I have an 87 f250 with the 300 six. It has always run cool mostly used for getting fire wood, but I just got a slide in pop up camper. Had to do 4 hours there and back on freeway which is the most time it has been over 55 in the 4 years I've owned it. On the way down no problem but on the way back it over heated for just a seconded. I was running 65 when it happened. I slowed down to 55-60 and it stay warmer than I like but not enough to hurt anything. I've got plans on removing the catalytic converter because I've been told that if it has stopped up it could cause over heating problems at higher speeds but since it over heat only when loaded it will probably need a bigger radiator. It has what looks like a single core now. would any radiator out of another f250 form the years 87 through I think 96 work? I just flushed the hell out of the cooling system last weak so that isn't it.

 

Different engines have different radiator supports, so not all radiators will swap.

Welcome to the forum Nada!

I'm not going to touch the other thread you mined. There's enough childish bickering on this board without bringing some back from the dead.

 

Sorry found the thread in a search and didn't look to see how old it was.

 

No need to apologize, you weren't the one having a tantrum.

I looked it up online and it seems the 2 1/4" thick core two row radiator will not fit because of different mounting.
Changing the radiator support is a lot of work.
If you're handy with a welder you might be able to modify the brackets in place.
I can't say for sure...

 

Is your fan shroud in place and fan clutch working correctly?

I wouldn't just go cutting off the cat if there's no evidence of something wrong with it...
Does your truck struggle at higher rpms regardless of gear and load?
Is the cat getting RED hot?
Does the exhaust hiss like an air hose?

 

The radiator for the six cylinder is different from the gas V8 radiators (inlet and outlet in different locations). If I'm not mistaken, there are only two core supports - one for gas and one for diesel, so pretty much any six cylinder radiator from '87-'96 should work. A 351 radiator from a '95 dropped right into my '87 with the 302.

 

Thanks for all the replies, Today I have pulled the water pump and the rad and both look fine. Checked the stat and it opened like it should in hot water. Thing is the truck runs cool as a cucumber until loaded and at interstate speeds. With out a load it doesn't run hot no matter what the speed is. 55 and under it looks to be running at about 180 which i confirmed by placing a heat probe off of a tester I got on the place were the stat is. The temp hand is just below the N on Normal. 55-60 it is between the R and M at 70 and up it is between the A and L. If I pull over immediately after running 65 or better it will boil over. I know that a better temp gauge would be nice and plan on picking up one soon. The truck has no lack of power and runs smooth as silk until it gets real hot than starts to miss a little.

As to the clutch fan and shroud, dad and me let it run for a long time in the drive way and kept an eye on it. It stayed just below the N which by the heat probe on the stat housing is 180-184. Never got any hotter than that. The shroud is busted up but it would only play in at idle or stop and go traffic in town which it has no problem with. Correct me if I'm wrong.

 

Hmm, overheating with a load. I'd say pull the spark plugs and see what they look like. Wonder if they show signs of high combustion chamber temperatures.

Too Hot

Symptoms: Blistered, white insulator, eroded electrode and absense of deposits. Results in shortened plug life.

Recommendation: Check for correct plug heat range, over advanced ignition timing, lean fuel mixture, intake manifold vacuum leaks, sticking valves, and [of course] insufficient engine cooling.

If all of the cooling system checks out, but it's still overheating, then you gotta say it MIGHT NOT be the cooling system. Any other abnormal running issues? Any funny sounds while idling or driving?

 

I think letting it idle in the driveway and running it high revs for a sustained period on the highway are two different things.
The truck it working to maintain highway speed.
You don't say it boils over -on the highway.
You say it boils over - if you pull over. (but the engine is still running, right?)
And this makes me think that the fan clutch and/or shroud is not doing its job.
Or you might have a cracked head that doesn't show up until it gets hot.

But I'm not too familiar with the I-6 engine.

 

When it boiled over we had stopped to check the camper. I pulled over and put it in gear and killed the engine because there is no parking brake. After addressing the problem with the camper I went to enter the truck and then seen the anti-freeze on the ground. Checked temp gauge and it was in the red.

I had just changed the spark plugs about 300 mile ago.


As you can see they look like new out of the box. The old ones that I took out had the look of heavily creamed coffee.

 

Okay, if that's how they look right now then yea, they look great.

How does your oil look? How does your coolant look? Anything look out of the ordinary?

I know we are all asking a lot of questions, but make sure you try and read and answer all of them (unless you already have) so we know as much as possible about how the truck is acting right now.

How old is your radiator cap?

 

The oil and coolant is fine. Dad and me shined a light down the rad and it was real clean looking. I have also replaced the upper and lower hoses. The Cap is most likely the one that came on it. How could I check the rad cap?

 

Never mind on how to test the cap I'll pick one up while I'm in town.

 

I don't think the rad cap is going to CAUSE an overheating problem.
The cap maintains a certain pressure. Fluid is less likely to boil under that pressure.
BUT the temperature is not changed by the cap.
If it's overheating, it's overheating.
The air pockets created by boiling coolant create hot spots.

BTW, when you replaced the lower radiator hose did the new one come with a spring in it?
Or did you remove the spring from your old one and pull it into the new hose?

 

A bad radiator cap can cause problems of boiling over. IF it can't hold pressure properly the coolant will boil. I had some numnut friend put a 13lbs cap on my 84 f250 once, drove me crazy trying to figure why it was boiling over after engine heat soaked after turning it off. Put a 16lbs cap on and took care of the heat soak boiling problem for me.


Get a good temp guage hooked up and that will help out on figuring this out.