Ran hot one time

So I added another truck to my collection to use while I work on my other trucks. This is a cheap 1988 F250, NA IDI, zf5, 4.10, 2wd, regular cab long bed with a spray can paint job. Somewhere around 150k miles. I drove it daily for a week to shake out bugs, it ran great, near zero smoke, (I get a small puff if I take off from stop in second gear, no smoke just running down the road, can get a haze if accel hard), air temps were 85-90F all week. I've done minimal work, oil change, changed to viton o-rings and new olives and air filter and fuel filter.

Then...I drove through Cresson Summit (elevation, 2000 feet above sea), on Rt. 22 in Pennsylvania towing about 3500lbs. I was moving right along, in fourth gear, 50-55mph, I think 2200-2500 rpm. It was raining, around 60F degrees. Temperature gauge showing needle at the N in Normal (as it had been all week). By the time I made it to the top, the needle was at the A in Normal and the check engine had come on. I pulled over and idled around 1500rpm, and within a few minutes, the temp was back down and the check engine light went out. Drove home the rest of the way without issue, and 500 miles since, although I have not gone back through the summit. Coolant is not low.

1) Is this a case of EGTs getting too high? Is this an issue on stock trucks? I thought by keeping rpms up, egt's shouldn't be an issue. It was not lugging.
2) Is my fan clutch bad? How to check? My hearing is poor, so I can not hear if it engages while running. I don't notice any power loss if it were engaging. So maybe this is my issue.

Check engine light??? Don't got one..... I suspect you mean the over temp light?

Don't trust the stock gauge, get a real one that actually has numbers - stock gauges are little more than a wiggly idiot light.

The stock overtemp sensor is setup for 243* IIRC, which is high but survivable. How long was the light on? If it just came on as you hit the top I doubt it would have hurt anything. If it was on for a few minutes while you still had your foot to the floor it could be problematic.

That being said, if you'd broken anything it would be apparent - if it's still running fine I wouldn't worry too much about it.

Likely not an EGT issue, but rather simple overheating. There's no stock EGT measurement of any sort of these trucks, and EGT shouldn't ever be an issue unless the pump has been messed with or the air filter is badly clogged.

From the sound of it I would guess you have a weak or bad fan clutch.

Thanks for the reply. Hmm...I have an "engine" light right next to the battery light. Which I thought was for low oil pressure and over temp. Yes, the light came on just as I got to the top. I was watching the factory temp gauge as I went up, and I was thinking the needle still being in the normal range I was okay. I understand it is only for ballpark and can't really attach any real numbers to it. I was not floored either, maybe quarter to half throttle. The truck was happy at that speed and rpm towing 3.5k. Thanks for confirming my suspicion of the fan clutch.

Ah, forgot that's how they do it on the later rigs. 80-86 has a 'engine temp' light. Yes, that is for temp and oil pressure. When I see 'check engine' I automatically think of a gasser OBD setup.

Fan clutch is hard to definitively troubleshoot. From the sound of it I'd bet that's the problem, but hard to say for sure.

I feel from what you posted either the radiator is needing rodding out or the fan clutch is failing. Look at the fan clutch for moisture around the shaft seal. Also use an inspection mirror to see the thermal coil spring on the front of it. If that spring has dirt piled up on it or you see moisture there then the clutch is shot. Buy ONLY the factory clutch. Many others sold like hayden are not top shelf quality anf fail soon. then you are into it for another clutch and a much higher overall cost. I don't usually recommend spending the funds for factory parts but its the best clutch out there.

I would do the oil fix first before messing with a new clutch - same labor and much much cheaper.

http://www.oilburners.net/forums/showthread.php?64852-The-4-fan-clutch-fix&highlight=

First test I would do is to cold start the engine and then immediately (within 5-10 sec, not like instantly petal to the metal) rev up to about 2000 rpm. You should hear a distinct roaring sound from the fan which will go away in about 30 seconds. If you do not hear this chances are good that the clutch has no oil, go to the fix above.

The fan clutch is a viscous type that uses a thick oil to 'lock' the clutch up. When you stop the oil eventually drains to the bottom of the clutch and when it's started it takes a bit to pump the oil out, resulting in the fan being engaged briefly on start. Most of the time what I've seen is that these fail from a loss of oil, so you woln't get this initial lockup and will be able to fix it by adding more oil.

Okay guys, I went out and looked at the fan clutch. My inspection mirror sprouted legs and walked off. But the the fan clutch is dry with no evidence of leakage. I could not see the front with the spring. So I will have to get back to that. With the truck sort of cold, last ran 4hrs prior, with it not running, and turning by hand, has some resistance. If I try to spin the fan, it will go 1/8 turn before stopping. After starting, if I slowly roll the throttle from the engine compartment, it will go from quiet to a roar and starts pumping a lot of volume of air. I'm guessing 1500-2000rpm, I didn't have anybody to watch the tach. This leads to believe the clutch is working (could still be weak). With my poor hearing, I can't tell from inside the cab even with the hood and windows open. Dang, I forgot to wait 30 seconds to see if the roar goes away. I'll check again.

What about the radiator cap and/or thermostat? Or maybe, as Icanfixall suggested, the radiator is plugged. I'll take a closer look this weekend.

I've got autometer 2398 gauges on the way. I got to know what temps I am working with...Also would be nice to know the oil pressure.

Look at the inside of your radiator: if you see any signs of corrosion, get it cleaned up. Keep in mind that if you radiator has some crud in it, so likely does your oil cooler, so its a little "double jeopardy". I'd also look at the bugs, dirt, leaves, etc that could be blocking the fins on the outside. The cooling system on an IDI is pretty robust on an empty truck, but pulling a load and elevation can tax it in a hurry.

Keep nosing around, you'll find the culprit eventually.

I'll also mention there's a 99.9999999% chance if you had crud in the radiator and have it cleaned out, you will now have new found leaks. For the price, I would just replace it. Can make some money back by junking or selling the old one.

Sent from my SM-T537R4 using Tapatalk

Hers about the least costly factory clutch from ebay.
http://www.ebay.com/itm/171036141793?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

Going east or west up Cresson? Seriously, east bound is a harder pull than west bound. If it was east and it ran hot by the top isn't too much to be ashamed of. My truck can hit 240 by the top of it if I don't let off of it empty. I'd bet your rad has some gunk in it.

If you have the tall skinny rad I'd buy the $186 champion rad from Amazon and then she'll run cooler

Thanks guys. I was going westbound through Cresson. Farmerfrank are you using the champion radiator? What temps after swap?

I had one in an 88 crew cab. I was impressed with it right til the day I sold it. Can't put one in my farm truck, it has the wrong core support. How'd it pull penn view? Or did you go up 422?

Went across 422. Not familiar with Penn view, is that staying on 22 to Pittsburgh? Went 99 to 22 to 422 to avoid turnpike.

If it stayed cool and ran good the whole way out 422 to Ohio if say your cooling system isn't that terrible. There's some pretty good pulls on that road. Yes penn view is about 25 miles past the 422 exit on 22, the home farm is on the top.