OIL VISCOSITY
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Joined: Apr 2010
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From: Manitoba
OIL VISCOSITY
ON MY 02 7.3 diesel, before we left the far north, we installed J.D. 0W40 diesel synthetic oil . Now we are in far south with temps over 80F and engine cut out.[shut down].. After putting on scanner, installed new fuel pressure regulator... Two mechanics told me 0W40 is too thin for this engine in warmer temps. So today we installed 15W40. Anybody heard of this type of problem ? We also had an engine miss when with the thinner oil but only for the 1st minute or so after start up... They think my miss may be gone after installing the 15W40.... Will see....DW
Post Fiend
Joined: Mar 2007
Posts: 26,966
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From: Texas
What was the spec on the JD oil? The 7.3 is a HEUI system and shears oil pretty bad. That means if you use an oil without a defoaming additive, you get foam when hot and that affects the way the engine runs since the injectors are fired off of engine oil.
Keep an eye on it and see how things go.
Keep an eye on it and see how things go.
Post Fiend
Joined: Jun 2004
Posts: 9,293
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From: Parker, CO
Now if the oil doesn't meet the minimum specs required by Ford, then you could have drivability issues. But a 0W40 that meets the specs for our engines, it will work just fine.
FWIW, I run 5W40 synthetic in my truck year round, even in temps over 100F. Quite a few others do as well. That's the good part about synthetics, they typically have a wider temp range.
Hotshot
Joined: Jan 2011
Posts: 18,849
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From: Puget Sound
Temps here go from -20 F on a January night to 108 F on an August afternoon - and all those temps are met by Stinky with the same 5-40 Synthetic oil in him.
If the oil change actually helped, the oil you had was out of spec or out of miles.
I don't really blame the mechanics - they are hit with a foreign material in the truck, so step one would be to get the truck to a configuration they recognize. That being said, find mechanics familiar with synthetic oil and our HEUI system.
If the oil change actually helped, the oil you had was out of spec or out of miles.
I don't really blame the mechanics - they are hit with a foreign material in the truck, so step one would be to get the truck to a configuration they recognize. That being said, find mechanics familiar with synthetic oil and our HEUI system.
Post Fiend
Joined: Sep 2006
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From: Sioux Falls, SD
The "0" in the 0W-40 is the weight of the oil when it is cold, and the "40" is the weight of the oil when it is up to temp. So once the truck is warmed up a 15w-40 oil and a 0W-40 are both 40 weight oils. So the only time period the oils are different is when the oil is cold. Like Pocket said - if the oil meets the CJ-4 or CH-4+ specs it is fine. Heck , the previous owner of my excursion ran 10W-30 diesel oil during the winter. In my experience when my engine would cut out or stall it was corrected by replacing my CPS (cam position sensor) or ICP sensor. There could be other causes as well but these are easy to check and/or replace.
Post Fiend
Joined: Sep 2006
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From: Sioux Falls, SD
I've got the John Deere specs somewhere.....I'll dig them up.
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Joined: Dec 2010
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From: SC
Lol, great thread. On other forums for other makes and models, I have seen this topic take up tens of pages and hundreds of posts. Here, it takes less than a dozen posts by half a dozen members to fully answer the OPs question. And we all know this topic can turn into a can of worms. I consider the OPs question fully answered and this issue resolved, I have absolutely nothing to add. I am glad the OP titled this thread well so that if others in the future search for this topic, they will be led here.
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Joined: Apr 2010
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From: Manitoba
Tks all for info shared.....will get the code on Friday.....also a code for the engine miss for the first 5minutes every morning....tks again.....DonW. Changed oil to 15W40 , erased all codes......still have a miss first 3 minutes after initial start.....will get a new code....talking to my mechanic back home, he says my miss is probably the wire that goes thru both sides of my valve cover , probably on inside of valve cover.....will update...Don
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From: Manitoba
Well, one of the mechanics has put in, two different times, a strong Motorcraft quart of fuel conditioner....the miss is getting less and less..and sometimes no miss at all ....the reason he doesn,t want to tear anything apart is because after the miss quits, the truck runs perfect the rest of the day. will run it two more days and then will see.... Don
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Joined: Apr 2010
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From: Manitoba
Engine Miss when cold
After putting in a 2nd dose of Motorcraft fuel conditioner, 7.3 has been running perfect 4 days out of 5.....injector probably was sticking....mechanic told me today he firmly believes the "thin" oil [0W40 Syn.] was the cause that the fuel pressure regulator failed.... been good since that was replaced..: