Thanks to everyone for the advise on the 4.6 Triton.
If a truck "grew up" on conventional oil, can you later switch to synthetic without any bad side affects?
Also, what about the reverse, once you are on synthetic can you switch back to conventional?
I've learned so much on this site that they ought to offer college credits just for reading the responses!

 

From my research..and information from the many experts on this web site...if a truck has been using conventional oil..you really should not switch to Synthetic if it is over 50,000 miles. This is because Synthetic oil supposedly will "clean out" the deposits and any build up on the internal engine parts...and could cause some problems.

You can, at any time switch back to conventional oil without any harm.

You can NOT mix different Synthetic oils though. Most are not compatible.

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2000 F-150 XLT, 4x2, 5.4L Supercab, Styleside, Black with silver two-tone, 3.55, class III towing package with heavy duty cooling package, overhead console, sliding rear window, keyless entry, dark graphite interior, in dash CD, Pendaliner bedliner, K&N air filter, rubberized undercoating, cabin filtration system, Bugflector II, 5W-30 Mobil 1, engine build 10/4/99

 

Dustoff, I wish I could discount your last post here but I've learned to respect your opinion. My truck had 50k mi. when I bought it. Now it has 66k, and I was going to buy Mobil 1 in a couple of weeks. No idea if previous owner used synthetic or not. I wish everyone HAD to use it. If I have to stick with the inferior "conventional" oil, which do you recommend?

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White 97 XLT SC 4.6, 4X4, 3.55ls, tow pkg, long bed, Rhino liner, Owens running boards

 

Dustoff,

Amsoil says its compatible with all conventional and synthetics! As far as switching, if you don't have any mechanical problems, I would say go for it. A friend of mine switched to mobil and he has 70,000 on his. Still no leaks or any problems.

Remember that now a days people put their miles on fairly quickly. And the cars are usually on 2-3 years old. Your seals and gaskets should still be relitively new. That is why leaks usually occur, because the gaskets are so old and dried out they crack and let oil through.

Moreover
I would suggest that run some engine flush through before you switch, because that will break up all the sludge and varnish. So you don't clog your new filter too fast. Also I would change my filter a little sooner to make sure that it's still doing it's job. After that you should have no problem running synthetic for the rest of the life of the vehicle.

You will be able to stop most of the wear on the engine. Though synthetic will not repair a broken or soon to be broken vehicle.

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Lube-Direct

[This message has been edited by msparks (edited 01-12-2000).]

 

Moveover...
Thank you for the kind words...I do want to say that I am NOT an expert at all on Synthetics and in fact recently began using it. What I posted earlier is only what I have read over the past few months.

I wanted to put Synthetic oil in our 92 Mazda 626 which has about 100,000 miles..but several board members posted that it was unwise to do so. I can't say for sure either way.

Msparks..that is good to know. I did read that some Synthetics are not compatible with each other. I know you have more experience in Synthetics and I just might switch our Mazda to Synthetic (if I can find the slight electrical problem in it).

I am using MOBIL 1 in both of our new vehicles (7 day old 2000 Saturn LS). I went to Mobil 1 based off of the comments from other F150online users. So far..it seems to be just fine. I am sure any of the other Synthetics would be just fine also. They ALL have to be certified, just like conventional oil.

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2000 F-150 XLT, 4x2, 5.4L Supercab, Styleside, Black with silver two-tone, 3.55, class III towing package with heavy duty cooling package, overhead console, sliding rear window, keyless entry, dark graphite interior, in dash CD, Pendaliner bedliner, K&N air filter, rubberized undercoating, cabin filtration system, Bugflector II, 5W-30 Mobil 1, engine build 10/4/99

 

Dustoff,

See the concern that I have with the 92 is the seal/gasket thing.

This is what happens: When you run conventional oil for that long, Varnish/sludge builds up on the inside parts of the gaskets. Then the outside of the gaskets get dried out and start to rot. Then in essence the varnish/sludge is the barrier that is stopping any leaks.

When you switch to synthetics that varnish/sludge is removed. Which is why synthetics are prone to leaks.

I am not a true expert in the subject, but I would not really push someone to switch to synthetics after about 5 years max. I belive these newer cars that are 3-4 years old, but with high milage are still new enough that when you switch to the synthetic the varnish/sludge is removed and your gaskets are still new enough that they swell and become more flexible, and lubricated all the way to the outside.

On motorcycles, when you switch to synthetics you will notice a dust ring around most of the gaskets. This is because the oil is getting to the outside of the gaskets and keeping them lubricated. They will last a lot longer this way. By the way it is not a leak, it is just a minute amount around the entire gasket.

The same is for cars/ trucks but since the engines are so hard to get too and see. You don't really notice it as much.

I have a 92 Ranger that only has 90,000 but I don't run synthetics. One reason I am selling, but the main reason is because of the leak thing.

Well I hope I made a little sense here sorry for being so long winded.

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Lube-Direct

 

msparks...

That was my main concern...that Synthetics "clean" out the crud in your engine. To be perfectly honest..I do not think it is worth it for the 92 Mazda..it will be our 3rd vehicle anyway...and runs very well on conventional Castrol oil.

When you say Synthetics are prone to leaks..I am assuming you are refering to how it cleans the high mileage engine and thus causes it to leak. I hope, since I am starting both of our brand new vehicles off with Synthetics, that they will not leak in the future.

Thanks for the information!!!

 

I hope to buy a new car this year. I am switching right away(1,000) miles to synthetic, though I think the car comes from the factory with it. I am looking at a Jetta TDI(diesel)

I switched my F 150 at about 6 thousands to synthetic-though its castol syntec, and we all know that story. Then I found out about Amsoil at about 18,000 And that is what I have been running for awhile. I plan on running Amsoil in every vehicle that I own from the get go. Until something better comes out. HAHA then I guess I will be out of work.

You should never have any leaks from a new vehicle because it causes the seals/gaskets to swell and stay lubricated. Therefore they should stay like new for hundreds of thousands of mile Hell even 1 million if the rest of the car will last that long haha.

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Lube-Direct

 

I have had bad experience with synthetics. Caused oil leakes in every vehicle I used it in. Including one's with less than 30k. A buddy of mine uses Mobil one in his suburbun. His son changed the oil one time and negleted to re add the Mobil one, The truck only went about a block before it locked up. So I don't see any real addvatages. Not to mention All the vehicles I have had in my shop with over 180k have run reg. oil and I have not seen one motor with over 180k that ran Mobil One.

 

Double Tap,

Are you SURE that synthetic oils caused the leaks? That seems like quite a statement to make if you don't have some kind of proof to back it up. Also, most engines run the same without oil, wether it's without Mobil 1 or without Castrol GTX makes little difference.

It seems like most of us here want the added benefits of synthetics, I know I do. I have never seen any data that hasn't shown they were a far superior lubricant to conventional oils.

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2000 F-150 4x4 SuperCab XLT, 5.4 liter Triton V8 - Windsor, 4R70W automatic, Sterling 9.75" w/3.55 limited slip, towing package, sliding rear window, CD, keyless entry, Amazon Green / Silver.

77 Bronco, 64 Falcon

 

Hi guys!
I just thought I add my .2c. I switched to synthetic oil from premium regular oil in my 95 GMC after 3 years at about 60000km (37000mi) and shortly after that had I had gasket leak at the rear of the engine. I switched because of the added benefits at cold start (faster lub, but have been wondering ever since. I used it only in the winter and am back at regular premium oil and no leaks.
To SDDL-Up:
I can tell you one independent study on motor oil that shows, that there is no added benifit to synthtics. Check the Consumer Reports 1996/1997. They did an extensive field test in New York on Taxi cabs and could not find any less wear on the engines with synthetics and the ones with Slick 50 etc.. I am telling you, this report is an eye opener! Very interesting!!!

 

SDDL-up,
I own a car lot and sell mostly muscle cars-new and old. I also deal with some Trucks. Every time some one tells me they use synthetic oil I almost always find oil leaks. I also was developing oil leakes after I used synthetic oils in some of the cars including newer cars with under 30k and older cars with newer motors. I go through a lot of cars and I have a few run with no oil due to owners who think the oil light means it's time to change the oil! Remarkably they usally take a long time to blow up. The suburban I metion had 100k on it and only went a block before it locked up with Mobil One. My freind drove his 318 work van 50 miles before it started Knocking because he forgot to put oil in it. Once he put a couple quarts in it, it stopped Knocking. He used reg. Valvoline. My company tow vehicles have always used reg. oil because it's cheaper and they are running over 200 k. before I trade them. Oil changes about every 5k and I have never had a problem with leaks or engine failer. My wife is driving an Expedition right now and I have not had a single problem with it. No start up knock or oil leaks. I just run reg. old 88Cent a quart Castro. I think synthetics are a waste of money. The oil companies want people to think they are making their cars last longer. When in fact they are just spending more for their motor oil! Hey, I use to think it was better too. But from what I have read and experienced there is really no addvantage.

[This message has been edited by Double Tap (edited 01-13-2000).]

 

Just my .02...I switched from conventional oil to Mobil 1 in my Ranger at 63,000 miles. It leaked slightly at the rear of the engine for about 3-6,000 miles. Now it has stopped leaking and is just fine. I know have 79k on it.

But, there is nothing wrong with conventionals either. I have 160k on my 4.9L F150 and that is conventional oil and I have 180k on my 3.0 Probe on conventional oil. So I guess I am a believer in both synthetics and conventionals if thats at all possible!!

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1994 Ford Ranger 4x4 4.0L, K&N, Superchip, 63mm T-body

1993 F150 Ext. cab 4.9L 5spd 4x4

 

Ford's 5w30 service bulletin: http://www.chekchart.com/fd99816.htm

 

This is what makes this forum great--A good exchange of information and ideas. So, as I have before just a few notes.

I have used Amsoil for about 20 years now. From the beginning, notes regarding the use of synthetics on vehicles that have extended miles on them can have negetive results.

Two reasons, 1) Synthetics (not just Amsoil) have a high detergent capability. They clean inside your engine. Their base stocks, the better they are, do not contribute to sludge or varnish the way petroleum oils due when heated.

Synthetics are designed differently and the molecules are built rather that refined.

2) Seal swell, seals get used to constant conditions i.e. petroleum based oil. When switched to Synthetics, this changes the conditions withing the seals and cleans the junk within too. In some cases leaks develop.

Even though I believe that Amsoil is a very superior product in terms of Synthetics, I really discourage customers with extended miles from switching. Not because the product is inferior, or because it will not benefit the vehicle, I don't want to contribute to the risk of leaks.

The focus then, no matter how good the oil is i.e. better heat protection, lower temp pour points and volatility, mileage etc. they will never get over the fact that it caused leaks. Even if the product had nothing to do with it, people will remember, it wasn't leaking before---

I have found though, those that take care of thier engine and have routine maintenance i.e. regular frenquent oil changes, when they did change to synthetics, experienced no problems at all---

Take care to all, thanks for the opportunity to share---Regards,

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Rick Medina
Las Vegas, Nevada