isn't entirely pushing over the "L" in NORMAL. But I am wondering if it isn't maybe the aftermarket fan clutch and pondering on buying a new one, since I have heard that sometimes they really don't do as well as OEM. (On here, I have heard that). I have a new pump, 2-row rad, new hoses, new belt, I even installed 2 electric fans in front from a wrecked taurus. I checked the mix, 50/50, or leaner.

The t-stat is 192F, and that's from the factory, and had the shop check it as well. Only when I run the A/C does the system seem to completely go past the "M", and whenever I shut it back off, it dips back down to say under the "M".

I'm gonna have the parts have order me the ford fan, and go from there.

I wonder if changing the fan with spacing further out from mounting holes..well thats getting complicated..LOL

Well, if you guys have any other ideas, Id love to hear them.

Thanks again for the replies!

 

The t-stat should be fine, that's right where you want the motor to be so the computer entered closed-loop.

Are the efans and clutch fan fighting each other? The clutch driven fan or the efan (look for Skandocious' efan convert for info) should be more than enough on their own to cool that engine if they're properly shrouded. The fan shroud makes a huge difference, is yours on and intact?

The factory senders are...ehhhh...at best. I'd consider running an aftermarket temperature gauge at least temporarily so you can get the real numbers. There is a chance that your factory temp sensor is crap and you're not really "overheating" at all.

 

When you put your AC on, where's the heat load of the AC system going? Right in front of your radiator, so in effect that makes the radiator less efficent and makes it warmer than if you did not run the AC.

A lesson I just learned about today as a few of the company trucks are overheating just like yours. Had the same things flushed/replace too. Make sure your shouds are correctly in place and condenser of the AC is not plugged up with bugs and ect. A little than normal temp rise is OK with AC on, but should not overheat.

 

More replies, thanks again. I have tried with the just the Engine fan, and it is shrouded. Replaced it with a new one 2 years ago, that was torn up. I've also tried with the e-fans, but they only help when the engine @ idle in traffic, or hauling and towing at slow to idle speed. The condenser is clean as the rad is too. I keep them clean in the effect of trying to figure out the problem. Also there is a digital gauge for the water temp and when at 70 mph and A/C and ambient air temp, the elec. shows about 225-230 temp and the "L" on the OEM temp gauge.

if the weather holds out, I will look into other possible problems tomorrow.

Thanks again.

 

It appears to me that your radiator has marginal cooling capacity if it cant keep up with the extra cooling needed when the AC is on. Sometimes a flush just won't do it and a new radiator is your next step.

 

Mine operates at about between the N and the O on the normal range when fully warmed up regardless of outside temperature and if the AC is on. The only time it seems to ever go up is sitting in traffic when its 100 degrees outside. Even then it only goes up about 1-2 needle widths or to about the O.

 

i have a 90 with the straight 6 and here, in arizona with temps in the 100,s plus it will read mid point or a little lower when cruzing, when stopped at a light it miight go a little above mid.

 

I believe he said the radiator has already been replaced. Not to ask a stupid question, but I am assuming you changed the cap when you changed the radiator, right? I had an old Dakota that I chased a coolant problem around for weeks, swapped the rad cap, and problem solved. FWIW, my temp gauge creeps up to about 1/3 until the t-stat opens, then it drops to about 1/4, doesn't seem to matter whether it's hot or cold, empty or loaded, that's where it stays.

 

The Ford gauges are pretty unreliable. If you really want to know what your coolant temp is, install a real gauge. The Ford one is a guide at best.

 

I agree. I've changed out the gauges when I installed the cluster with tach on both my '95 and my '86 and both times the needle was on a different letter in "NORMAL"

 

Hello to everyone who viewed and/or replied. I have installed digital gauges and when I'm running 70 mph, w/AC on and ambient air temp about 85-90F, it resides in the "L". Digital gauge reading 225-235F.

I did notice one thing today as I pondered why the Parts house didn't get my Motocraft Fan clutch in today, that as I checked around the front housing of the spring, there is oil, gunky buildup around it and that around the bearing housing, nut, etc, there is some oily gunk around it. I do keep my rad and condenser clean, so after I rent the tool fo rthe fan clutch tomorrow, I'll have it off and can take a closer inspection.

Thanks for all the views and replies everyone! That question has bothered me for years!

 

Have you considered that you may have the wrong water pump? Later models (those with the serpentine belt) use a reverse rotation pump. Consider also: Has a previous owner (or repair shop) put the wrong fan on your truck? I discovered that, on a 95 F150 I had bought, it had the older non-reverse rotation fan on it. While doing some other work on the truck several months ago, after parking it & leaving it idle in the drive that warm air was issuing forth from the grill: The fan was blowing forward! After changing the fan & clutch assembly the truck started cooling properly and the AC continued to cool even after coming to a stop while in traffic.

Also, when the radiator was replaced did it get the heavier two row type or the lighter single row?

dn.