O/T: 6.9 turbo diesel reviews?

MeAnthony · Nov 26, 2011

I'm going to look at an 1984 27' motorhome with a 6.9 turbo in it. It has just over 100,000 miles. I would like to make a trip from southern Michigan to central/southern New Mexico with it.

What is the durability of this engine? How economical will it be to run down the road? will it be under-powered in this size camper? What issues should I look out for? What issues should I expect to come up?

Any info, suggestions or opinions are appreciated, as is the fact that you took your time to answer my questions.

Thank you,

Anthony

oldtanker · Nov 26, 2011

I had a non turbo 6.9 in a 88 F250 that drove over 300,000 miles. Would get about 18 empty at 55 but would drop to about 12 at 70, but it wasn't really geared for mileage. I liked that pulling power and got a weight slip from the elevator when hauling corn for my BIL at a little over 28,000 LBS gross.

Bout the only thing I did care for was the glow plug system but when it worked right the engine would start at -20 without plugging in the block heater or starting fluid.

Rick

Super Trucker · Nov 26, 2011

EXCELLENT ENGINE !!!!!!!!! If it does not have fuel,air,12 volts it does not run,that simple. I would check the rubber lines between the injectors [2" piece of 5/16 rubber] and the umbrella over the injectors for leaks. They are prone for cracks for leaking and sucking air when you shut it down making it hard to start along with the mystery diesel smell. As far as performance your not going to set the world on fire but you will get there come the second coming of Christ. Mileage should be about 10+ if your not running 70+mph I would expect 12-15 mpg. I would replace the exhaust with a true a single 4" that alone will make a major improvement in performance and mpg. Is the turbo a ATS kit? I loved my 85 and I wish I had it back!!

F-350 · Nov 26, 2011

I have had experience with the 6.9 and 7.3 IDI Ford engines,but none of them had an add on turbo on them......They are reliable,fairly cheap and easy to work on,will run forever,but are pretty gutless when it comes to pulling real heavy loads.....That turbo was put on there for a reason....

Keeping working glow plugs in them was sometimes a problem..They always got decent mileage empty in a pickup...A motorhome has lots of wind drag so I dont know what to tell you....

Mike (WA) · Nov 26, 2011

I had a 6.9 in a crew cab pickup. Good engine, glow plugs were a problem- 3 different sensors, hard to tell which one was faulty- when it misbehaved, it would come on at 70 on the freeway and fry all the glowplugs.

During my second go-around at replacing them, I rigged 10 guage wires from the relay, and a 30 amp push button switch, and bypassed all the sensors. Push the switch for a few seconds, and the rig started fine. End of problem.

During real cold weather, I'd push the switch again for a couple seconds after it started, every 10 seconds or so, until it smoothed out

LJD · Nov 26, 2011

They are good engines, as compared to what GM had in pickups at the same time. Forged steel crank, heavy block, gear drive cam, etc. I've had several and never had glow plug problems. When Ford switched over to the German-made Beru plugs - the system became very reliable.

But fuel milage? Not so hot, in part because it's an indirect-injected engine. My 1985 F250 4WD with no overdrive and 4.10 axles gets a best of 13 MPG empty, going down the highway. My 94 IDI has a turbo 7.3 which is just a 6.9 with slightly bigger pistons. It is also 4WD but has overdrive and 4.10 axles. Highway mileage empty in NY is 14-15 MPG. In the flatlands of Michgian I've gotten almost 17 MPG.

27 foot motorhome with no overdrive (maybe got a C6?) is going to get 8-9 MPG if you're very lucky.
Some came with GM 6.2s and they got around 7 MPG and didn't last long. Many got replaced with Isuzu or Cummins 3.9 liter engines.

rrlund · Nov 26, 2011

You've got a 6.9 with a turbo? My 85's naturally aspirated. Guess I never saw one with a turbo.
I've got almost 200,000 on mine now,been bulletproof so far. After a mere 26 years.

LJD · Nov 26, 2011

ATS and Banks sold kits for the 6.9s at one time. Then Ford started factory installing the ATS turbos early 90s. My 94 has a factory ATS turbo.

rrlund · Nov 26, 2011

Were the rods and pistons beefed up some on the ones with factory turbos? The local Ford diesel guru advised me and the neighbor both againt putting them on our old 6.9s.

LJD · Nov 26, 2011

Yes. Not sure when it started. Maybe 1992 as an option? The factory turbo 7.3s have (as I recall) different wrist pins in the rods, pistons, piston oil jets, injectors, and injection pumps. Probably a few other improvements here and there.

I wouldn't be afraid to put a turbo on a 6.9 as long as the boost was kept down to 5 PSI max.

Hogleg · Nov 27, 2011

That 6.9 engine platform was the diesel engine that was in the U-haul fleet in those days, many of them ran well over 500K miles. Damn near bullet proof.

John

O/T: 6.9 turbo diesel reviews?

MeAnthony

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oldtanker

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Super Trucker

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F-350

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Mike (WA)

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LJD

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rrlund

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LJD

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rrlund

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LJD

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Hogleg

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