Synthetic Rotella

Junkman · Oct 2, 2004

Opinions please...... a 85K mile engine..... switch to synthetic or just stay with what has been used in the past? Just had a discussion about this and the opinion was NOT to go to synthetic if the engine has over 50K because the engine will develop leaks with the synthetic.... your thoughts????? /forums/images/graemlins/confused.gif

BRIGUY · Oct 2, 2004

Junk,
I just went through this 2.5 years ago. I bought a dodge with 82k on it's Mitsu 3.0. It was leaking 1/2 qt per 3k on dino, mostly from the cam seals. Normal occurrence for these SOHC engines. I switched it to a steady diet of synthetic and I think the leaks slowed a little.

At 90k I did a good coolant flush and caused a small coolant leak. So I decided to rebuild the top end. These motors have a lot of problems with the exhaust guides dropping, causing the valve seals to come off. When this happens they really puff. So I rebuilt the heads with the updated guides and resealed the top and front of the motor. Good thing I did because the valve guides fell out of the heads on the bench when the heads were disassembled.

Well 40k later on Mobil 1 still no leaks (Knock on Wood!!!!) Rear crank seal still original.

I read somewhere that most of the synthetics have more distillates in them now for seal swell. Todays synthetics are not prone to the leaking problems of earlier formulations.

Maybe you can find a better answer on bobistheoilguy.com

gsxr1100 · Oct 2, 2004

junkman- Yes you can switch and be fine. I would not use an engine cleaning additive in the oil. Let the oil clean the engine and I would drain sooner then normal to get rid of the junk in the engine.

Synthetic does not cause leaks. That is incorrect. Synthetic cleans out areas that have sludge. If it has a leak and the sludge is covering the holes if would leak down the road. They clean sludge and junk out; the problem was always there.

My current car has over 80K miles and I started using synthetic over 40K miles. My last 91 ford mustang 5.0 had 48K miles when I got it . Now has over 120K miles on third co-worker and is fine.

Back in the 80's yes, they did not have seal swellers in them; but this was corrected in the early 90's.

WilliamBos · Oct 2, 2004

Hi All,

Seal swellers? really? So if I were using a High detergent oil in something ( Rotella t 30w ) and wanted to swap in diesle synthetic, does the synthetic have a high detergency or equivelent additive in it? GEEZ, I am way behind on this syn technology?

What about using it after an overhaul or fresh rebuild? We are rebuilding a A3.152 Perkins and after the second or third ( to get out all assembly lube ) oil change I may switch to Synthetic.

Thanks

Will

BillyP · Oct 3, 2004

Junkman, I switched from dino to Mobil 1 last year, in a Nissan with 110K miles. No leaks to be seen but I did get an increase in gas mileage.

gsxr1100 · Oct 3, 2004

yes, thy had to add this since the seals do not hold. It was a huge issue 15 years ago but now, it is not even known.

I can't answer since all oils are different. Some are high detergent and some are low. It depends on Ca, Mg & Ba.

You can install synthetic from mile 000.000. THe breakin will happen no matter what. So the rings do not seat as fast. Who care with less wear. When you wait for some milage interval, it is seating the rings, but adding wear...Up to you; High end cars from from manuafacture with synthetic oil in them.

WilliamBos · Oct 3, 2004

Hi Guys,

After reading all these posts on the positives of syn oil, next oil change I am going to put it in my 1996 Escort. It has 190,000 km, ( 120,000 miles ) on it. I am going to run it at regular intervals ( 5000km, 3100 miles...) for a couple of changes, the I am thinking of extending them a little, maybe 7000 km ( 4300 miles ). I dont believe in over extending too far, but I am used to Dino oil. What do you guys think about this interval? I am going to run mobil 1 full synthetic.

Thanks

Will

gsxr1100 · Oct 3, 2004

I do not think 4300 miles is extended oil drains. I bet the manual says every 5 or longer drains. I would do what is stated in the manual. The first is the shortest to clean and then you can go longer. The problem with M1 is that the TBN drops like a rock and that is surprising. I would say that you could go around 6 to 8K miles without a problem. Look in the book and see what they say. The 3 or 4K mile drains is a waste and not even stated by the conservative manufactures.

Unless you are testing oil, you are only guessing.

I am going from over 12K mile drains in my Lexus and it is perfect. I will be doing the next at the same or 13,500 miles. I am also doing these drains in my wifes MB -ML420. These are extended drains so to speak, but not even 2x times what the manuafacture calls for. My Lexus is 7,500 mile drains and could double it no problem but I need to see the oil results first since I personally like to see what is going on.

WilliamBos · Oct 3, 2004

Hi,

I checked my manual and 5,000miles ( 8,000km ) are the recommended milage for regular driving, and severe driving is 3,000 miles ( 5,000km ) So I a going to put in 5W30 M1 on the next change!!

Now I just need to find a syn oil that is god for diesels ( older ) and has something equal to high dteregent that our tractor needs.

Thanks,

Will

gsxr1100 · Oct 3, 2004

go 4k miles next change to clean. Then I personally would go like 6,500 on changes.

Just look at some synthetic oil and it properties and see what is good in those areas.