I've been wondering about doing a full conversion in my truck to synthetic lubricants. Not just engine oil, but transmission, transfer case, and differentials as well. The thing is, it is a 1996 Nissan hardbody 4x4, and currently, the truck leaks no fluids. I've heard things about synthetic oils causing leaks before, especially in older vehicles, so I'm a bit worried about that. If I were to convert everything to synthetic, would it do anything to benefit fuel economy?
I changed to synthetic engine oil in my Civic after 160,000 miles. Now, 10k miles later, the level is exactly where I filled it. There is no leak at all. I also changed from 5w30 to 5w20 at the same time, which could possibly make any leaks worse. Studies have shown a couple percent improvement from low weight synth oil. Not something we could measure, but it would be helping that small bit. I like it because it lasts longer between changes.
Make sure the lube blender SPECIFICALLY says, in writing, that their lube meets the spec associated with your auto tranny.
Actually, my truck has a 5-speed manual transmission. I was thinking of draining the gear oil out of it and replacing it with the synthetic of the lowest weight that I can according to the owners manual.
I'd guess that the main FE benefit of going synthetic is if you can reduce viscosity while still protecting your engine/driveline. I know my engine can use either 15W40 conventional or 5W40 synthetic, and the synthetic is supposed to give a few % boost to FE. I'm guessing that that few % is because the synthetic flows easier when cold, reducing the cold-start penalty a bit. I'm planning to use conventional for the first 12 months (have a few months left), then switch to synthetic and see what difference it makes. Let us know what difference you see if/when you switch, and what fluids you changed from/to. I'll do the same.
I just changed all fluids in my 155,000 mile 1997 blazer - no 'new/worse' leaks. I have done synth conversions on cars with 400,000+ miles and have NEVER seen a leak caused by synth oil. I have seen existing leaks get worse as the synth oil flows better @ operating temperature - but not a new one caused by it.
Well, I did the switch today, since it was approaching time for an oil change. Before, I had Castrol 5W30 conventional motor oil. The owner's manual recommends either 5W30 or 10W30. The local AutoZone had a special going, $29.99 for 5 quarts of Mobil 1 AND a Mobil 1 oil filter (that's a steal considering what both would have cost without the sale). So I put in Mobil 1 0W30 advanced fuel economy full synthetic, which says it meets warranty requirements for 5W30 and 10W30. I'll be sure and keep you posted. The truck seems to run just fine on it, but we'll see if there is a FE benefit.
I switched to the Moble 1 0W30 at last oil change and it seems to have helped with engine rpms dropping faster when going to NICE-on coasting. i would think that it would help bigger engines as there is much more surface area to cover than a 4 bangger, thus reducing more of the friction. I am going to replace the diff fluids in the next month.
For crankcase oil, suggest reading here: www.iea.org/Textbase/work/2005/EnerEffTyre/calwell2.pdf Interesting quote, page 13: "Most commonly found fuel economy benefit in SAE literature is about 1 to 3% (higher in regions with colder than average temperatures)." Keep us updated!
Colder than average temperatures... I think Maine might apply there. lol Fort Kent, Maine (about as far north as you can go in the continental U.S.) hit -50° F this past winter. Where I'm at -- about 216 miles south of Fort Kent -- made it sub-zero numerous times. I'll be sure and let you know. So far, my tank average is around 23.6 on the ScanGauge. Not quite as high as it was on my weekend trip, but for just driving around town (average trip less than 10 miles so far) I'd say that's fair. Now that I have synthetic oil in the truck, do y'all think that the 7,500 mile oil change interval suggested by Nissan for non-severe use would be OK?
Well, what does Nissan consider severe duty? If you're in severe duty, you can't go extended drains on your oil, regardless of the oil installed. At best, I suspect you can do a non-severe oil change interval in the summer months, and have to stick to severe intervals for the winter. Most automakers think that a Maine winter counts for "severe".
Nah, that " it will leak with synthetics" is from the old days when synthetics first came out-late 70's . There was a very thin synthetic that actually has graphite syspended in it-stuff was jet black. When you put it in your old clunker it would ooze from every seam and look horible.It did leak more , but that was maning because the base syn was sooooo thin.The leaks would show more because the graphite made the leaks really look horrible-black as soot. I switched my Suburban-1998 -when I bought it 2 years ago with 195,000 miles on it-now it has 210,000 and runs great-no leaks and good mpg(considering what it is).I use Mobil 1 5w30 and just the last change Mobil 1 10W30 high mileage. 21 mpg on long trips-all highways CC set to 68 mph. Switch and don't worry Charlie
The cars I work on have a 15,000 mile service interval, and suprisingly enough I have yet to see it really be a problem even in cars that are getting up in years and miles. I however do my oil changes every 5,000 miles. A bit in between the usual 3,000 and the 6-7,500 that is listed for regular intervals, it seems to work well and is easy to remember as I just change at 150,000 and 155,000 and 160,000 ect.....
satchel, Thanks for the rebate form! Printer is humming, I'm going to Walmart! $22.00 for 5 quarts of 5w20 before rebate! :woot: - Dale
Just finished putting synthetics all over the truck: Engine Rotella 15W40 conventional => Rotella 5W40 synthetic Tranny ???? factory fill (calls for Transynd or Dexron III) => Transynd (Allison's synthetic ATF) transfer case ???? factory fill (calls for Dexron III) => Valvoline Dexron VI synthetic Front axle conventional 80W90 factory fill => Mobil 1 75W90 synthetic Rear axle synthetic 75W90 factory fill => Mobil 1 75W90 synthetic Didn't notice much drivability difference when doing the axles. Just did the rest of the driveline yesterday and it was immediately noticeable that everything just felt slicker and smoother. Coasting in neutral seemed to have less drag also, so it wasn't all the engine oil. I may never know which had the most impact, but I'm eager to see how the FE numbers change, especially this winter.
I don't know how much of a difference switching the blazer to all synth made in mpg, but it does run noticeably smoother also. I have been using royal purple for everything (it's stock by my parts department so it doesn't get any more convienent or cheaper than that), But I got some Mobil1 0w30 for the next oil and filter change to give it a try and see if that helps any. Damn, should have saved my receipt for Dale's rebate post!
The big difference I've noticed in the synthetics is in cold weather--my vehicles running synthetic seem to start much easier and run quieter. It's particularly noticeable in the tranny on start up in pretty cold (i.e. sub zero F) weather. I haven't noticed so much difference in the summer.
