Synthetic oil in high mileage engine

[Koz]

Koz - I'm not questioning your knowledge. After reading through a lot of posts over the years I know you are one of the "go to" guys on the site.

I just wanted to put what Mobil 1 says about it - granted they have something to gain and want to sell their oil. And as others have said, I'm sure many have done it on high mileage engines without any problems. It really boils down to risk/reward and if the person is willing to take the risk.

Not to Hijack the thread - what is the latest you would consider switching? Is 36K to late?

There is a difference between an engine that has over 100K miles that you don't know how it was maintained and an engine that has 36K and was maintained. At 36K miles I would not even give it a second thought, make the switch. What I do recommend is using either 0w-20 or 0w-30, don't matter what brand. 0w synthetics will provide the best pour rate which is one of the most important qualities in protecting an engine from (cold start) wear (which is the BIGGEST cause of engine wear).

To anwser your question; it is never too late to switch to synthetic, you just need to make sure you do not have sludge. Even if you do, you can flush the engine with a high quality flush and then use synthetic. I just wanted to caution members to the fact that if there is sludge and you do not remove it before going to synthetic, you will regret it!

Koz

 

[RonMAIDEN]

Caution should be taken if you are unsure of the truck's history like Koz stated.

Mine was a dino oil truck til about 98k miles in '05 (which was changed regularly) and I run M1 with a Puralator PureOne filter and do oil changes every 8000 miles or 10 months and now have 162k on the engine and still has zero leaks and is as smooth and quiet as my mom's '99 Limited with 90k on it.
It also had the right side valve cover off (coil pack issue) at 154k and my mechanic said it looked very clean for a 12 year old truck and no signs of sludge.

 

[blaniac22]

There is a difference between an engine that has over 100K miles that you don't know how it was maintained and an engine that has 36K and was maintained. At 36K miles I would not even give it a second thought, make the switch. What I do recommend is using either 0w-20 or 0w-30, don't matter what brand. 0w synthetics will provide the best pour rate which is one of the most important qualities in protecting an engine from (cold start) wear (which is the BIGGEST cause of engine wear).

To anwser your question; it is never too late to switch to synthetic, you just need to make sure you do not have sludge. Even if you do, you can flush the engine with a high quality flush and then use synthetic. I just wanted to caution members to the fact that if there is sludge and you do not remove it before going to synthetic, you will regret it!

Koz

Thanks! Mine has been maintained regularly, no more than 4700 miles between changes - sometimes a lot less because I'd change it before going on a long road trip and then again shortly after. Probably a little overkill, but the changes were free and it was in warranty.

You answered my next question - the Mobil site suggested the 0W oil - I wasn't sure about that...but that's what I'm going to pick up and plan on doing it this weekend.

RonMaiden - thanks for your input as well! I love this site!

We now return to our originally scheduled program.

 

[Toyodas]

No problems here with switching over from conventional oil to full synthetic.

Got our 1997 T4R Limited two-wheel drive with 112,000 miles and fed conventional dealer bulk oil all its life.

My first oil change was with Valvoline MaxLife synthetic blend at 3,000 miles the oil was already dark, jet black. So already I knew there was some good cleaning going on internally. I replaced the MaxLife out early at 3,000 and since then I use whatever full synthetic I can find on sale and now the color of the oil stays amber until about 5,000 miles or more.

I also use an extended drain capable oil filter like a Mobil 1, Bosch distance plus, or a Fram Extended Guard. All are capable of yearly changes up to 15,000 miles with a full synthetic.

If you're planning to use synthetic at least decide on a longer oil change interval than you were doing with conventional oil.

 

[WillK]

Sorry for bringing up and old post, but I'm considering switching to synthetic from dino oil.

I'm doing plugs,wires, fuel filter, oil and filter today and was going to switch over to M1.

My Runner has 192,9XX miles and it was well maintained(verified by Carfax and dealer as previous owner had all of the maintenance done at the dealership).
I don't have any leaks, but don't want none either.

After reading some other member's posts, I feel pretty comfortable with doing this.

Anyone have any thoughts why I shouldn't, other than the potential sludge issue...

 

[TNRunner99]

Glad this thread came back up. One thing I was wondering was what if one made the switch to a synthetic blend oil before gong full synthetic. I got my 99 runner with about 50,000 on it. After 75,000 I switched to 10w 30 Valvoline Max Life synthetic blend. I'm a 176,000 now with no troubles and no leaks.
I'm thinking of making the switch to Valvoline full synthetic soon. Any thoughts?
Would this be a better step to make than going straight full synthetic?
It seems everyone is using Mobil 1, what is the reason for so many using this brand of full synthetic oil?

 

[XJeepguy]

No point in doing 'blends' before . Just go full synthetic , I've switched in engines that had 150K+ , no issues whatsoever .

 

[Neumonic]

Excellent thread!

I purchased my 2003 from a close friend that bought it new, she had the oil changed religiously and kept a folder on all the TSB's, repairs etc. I used a synthetic blend on my first oil change right at 180,000 miles. Thanks to this thread I will go ahead and put full synthetic in on my next change. Wasn't thinking about 0-30 until reading the information here.

Thanks,
John

 

[TNRunner99]

Made the switch today to Mobil 1 High Mileage 5W-30 with a K&N oil filter. We will see what happens. I will probably check it around 3,000 and see what the color looks like. May do a change then if its dirty.

 

[mikejones686]

bought my 05 with about 67k on it and switched over to mobil 1 at about 70k with no leaks or problems. We have a 03 camery v6 with 280+k and only using cheaper dino and cheap oil filters and have never had a problem with the car. Im sure it has some sludge build up but we have gotten our monies worth. Obviously dino works. mobil 1 just gives me peace of mind. just my thought.