Greetings!

I just bought a 1989 Ford F350 2wd truck. (XLT Lariat, 5 speed, Flatbed car hauler.)

When checking it out, I noticed the passenger side valve cover said the engine was a 6.9L International Harvester engine. The seller said that was incorrect. It is a 7.3L swapped in from a later year truck. Who should I believe? Is there another way to identify the engine?




Also, this is my first vehicle that has a diesel engine and dual rear wheels.

I'm a fairly compitent mechanic when it comes to compact gasoline cars. About the only thing I DON'T do at home is alignments and tire mounting.

Is there anything I should know when caring for a diesel? I know they use a different quality of crank case oil to protect against soot pollution and have multiple stages of fuel filtering to protect the injection pump...

I've seen specialized coolant. Is it any different than standard ethylene glycol used in a gasoline car? Why would coolant be any different?




Weight aside, is it harder to work on the dual rear wheels than on a regular vehicle?

I am employed with a Mass Transit company, and when I see the mechanics work on the busses, it's like a totally different world. They bolt one wheel to the brake drum with nuts that have threads on the outside, then they bolt another wheel on using larger nuts that fit over the first set of nuts. Then the whole assembly, dual wheels and drum go on the drive axle... I really hope I won't have to be doing this.

On my buddy's '98 Chevy 3500, you can unbolt wheels individually from the rear and even swap one around to the front if needed.

 

Bump to the top.

 

are you sure it an 89 latest year for a 6.9 was 87
to know for sure the block number is on the driver side of the injector pump on the flat spot under the a/c comp.
6.9l will read 6.9 D U2 U4 #######
7.3l will read 7.3 D U2 U4 #######

 

Pele,
Welcome to FTE and the IDI diesel forum.

Oil should be rated CD or CE in the API rating for a diesel engine.
10 quarts capacity for oil to do a change.
I change mine every 3000 miles.

Diesel antifreeze should be low silicate, there is no aluminum to protect and the silicates counter act the SCA addatives.
SCA is DCA 4, an addaitive that protects the engine from cavitation.
You can use a heavy duty diesel antifreeze that is premixed, or you can use diesel antifreeze and add your own SCA.
You should test the coolant every 3 months to make sure you have enough SCA.

The weight and bolt torque values are bigger on trucks, same basic principal as far as the mechanical things go.

You can remove the wheels, then remove the brake drum without ever pulling the axles out.

 

I don't see any of that under the A/C compressor or near the Injection Pump. Should I remove the A/C compressor bracket?

 

the engine number is just to the right (driver side) of the injection pump. there is a flat spot just before the valve cover where the number is located.
the 7.3 engine has strength webs at the lower edge of the heads right along the bolts where the 6.9 is basically flat without the webs.
you can use regular antifreeze but add coolant additive (nalcool, or napacool) as indicated on the container to help alleviate cavitation erosion (internal wearing of the water jacket along the cylinder walls). Also use a fuel additive (power service, stanadyne performance) that will lubricate the internals of the injection system because the new low sulfur content fuel wont do it.
Any other questions, ask ... lots of help is available in here.
good luck and enjoy the ride.

 

The engine Id will not jump out at you, they are very lightly stamped into the block, unless the engine is factory new, you wont see it. Any light rust or grease will hide it.
Wipe the area clean of grease, then you will probably have to lightly sand down the rust, then with a bright mini light crawl up in there and look aroung. ( the letters are about 1/8 " in height and are lightly stamped into the block

 

I see numbers there, just not in the format as posted.

And they're not stamped, it looks cast into the block.

It looks like 0203P to me.

 

OK thats the head casting number, In your picture, near the top you see the wire comming from the temp sensor, if you look about an inch beyond the sensor toward the pump, you can just see the area in your picture (Its a flat machined area) If you clean that area to shiney metal you will see numbers that were stamped in after machineing. You wont feel them they dont stick up like the casting number in the picture. They are very lightly stamped into that machined area.
In your picture you could see them if that area were polished to shiney metal and they start at the back of the housing where you add the oil.
Dont get discouraged your in the area and they are there but you have to really clean that area to see them

 

DOH! Now I feel like a complete fool. I know what a cylinder head is. (I have a Geo Metro Cylinder Head sitting on my kitchen table, ready to go to the machine shop for a valve grind and resurfacing.)

Why the hell would a BLOCK cast number be on a Head?!

The turbo is that big spinning thing behind the radiator, right?

I had to use a razor blade to trim away the RTV someone used, but it cleaned up pretty well.



Should I have ANY doubt what so ever that it's a 7.3 and not a 6.9?

I guess putting a 6.9 crank in a 7.3 block would make for a very low compression ratio, not to mention not be worth the effort to rip someone off.

Any way to ID the year this engine came from, as the previous owner said it's a transplant. 7.3D U2 U6 74042

And will the head casting numbers in the previous pic tell me anything about them?

 

Most of the id info I know Ive picked up on this site. Most of the components of the 6.9 and 7.3 are interchangeable ie crankshaft cam lifters timinng gears connecting rods valvecover oil pan etc.
Basicly the major difference is just bore diameter and the 7.3 has lager head bolts. From what Ive read the 7.3 is just a re-machined 6.9

 

Looks like a 7.3 to me. Another easy way to check is to see what size the head bolts are. If a 12 point 1/2" wrench fits them it's a 7.3. 6.9s are 7/16".

 

Ah! so it's bore, not stroke thats changed between 6.9 and 7.3... So there's no way to make a "counterfeit" 7.3... Good to know.

I know of several engines where a change of crank and/or head is all that's needed for a different engine model than what the block is stamped with.

It's kinda impossible to make the cylinder bore smaller.

 

No, but you can bore a 6.9 110 thousanths and make a 7.3 out of it.

There have been minor changes to the 6.9 and 7.3 blocks over the years.
But most of the internals are interchangeable between the 6.9 and 7.3.
The exception being pistons, heads and head bolts.
Some of the 7.3 turbo engines had larger wrist pins than the NA motors had, so that could be one other exception.

And in diesels it is not impossible to make a bore smaller, that is what sleeving the block does.