When is it to late to switch to synthetic?

[TimCat]

My Elantra has 70K miles now. Is it to late to switch to synthetic? I was always told if your car wasnt low mileage you shouldn't make the switch. Anyone have any knowledge or experience of this?

[GTSTISL]

you should probably switch to high mileage if anything. it would be the best for your engine at this stage.

[mtlelantra]

I bought my 89 Civic used in 97 with 100k miles and I switched to Mobil 1 with absolutely no problems. It's getting close to 200k miles now... I do an oil change around every 5000 miles.

[Cypher]

well if you wanna go to syntheic first use semi for a couple oil changes to make sure your seals are going to leak then if after a couple changes it isn't leaking then switch to full

[TimCat]

Okay, so I got 3 different answers here lol. Now I am REALLY confused *sigh*

[2loud2k2xd]

ok, i have 68,000 on my car. i used dino oil for all of them. i switched to full syn (mobile1) at 66,000 when i started to spray. no leaks...any where. the rule is going from dino oil then to syn, then back to dino oil= leaky seals and gaskets.
i personally would just make the switch to syn and see what happens. just dont go back to dino oil after the switch.

btw: i change the oil and filter every 3000k. yes even syn i change at 3000k. i get it FREE from work :D

[blupupher]

Biggest this is what has been the oil change history on this vehicle? If it has been regular, you should have no problems switching.
The only prouduct I would recomend is called Auto RX (http://www.auto-rx.com), which is an engine seal conditioner/cleaner. Does a good job and would be a good thing to use before going to syn.

[Soron]

Whatever you do don't use the high milage oils, they mess up your seals good as they "help keep the engine sealed" by making the seals swell and if you switch to any other type of oil, dino or synthetic, the seals un-swell and you have leaks. I switched at 60k myself and I did the semi-syn oil change for awhile to check for leaks before I switched. I am using lower grade synthetic (valvoline synpower) to clean out the engine to get it ready for the real stuf, Royal Purple ;)

I am against using oil flushes myself (which is what auto rx is) as they can clean too much too fast. What I mean by that is that they clean out the sludge and crap from your engine but you find out REAL QUICK if you have leaks, usually on that oil change and you will have to get the seals changed out by a mechanic as the leak will be too large to re-plug up with dino oil. Going the semi-syn route, if there is a leak you can switch back to dino to re-plug the leak with no harm done. There should be no problem with using an engine oil flush when the engine is still young but for those of us with older engines (ie 60k in my case), unless I have the money saved up just in case a leak develops when I make the switch, I would not use it.

[blupupher]

Soron, please do a little more research.
For starters, HM oils do not "damage" seals. Myself and others have switched back and forth between HM and dino and syn and never had a problem. Also, all the HM info I have ever seen says no problems switching between them and other types of oils. You can even use HM oils in a new vehicle with no ill effects.
As for Auto RX, it is not a quick clean product. It is used over the interval of a normal OCI. Is contains special esters and seal conditioners (not seal swellers) that clean the engine over time. It is designed to stop leaks while cleaning the engine. I do agree with you with pretty much all other engine oil flushes and additives, they can cause more problems than they fix.
For the original poster, as for which type of Syn to use, it is up to you. RP is a good oil (although my run with it had a poor used oil analysis (http://users4.ev1.net/~nlhoyt/oil/uoa2.jpg)), as is Mobil 1, Amsoil, and Redline.
For more info than you need on oil, visit www.bobistheoilguy.com.

[Soron]

I have done the research, thats how I found out about HM oils damaging the seals, thats how my ford contour died. The HM oil swelled up the seals so that compression was increased and seemed to run better (only while I was still running the HM oil, started at 75k and kept in in till 125k) but when I switched back after 2 oil changes of normal dino oil and the seals were shot, and I just ran it into the ground after that as it was not a car worth saving in the first place, but I did use it as a trade in for my elantra. I found out about HM oils "properties" when I did research on it and found out it was basically marketing hype and then ran across a small website that showed the damage it did, which made me want to switch back to dino, problem was it was too late for me to switch back by then as the damage had already been done, short term use will not damage the seals, but long term use, I can tell you from EXPERIANCE it definatly does. BTW the HM oil in question I was using all that time was Quaker State HM Oil, I know I know bad Soron! I didn't know anything about oil then, and just got the cheapest stuff available but the damage that oil has caused prompted me to learn much more about engine oil in general, bob the oil guy is a good start to start learning about oil but its not the only place on the net that provides oil information.

As for auto rx, call it what you will but it basically comes down to an oil flush, as it was designed to remove sludge and gunk rather than lubricate as its main function.

Original poster, avoid amsoil and redline at all costs, they are not an api certified oils, which basically means that if you run it in your engine your warrenty is voided.