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.
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.