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I'm looking into purchasing a 1986 F-250 diesel with 75k miles and I was wondering if its a good deal at $2400. Some people told me that the older diesels weren't good... is this true?
Trevor, that's a question with a long deep answer.
What "Somebody" was probably referring to was the problem of cavitation.
Thats pitting of the cylinder walls from the water jacket out into the cylinder. That can be the end of the block. Some people have sleeved the blocks and had good luck with it but no matter how you look at it your looking at a minimum of $2000 to $5500 bucks and a lot of work.
There's a treatment for the water jacket, but it's the kind of thing that has to be done on a regular basis to prevent Cavitation.
If your not handy as a mechanic you might be making a mistake.
Owning a Diesel is kind of a Kick. You get the power without a lof of RPM's, but it only gets about 10 Mpg. When you turn the Air on, the engine doesn't slow down a bit.
The Price is between you and your concience.
In my opinion that truck would have to be real berry berry nice before I'd pay that much for a Truck that old, with so much potential for disaster. I paid $10,000 for mine in 96, and I'll keep it till either I Die or it does.
Your truck is a 1986 and has a 6.9L IDI and this engine does not have a major problem with cavitation. It is only a major problem in the 7.3IDI's and especially the 7.3L powerstrokes. In very rare and extreme cases do the 6.9s cavitate. Engines that are worked hard and put under full loads are the ones at a greater risk.
I think that price is fair, the only problems you will run into engine wise, are starters, inj pump, injectors, and the water pump. Most of the engine parts are trouble free.
I think its not a bad price. Assuming the body has no major dings, and the interior is clean. It would be a steal if it was 4wd. I'm assuming no. Those old 6.9's had problems with their glowplugs. Always going out. If cold starts become problems. Spend about a hundred or so bucks and replace all the glow plugs about 8.50 each and buy the glow plug relay and then fix the temperature sensor in the back of the engine. That's all. I had a buddy who had the same year with a 150k on it. Only thing had to fix was glowplugs and normal. He put 16k on it in less than a year. Good truck.
>Owning a Diesel is kind of a Kick. You get the power without
>a lof of RPM's, but it only gets about 10 Mpg. When you turn
>the Air on, the engine doesn't slow down a bit.
I never heard that diesels get bad gas milage.....i always heard they got exceptional gas milage. my dad drives a 98 dodge 2500 diesel sometimes and he said it does very good even hauling heavy loads. A client that lives in my neighborhood has a 99 E350 cargo van that regularly hauls 5,000+ lbs. cross country and he said that he gats about 25 MPG combined. I consider that excellent milage as my mom with her 94 E150 fullsize and a 351W only gets 11-12 MPG combined.
Sorry I gave you the impression I said all diesels got bad milage! All the newer Computerized Engines get great milage.
Even in the OTR'S the Computer increases fuel mileage from 3 to 7 Mpg.
The 6.9 and 7.3's only get 10 to 13 Mpg. It can be worse too. Mine's been down as low as 5 Mpg on some pulls with our 5er on. Normally it's 9 or 10.
We've put 119K on ours, and 70% of that has been with the 5er on. One trip with just the Camper shell on the back was 11K miles and it averaged 12 Mpg and the High for the Trip was almost 13.9 coming down the ALCAN on all that Gravel. Going was pretty slow on that trip so it got real good milage.
The Mpg in these old IDI's has to do with the Gear Ratio, the Streamling, say with a nice aerodynamic Shell on the back, the Terrain and the Wind and if you stay under 60 Mph.
You'll hear guys saying they get as much as 18!?!?!?!?
The Computerized Diesels do get 18 Mpg.
I own an 84 6.9L. I did replace on head (due to my own stupidity). I bought it it 1992 with about 100K miles and paid 2400 for it. I have since put about another 150K on it. It is now a plowtruck, but when it was on the road, it always got between 16-19MPG. The only problems I had with it was that it tended to eat starters and alternators. I think that was due to some bad electrical tinkering by the previous owner. Good luck if you decide to purchase it.