Hi all, I got a 1989 f150 reg cab long box it has a 89 302 h.o carbed with a c6 tranny 3.73 rear 31" tires. Now my problem is when I'm driving at around 45 it's fine can do that all day long. But when I speed up or run it hard it starts creeping the temp gauge up. It usually runs about 180 at 45. But on the highway at 65+ it wants to get up to about 200-210 I don't run the serpentine I have the old school v belt on it has brand new 4 core radiator new pump new stat. I just don't know if that's normal for this motor or what

 

could it be getting lean at 65+? That will cause it to heat up.

 

What brand and what temperature thermostat did you put in?

 

Pump running the correct direction?

 

I have a 180 fail safe stat. I'm running the old school standard rotation water pump. I'm not sure about the lean thing. I put an aftermarket oem dizzy in it I have base timing set at 8 I do believe and total is around 38. I bought the lighter mr gasket springs for the dizzy but haven't installed them yet I'm not running the vac advance it was causing pinging. How would I check for lean over 65

 

Without an air/fuel ratio meter you have to look at plugs. The ground strap, and the base ring are what counts.

The old school way was to decrease jet size till bucking and "lean surge" at highway cruise, then go back up a size or two.

 

Couple of thoughts...

At 65 mph, how many rpms are you running?
If its over 2500, then, no matter what t-stat you have in, temp is gonna climb 8-15°, and even 20° with warmer weather.

Is the fan shroud in place?

The mechanical fan clutch is a mute point after a certain speed, do to the vehicle having air being forced over it.

And as mentioned, running lean after certain rpm would cause an increase in temp.

Most of these trucks or engines are gonna run into the 195-220 range, even stock engines will, due to the stock t-stat being 192°.

Your water pump may be slipping at higher rpms and that could also cause a significant increase in temp.

 

Ok I pulled plugs and I kid you not they look just like that picture except for where it shows the carb jetting mines are black. But I'm thinking it could be because of cold weather here ( which is about 40) and not running a choke......I know I know but it only gives me problems in the morning. Anyway yes the shroud is in place it has a flex fan on it I think a 5 blade. Hadn't considered the belt slipping at higher rpm. At 65 I'm running about 2600-2800 rpm I usually don't drive the highway because gas kills me.

 

use ford motorcraft thermostat, have had aftermarket fail after 10000 miles

 

what degree stat is everyone else running?

 

I run Motorcraft 192° t-stats in the '92 300, 2000 5.4, '95 351.

Note, I run a Mitshimoto 180° t-stat in my 302, .040 over, Comp Cam, flat tappet, 1.7 Crane Cobra roller rockers. It doesn't like OD above 55mph with 31x10.50, w/3.55. If I'm doing 70mph+, the temp runs over into the 220's, and I hate that since I'm usually doing 70+.
That t-stat isn't your over the counter type that the parts store sells you.It matched my OEM Motorcraft t-stats perfectly.

 

Definitely run a Motorcraft thermostat if running into problems. Sounds nutty, but it's worth ruling out as the source of trouble.

 

So I should get a motocraft 192 maybe?

 

Run the temp whatever the motor is designed for. Is there a spring in the lower radiator hose btw?

 

So I should get a motocraft 192 maybe? Also where would I find a motocraft stat? And when I'm driving I can see the gauge drop a little to about 200 then go back up doesn't ever go over 215ish I just thought the stat was fine. One thing I do know but can't find a correct hose is the lower radiator hose doesn't have the spring in it and when I rev it up in park like under the hood I can see that hose suck down a little probably not all the way but who knows. Could that be contributing to the problem