I finally took the time to clean off the engine blocks on both of the IDI's I have and discovered the 6.9 engine I thought I had is actually a 7.3. Now I'm wondering just exactly what I have. The engine I removed from the 1989 F350 has serial number 7.3DU2U6239461 and the engine currently installed in the 1987 F250 (which I thought was a 6.9) has serial number 7.3DU2U617160* . Yes, the engine in the 87 appears to have an * at the end of the serial number. So, the questions I have are: #1.) Does the * mean anything? #2.) Can anyone decipher these numbers into anything meaningful?
IDI Serial Numbers
- Thread starter catbird7
- Start date
The * could mean that the engine does NOT match the VIN number. In other words, the truck came with a 6.9 and a 7.3 was swaped into it. Googling the serial numbers didn't come up with anything.
It has 6.9 valve covers on the engine so I assume these were from the original factory installed engine. Aren't most "crate engines" supplied without valve covers and oil pans? Maybe it was a crate engine from somewhere and the original tins were re-used??? Still curious about the * at the end of the serial number. I googled it and found nothing useful and hoped somone on here would know. I assume the serial number is stamped by Navistar and theorized the * denoted a factory (Navistar) reconditioned engine. (Wishful thinking!)
madpogue
Full Access Member
The engine number NEVER matches the VIN. The engines were made and shipped in bulk by IH, with the numbers assigned/stamped by IH. It's unlikely they were installed in the trucks in engine number order, so there's no relationship between VIN and engine number. I'm thinking the * is a place-holder for six-digit serial numbers (the part after the U). My engine is a Dealers Diesel reman, which had its own DD number on a badge riveted on top of the OEM number. The OEM number is six digits after the U, and has a * on the end. The "renumbered" engines that have shown up recently have either been with a separate badge like mine, or with the original number ground off, and a completely different number stamped in three rows (see IDIoit's recent thread).
madpogue
Full Access Member
Update - so much for my theory. Here's a 7.3 with seven digits after the U, AND a * on the end. http://www.oilburners.net/forums/showthread.php?21865-ID-this-7-3-serial-PLEASE-7-3-U2U-1206784* .
WRONG AGAIN.
Who the hell said the engine serial number is in the VIN number.
Checking the VIN number will tell you whether the truck came with a 6.9L or a 7.3L diesel.
Read it again.
What ever happened here? Why do some serial numbers have * at the end? Diesels destined for trucks had a 6.9DM2U... What does 6.9DU2U mean about the engines original intended use?
I'm sure we all a kick out of searching through old threads only to be left hanging.
Thanks.
Edit : I have been set straight on M2 and U2...
M for Internationals and U for Ford.
Still wondering if they all have *...and why there are so many threads without conclusions? Ha Ha.
I'm sure we all a kick out of searching through old threads only to be left hanging.
Thanks.
Edit : I have been set straight on M2 and U2...
M for Internationals and U for Ford.
Still wondering if they all have *...and why there are so many threads without conclusions? Ha Ha.
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Tom Clifford
Registered User
I don’t know anything about the asterisk, YET, but I found this:
7.3L IDI 1988-1994
Block c/n 10809000C1 was used for the entire 7.3L IDI years of production. The serial numbers for naturally aspirated applications are 500,079 through 1,116,330.
Mine is: 73DU2U509783, which, I believe, was, originally, installed in 1988 F250s, F350s, etc.
7.3L IDI 1988-1994
Block c/n 10809000C1 was used for the entire 7.3L IDI years of production. The serial numbers for naturally aspirated applications are 500,079 through 1,116,330.
Mine is: 73DU2U509783, which, I believe, was, originally, installed in 1988 F250s, F350s, etc.
The Astrix could mean anything. Mopar added different designations for an under size crank journal or an over size lifter hole.
Maybe ihc did too?
Yours may be an employee added it for fun after he test ran it. Or maybe a different plant built it etc.
Maybe ihc did too?
Yours may be an employee added it for fun after he test ran it. Or maybe a different plant built it etc.
I think what the asterisk is for is a placeholder/modification deterrent.
If the asterisk is at the end, then it would be more difficult to modify the serial number. Since there are changes that have a serial number break, some of those breaks are significant. I could see IH wanting to prevent modification, since there is the block heater/webing break. The pressin/bolt in oil squirters........ I could see a less than honest seller try to make the serial number “newer” on and older engine to make it more desirable.....
If the asterisk is at the end, then it would be more difficult to modify the serial number. Since there are changes that have a serial number break, some of those breaks are significant. I could see IH wanting to prevent modification, since there is the block heater/webing break. The pressin/bolt in oil squirters........ I could see a less than honest seller try to make the serial number “newer” on and older engine to make it more desirable.....
ttman4
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That's what I think^^^ My '94IDIT engine has a * at the end & I have seen an * on other 7.3s
genscripter
Full Access Member
I was just looking up some stuff in my 1991 IDI Diesel Engine SM Supplement, and on Page 4 under Table 1, the Asterisks was stamped on the block at the end of the serial number and "used to Prevent Tampering."
69idi-Ryan
Registered User
Does anyone know how to decipher s/n?
I have a 143790 on my 6.9.
I believe it is either a 84 or early 85? It has a 85' cast into the block.
I have a 143790 on my 6.9.
I believe it is either a 84 or early 85? It has a 85' cast into the block.
ttman4
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Here are a couple threads that's loaded with VIN/ SN information.
www.oilburners.net
https://www.oilburners.net/threads/what-can-you-figure-out-about-your-truck-with-the-vin.86761/
and there are several good OB threads about this info.
& I think @icanfixall posted this one time, I saved it but not the link.
If you can find the markings on the block, you should see 6.9D, 7.3D or 7.3TU2U
The block serial number will start: 7.3TU2U on a factory turbo block
Its well known the 7.3 block run started at 500,079 and ran up to 1,116,330. Then the turbo block ran from 1,116,331 up to the end of the run. It was a short run that lasted about 6 months of trucks so equipped with a turbo idi engine. We do not have the number nor the finial block either. But it was not very many. At one time in 1993 you could buy from Ford a non turbo truck. a turbotruck and finally in the same year you could buy the first powerstroke truck.
6.9 serial number
Just needing some confirmation on which updates my 6.9 has and if this is possibly the original engine in my 86 250. Looks like serial number is... 6.9DU2U247433. Also included is a picture of the block heater and freeze plug area found on passenger side just above the starter. The heater...
www.oilburners.net
https://www.oilburners.net/threads/what-can-you-figure-out-about-your-truck-with-the-vin.86761/
and there are several good OB threads about this info.
& I think @icanfixall posted this one time, I saved it but not the link.
If you can find the markings on the block, you should see 6.9D, 7.3D or 7.3TU2U
The block serial number will start: 7.3TU2U on a factory turbo block
Its well known the 7.3 block run started at 500,079 and ran up to 1,116,330. Then the turbo block ran from 1,116,331 up to the end of the run. It was a short run that lasted about 6 months of trucks so equipped with a turbo idi engine. We do not have the number nor the finial block either. But it was not very many. At one time in 1993 you could buy from Ford a non turbo truck. a turbotruck and finally in the same year you could buy the first powerstroke truck.
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