To the naysayers, if the many advantages of synthetic oil are myths, this product would then have become the greatest hoax on the American public. American consumers are too smart to let this happen. Mobil 1 is very close to being the number one seller of all oils at the Advance Auto store I work at. Why do you think synthetic has become the factory fill of so many of the new cars on the market? This arguement has and will continue to be debated for many years, but interrestingly, a lot of those who say it is a waste of money have never worked on or seen an engine torn apart or read research reports on test results.

 

Hey Jud
I run Mobil 1 in my newer vehicles
Many of us here are speaking about 35+ year old cars which is a very touchy topic

 

Hi Bob, I do have a '76 (not quite 35 years old) which I've been using Mobil 1 in for about 8 years now and have never had a problem. The benefits that I noticed immediately were a slightly higher oil pressure reading and a lower operating temp. (Actually, I've read that the lower operating temp is the main reason Vettes and Porshes use synthetic as a factory fill as there is then no need for an oil cooler which translates into lower production costs).

As far as oil leaks go, though, I did replace the rear main seal and all other engine gaskets including timing chain cover and valve cover gaskets as well as valve seals just prior to the switch. This wasn't done because I expected leaks but because I was going through the engine and noticed some leaking and wanted to replace the timing chain and gears . I have no leaks now but perhaps if I hadn't changed all the gaskets I would have some. Who knows. I could be wrong but I think that a lot of those who are against using synthetics is because of the price issue.

 

I actually contend synthetics are cheaper. Although the oil itself is more expensive, there is less cost in engine wear, your time changing it, and the fact that it needs to be changed half as often. Once I get a couple thousand miles on my motor im going to half syn for a while then full syn.

 

I tried Syn in my 69 and it leaked...
I will shortly be replacing the rear seal and valve cover gaskets...

I don't want to hijack but this post is bringing questions to my mind....

Is it safe to try Syn again? Do I have to flush before putting Syn in? Should I change the oil after 100 or so miles on Syn to get the **** the Syn cleans up out? Can I run 50 Syn and 50 Dino? I don't know if you can mix them.

 

I would change the seal and any other gaskets that start leaking and then use synthetic. There is no need to flush the engine or change the oil before your normal oil change schedule for syn. I would use a straight synthetic of your choice and not mix it with another product.

 

I work for one of the largest manufacturers of gasket and seals. From our experience, Royal Purple is the most agressive (meaning it chemically attackes seal and gasket compounds) synthetic oil on the market. Mobil 1 is the least.

Second point, mixing synthetic and dino oil, even mxing different brands of oil, is about the worst thing you can do from a seal and gasket standpoint. The problem is you have no idea how all the different additive packages will react with each other. You will end up with chemical reactions that produce harmful side affects. You can never drain any engine completely, so there is no way to avoid this.

Please keep in mind that the work we do is based on making an engine last 150,000 miles. Mixing oils and using Royal Purple will not destroy your seals and gaskets overnight, but it will shorten the lifespan of your engine's gaskets and seals.

As for synthetics, my brother in law is a mechanic, and he swears by synthetic because of how clean the engines are when torn apart. I talked directly to the chief engineer at Cummins, he said the same thing. I was using Mobil 1 in an air cooled motorcycle when the drain plug fell out. The engine completely seized. I let it cool down, put more oil in it, and rode it for several more years. I run Mobil 1 in everything except my truck. In that, I use the exact oil that came from the factory.

Ken

 

Great informative post!

 

I have worked on Oil Rigs offshore that have used Royal Purple. The stuff worked very well in our Wartsila VASA 32 engines. These engines have 32 cm pistons and we use them in V-12 and V-16 configuration. They pump out alot of torque. Using RP saved us parts and time for rebuilds, simple.

carbster

 

I bet that sucker used a lot more than 6 quarts!

 

I thought rotella T was a good oil for older flat tappet motors. I switched to rotella by advice from this forum.

 

I use the RP Syncromax in my T-5...no probs yet

 

And you are well-advised! Either Rotella T or Mobil equivalent Delvac 1300 are great choices.

Back to the original question about RP worth $ ... if it's a true race car, Maybe. If it's a street C3, NO.

 

I have my own personal theories that are supported only by looking at many relatively new motors that've failed & are replaced. Primary cause has been sludge. I suggest most new motors' fuel/emission-efficient designs result in very high combustion chamber temps ... oil that runs across the valve train & roof of chamber & any valley is subjected to those higher temps. Synthetics tend to be more resistant to those high temps ... along with scheduled oil changes. It seems on many new designs the temps are so high that dino oil may not hold up. It also seems many folks are not refilling their newer motors w/ synthetic; primarily because it doubles cost of an oil change. I suggest a coupla reasons synthetic factory-fill is specified because the engine manufacturers know their temps are high & that dino may not hold up during warranty period ... and, synthetics do tend to yield improved fuel mileage; a major marketing issue for all mobility mfgs. However, I do not consider C3 sbc/BBC a new design. Have no studies to support any of above ... have plenty of eyes-on & hands-on experience.

 

I think one of the reasons we are seeing failed engines is that they are run too long without changing the oil. Mercedes now advises 15k miles between changes which, imo, is riduculous.

 

Mercedes makes lots of money on replacement parts.

 

Very true. Have you priced an ignition module for an E190 lately? Over $1,000!

 

They sell synthetic blends that are basically 50/50 mixes, I have never used them though, I would just put straight syn in next oil change.

 

Amsoil sells a motor flush to use when changing from dyno oil to synthetic.

 

AMSOIL Engine Flush

There are a couple things I'd keep in mind when considering switching a high mileage engine from conventional to synthetic oil. First, synthetics in general have higher levels of detergents which will clean out the sludge in the motor. As a result, the first oil change after switching to synthetic should be at a shorter rather than longer interval to get that sludge out of the motor. Using a product like the above mentioned flush can help get that sludge out before you drive the car for several thousand miles. In addition, that sludge may have been blocking the oil flow to seals allowing them to dry out over time. As the new synthetic comes in contact with the seals, it may leak. Something else to keep in mind is that all synthetics are not created equally and their impact on seals may likely be different. Most synthetics on the market use a Group III, highly hydroprocessed petroleum, basestock. These oils will likely have the same effect on seals as typical petroleum oils. Mobil 1 and AMSOIL use a predominantly Group IV or PAO basestock. PAO causes seals to shrink. I've read that AMSOIL adds ester to their basestock which causes seal swelling and that the overall effect is a few percent swelling of the seals. I don't know how Mobil 1 addresses seal shrinkage with their PAO basestock. Finally, some oils like Redline use a Group V or ester basestock which causes seal swelling.