1989 F250, 7.5L, C6 tranny, 85,000 miles.

I am going on a vacation this spring, the round trip is 4,000 miles. I want to get the best performance out of it. I also don't want any emergencies and having to mess with it on the side of the highway at night.

I have done a complete tune up - plugs, wires, dist. rotor and cap, all filters, check PCV valve, new oil, coolant flush, installing new differential oil and a few minor mechanical repairs. Tranny has been serviced 2 years ago, so have the brakes (and not much mileage since then). It runs good without any problems and the 7.5L gets the usual 11mpg running empty and between 6-8 towing depending on speed, which is as good as it gets, I hear from other "460cid" people.

I am thinking of doing even more work to it:

• Replacing the O2 sensor (Is it too early at 85,000?)
• Cleaning EGR valve
• changing the oil to fully synth. (The good dino in there now has 500 miles, still clear - I can drain it and use it in others cars, not throw it out.)
• Changing the radiator hoses, both lower and upper to new ones, just in case, because they are also maintainance items as far as I understand. They are not leaking, but they are 15 years old.
• It runs good, but should I check timing?

I have no evidence any of the above are not working, maybe I am overreacting. Any other suggestions? I think I will also pull the codes on it just in case.

 

I wouldn't bother with he O2 sensor, or the synthetic oil (although the oil wouldn't hurt). Cleaning the EGR wouldn't hurt, either. The radiator hoses are a "must do", as well as the heater hoses. And as long as you're replacing the hoses, you should replace the thermostat and the radiator cap, since they are the two most common causes of overheating, and besides, they're cheap. You should also replace your accessory drive belt (spins the fan). You can check the timing if you know how to, but you must remember to remove the SPOUT connector first. If you want to be really prepared, have your tires rotated and balanced before you leave.

Take care,
~Chris

 

I think the 02 sensor would be a good idea, if it goes bad it won't leave you stranded, but it;s a good idea to replace the sensor every 50,000 miles to help with gas milage. A new sensor can give you 2-3 mpg and about 10 horsepower. It might be more trouble than its worth to get the old one out though.

Make sure your water pump isn't leaking out the weep hole. And make sure your spare tire is aired up and ready to go.


-Jon

 

I read quite a bit about O2 sensors - different opinions out there. Some say it must be replaced every 80,000, others say replace only when it sets codes. I am going to pull the codes on it anyway, but I also know that O2's degrade with time. I know on my Chebby, it was really dead with about 150,000 miles.

If I gain even 1/3 mpg improvement, it is will pay for itself over that distance. 460 is a gas hog. The difference is marginal anyway. Instead of 7.25 MPG, I may get 7.6MPG. Don't expect better than that. That's of course towing.

Coolant hoses - check. They are easy.

Drive belts look new.

EGR valve - will spray inside of it with the brake cleaner to avoid damaging anything. It is not really high mileage, but...

I will think about the T-stat and radiator cap. If I do replace them, I want OEM ones. I have some issues with a lot of aftermarket stuff.

 

Question?????


Does that truck veer off to the side of the road when you pass a gas station???
Passes everything but the gas station???

 

Loosen up a pulley enoutgh so that you can twist a belt with your fingers. Examine the back, looking for tiny cracks. If there are any, replace the belts. New looking belts are still prone to weakening from age and the environmental factors.

The t-stat and rad. cap are really easy, and I can't emphasize enough how wise they would be to change, especially prior to a 4k mile drive. I also agree with OEM parts. Avoid Stant t-stats at all costs.

 

Robertshaw.

 

Who makes OEM T-stat for this vehicle, and what opening temperature is it? 195F I presume? Also, I would think it is in the upper radiator hose where it meets the engine?

I had a T-stat fail at around 130,000 miles and stuck in the open position, so I was running permanently cool, and without heat. So I replaced it.

Any idea how long they last on the average?

 

I'm not sure who makes the OEM t-stats now.

The factory one is anywhere from 192 to 195 degrees.

The t-stat housing is the part that the upper hose attaches to.

T-stats and radiator caps rely on a spring to control the temp at which they work properly. Even though the springs are a "memory" metal, they are still subject to weakening from repeated hot/cold cycles. I replace both every 24k miles in my vehicles.

Take care,
~Chris