synthetic oil question

[emmer]

I have about 2500-3000km on my newly rebuilt 7.3 idi, and i was wondering if it's safe to run synthetic now.

I was told not to use synthetic for the breakin period. Also I was told to stay away from synthetic because it's ******* seals.

Another guy told me a buddy of his had a car with lots of km, but in not bad shape.........as soon as he went synthetic the car started smoking..

I really like the way synthetic doesn;t thickin up in very cold temps but....

any opinions or suggestions?

 

[87crewdually]

Here's a couple from the Mobil site. All the major brands have a fact and fiction answer guide like this.


Myth: You should break in your engine with conventional oil, then switch to a synthetic oil like Mobil 1.
Reality:
You can start using Mobil 1 in new vehicles at any time, even in brand new vehicles. In fact, Mobil 1 is original equipment (it is installed at the factory) in:
Acura RDX

Aston Martin

All Bentley Vehicles

All Cadillac Vehicles

Chevrolet Corvette C6 and Z06

Chevrolet TrailBlazer SS

Chrysler 300C SRT-8

Cobalt SS S/C Coupe

Dodge Caliber SRT-4, Charger SRT-8, and Magnum SRT-8

Jeep Cherokee SRT-8

Mercedes-Benz AMG Vehicles

Mercedes SLR

Mitsubishi Evolution

Pontiac Solstice GXP

All Porsche Vehicles

Saturn Ion Red Line and Saturn Sky Red Line

Viper SRT-10

One of the myths surrounding synthetic oils is that new engines require a break-in period with conventional oil. The fact is, current engine manufacturing technology does not require this break-in period. As indicated by the decisions of the engineers who design the high-performance cars listed above, Mobil 1 can be used starting the day you drive the car off the showroom floor. Watch our answer to this myth.

Myth:
Mobil 1 can't be used in diesel engines.

Reality:
Yes it can.
For heavy duty truck engines that require API CJ-4, CI-4 Plus, CI-4, CH-4 or CG-4, there's Mobil 1Turbo Diesel Truck 5W-40*.


Be sure to check your owner's manual for the oil quality recommended for your diesel engine.

Heavy duty trucks requiring a viscosity other than 5W-40 should consider one of the Mobil Delvac 1300 Super products. Mobil Delvac products can be purchased at a large number of truck stops across America, and select retail and auto parts stores, as well as from ExxonMobil Distributors.

*When buying Mobil 1 Turbo Diesel Truck 5W-40, please check your bottle labels while inventory transitions to the new CJ-4 formulation.

Updated May 2009





Myth:
Mobil 1 will leak out of the seals of older cars.

Reality:
Mobil 1 does not cause leaks. In fact, new Mobil 1 was tested in dozens of industry standard and original equipment manufacturers (OEMs) tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made. If an older engine is in good condition and does not have oil leaks, Mobil 1 provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1. ExxonMobil also recommends following the automobile manufacturer's manual for the proper oil to use. Also watch our answer; it's myth four of five in our online video.

http://www.mobiloil.com/USA-English/MotorOil/Synthetics/Myths.aspx

 

[TBigLug]

I'd be leary about trusting a company's own FAQ. For one, "The fact is, current engine manufacturing technology does not require this break-in period." Bottom line is his motoris not designed with modern technology. Its an old motor regardless of being rebuilt or not. I'm metric impaired but we always went through two oil changes (6,000 miles or so) before we switched over to full synthetic. Given the motor and the old technology, I'd run Rotella but, it's your call. Maybe the synthetic oil company will refund the price of your oil if it makes your truck leak and smoke.

 

[TBigLug]

BTW, as far as synthetic oil in general goes, I've used it in my Cavvy since 3,000 miles. Car still runs like the day I bought it and has needed NO repairs in 120,000 miles. Conversely, be it coincidence or not, we started running synthetic in my buddy's 1980 Chevy K10 and within 50 miles it started leaking oil and blew up within 3 months. Coincidence, maybe, did the oil cause it, maybe- maybe-not. All I can tell you is he had owned and drove that truck for 3 years. The ONLY thing that was differant during that time period was the oil. I'm not saying the oil did it since I can't prove it, but, it was awful strange timing. Eversince then, if a buddy buys a new car and starts wanting to run synthetic oil in it, I have them change the oil filter at 500, 1500 and then change oil and filter at 3,000. My personal belief (not saying it's true, just what I believe) is the synthetic oil cleans the inside of the motor and dislodges all of the sludge that was left there after using conventional oil. That's why I recommend the additional filter changes. Bottom line, it might not help and it might be in my head but it doesn't hurt. Oh, and we've never lost a motor after converting to synthetic since we started doing that.

Sorry, long post over.

 

[emmer]

Thanks for the post TBL, I asked for opinions here because like you I simply don;t buy the jargon I here from sythetic oil makers. It's soo biased, it aint funny.

It's thier job to openly deny any problems concerning sythetic oil.

One from Amsoil , came very close to blaming seal manufacters and not synthetic oil for the disolving of seals.

I am impressed with some of the qualities of synthetic oil, but (so far) not enough to switch form conventional oil.

We have machines at work that have 15-17,000+ hrs on them (being run with conventional oil) and still running strong!

Thanks for the imput.

 

[CDX825]

If you have any leaks synthetic will leak faster at first but after awhile it will slow down back to normal.

Your engine being freshly rebuilt it should be fine.

You may want to also look into a bypass filter setup to take full advantage of the synthetic oil.

 

[fx4wannabe]

I had a buddy that switched his Bronco over to synthetic and but some seafoam in the oil. A week later the motor locked up. Motor had about 150,000 on it or so. When he tore it down every oil passage in the motor was clogged with garbage but he said it was clean enough to eat off of inside. He thinks that the change cleaned all the sludge out and it clogged everything up. Being that yours is still pretty new I would switch it now if you are going to. I used to run Amsoil in the Cummins and I liked it. Go about 15,000 on an oil change.

 

[CDX825]

That sounds sea foam related to me. One problem with solvent based engine flushes like sea foam is they will break large pieces of sludge loose that will plug oil passages. In my opinion this why Auto RX is the only safe engine flush.

 

[87crewdually]

You ol timers crack me up. The seals and gaskets being over 20 years old has nothing to do with leaks huh. And the 80's blazer, they didn't make enough power to "blow themselves up" it's more likely the 29 year old seals gave out and he beat the snot out of it and ran it out of oil. Plus who knows the prior history.
I guess I'll drain my 5w50 Castrol Syntec out of my "old technology" 65 bug. Metals metal.
There's always 2 outlooks to every story.

 

[emmer]

You ol timers crack me up. The seals and gaskets being over 20 years old has nothing to do with leaks huh. And the 80's blazer, they didn't make enough power to "blow themselves up" it's more likely the 29 year old seals gave out and he beat the snot out of it and ran it out of oil. Plus who knows the prior history.
I guess I'll drain my 5w50 Castrol Syntec out of my "old technology" 65 bug. Metals metal.
There's always 2 outlooks to every story.

....well I don't know about you, but I have learned (in my 48 years) not to listen too closely to makers of a product, for a unbiased opinion..... it's foolish too.

For me to believe that synthetic oil NEVER harms seals or engines in any way, I would have to believe that EVERY story (first hand or not) ,of motors being adversely affected (right after switching to synthetic) is
100% coincidental.

..........that's asking me to stretch my faith a little too far.

Yes, I'm an ol' timer........... but with age comes wisdom

 

[fx4wannabe]

I can see that maybe it could damage the older seals kinda the same way ULSD fuel can damage seals in the pump. The material that the older seals are made from were not designed to work with the newer additives in the oils while the newer seals should be. just my 2 cents.

 

[argve]

all I know is what I have seen.... Switched the E over to AMSOIL and the oil sample reports from Blackstone about hit the floor on wear levels, and she smelled like she seeping oil for a month or so then the smell went away - could not see any leaks but she smelled like I had spilled a little bit of oil on the manifolds - fresh burning oil smell.

Switched the 99 Cavalier over to syn oils - it also picked up the oil seepage smell for about a month....

Switched the 95 Blazer over to syn oils - again it picked up an oil seepage smell for about a month.... hummm I'm starting to see a trend here....

Switched the Goat over to syn oil - again smelled a burning oil smell for about a month - also again - I seen the wear levels drop (not as much as the IDI but still a noticable drop in material)....

Switched 02 buick over to syn oils - again picked up a slight oil seepage smell for about ... you guessed it about a month or so....

I was told that they will do this because the molecules in SYN oils are smaller and can penetrate the gaskets and will seep a little oil but will stop after they soak the gaskets fully.... Made a little sense before the first swap - after doing it to the rest of the vehicles - I knew it to be true....

As for break in - I don't really think it matters much if you use dead dinos or syn oils...

 

[sle2115]

I always run dino for 500 miles then go synthetic...it's worked for me. I've also switched non synthetic engines with 70, 80 even 145 k miles with no issues. If you have a leak, synthetic will leak too, worse, not in my experience, but my uncle had a honda he said leaked on synthetic but not dino. He switched back, but I'm running it in everything but my truck because it simply is better IMO (based on what I've seen in the machine shop and personal experience). I run synthetics 10,000 miles and change. It ends up the same price or cheaper for better wear protection (again, my opinion). I can tell you the axle of Darrin's I just tore apart also looked new in every way. I believe he ran Amsoil in it.

 

[emmer]

I always run dino for 500 miles then go synthetic...it's worked for me. I've also switched non synthetic engines with 70, 80 even 145 k miles with no issues. If you have a leak, synthetic will leak too, worse, not in my experience, but my uncle had a honda he said leaked on synthetic but not dino. He switched back, but I'm running it in everything but my truck because it simply is better IMO (based on what I've seen in the machine shop and personal experience). I run synthetics 10,000 miles and change. It ends up the same price or cheaper for better wear protection (again, my opinion). I can tell you the axle of Darrin's I just tore apart also looked new in every way. I believe he ran Amsoil in it.

why don'tcha run syn in your truck?

 

[DragRag]

I calculated what it would cost me to use synthetic over a 5 year period. For me it would be about $1488 additional over 5 years. I could buy three used engine or parts trucks for that amount. I don't think it is even close to being worth it to spend the extra money on synthetic oil. I change my oil and filter every 5k miles, and don't spend money on blackstones. I figure once she goes, another goes under the hood, or part it, and get another one. It's my own approach to keeping cost per mile down. Not knocking ya, just sharing my way of seeing it.