Just wanted to get some of your opinions on running synthetic in our 4.9's.

I had my mind made up that I was gonna switch over but then I read a thread that said some guys thought that the synthetic oil was so slipery that it would actually back syphon out of the lines and pump and stuff so that when you start her up it runs dry for the first little bit till the oil gets pumped back up.

I like the Idea of the synthetic after its running but I am bothered by the threat of dry starting.

However this may not be true so give me your opinions and what you guys have been doing and thoughts ect.

 

i've ran synthetic in my car since i got it and never had any problems it has 105k on it now its possible that if you put it in before its broke in it won't break in properly

 

I run a semi-synthetic in my truck as the guy that owned it before me. I have never had a problem, 185000 mile on it and still runs like a top.

 

I tried synthetic oil fairly early in my trucks life. Sadly, not a lick of improvement in fuel milage over the dino. I had high expectations. very disapointing.

 

On a high mileage vehicle don't be surprised if your engine starts leaking oil like a sive if you switch to synthetic. The synthetic washes away the gunk that builds upon the seals and can actaully open a leak. For this reason too if you go synthetic the first oil change should be in 300-500 miles to get all that extra junk out of your motor.
Also once you go synthetic it is a REALLY REALLY REALLY bad idea to go back to dino oil, they don't mix very well and what's left of the synthetic in the motor can be enough to cause bad things to happen.
NEVER EVER EVER use synthetic when you're breaking in a street motor. It's too slick and the rings won't seat properly. If it's a race motor that'll be torn down often who cares, throw the synthetic in and run.

If it's a fresh motor run whatever you want, but if its got some miles on it I'd stick to dino oil. It's worked so far.

Justin

 

Go ahead and use full synthetic or a synthetic blend in your motor. Sythetics blend well with dino oils if there is any dino left. You can change from synthetic to dino and back to synthetic anytime you want without any adverse effects. Most synthetics have higher lubricity than dino oils but their real strength is in their low temp pumpability and ability to last longer in the engine. I know people that actually mix their own semi-synthetic with dino and full synthetic.

If you are looking for an oil that will give you better lubricity I would stick with a good dino. If you want to increase your drain interval or plan on operating it in a colder climate then I would definitely go with a synthetic.

I switch between a full synthetic in the winter to a semi-synthetic in the summer in my 96 I6. I run the oil changes out to 15k kms and the oil analysis have looked good. The oil is still good at this interval but the wear metals are starting to climb.

P.S. My 96 has 190k on it and it dosen't burn or leak a drop of oil. It was switched to my diet of synthetic at about 175k.

 

Woah, now we've got conflicting opinions here, and you've got me nervous.

I run semi-blend in the summer and full synthetic (Mobil 1) in the winter.

I figure that if something awful happens in the winter (as it has a tendency to do) at least I'll have indestructable oil in there. And that actually paid off HUGE the other day on Christmas night when my radiator leaked completely out and my temp went red as I tried to limp home. I hope I didn't do too much damage, that was really stupid of me, but it was COLD AS HELL out and I thought not only did I not wanna stop and freeze, but maybe the cold air would help me get there. I finally gave up when the temp hit the red.

I figure at least I had oil in there that could stand up to some serious heat.

I haven't seen any real difference in my leakage since I switched over to my semi/full-synth regime.

 

I run full synthetic in everything incuding the lawn mowers, that way I don't have to have more than one oil and try to remember what goes where. The only vehicle that tends to leak or use any is the old courier with 500K+ on the engine, it has bad valve guide seals. I use the synthetic gear oil too, not that it gets cold enough here to matter, it hit 80 today. The synthetic has a higher film strength and will form a coating on the parts that lasts longer when the vehicle sits so its better protected at start up.

 

I have had good luck with every vehicle I've used synthetic oil in. I will never use synthetic on a fresh engine, as was mentioned, it is too slick to let the rings wear into the bores. I run a fresh engine through two 3,000 mile oil change intervals on conventional oil then switch to synthetic. I have an Inline Six with 208,000 miles on it that I pulled out because I got greedy for a V8 (BIG Mistake, the six is going back in the spring!). I tore the old six down to see what she looked like inside and found an engine that looked like it had been freshly assembled yesterday. Not one single speck of sludge or varnish anywhere. Bearing surfaces on the crank and cam that measure as being in new specification... not service tolerance, NEW. I found cylinders with full cross hatch visible, and zero taper. The only part with appreciable wear is the fiber cam gear, but that is being replaced with a metal gear. Hell, even the cam and lifters are within new specifications... each lobe has full lift, and the lifter bottoms still have the .001" taper that they had when they were brand new.

That being said, however, if it is a high milage engine that has always run on dinosaur sauce, be perpared for an oil slick that rivals the Valdez's unless you change the seals and gaskets. If the engine always ran synthetic, the seals and gaskets will remain pliable and soft. Conventional oil will eventually cause them to harden, and leak. However, these leak spots are magnets for sludge and varnish, as there is access to fresh air and therefore oxygen, which acts as a catalyst in the formation of these contaminants. Run synthetic through this engine, and it'll disolve the filth in a few thousand miles, causing the engine to do an impression of a sieve, and muck up your driveway. I wholeheartedly endorse synthetic fluids of all varieties, as they are always far superior to the conventional stuff. The extra level of protection from extreme heat, cold, and pressure they afford is a nice feature as well. Just remember to not neglect the oil filter or the PCV system, as these are also vital to lube system health.

Dave

 

What Argo posted is 100% correct, I had the same issue with my Mustang, I had to replace both valve cover gaskets and my rear main because they all started leaking soon after I switched the car over to Synthetic after I bought it. I run Mobil 1 5w30 in everything I own, Mustang, Truck, as well as the 1931 Chris Craft runabout with a very well done up 312 Interceptor, that beast rev's to about 8-grand and needs all the lubrication is can get. Mobil did a test a few years ago, I don't know how "real" it was but they put a milion miles on an Audi or something similar to one, using Mobil 1 Synthetic exclusively in it and changing it every 12,000Km, and their results were very similar to Argo's, everything was completely within manufacturing spec on this motor with a million miles on it. Its on their web page somewhere if you want the full details. I know that the oil pan on our 89 Town Car went out finally and its got 247,000Km on it, and when the pan was pulled the mechanic who was doing it came over to my father and said there was no way that motor had 247,000Km on because it looked way too clean inside and that it must be a new short-block. My dad assured him that he'd owned the car since new and that this was the original motor. The mechanic was appalled to say the least. Its great stuff, it does mix fine with conventional oil, though I'd never switch back after running Synthetic, I know people who have and with no adverse affects. Mobil 1' Synthetic is also slightly ionic so that it bonds about a 1-molecule thin layer on the metal on the inside of your motor, its not enough to give you any long-term protection, but it does prevent metal-to-metal after its been sitting all night.

 

the only thing i have to add to argo and shinoda is that earlier statment about not mixing dino with syn. what do you think the
synthetic blend is. part dino part synthetic.

 

here is an article...a few years old that might suprise you. keep in mind synthetics must have surely evolved since then. https://www.ford-trucks.com/articles...itives.phphave

 

I raed an article recently about a Chevy pickup truck delivery person who changed the dino oil weekly after doing about 3,000 miles on his route. When his truck reached 1 million miles GM gave him a new truck and took his for research.

 

vehicles that are driven a lot last longer. if a truck is driven a few thousand miles a week highway it will never die. thats why you see towtrucks with like 400k miles. as for oil type i prefer dino or maybe synthetic blend. i've read a lot about synthetic oil. if you switch over to it on an old engine be prepared for leaks AT FIRST. what many people dont realize is that after a few oil changes of synthetic everything usually runs fine. some people say that, because the first change will really clean out your engine you should only leave the first change in for about 500 miles to get the gunk out. the only reason i keep dino is because its half the price. i'd rather change the dino oil every 2000 miles than synthetic every 3-4k. i like changing the oil. the truck always feels better. most of its probably in my head but i do it anyway.

 

Roger that, Jess.

I like giving my old Beast her TLC too.

How can I expect her to get me to class and work every day through sub zero temps and tons of snow and salt, and on those long trips home and back to college again, and then NOT treat her nice?

I've got a theory that people have bad luck with their cars because they just don't show them enough love and attention.

"Yeah, I could give you the nice anti-freeze, but I'd rather hook you up with K-mart brand pee-water 'cause I don't feel like dropping that kind of cash on you."

If you were a car would YOU run for a guy who acts like that to you?