Evening gents,

Recently lost my beloved ‘99 F-150 and am sadly looking at replacements. Currently, I’m looking at potentially picking up a 1986 F-250 XLT Lariat, extended cab, 2WD, with the 6.9 IDI. Always wanted a diesel bullnose but don’t have any hands-on experience with them (though I am fairly experienced mechanically). Anything specific I should look for or ask about?

It’s had the C6 rebuilt within the last year, and had the injectors and return lines replaced around then too. Plus little bits and pieces, ignition switch, window motors, stuff like that has been replaced recently. Looks to be pretty clean; paint is burnt a little bit but the inside looks pretty nice. Odometer reads 83k or so, but given that the trans went out I am thinking it’s probably 183k. Not sure. Tires are fairly new, 1.5 years old or so. And it has working AC, so I hear.

Guy’s asking $9.5k. I know prices are nuts right now, but that seems a bit high to me. I’m in CA, FYI. What do you guys think?

Thanks for any advice you can give!

 

Yes that is pricey but I don't yet get the new market.

You will be interested in the age of the injection pump. But a rust-free truck with an IDI is a valuable commodity. You can guess mileage based on the wear of the pedals, but the pads are replaceable so too new or really worn would be a thing,

Injectors and returns are easy, the IP is another thing if you are a pay-someone-else-to-do-it person.

If it isn't rusted out, and you are aware of the fuel economy inherent to whatever you have, go for it. The 6.9 is robust.

Maybe ask about oil consumption. Maybe seller will tell you the truth, excessive is a devalue-er.

Most important is to drive the thing,

 

Good info, thank you. I'll have to ask him about the age of the injector pump. I'm definitely not a pay-someone-else kind of guy, usually, but I'd rather not have to tear into something immediately after purchase (unless I know what I'm getting into ).

Plan is to go see and drive it this weekend.

 

When looking at one of these old diesels, make sure you are hearing it start cold. Lift the hood and feel if the engine is warm. If it is, ask to come back tomorrow and hear it start cold.

 

What should the OP be looking and listening for on the cold start? If the glow plugs are operational should start up cold.

It would be good to find out if the vehicle has been switched over from automatic glow plug controller to manual. If not put that on your list of priority upgrades.

The cold start doesn't tell you much more than the condition of the glow plug system in my experience. They usually fire up cold even with many miles on the injectors and IP. A warmed up test drive will tell you more about the fuel system condition than a cold start.

 

If the engine is original, the rings used were soft and subject to wear. You may notice excessive blackness around the exhaust and on the ear of the rear bumper. A quick stab of the accelerator when warm will reveal any oil use due to worn rings. If you see excessive black exhaust smoke it may be indicative of soft rings being worn.

The original engines are usually good for about 300k miles. By then the rings will be worn and oil consumption increased. A head gasket failure is common on high mile engines.

 

Sorry to hear that.

Are older diesels subject to emissions testing in the People's Republic of California? Was any special equipment fitted for diesels sold in CA? If either question is a yes, you'll want to make sure the truck can pass before purchasing. Otherwise, things can expensive fast.

I used to have a diesel when I lived in Washington state. For emissions testing, I remember doing a snap accel and they had a special monitor to measure opacity of the exhaust.

 

Cold start tells you a lot.

1. If the glowplug system is working or what is required to make it work like you said above.
2. Air intrusion leaks which will introduce air into the fuel system and make it hard to start.
3. If the engine is wore out, it will not create enough heat when it cranks over, and usually needs some help with some other aid starting, or takes a long crank time to start.
4. The batteries are good along with the starter. A cold engine and using the glowplugs takes a lot of power, which is why it has two batteries. A warm engine is easy to start, even on one battery. I have started mine with one battery during the summer months when it's warm outside. If the starter is iffy, it will not crank it over very fast, which will make it hard to start cold.

Once you get one of these engines running, they are hard to stop. But getting them running on a cold day means everything has to be right.

 

On number 2, if there is air intrusion then there is a leak and that means you'll see fuel leaking out somewhere. Check for any leaks. If you see leaks they can usually be solved by tightening up connections. Check the IP for leaks too.

On 3, 4, yes the batteries should be in good condition, bring a multimeter with you and check them. Starter motor should run strong. If there is a problem there it would show up more on a cold start. But you can still tell if the batteries and starter are in good shape with a warm start. You can crank the engine without cycling the glow plugs to test the starter. If the engine has cooled for an hour or two it often requires a glow plug cycle to start. If the glow plugs are on a controller crank the starter right away. If manual test the starter with out using the glow plugs.

When you go to see the truck you can ask for a cold start before you visit. But depending on how far away the truck is coming back the next day for a cold start may not be convenient.

Without the cold start you should be able to tell if there are issues with worn rings, bad batteries or starter motor. I agree a cold start would be good but not essential in determining the condition of systems.

 

Thanks guys, good info on the cold start. As far as smog, no, diesels this old aren’t subject to smog. Anything 1997 or older is good to go.

Edit:

I got a kick out of this btw. I'm sorry too

 

I added this edit above FYI

You can crank the engine without cycling the glow plugs to test the starter. If the engine has cooled for an hour or two it often requires a glow plug cycle to start. If the glow plugs are on a controller crank the starter right away. If manual test the starter with out using the glow plugs.

 

If the engine is warm it should start with a minimal bump of the ignition. If it doesn't do that on a warm start it could indicate issues with the fuel system as well.

 

Gotcha, that makes sense. All good things to keep in mind when I go see it.

 

Most common place for this type of leak is around the o-rings on each injector return. It can be very difficult to spot these leaks, usually they are just a fuel dampness, not a real leak. Air leaks through more readily than the fuel does. Another common place for a air intrusion leaks is the fuel heater on top of the fuel filter. Again, you may notice some dampness, just enough for dirt to stick to it. But no real drips or anything.

If you have this problem you will find the engine starts right away or attempts to start right away and then dies. Then it's a bunch of cranking till it works the air out of the system. I have had small leaks where it hiccups a little or stalls and then starts from sitting overnight. But leave it a few days and it requires more cranking to get all the air out.

 

Sometimes the lift pump leaks. That can also be a source of air intrusion. Lots of cranking.

Even with a visible seep at an injector it did not cause too much extra cranking for me but some I recall.