It is about time to change the oil on my 92 Buick Roadmaster. I hear a lot about synthetic oils, are they worth the cost in an older wagon? If so what brand and weight ?
I've used syn oils in all my vehicles since my '74 Ranchero Squire. As long as the seals and gaskets are not leaking badly or the engine's not burning a quart in 3000 miles or less, it's a good candidate. Some people say the higher cost (averages $5/qt when you buy a 5 quart bottle at Wally World vs. $3.50/qt for mineral oil-based oil) is not worth it, but I go 6000 miles with two filter changes, one at 3K and one when I change the oil. If you're sure you want the extra protection and can deal with the higher per quart cost plus the extra filter, then go for it. One more thing: Lemme post up a couple pics of the 3.8L V6 that was in my '93 Taurus. I had to pull the engine at 132K for bad head gaskets (coolant corrosion), and when I got it at 92K, I immediately started using syn oil in it.
You can see on the balance shaft the creepy crawly crud simply cleaned off because of the syn oil--I did not clean it. The old heads, when I pulled the valve covers, was as clean as these two heads. NO brown coating on the aluminum, and the rockers and pushrods needed NO extra cleaning.
filter Thanks very helpful, after doing online research it looks like the only down side for synthetic oil, aside from cost, is that it tends to cause oil leaks in an old car. It cleans the sludge that was plugging up the leaks. Well my Roadmaster has only 93K miles and has no oil leaks, a very clean engine outside. I do tend to let oil changes slide, so a longer interval sounds good. BUT you say, you should change only the filter after 3K and both oil and filter every 6K? I imagine you need to top off the oil when you just change the filter?
I just use whatever oil is on sale and just change it somewhat regularly. I also try to check my oil every time I get gas. I've owned many cars and have never had an engine failure due to oil related problems. I also, change my own oil. Not to save money, but to make sure it's done right. It's a simple procedure, but some of the guys they have changing oil at the lube shops, shouldn't even be allowed to have a wrench in their hands.
I've been using Full Synthetic oil in my Dad's caravan. I figure that at the cost of $17-$32 for the five quarts (depending on the brand and where it's bought at) plus a 6,000 mile (or higher) oil filter isn't so bad if the engine can take it; If the engine doesn't use much oil or any during that time, it doesn't cost a whole lot and may cost less than $1 for every hundred miles which at this time I think is a good way to measure. I've read that Full Synthetic Oil lasts twice as long but it doesn't cost twice as much as conventional oil when staying within the same brand. Speaking of oil, have you heard of that Castrol Magnatec type oil? Apparently it's this new type which holds on to the engine walls just enough to lubricate during start-ups instead of all of it draining into the oil pan. I haven't tried it yet, maybe if I get an engine rebuilt I'll switch to a Full Synthetic type of that after the break-in period. It won't reverse wear that is already on an engine, but it will prevent start-up wear from occurring if it works as advertised. Another thing; There's Conventional oil, then Part Synthetic; Then there's Synthetic, then finally there's Full Synthetic. I won't use anything but Full Synthetic in my Suburban since it's a Diesel and I plan on towing with it. Full Synthetics are supposed to retain their viscosity more easily than conventional type when under stress. I also read that in America this whole "Synthetic" or "Full Synthetic" system isn't quite on-target with how it's advertised and in Germany it's actually "Full Synthetic" - Whatever that means. I haven't looked it up much yet so you'd have to do some research on the subject since I just don't know. What I do know is that I read to not be surprised that after I change the oil in a Diesel if the oil is black right after I turn the car on, but when I turned it on after installing Mobil-1 Full Synthetic Turbo Diesel 5w40 in the engine with a Mobil-1 filter I literally had clean-looking oil for about 200 miles before it turned black. I also haven't needed to add any oil since it was changed about 600 miles ago; In fact, the changing station added a quart too much so I removed it.
these oil discussions are always tricky, I think... of course I am not an engine oil specialist, but the first point is, as far as I know, that, except for special oils made specific for vintage cars, there is no longer an engine oil on the market that is "true" mineral oil...all oils are at least partly "syn" because of the several additives. The "real" syn oil is also mineral oil, but is cracked and the molecules built together in a certain way the manufacturer wants to. Plus they have some additives too, of course. The point is now, that engine oil development goes along with the engine development. Oil is synthesized somehow to meet engine requirements. With todays engines with tighter tolerances, maybe flatter surfaces, higher cumbustion temperatures, new gasket materials etc., the oil has to change too. From my perspective, I do not see any reason to use a today, very expensive "high tech" oil in an older engine. If your engine is a ´93 (and that means more than 20 years of age!) and requires maybe a regular 10W30, then go for a cheap 10W30 and it will suit your car perfectly. I believe ANY 10W30 bought today will exceed the requirements of your ´93 engine (maybe except for the absolute cheapest you may find somewhere). The additives of the new 100% syn oils may be to aggressive for your engines materials as gaskets, plastic parts, o-rings, etc. ...just my opinion... Matt
and, by the way, the newer oils try to keep contamination, particles etc. in abeyance. This help to keep your components clean inside the engine. That´s a good thing, as long as you keep to the oil change intervals. Also I do not see any reason for changing the oil without a filter change. The filter is designed to draw contamination out of the system, therefore it should be replaced every oil change. Otherwise it could be overloaded, maybe burst, and release all contamination into the system at once. I do not think that you want THAT ;-) Matt
good advice I think after all the advice, a good high milage regular oil seems like the best way to go in an older car. Regular oil is all the car has known for 93K miles and the engine runs so well, I see no reason to chance an over cleaning synthetic oil.
Then I recommend oil changes every 3K. At an average cost of $30-40 every few months or so, it's definitely much cheaper than replacing the engine or the whole car.
This is the same way I feel about motor oil. Plus always change the filter when changing oil. I try to stick with 3000 miles or not much over it if traveling. Lucky most times my son changes the oil so I don't have to trust the new kid at the oil change places. I'll admit I'm too old to climb under and I don't like getting dirty anymore.
Jup, in my opinion definitely the way to go. And please consider also what a full syn oils with a high cleaning potential would do to your old engine that is used to "regular" low syn mineral oils. All the deposit built up over years in the engine will become loose and get washed off the components. All these deposits will be around your engine for some time until they´ll get catched in the filter. During this time they may harm the engine somewhere. Also the filter may be overloaded very fast etc...in my opinion the risk is not worth it, besides the higher cost. Matt
My younger brother is a Stationary Engineer. In his 79 Thunderbird as well as his 86 Colony Park he used nothing but Castrol Syntech 5W50 full synthetic after doing an engine flush. . Both engines were around 150,000 miles when he got them. The 351 in thebT-Bird was out of an 86 Grand Marquis. That engine was still passing the 87 emissions standards when it went into car number 3. Both engines were well over 500,000 miles when the cars were scrapped, and neither engine burned oil, and both had compression and leak down that was well within spec. The Chevy 305 in his 86 Parisienne Safari was not burning oil and passed the compression and leak down tests at 400,000 miles when the floor fell out of the car and the engine went into a neighbour's car. I did the same in the 302 in my 79 Thunderbird. We also found we got about 100 miles more range per tank using synthetic. That is what I still use no matter the age of the engine.
