Synthetic vs. old-fashioned?

[pbnjsellers]

Hello all, have the 345 in for some adjustments and we are thinking about an oil change. I just read through Chaplain Kent's awful experience with same - consider myself forewarned! It is at a reputable truck center. Anyway, we have been discussing whether or not to use synthetic oil at this point, 69000 on an 86 345. Any strong feelings either way?

[87MH]

I made the switch to synth with about 10,000 miles more in the engine than you now have.....remember, the 345 is a heavy beast and the 454 COULD give up the ghost at any time - with or without synthetic oil.

Another thing to remember, oil life should be limited by a time interval as well as a mileage interval...a good arguement for Dino oil since it is a whole lot cheaper.

One of the things that caused me concern was the warning that using Synth in an "older" engine could cause some "oil weeping" at marginal seals - didn't have the first leak - but it didn't improve the gas mileage either.

I do run Synthetic in the rear end - was advised to wait until the tranny had about 10,000 miles on it prior to making the switch, but the new Allison trannies now come from the factory with non-Dino installed.

Luck

[ALANSD]

I have used Valvoline synth blend, and now gone back to regular Castrol as an oil "review" I had read rated it very high.
Regular oil changes, proper warm up, regular use and care means a lot also to your 454's longevity.

[swebster]

I run dino oil (Castrol) and just do the oil/filter change every 3000 miles. It's cheap and easy to do yourself. I also know that it's done right and I gets me under there to look at everything.

I've also taken to performing some routine "preventative checks" at each oil change. I pull each plug and check it for burn properties, while the plugs are out I perform a compression check on each cylinder, check the air cleaner, breathers, check the coolant levels, look for oil in the coolant, etc.

A little overkill for an oil change but with 186,000 miles on the coach and who knows how many on the motor it's cheap, simple preventative maintenance that might alert me to a larger issue before it becomes catastrophic.

Of course my wife wonders why it takes me two hours to do an oil change

[74Argosy24MH]

Originally Posted by swebster

I also know that it's done right and I gets me under there to look at everything.

Very good idea. Most "oil change techs" probably don't have a clue about anything under a vehicle other than the filter and drain plug, and as Chaplain Kent unfortunately discovered some are just clueless. Unless it is a glaring safety defect I doubt if you would even hear about any problem even if it was noticed. A lot of shops don't want to deal with a vehicle this old or large. If yours is a gas engine it will use a spin on filter, less chance of the wrong part. It is not a fun place to spend time, but one of those jobs that is the price of ownership.

I vote dino oil. Probably more important than the type is the time interval between uses. Even with the best of intentions these engines are not really properly used, they sit for weeks then haul 14,000 lbs. down the road. Daily use is better. Considering the price of synthetic oil and common rv usage, I would rather use cheaper dino oil and keep shorter oil change intervals.

John

[eubank]

We've decided to switch to synthetic because of the low morning temps here in the winter. At -20 degrees, adequate lublication during cold starting would be nice.

Lynn

It seems that unless your engine is new or your running it at high temperatures for prolonged periods the price difference would be better spent changing it more often. It's my understanding that if you've been using a standard oil changing to synthetic will cause it to leak past the rings and you'll be burningthat price difference.

[Pick]

Lots of good oil information at http://bobistheoilguy.com

[Tarheel]

I put penzoil synthetic in the jeep at 16k miles and have used it ever since. I change oil and filters every 5k. I have not had any leaks in the seals, but you are susposed to run one oil change interval before switching to synthetic so that the seals will properly seat. Right now the engine has 140 k miles on it. Is it worth the difference in price, no. Would I do it again, yes. Its a 92 jeep that has been garaged its entire life and I am passing it on to my grandson. I run dino in my 92 Cummins and in my 2001 town and country. I doubt that the chrysler will live as long as the jeep. Synthetic for engines that sit unused for long periods as well as cold start-ups.

[uwe]

I run Synthetic ( 100%) in my 5.7l Suburban, and am very happy with the overall result. My engine uses no oil now, ( used to burn a quart every 600miles) and runs quieter and smoother at startup. I use Amsoil, but do not believe in their 25000 mile oil change interval. I change my oil every 6 month or 9000 miles, whichever comes first. I will not go back to dino oil for this vehicle.
I costs me about $ 40.00 in materials, including their HD filter. I find this reasonable, in relation to the improvements that I noticed.
I do believe that it is of advantage, especially in an engine that is used in extra duty service such as towing or motorhome use.
Otherwise, all fresh oil is good oil......

[Ken J]

Welp - I use synthetic and I change it every 3,000 miles............. I'm sure I'll hear about how crazy I am, but nothing is too good for my autos.

Ken

[Tinsel Loaf]

I use synthetic engine, transmission and differental. I noticed a two MPG increase after I started using synthetic lubricants.

[wingfoot321]

The old 454 cubic inch in the motorhomes is one of the most overworked engines I am aware of and would benefit from the higher operating temperature of synthetic oil. However, if you use it fairly low annual miles, then it is expensive to use Syn. and change it because of time and not distance.There are partial syn oils on the market and they might be a good option for an older motor that works hard but, is changed due to time.

[overlander63]

Originally Posted by eubank

We've decided to switch to synthetic because of the low morning temps here in the winter. At -20 degrees, adequate lublication during cold starting would be nice.

Lynn

Depending on what vehicle you have, there is now a 0W-20 oil out there, it is pretty thin, even at very low temps.

[overlander63]

Originally Posted by wingfoot1

The old 454 cubic inch in the motorhomes is one of the most overworked engines I am aware of and would benefit from the higher operating temperature of synthetic oil. However, if you use it fairly low annual miles, then it is expensive to use Syn. and change it because of time and not distance.There are partial syn oils on the market and they might be a good option for an older motor that works hard but, is changed due to time.

You can also "grow your own" synthetic blend. Synthetic will retain its benefits to engine wear and mileage with as little as a 25% ratio. So, you can use 3 quarts of organic oil to every quart of synthetic. I would recommend using the same brand organic oil, and the same viscosity, as the synthetic. If you want to use Mobil 1 10W30, find Mobil 10W30 to go with it. I am not, nor have I ever been, a proponent of mixing oil brands in your engine. They contain proprietary additives that, while not neccessarily being detrimental, could counteract each other, rendering the additives useless.
I personally use organic oil in our Jeep, and Havoline 10W-30 synthetic in the van (tow vehicle).

[alfalsetto]

I'm a good old Sythrtic oil Man! I started useing it back in the 60's and I'm stell useing it!!!!

[Silvertwinkie]

I've been in both camps on this one. On one hand, had a 25 year old car I just parted with....at 16x,000 miles on it, never burned one drop of oil. Regular changes near or at 3000 with conventional quality motor oil and filter since day and mile one.

However, since I started towing with the Impala and now the Suburban, I have started to move to fully synthetic. There are a few reasons why:

First, the synthetic oils can take more heat and abuse and still keep the mechanicals in great shape. For example, conventional trans fluid's sweet temp spot is between 10 degrees and 170 degrees. Get far off the mark on either end and it's not as good as it is in the sweet spot, plus the warmer it gets the more the conventional oils begin to breakdown. Syn trans fluid's normal temps are between -30 degrees and 270 degrees. Now I'll be the first to admit that if your trans gets above 200 regularly, no oil is gonna do anything for you because even with syns ablility to take 270 degrees, much warmer than 220-230 degrees and you will frankly cook the trans, warp and burn out the internals.

Second, in cold climates, syn fluid flows better at low, low temps providing better protection without having to have the car sit warming up for 10-15 minutes on the coldest of days.

Third, I've seen less "sludge" and varnish in the internals.

In the end, it is a tough call which to go with. I may be pouring $$$ out the window on syns, but given the above average service these vehicles do towing 6000+lbs (in my situation), to me it's worth the extra protection given the fact that a new SUV or pickup can cost between $30k and $50k. One other note that was touched upon here is that it's starting to be common practice for the factory to fill a lot of the areas of the vehicles now with synthetic. Me, I'm still kind of old school, I let the dyno oil break it in, then switch it, but in your case, I think you have yours broken in by now.

[Tarheel]

Is anyone running synthetic in their diesel? I am using Rotella T and have no problems, but just wondering.

[uwe]

Originally Posted by Tarheel

Is anyone running synthetic in their diesel? I am using Rotella T and have no problems, but just wondering.

I used to run Synth in an old Mercedes Diesel, with no noticeable improvements whatsoever. It got black just as quick as dino oil.
It did cause immediate oil leaks, though. I guess the stuff seeps past marginal seals much easier than regular oil. The leaks all but stopped when I returned to Valvoline oil 2 oil changes later. Go figure....

[Pick]

Running Rotella T Synthetic 5W40 in my Duramax right now. Rotella Syn is not a "true" synthetic but a Group III dino oil. My next change will be to Mobil 1 Truck and SUV 5W40, a true PAO synthetic.