Running Synthetic in a older high mileage engine?

[adventureduo]

Can you guys school me on this topic?

So as some of you know, my buddy is now a vendor for AMSOIL and he is supplying us with fluids for our rig. As most of you also know.. they only make synthetic lubricants.

My question is... how do you guys feel about switching over to synthetic on a high mileage motor? I've heard so many different things, i dont know what to believe anymore. The seals will leak now if i switch over?.. the oil burns cleaner and i'll have to change it every 2k-3k miles to 'train' the engine? It will be fine. It will burn oil like a madman.. I've heard so many different views.. im really lost. I talked to my long time mechanic on Friday and he said that he wouldn't do it. That basically.. got me thinking.

Well, what do you guys think? Should i just leave it be and keep running the old regular motor oil?

Side note: He's offering me the extended life/high mileage synthetic by the way. And i have a 185k miles on our 1993 FZJ80 4.5 liter.

Any input on this would be greatly appreciated.

[bigreen505]

I switched the Pathfinder to Valvoline High Mileage dino oil at about 275,000 mi and it just made a mess on many different levels. I switched to synthetic 5w-30 at 300,000 and 0w-30 at about 315,000 and the engine has never been happier. On dino oil, including the high mileage stuff, I would burn about a quart or so every 3,000 miles. On the synthetic I burned about a half-quart every 5,000. To switch over I ran a can of engine flush (the thin oil, not the kerosene). I did the first change at 5,000 and then 10,000 after that.

Based on limited personal experience, I'm not sold on any high-mileage additives, just high quality synthetics everywhere except hydraulic fluids.

[DaveInDenver]

I ran Syntec in my truck and will again after I break in the new engine. BTW, the engine work has nothing to do with synthetic, I broke a timing chain which is most likely due to the piece of junk aftermarket parts. The only reason you don't want to run a modern synthetic is if your engine is in such poor shape that it actually leaks a lot of oil currently and that's only because synthetic is too expensive to let pool on the ground. If the engine is in good shape, decent seals and condition, synthetic isn't going to hurt anything and will only help. My truck was at ~200K when the timing stuff went and showed no signs of problems with the syn stuff.

[adventureduo]

Great responses! keep em coming please!

[Jonathan Hanson]

In my original F engine in the FJ40, I switched from Castrol GTX to Castrol Syntec at around 200,000 miles. No dramas, no leaks, no magic differences in power or fuel economy, but I felt like I was treating the engine a bit better.

[Skillet]

Great responses! keep em coming please!


Immediately put Mobil 1 full synthetic in the 80 when I got it and it had 183k on the ticker. To the best of my knowledge, it had only used dino before that.

Runs beautifully for 27K so far.

Had a Blackstone test on the last batch with 6k on it and they said the oil could have gone to 12K.

When I first switched, it ate up oil at a fair pace but after the first 3K, that diminished.

Honestly, you cannot go wrong changing to full synthetic.

There are a lot of write-ups about it on mud if you want to poke around in the tech sections for your specific vehicle.

My .02

[Boston Mangler]

Immediately put Mobil 1 full synthetic in the 80 when I got it and it had 183k on the ticker. To the best of my knowledge, it had only used dino before that.

Runs beautifully for 27K so far.

Had a Blackstone test on the last batch with 6k on it and they said the oil could have gone to 12K.

When I first switched, it ate up oil at a fair pace but after the first 3K, that diminished.

Honestly, you cannot go wrong changing to full synthetic.


My Experience Mirrors Skillets Exactly! Blackstone actually commented on how good mine looked! :D

Mine was switched at 118k and was dirty as hell at the first changed, now comes out very clean at 135k +/-

[cruiser guy]

IF the price on the synthetic is comparable to dino then use it, otherwise why change something that works well.

I've had synthetic in my 3B when it had 400,000 or so on it and it didn't seem to make a difference. Now the drive train is different, I'm convinced that synthetic there is worth while (I noticed a mileage improvement) and I have my own stash here in Central America because it is hard to find it here.

[adventureduo]

Thanks all. I will take your advice and go for it. The case of oil should be here any day now. Thanks again for your real-world experience responses. You set my mind at ease.

[pnwadventurer]

About 4000 miles ago, I changed over to 0-40 Mobil 1 on my 3FE powered Land Cruiser with now 185,000 plus miles. No leaks, no consumption yet.

It was probably not needed, but I changed the oil filter at the factory recommended interval of 3750 miles for severe service. I now need to figure out how many miles I can run before an oil change.

Steve

[grouch]

While I didn't have the major miles that others had, I switch to synthetic and won't go back. Nowing that I can put 10,000 miles on a oil change is very comforting although I change it at 5,000. All my stuff, diffs, transfer case and tranny are all Mobile1 and I couldn't be happier. It's in the wifes Crand Cherokee as well. Since you are getting an inside deal on the Amsoil, I say go for it! Switch it all over to synthetic. I just wishe Mobil1 would come out with synthetic gas!!!

[cruiser guy]

Just a quick comment. In my case I'm running a diesel and an extended drain interval in a diesel is not a good idea due to soot buildup in the oil. That's one of the reasons I don't do synthetic in my engine but I still use it everywhere else.

[dieselcruiserhead]

It makes worlds of difference in cold weather. If you have no small leaks I would say run it.. There are some interesting studies on turbo diesel register about extended intervals with diesels. Some guys have as many as 50K miles on their amsoil and purple (forget the name), sending in oil samples for analysis every 5-10K miles, and no problems..

I run it in my higher mileage Saab as well. Not sure if it ran dyno or not before but it runs great and also no oil loss. I run about 10-12K intervals usually..

[mike h]

I've been thinking about it just for the longer change intervals - dropping my skids is a PITA, and it means I can never use a JiffyLube on the road.

I ran Amsoil in an older Quattro and did experience seal seep, and synthetic in the gear box made the shifter feel notchy; the fluid was so much thinner than dino. The Quattro was short-lived love affair for me so I can't give a longterm report. My mechanic at the time was a synthetic preacher, and I'venever heard anything against using it.

If I were to swith my 97 Nissan w/ 120k to synth this season, is there a 'flush' recomendation? Such as run put in synth for 1000 miles, and drain/fill, then go the 5000?

the seals are tight on the Nissan, and knowing how improved tolerances are now I'm not concerned with seal seepage, although my 3 months of subzero may prove otherwise.

m .

[cruiser guy]

There are some interesting studies on turbo diesel register about extended intervals with diesels. Some guys have as many as 50K miles on their amsoil and purple (forget the name), sending in oil samples for analysis every 5-10K miles, and no problems.

The other brand you are talking about is Royal Purple I think. Extended drain intervals work if there is an oil lab nearby but by the time you've taken a sample you may as well just change the oil.

Sampling is $15 more or less. For me thats about the cost of the oil and filter. The work isn't too much different. You still need to go and get all dirty.

[bigreen505]

If I were to swith my 97 Nissan w/ 120k to synth this season, is there a 'flush' recomendation? Such as run put in synth for 1000 miles, and drain/fill, then go the 5000?

There are two types of motor flush you can buy -- one that is kerosene and one that is just a super thin synthetic oil. I have used both, but I am a lot more comfortable with the thin oil. Basically just dump it in, let the engine idle for a while and drain. I replaced the first round of synthetic at 5,000, then switched to 10,000 mile intervals.

I just realized that I forgot to flush with the Trooper, but I only had about 4,000 on the new engine.

[rgsiii]

The only way to tell what will happen is to try it. Not all synthetics are the same. My '94 LC used excessive amounts of most of the Mobil1 oils, but did fine on what was their SUV/truck flavour (I believe it is something like 10/40) and now is their diesel one. I now use Rotella synthetic without problems.

[pskhaat]

Go for it. Synthetics make a lot of sense to me.

Personally, I only change my synthetic oil in all my vehicles once a year regardless of mileage. Once a year I also send in my oil for analysis, and I have been able to maintain outstanding results.

I'm sure Amsoil is very good stuff, as well as Royal Purple and Redline, I've never heard bad things about any of them. One anecdotal note however being an Oil Brat: the major oil companies use Mobil lubricants for their own equipment. There are many stories about rigs and pumps where the companies' own lubricants are either given away or sold and Mobil lubricants are silently used from petty cash funds.

[Erick Lihme]

Before running it in Toyota manual trans, check the specs. For example, G52 and W56 as well as many other Toyota transmissions require GL4/GL5. A gear lube which is rated as a GL5 only, has additives which may erode the brass syncos.
Read the label. Royal Purple 75w-90w, and Redline MT90 are two which have a GL4/GL5 rating. Diffs requiring a hypoid oil might be best served with a Redline oil as it needs oil which clings, and provides ample cushioning. I am partial to Redline in gear boxes. One can email Redline to get their recommendations. Synthetics are THE way to go in very cold climates. A standard 10w-30 may have a pour point at about 30-35 below zero. Mobil 1 would have a pour point at -58 below. Much easier cranking is noticable even above 0 degrees. The same goes for gear oil. With Dino oil in the box, it it feels like the brake is on, but no so with a synthetic.

There is a risk when changing over to synthetic in a high mileage motor, especially in which has not been served adequately, as sluge and varnish build up on worn and hard seals can help prevent seepage. A synthetic oil is highly detergent and can remove that build up. This may not as an important factor if the motor was run a Dino oil which itself was highly detergent and/or change regularly. That said, my personal experience has been good.

I totally lucked out last year on a purchase of 85' EFI 2WD extra cab auto pickup with only 53K. Cherry! They are still out there! The 80 year old fellow couldn't drive anymore. It had been poorly serviced and sat in the garage for years. The diff oil had actually separated and the seals leaked. All other was good, but the timing chain rattled excessively on start up. Mobil 1 apparently cleaned out the timing chain tensioner, and she rattles no more. And just as important, eventho I expected it to leak like crazy, there has been no leaks and does not burn it.

[Diesel Joe]

IF there is a problem that using synthetic brings to the surface, (it is VERY slick and often causes leaks in old engines) then that's a problem you NEEDED to fix in the first place. There is nothing bad about synthetic oil.... Save maybe the cost in comparrison to dyno oil. It has been being run in old and new diesel engines around here for twenty years!


That's the thing about synthetic oil. With proper filtration you CAN safely extend drain intervals. If youre going to go much beyond 5000klm you should change your oil filter so that the extended oil gets good filtration. What you should do is add in a bypass engine oil filter. The standard oil filter passes 100% of the oil ever 60 seconds or so. The bypass filter passes the oil every ten minutes or so. A standard oil filter is good for around 25+ microns. Many bypass oil filters are good for LESS than 4 microns!!!!

[Erick Lihme]

PRODUCT DESCRIPTION
The Ea By-Pass Oil Filter (EaBP) provides the best possible filtration protection against wear and oil degradation. Working in conjunction with the engine’s full-flow oil filter, the AMSOIL Ea By-Pass Filter operates by filtering oil on a “partial-flow” basis. It draws approximately 10 percent of the oil pump’s capacity at any one time and traps the extremely small, wear-causing contaminants that full-flow filters can’t remove. The AMSOIL Ea Bypass Filter typically filters all the oil in the system several times an hour, so the engine continuously receives analytically clean oil.

http://www.amsoil.com/storefront/SearchResult.aspx?CategoryID=77

[Mike S]

I have run Mobil 1 in all my vehicles for years. When I bought my FJ60, the owner had run dino in it, and I switched to Mobil 1 - no leaks after the change.

My FZJ80 used Catrol Syntec from the beginning, and I recently switched to Mobil 1. Again, no leaks.

I have used Mobil 1 in my Ford F250 Deisel, My Ford Explorer, both My Landcruisers, my Maserati, and my Ford Expedition. Some of these vehicles had some extreme miles on them, but no problems. My son-in-law drove my Explorer home after blowing the bottom radiator tank - it was dry and HOT when he got home. The shop had to mill the head because of warpage, but they reported zero problems with the block, crank, bearings, etc. My daughter drove that little truck for over 150,000 miles after that incident. So I believe that synthetics are money well spent.

[Erick Lihme]

http://neptune.spacebears.com/cars/stories/amsoil.html

[Grim Reaper]

http://neptune.spacebears.com/cars/stories/amsoil.html

Curious to see what the next mobile 1 test shows now that the motor is worn in.

I have TWICE on two different motor run into leak issues when I went to Synthetic. The first was on a 350 Chevy that started leaking around the mechanical fuel pump and out of both valve covers and it was MAJOR leaking. The motor was relatively dry before that. That was Syntec that time. I did notice and improved MPG and went to a 6k change interval. After new valve cover gaskets and pump gasket I didn’t have any other leak issues. Motor have about 80k when this happened.

The second time is on my 454 Suburban. This time with Mobile1. The valve covers were already seeping a little and the Mobil1 made it worse. That truck see’s very few miles (under 3k last year) I change yearly more out of fear of condensation in the block then anything else.

I have in the past run the Redline MT90 in a Toyota W58 (N/A supra) and noticed a BIG improvement in shift feel. The W56 (nearly identical to the W58) in my 4Runner has Mobile1 in it and I have noticed it is a little notchy. It have about 5k on it now after a full rebuild. After the post about the Redline and Toy tranny’s I think I may switch it to Redline since I previously had good results.


In the last 2- 3 years I have been going through my truck and rebuilt the engine transmission and now the rear end when I swapped in a E-Locker. Everything is about broke in now. Next change on everything but the front diff is going Synthetic. Probably Mobil1 on everything but the Transmission since it is the easiest to get for me (they have it at Autozone). Try the Redline again in the transmission.

[Erick Lihme]

Royal Purple 75-90w GL4/GL5 in cooler tempatures seems fine. As we are going into summer, the shifter felt 'notchy' and a slight bearing noise could be heard in 5th under pressure, where the dino oil, 80-90w GL4 was replaced by the Royal Purple at the onset of winter, the Vavoline felt good at all temps, and no bearing noise was heard.
The Royal Purple was replaced with the dino oil until I get around to the MT90. Again with dino oil, the bearing noise went away.

Given how Royal Purple seemed to do in the trans, the diff's may get one of the other GL5 Redline heavier gear oils. I've read that the MT90 does best in the W56 trans because it is thicker.