New to me 86 6.9l - What now?

[RSchanz]

Hey All,

I just got home to California after finding an 86 6.9l f250 in Idaho and driving it back. The truck has 148,000 miles on it and it seems to be in pretty solid condition. Fuel pump busted on the drive home and I replaced that. I burnt through probably almost a half qt of oil on a 680mile drive, I'm new to diesel engines... seems like a lot? Doesn't seem to visibly smoke much, only when I gas it a little more to climb etc.

Any pointers on what to tackle/check first? I read Agnem's sticky on "New to the IDI..." and found a ton of helpful information when looking at the vehicle. The radiator basically had no fluid in (which I read the warning to possibly not buy if this is the case) so I filled it to the top and bought a new radiator cap. I purchased it from what I perceived to be an honest farmer so I don't really suspect anything is off. I'll definitely be on here often looking for advice on replacing things, I've already got a small list . Excited to trade in the 63 GMC for this and start getting to know how these diesel engines work.

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[IDIBRONCO]

Definitely a good trade. It sounds like a lot of oil usage, but it's not really terrible. I would keep driving it for a while and see how it does. It may just need to be driven. Another thing to keep in mind is that a lot of us say that these engine like to burn Shell Rotella oil. You could also try switching to a different brand at the next oil change.

 

[david85]

Welcome!

Mine would burn 1 qt per fillup before I rebuilt it. Most of it was probably getting past the valve stem seals (which were completely rotted away). Compression was still good and the truck ran fine otherwise. The rebuild was due to glow plug tips breaking off into the engine.

The only thing I'd be a little concerned about was the low coolant. Did the level hold steady after you topped it up?

Other then that, it sounds like a solid truck. If something major was wrong, a 700 mile trip probably would have found it.

 

[stick_witch]

Welcome!!

I just joined the idi world not that long ago as well, and let me tell yah you’re in for a treat, these trucks are a lot of fun and perfect if you’re just getting into diesels and wrenching on your own stuff! Super simple and easy to work on. Hahaha but it ain’t cheap[emoji23]

First things first, with idi’s you will hear a bunch about coolant and cavitation, since you have a 6.9 this is not something to really worry that much about since it was mostly the bored out 7.3 that had this issue. So i wouldn’t start worrying about this unless you’ve got a good amount of oil/diesel in coolant or vice versa.
Second, straight off the bat I would check for any oil leaks (valve covers, oil cooler and oil pan are popular spots), diesel leaks from the injection pump, injection lines, injectors and the return lines and coolant leaks. These engines are leaky by nature, especially the darn return lines...
If you have trouble with starting it, check out your glow plugs and GP controller. If you have problems starting when engine is warm, your injection pump is bad and needs to be rebuilt$$$.
These trucks also need a solid set of batteries and a good working alternator to crank over the engine and keep starting it day after day, so test your voltage readings, batteries and alt. Ford 3g alt swaps are pretty common if you’re stock 1g alt isn’t up to *****. Minimum 850cca batteries, always replace in pairs.
If it runs good, sounds good (no loud knocks or ticks), starts good and doesn’t leak then you’re off to the races! Drain all the old oil and coolant, do a full coolant flush of the rad and block with distilled water, then get new fluids, new motorcraft thermostat, rad hoses, etc.
For oil you want to be running diesel specific 15w-40 dino or synthetic in most all climates. If its using a lot of oil i recommend dino Delo over Rotella to start, and then also add a quart of marvel mystery oil or do an autorx treatment to help flush things out and help piston rings seal better, either of those 2 oil additives can really help with engines that burn a lot of oil or have sticky valves, and have been known to bring engines on the verge of death back to life. You can also upgrade to the larger 7.3 powerstroke fl1995 oil filter on these and it gives you a quart more capacity and better filtering, but can be a tight fit for some.
For coolant, the easy way to go is 50/50 fleet charge sca precharged. Other way is to use normal green coolant with an additive like motorcraft vc-8 with or w/o a coolant filter depending on your preference. Personally, I use/like fleet charge.
Also, just go ahead and replace the diesel filter behind the alternator while you’re there. Also a good idea to replace the cdr valve (tuna can at the back of the intake by the gp controller).
It’s good to run a diesel additive in these old diesels as well to help lubricate the injection system. Popular additives are Diesel Kleen, Stanadyne, obti-lube, hot shot, marvel mystery, etc. Some like to add a splash of 2 stroke oil to their diesel as well. NO 911! NO ETHER!

Thats a clean looking truck! Low mileage too for these engines! You got a good deal! Looking forward to seeing what you do with it! Welcome! And enjoy![emoji16]


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[stick_witch]

Doesn't seem to visibly smoke much, only when I gas it a little more to climb etc.

What color is the smoke when you give it gas on the hills? Blue? White? Grey/black? How much? Does it smoke a lot on start up? Could be burning oil or the timing is off.


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[Black dawg]

I wouldn't be concerned about that oil consumption in a 6.9. From all of the ones I have owned, and all of them that I work on, yours sounds like it is on the low side of normal for oil consumption.

Most I see use a quart between 500-1000 miles.

 

[IDIBRONCO]

When you turn the key and the wait to start light comes on listen for any ticking from the glow plug controller behind the intake. If you get repeated pulsed ticking you most likely have bad glow plugs, go ahead and get 8 new motorcraft/beru zd9’s ONLY and throw them all in.

This is for the 7.3 style glow plug system. Unless someone changed it out, RSchanz has the 6.9 style. The controller is screwed into the back, top of the driver's side head. The glow plug number is ZD1A (Motorcraft). This style controller likes to fail by sticking in the on position. I definitely recommend a manual control for this style.

 

[RSchanz]

Thanks for all of the input and replies!

Glowplugs: I believe I'm the 3rd owner of the vehicle and the first owner installed the bypass system so I have a button that I push for about 6 seconds depending on outside temp.

Coolant: The level maintained well, I didn't go straight to the top before the long haul, just a little below and before the last 3 hr stint I topped it off. I'll check it again after some daily driving here. I used 50/50 greenn - no additive. I think I will look into an additive today.

Smoke: When it cold started up in Tahoe yesterday morning (38 degrees) it shot a nice puff of white (mayyyybe a little blueish) smoke out but other than that nothing on the starts. That was the coldest start I've done so far. When gassing up a hill it looks white out of the mirror.

Oil: I topped it off with Delo 15w-40. The previous oil in it was done by Les Schwab and I don't know what oil they used.

Any good suggestions on aftermarket gauges? The gauges all seem to work fine but I'm seeing that I shouldn't really trust them, is this true? Did a fine job in '86 right? haha. The speedo also seems to be off by about 5mph. The tires are stock 235/85 r16 but I'm replacing them today with Falken Wildpeak at3 265/75 r16 because these tires look like they could be the originals, haha! I honestly didn't pay much attention to it and just ran it around 2500-3000 rpm on the highway - assuming the tach works right.

 

[stick_witch]

This is for the 7.3 style glow plug system. Unless someone changed it out, RSchanz has the 6.9 style. The controller is screwed into the back, top of the driver's side head. The glow plug number is ZD1A (Motorcraft). This style controller likes to fail by sticking in the on position. I definitely recommend a manual control for this style.

Totally forgot the 6.9s have a totally different glow plug system. Thanks for the correction!


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[stick_witch]

Good deal, yeah I recommend just swapping all fluids when you take in a vehicle like this, but thats just my preference. I guess i'm just super **** about having to know exactly what my truck is running in it at all times.

If you add additive to the coolant already in it, which isn't really my first recommendation, make sure you pickup some sca test strips from a parts store and test the coolant before and after you add the additive to see your additive levels. Like I said, if you plan to do this really id just replace the coolant unless you know exactly how long it's been in there. Same with oil, if you don't know whats in it and you're potentially mixing up some unknown oil concoction, just go ahead and replace it.

As far as the smoke, thats pretty normal. What that is is just unburned fuel and/or oil. A puff of white smoke is kinda the norm on cold cold starts and then it should go clear. Might be a little too much given its doing it on the hills as well but that could be for a number of reasons that someone else on these forums can talk to better than I can. But, for the most part, pretty normal as long as it runs strong and it isn't doing it ALL the time.

Currently looking to get gauges so i can't talk to that, but yeah aftermarket gauges are a great idea! The consensus on the stock gauges is that they're pretty much all garbage, dummy lights in disguise as gauges

Also, when you get a chance put all your truck specs and info in your signature for us to see.

 

[IDIBRONCO]

Glowplugs: I believe I'm the 3rd owner of the vehicle and the first owner installed the bypass system so I have a button that I push for about 6 seconds depending on outside temp.

Good. That's just one less worry that you have now.

The level maintained well, I didn't go straight to the top before the long haul, just a little below and before the last 3 hr stint I topped it off.

If the coolant level went down slightly, I'd first suspect a small external leak such as a loose hose clamp. Since you've checked the oil level multiple times on this trip, you know that you don't have any coolant in the oil since you didn't mention it being any color other than the lovely black that diesel engines like to make their oil.

Smoke: When it cold started up in Tahoe yesterday morning (38 degrees) it shot a nice puff of white (mayyyybe a little blueish) smoke out but other than that nothing on the starts. That was the coldest start I've done so far. When gassing up a hill it looks white out of the mirror.

This could be nothing more than your injector pump timing being a little bit slow.

Any good suggestions on aftermarket gauges? The gauges all seem to work fine but I'm seeing that I shouldn't really trust them, is this true?

Yes it's definitely true. Wes says that he runs nothing but Auto Meter gauges. I think I'm going to copy him and do the same with my build project except for maybe the VDO pyrometer that's in there. VDO is another good brand of gauges as far as I know.
Overall, I think that you probably have a good truck. You may have to play catch up on some of the maintenance like most of us do when we buy a different truck, but it's to be expected.

 

[IDIBRONCO]

Totally forgot the 6.9s have a totally different glow plug system. Thanks for the correction!


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Until you get to the crazy 1987 crossover year when the 6.9s used the 7.3 style glow plugs and looked like a 7.3 on the outside. Between the year and the fact that I'm not all that familiar with the Brick Nose trucks in general, my Ex Wife project keep throwing me for a loop. I've only owned Bull Noses and Debt Sides before this one.

 

[stick_witch]

Until you get to the crazy 1987 crossover year when the 6.9s used the 7.3 style glow plugs and looked like a 7.3 on the outside. Between the year and the fact that I'm not all that familiar with the Brick Nose trucks in general, my Ex Wife project keep throwing me for a loop. I've only owned Bull Noses and Debt Sides before this one.

I had no idea. Hahaha Im the complete opposite, I’ve pretty much worked exclusively on brick nose gas and diesel trucks. Not very familiar with the bull nose and obs trucks at all.


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[RSchanz]

Per the radiator fluid... this might be a stupid question.

Should I top off the radiator and top off the reservoir to the hot fill line? I only topped off the actual radiator, the reservoir has a small amount in it right now like 1 inch maybe.

 

[snicklas]

What I normally do (not saying it’s right or wrong, just what I do), if fill the radiator, and let it burp out while filling it. Get it as full as it will let you. I then fill the bottle completely full. That way it can pull in the extra it needs. After running the truck for a bit, I will check the fill in the radiator, and then add to the bottle if needed. If it’s already above the “full” mark, I just leave it alone.

IDI’s can get a fair amount of air in them when they are empty. They normally will need a couple of heat cycles to get all the air out of them...... and could take a surprising amount of additional coolant to be full....