I'm working onbuying a new hauling truck, I've pretty much decidedon an IDI turbo. but I've not totaly ruled out an older PSD if I can find the right truck.
any how what should Iknow be for bying a used IDI.

I know to check for SCA in the coolant

but what dose the differant colorsmoke mean??Black, blue and gray??

Are there any years I should avoid?

I will be getting a manual what ever I get so I dont need to wory about the autos.

What about blow by and how do I test for it?

IS there any thing else I shold know about. be for getting oneof these?

Thanks to all J

 

first of all, make sure it cold starts easily!!!, tell the guy you want to meet him on a saturday at 7:00 or something to look at the truck, if he has it alredy warmed u good when you get there, it robably doesnt start that good.... blowby is usually pretty rare in these engines, mine has 330,000 miles w/o any major overhaul and it has very little blowby. make sure the clutch and tranny shifts good in it. black smoke on hard accelleration is fine. if it is bellowing white smoke when it is alredy warmed up, don't buy it. some white smoke when cold is normal if you want a haul truck, make sure to get 3.73 or 4.10 rear end. a 3.55 will run 70 at 2200 rpm's, a 4.10 will run 2700 rpms at 70 and a 3.73 will run 3400 rpms. dont let someone tell you it has 4.10's b/c most of them came with 3.55's. if you get a 6.9 with a 4-speed, get the 3.55's

 

Just check everything out good. Make sure things work. I bought an old truck because it was super cheap, but the little fixes are adding up quick. Check brakes, open radiator cap(when cold) should be no pressure release. If there is, stay away from it. May have head gasket problems. Same with white smoke when warm. I learned all these things the hard way and still have $ to spend to get it rolling again.
Check under truck to see if there is fresh oil dripping anywhere. Check for coolant leaks also.
Most important is not to rush into a purchase. Take you time and ask lots of questions. When you get a lot of "I Don't knows", be careful.

 

Thanks Thats all good advice!

 

So what dose pressure releasing form the radiator mean? What would that tall me about the truck? Thanks J

 

The truck I got had been over heated and had a bad headgasket. This allowed compression to leak into the cooling system. When the truck was cold, and I opened the radiator cap, "pshhh". Pressure not good. Indicates headgasket problems and big $ to fix. My heads were damaged also, among other things. Have been working for two months to get it back together and have spent more than I would like to admit doing it.

Lesson: Just take you time and examine evrything carefully. If fluids are low? Why? Must be a reason? Check why.

 

make sure there is no oil in the radaitor and it doesn't blubble up when it is running(blown head gasket) ask him about sca or dca and what does he know about it if he does know anything I would not buy it.

 

If you get one with a 5 spd, check reverse, the ZF-5 is totally syncronized. So 5th and reverse BOTH use syncros. So don't grind it going into reverse,and pop the clutch a little in reverse to see if it trys to jump out. I found out the hard way, and replaced the gears and syncros for 5th and reverse, PARTS only over $600.00 good luck Phil

 

. a 3.55 will run 70 at 2200 rpm's, a 4.10 will run 2700 rpms at 70 and a 3.73 will run 3400 rpms.

Why will a 3.73 run 3400 rpm, if a 4.10 runs 2700 at the same MPH?

 

He probably meant 2400 rpm.

 

When you have 5:13s like I do in my 450 the engine revs 3000 at 62mph the old truck is topped out at 100km/h or 62mph maybe if I had a taller gear than OD I may beable to squeek more speed out of it. I don't think the engine could handle any gears taller than 4:63s or the engine wouldn't have any pulling power when loaded. For highway travel 1-2-3 is pretty much useless only can use 4th and OD its pretty hard for me to pass anybody I have todo it in OD 4th gear pegs the engine.

With the engine revving around 2000 in OD I can put my foot into it and she pulls like a bat out of hell. Once you have a old IDI humming they pull good just don't let the revs drop below 2000.

A old IDI does pull fairly well down low if your idling along somewhere looking for street adresses etc. When I go through the school zones where the posted speed limit is 30km/h (19mph) I can idle through the zone at 1500rpm in OD or 4th.

The first thing you ask is have the SCAs been kept up if your in doubt you may have a cavitation victim waiting to happen its the crappy thing about the IDIs. All engines have cavitation but the IDIs seem to have it a bit worse because the compression is so high being a N/A so the cylinder walls see more stress.

I was scared of the IDIs before I learned more about them a diesel can be a money pit if your not carefull. To replace a IDI is 6-8 grand you look at replacing a 460 gasser is would be max 5 grand.

I wouldn't go back to gas again I'am so used to the IDI now I don't think I could suffer with the 460s bad gas millage plus the fact the smell of gasoline exhaust gives me a head ache. My previous F-450 had a 460 used to get 8mpg tops the truck burned about 10-12 dollars of fuel per hour. My IDI gets 12mpg burns about 6-7 dollars per hour.

 

Things to check.

Push the clutch pedal while somebody else watches the clutch master cylinder under the hood. If the cylinder moves up and down more than just a little bit, the firewall is cracked.
The glow plugs should cycle for 7-10 seconds on the first try of the day. Any less and you might have burned out plugs, any more and there is something wrong with the controller.
Low oil pressure from internal wear or malfunctioning bypass valve.
Erratic idle from bad injectors or pump.
High idle speed that wont go down when you manually pull back on the throttle lever on the side of the injection pump, indicates worn injection pump.
Overheating at speed or when pulling up a hill. The guage should never go above 1/2 to 3/4.
The usual rotten hoses and leaking fluids, especially around the fuel injectors.
If you live in salt country, the back brake cylinders tend to rust up tight. Make sure you pull the drums, it's easy, just take off a back wheel and look for leaks and severe rust under the rubber caps, also pull a front hub if you've got the time and tools, they rust shut all the time where they salt the roads.
The clutch should release smoothly without chattering or rattling. Make sure the t-case lever works and that low-range works and doesn't make any unusual noises.

Mostly these trucks are pretty bulletproof and easy to work on. Anything wrong with the engine makes the selling price drop drastically. Where I'm at, I could have bought two 85-86 F-250's 4x4 with dead 6.9's for $1500 last year. The rest of the truck was decent, but the engines were shot. The parts for everything tied to the engine are 2-3 times the price, but mine is getting 17 MPG with a worn out injector pump and 400,000 documented miles on everything but the rings, heads, bearings and gaskets.

I spent $2500 for my 87 F-250 4x4 last spring. So far I've got another 800-1000 into it, including tires and misc stuff. I had to replace the rear diff due to water/rust damage. I found one for $50 in a local yard with 4.11's and factory l/s. I've replaced all the hoses, belts, fixed the a/c, blower motor, brakes front and rear, front hubs, bearings etc. Rear tranny mount and other things I've already forgotten. Part of that cost was adding a $350 front locker for hunting season. The cost would have been dramatically higher, but I already had a lot of the parts from my grandfather and his old truck. You can imagine how my heart sank when I pulled the rear diff cover and brown gritty milk came out, not to mention when I pulled a front hub and I got a handfull of rust with it. That and the spindle's that were beaten to a pulp and had all the threads chewed off.

Any other things we can throw out there?

Good luck and remember. A good deal will always be there tomorrow for a small deposit.