I have a 2001 4.0 SOHC with approx. 112,000 miles on it now. I have always used 5W-30 Castrol (conventional oil) since I bought the truck used in '05.

Now with this many miles in it, would it be ok to change to synthetic oil (5w-30) or even 0w-30 Mobil 1 b/c I have had the timing chain rattle since 30k. I have heard some on here switch to the lighter weight oil and synthetic oil and it reduces the rattle a little bit.

Or would this be a bad idea with having over 100k on the engine?

 

There shouldn't be any problem changing over. Some will say you'll have leaks but I've done it in a few vehicles with no issues!

 

Switching to synthetic would be fine

 

The leaking issue was brought about by the first synthetic oils. Supposedly it is no longer an issue.

 

Switching to Synthetic isn't an issue, it'll take about 2 or 3 oil changes to get all of the old stuff out, but you shouldn't have any problems or leaks.

 

Ok cool thanks. Should I use 5w-30 or 0w-30 in my engine? Mobil 1 or Castrol?

And I have always used Motorcraft filters in my truck too. Is that fine to keep using also?

 

Since you never get really cold, 0w-30 should be alrite. same goes for the filter

 

Yeah the Mobil 1 site recommends changing to synthetic, then at 2500 miles change it again, then again at 3500, and after that one continue on with the usual 5-6000 oil change.

Does that sound about right?

 

I would stick with 5w-30. I use mobil 1 but have used castrol before. I believe mobil 1 to make the best synthetics. Just my opinion. Motorcraft filters are fine, though places often have deals with 5 quarts of oil, which is why I also have a mobil 1 filter. Five quarts and a filter for 29.99 pretty good for full synthetic

 

Sounds good. depending on how clean your oil is when you change it at the 3500 is how you should gauge changing it in the long run, I've seen some trucks go 10k between oil changes and their oil still didn't look too bad.

 

Yeah that ain't a bad price at all. Especially with the added benefits of running synthetic. I should have switched a long time ago....

But I believe I will go with Mobil 1 too. Lots of people on here use it and are very happy. I am also changing the front and rear axle oils and transfer case oils soon at 115k mark over to synthetic. Is that a good idea to do too? I have never changed the axles or transfer case oils.

 

Yes, most definitely a good thing.

 

Sweet thanks. I will for sure keep an eye on the condition of the oil as I change it for the first time at 3500 miles and so forth. I am thinking it will look like crap after the first time of running synthetic through it lol.

 

Haha ok, I will take note of that.

 

Alright changed over to Mobil 1 5w-30 with a new motorcraft filter this morning and drove it around for a good 40-50 miles. I am really impressed with the reduction of the valve train noise. It is almost gone unless you listen really hard around the 2300-2500 RPM mark. Other than that it seems that the engine runs smoother and idles better too, and this is just the first oil change. I hope it continues to improve even more after the next couple of oil changes. Thanks a lot for the help fellas, much appreciated!

 

When I do a 'conventional to synthetic' swap on an older engine I run it for about 200-500 miles then do another oil change and run that for 3k, then another change and run it for 7k and that's where i change it every time.

The first two oil changes are to clean the engine and get fresh oil in there to continue cleaning it.
Just my method.

 

I did the transition from conventional to synthetic oil in my truck at 142,000 miles, and i was sold on it (im at 163,000miles now). Even though they say you can go longer on a synthetic change, i still change at 3,000 but maybe im just too old fashioned when it comes to oil changes. lol I definitely experienced quieter overall operation and it even seems to greatly reduce any timing chain rattle i experience with my sohc.

 

Changing you axles to synthetic is the best idea. Conventional only lasts about 5000 miles. I have royal purple front and rear. I run motor craft on the tranny and nothing on my cracked t case lol. I've only run Mobil 1 with its filter in every vehicle I've owned

 

Yup. Im a mobil 1 guy.

Even after 3k-4k, the oil still doenst look that bad. I believe I could easily run up to 5k and be fine, but Im a 3k mile oil change guy as well.

 

Yeah, I think I might go with that route. That's what I did with my 93 Mustang when I changed from conventional to synthetic. I just didn't know if that concept could work on a Ranger or not. Thanks!

 

Ok cool. I was wondering how people were fairing from changing to synthetic so late in the mileage on the engine. Yeah I am right on the book on maintaining my truck also. I change the oil every 5k and what ever else the Scheduled Maintenance Guide says to do lol.

But yes I would have to agree, I put some more miles on the truck going to my night classes tonight and I am very pleased with the reduction of the timing chain rattle. It is almost gone unless you listen very closely.

 

What synthetic oil brand did you use in the axles?

Yeah I went with Mobil 1 just b/c almost everyone on the internet or my trusted mechanics say its the best.

 

Haha when I ran Castrol (conventional) I only changed my oil every 5k. But I never saw any problems. Every time I changed the oil of course it was dark in color, but it was still the same texture (almost) as it was when I put it in 5k miles ago. So I am going to use the same regiment of changing oil.

 

And 112,000 miles is nothing by the way. That is still a new motor.

I have been running synthetic for as long as I can remember, 10w-30 on my '96 for years now. I'm at 219k and still the same small leak I have always had.

In no way will synthetic harm your system.

 

^ oh haha I thought over a 100k was old. Oh well!

But thanks for the info. Helps put me at ease over the whole issue of not messing anything up.