6.9 Sounds Hollow, Clatter/Rattle with Low Oil Level.

bumblebeer

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I really appreciate everyone on this forum for your time and patience! If I'm ever able to actually bring an idi home with me, I'll keep all my noob questions together in a single project thread. Until then....

I went the other day and looked at a couple of idis that are coming up for auction. One was a 7.3. It'll need glow plugs, and the auction house got it started with ether. But once it was running, it ran well and sounded like every other idi I've listened to. Very little blow by. Overall seems like it's in really good shape.

I also took a look at a '86 6.9 while I was there. It's the first 6.9 I've listen to in person. I'm more interested in it cause of the body and drive train, but the engine don't sound right. Its glow plugs are also bad and ether was used to start it as well. And it was a little harder starting. It's got an oil leak somewhere cause the bottom of the engine and oil pan are coated in it. The oil level was also low. When checking the dip stick, oil level didn't even register. Once it was started, it kicked enough oil on the stick to be able to check it out. That oil seemed fine. No sparkle to it. Didn't smell burnt. Didn't smell like diesel. Did smell like exhaust as expected. Don't know if it's actually circulating oil or not cause none of the gauges work. Also had one of the injector clips leaking pretty bad.

The sound of it running is kinda hard to describe, but it sounded hollow. There was some clatter and some rattling, but nothing that sounded like a bad knock or miss. Just really noisy. It didn't seem to get better or worse at higher rpm. There was a big difference between it and the 7.3. I have a video of each that I'll try to get uploaded this evening, but I don't know how much good it'll do. The audio quality is pretty bad.

With the truck being on an auction lot, there is only so much inspection and testing I can do with it. I know it isn't a lot of information to go on, but I'm just wondering how likely it'd be to behave when the fuel leaks are fixed and it's full of new oil. Or if I should expect there to be further problems or more damage caused by the way it's running. And if there's anything I could do to diagnose further before I have to decide what I'm willing to bid on it.
 

Farmer Rock

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Is it the plastic return line caps that leak? If it's a high pressure line leaking, you will absolutely have a knocking sound, being that it's really only running on 7 cylinders at that point.
I do have to ask though......why would you start it up knowing there was very little oil, if any.


Rock
 

chillman88

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If it's that low on oil it'll definitely clatter like that. If I let mine get away from me you can hear the valves clatter when it's low on oil.
 

bumblebeer

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Is it the plastic return line caps that leak? If it's a high pressure line leaking, you will absolutely have a knocking sound, being that it's really only running on 7 cylinders at that point.
I do have to ask though......why would you start it up knowing there was very little oil, if any.


Rock

It was leaking just above the plastic cap on one of the injector lines, so I believe it would be on the HP side. Although I could see which line was leaking, it was difficult to tell wether or not the racket was coming from that cylinder.

It was at an open lot farm equipment auction, and was listed as running. So I figured it was gonna be started up at least a few times in any case. Maybe not the best decision, but given the circumstances I'd rather see it run than bid on faith.
 

FrozenMerc

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Being that it is an auction truck, and based on the oil leaks and other problems you described, approach the bidding under the assumption that you will be pulling a motor and doing a rebuild in short order. If the price goes beyond what you want to pay + the rebuild, let someone else deal with it.

There are still plenty of fish in the IDI sea. You will catch one sooner or later.
 

captain720

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Most engines make noise when they are low on oil so it could be just that, that being said @FrozenMerc is spot on with his statement.
 

IDIBRONCO

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It was leaking just above the plastic cap on one of the injector lines, so I believe it would be on the HP side.
Helpful hint: if it's a high pressure fuel leak, the fuel will most likely be spraying/squirting because it's under high pressure. If the fuel is just slowly running out, it's a low pressure leak. The fuel on top of the return cap probably meant a bad o ring and probably wasn't squirting/spraying out.
 

bumblebeer

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Didja buy it?

By the title, thought you were taking about my truck...

Goat
Nope, it went a bit too rich for me unfortunately. Ended up with an 88 single cab flat bed. It was funny though. The guy that won it was loading at the same time I was and offered to trade even though he had paid more. I had to pass cause I really needed a flatbed, but kinda regret it now... May have needed a rebuild, but even so was a really clean bullnose at that $.
 

Old Goat

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Clean one`s are far and few in between.
When we bought the 86 coming up on 9 yrs ago, paid $1800 for it. Didn`t know if it would make it back home the 153 miles.
Body wasn`t in the best of shape, but now after 140K miles, the engine just keep going. Replaced every thing between front and rear Bumper though.

If you come across a clean one, suddenly it becomes gold plated and the price is through the roof. Here is an example.


We have an 85 similar to this one with about the same options. Saw it on CL about 4 yrs ago, listed for $3500. Wife said "Buy it". next morning price dropped to $2500...had to buy it. Been sitting since then, just last week started going through it to get everything road worthy for a driver. OH, 165K miles.

Goat
 
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IDIBRONCO

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Clean one`s are far and few in between.
This is true. I've seen several clean ones advertised for Covid prices or higher. I've also seen "not so clean" ones advertised for almost 2/3 of what the clean ones are being advertised at. All I can think about those is "there's no way that I'd give that much for that POS!"
 

bumblebeer

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If you come across a clean one, suddenly it becomes gold plated and the price is through the roof. Here is an example.

Oh wow it wasn't near that clean! I mean if that thing is as good mechanically as it is aesthetically, I can totally understand the price. Looks like it just rolled off the dealership lot.

I just thought it was in good shape for a nearly 40 year old truck. Would have needed a dash, some other trim pieces, a headliner, and a full paint job at least. But good frame, no rust, chrome in excellent shape. 4x4 t-19 4.11 with a full float rear. Think the winning bid was $2,950 would have been just over 4k with premium, fees, title, etc. Like I said still kicking myself for not taking the trade. Bullnoses are definitely the coolest ford body style. But oh well. :dunno Live and learn.
 

Old Goat

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That 85 is still a 38 yr old truck. If they have not stayed up on replacing rubber Bushings, Window Channeling, Window wipes, resealed Windshield Belts, etc...
If that truck has sat a lot, it may have good tire tread, but they may be dry rotted.

So there is always the cost of stuff you don`t think about.
Another one will come along.
I agree the Bull Nose is the best looking one.
Can you se a 94 with a Bull nose?


Goat
 

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