I searched and didn't find anything like a buyers guide or a prepurchase check list. I need help, can someone point me to some search terms or threads along these lines. Thanks in advance for your help.

What should I be looking for?

Today I looked at a 1986 F250 6.9 C6

Looked for oil and stopleak in the coolant - found none
no pressure in radiator - didn't warm it up
Looked for water in the oil - found none
Trans fluid dirty but not smelly
Cranked without glow plugs - didn't start
Started quickly with glow plugs
little smoke from exhaust or crankcase

Good points: new tires and batteries, it runs and drives

Bad points: It is a beater, basically good for a work truck and/or parts truck

Coolant is rusty colored.

Napa wanted $23 for a coolant test kit to test for Nitrides? It mentioned the additives DCA4 or SCA, is this what I want and is it available cheaper?

Check out this link to a coolant test using a voltmeter:
http://www.napaechlin.com/tmt23.htm

 

Can you road test one of these diesels and tell if the drivetrain is good? I am after the "acid test" of road tests here. What would you have to do to expose hidden faults?

 

I have searched enough to decide that the truck I want to buy is an idi turbo. I would be happy with either a factory turbo or an aftermarket. I would have to research the aftermarket installation to be comfortable buying one that is properly installed and not just a hack job.

I am not in a hurry to buy a truck, I can take my time, I am just starting to look. Would it be worth it to buy the beater I mentioned above to learn on, use for a work truck and later for a parts truck? Would enough of the parts interchange to make useful as a parts truck?

 

Inherent weakness in head gasket on idi engine

Good thread on coolant additive and cavitation

Thread recommends coolant test and compression check - good info on compression check

Glow plug thread

 

What to look for

cavitation???

Searches for 'purchase' are turning up more results.

6.9/7.3 Diesel Questions:

sca test strips...7.3IDI non-turbo...

 

WOW, that's a lot of stuff. look for turbos on 92-94 diesels. 6.9's had head gasket issues, 7.3's had cavitation issues. save your money and buy something in good condition. Diesels are expensive to repair.

 

Here a couple links to articles over at the Diesel Stop:

Buying a Used Ford Diesel

Buying a Used Ford Diesel II