I purchased my 97 F350 Dually 7.3 about a year ago. It had been bought new at our local Ford Dealership by a retired mechanical engineer who bought all necessary shop manuals and did all maintenance work himself. The truck had 97,000 miles when I bought it. He was a perfectionist of the highest order. Since I planned to pull a 9,000lb 5th wheel camper I added a DPTuner. I spoke with Justin[I believe] and told him what I was using the truck for and trusted him to sell me what I needed. I installed it and was amazed at the power difference. That is the only deviation from totally stock. I carried it to Ford shop to have trans serviced[fluid and filter change]. I asked the heavy diesel mechanic to give the truck a good going over and to check everthing for correct operation that he could, short of dismantling anything. He kept the truck a couple of days and I believe he gave it as good a inspection as he could. The only thing he could find was the oil seperator that mounts on the driver side rocker cover. I went to parts dept and found out they are a little pricey. I went back and asked the mechanic if they could be washed out and cleaned and reused? He said he had heard of some owners doing this, but of course , he would not. I pulled them off and separated them and discovered they did not appear dirty or gummed up. I also found out I could not put them back together correctly. I tried and tried, but it would not work satisfactory. So I bit the bullit and put new ones on. What signs would the mechanic have noticed to lead him to think they needed replaced. What are they supposed to separate the oil from? They were simply filled with steel wool. If I could have put them back together they would have been fine. By the way , the customer service I received from Justin at DPTuner was second to none. I am just concerned about being miles and miles away from home and breaking down on a interstate somewhere.

 

The "oil seperater" you describe is like a PCV valve in a gas engine. Your mechanic may have found excessive oil in the intake tube running from the air lilter to the turbo. Was the truck burning a lot of oil?

 

I have not had truck a full year yet, but I have put enough miles on it to have changed the oil twice. I change it every 3,000 miles. I spoke with previous owner before I bought it and he stated that oil had been changed every 3,000 miles without fail. He had already traded truck in and had no reason to be untruthful. As of yet, it has not used any oil between changes. Most of the miles that I have put on truck was done so pulling my 5th wheel camper to Fla and back several times. When it is not hooked up to camper , it just sits as I have another older Dodge with slant 6 that I use for ever day driver. Thanks for your reply.

 

Sounds to me like the mech couldn't find anything else to try and charge you parts on so he picked that.....FWIW I have never heard of one "going bad" they're just steel wool inside a housing.

Also, stop wasting time and resources by changing your oil every 3K, I don't know why every thinks this is such a good thing, all your doing is wasting oil. there are PLENTY of PSD's with 300K on them and I highly doubt any of them saw less then 5-6K on the oil, I go 7500 and have put over 250K miles on my 3 PSD's.

Diesel Rod

 

If your concerned about the oil in the intake try old birds mod. I think he flipped the breather over and ran a hose over the brake booster then to the ground. With the hose going up like that most of the oil runs back into the engine

 

I pulled the Ford recommended maintenance schedule and reviewed it. Ford states that if I use truck to pull RV or any type trailer , the severe duty schedule should be used instead of the normal schedule. The severe schedule recommends that oil and filter be changed every 3,000 miles. I appreciate your advice on the oil separator , but since the only time the truck is used, it is coupled to a 9000 lb 5th wheel camper, I think I will go with Ford on the oil change.

 

I towed 9-15k daily with mine and changed the oil every 5-6k
It had 279k mile when it was totaled a year ago

 

I change mine every 5 to 6 k miles,when I got it ,it had 217k and now it has 312 K still uses no oil.
JIM

 

I know what ford says but you need to remember the PSD was introduced in 1994, meaning the testing that decided what is that manual was done in 1992-1993 making it 20 years old....Oil has changed by leaps and bounds in 20 years.

The HEUI system is hard on oil and I'd guess the oil used in the initial PSD testing was prolly late 80's technology so the test determined 3k was enough.

Plenty of seasoned PSD owners will tell you 5k is move then safe with today's oils, we're just all trying to save a fellow PSD owner so money, that's why were all here.

Diesel Rod

 

I ran 7.7k miles on Rotella T6 and the oil analysis (the real test) said run it longer. I have heard of people running 15k miles on T6 (synthetic) and still have good UOA.

I will be changing my oil earlier because of a oil cooler leak (I figure it will be about 6k miles.

Richard

 

I go between 7500 and 10k on my T6 oil. My analysis have been fine. If I push to 10k then I change the filter and add some fresh oil to fill it back up. I am definitely going to add the bypass filter soon and then quit worrying about it. I suppose this is one of those topics that has about a million different opinions, so if you are convinced that changing every 3k is a good thing, then by all means keep supporting the economy! Nothing wrong with that at all. I know I do some things just because it makes me feel better and that feeling is worth the money.

 

Thanks Guys, I believe that 5/7 thousand is fine. If I believe I am wrong about something I will admit it, and it appears Diesel Rod along with all of you that were good enough to try and help me, is correct, so I stand corrected. Thank you all. I was getting ready to change it again, but the wife and I are getting ready to make another south Fla run and try to find some warm weather, so I will wait until we return to change oil. I do as much maintenance as I can myself, and believe it or not, I enjoy changing the oil, but taking the price of oil into it, I don't enjoy it that much. One other oil question. The truck has just turned over 102,000 miles and per the previous owner, synthetic oil has never been used in it. He kept a supply of Motorcraft 10W40 on hand, and that is what I continue with. Would there be any advantage in switching to synthetic oil at this late date?

Diesel Rod, Thanks!

 

Talk about opening another can of worms!! lol

I am no expert but I really have a hard time believing you have to stick with a certain oil and the engine becomes conditioned to it. I have an old Harley and a guy told me if I switched oils it would leak all over. Never happened. But I am sure there are others on here with much more chemical knowledge than me so I will be interested in their advice as well.

 

I hope that 10w40 is diesel rated

 

Yes,it is. I bought what he had left as he did not need it anymore. He used the truck to carry a slide-in camper. But he is approaching 90 years old and was having trouble driving. Hate to see that, but he was happy his truck went to someone who would continue to take the kind of care he did. Plastic jug says "SuperDuty Sae 15W-40 Diesel Motor Oil".