Switching back and forth between brands of oils

Not open for further replies.
Jan 16, 2003
Shippensburg, PA
Is there any problem with running Chevron Supreme 10W-30 in the summer, and Pennzoil 5W-30 in the winter? Is there any reason to pick one brand of oil and stick with it? I like the Chevron for the price, but it is hard to find in 5W-30. Pennzoil is much more common. I am not sure I want to use a 10W-30 year round, as it can get cold in PA winters. What do you guys think?
Personally, I think repeated switching will ultimately lead to shaft seal failure. Each oil will have a little bit of a different seal swell or shrinkage rate. When you change brands the seal swell/shrinkage agents will be displaced/replaced in the seal. I can't really prove this though. Its just a gut feeling.
Hmmm... I never thought about seals. Anyone else think changing back and forth is bad? What about with similar oils... for example, TexacoChevron Havoline and Chevron Supreme?
When i bought my 95 Jeep a few years ago i was always trying to find a better oil. I went from Havoline to Mobil to Castrol to Shell to Valvoline. Sometime changing with only 500 of so miles on the oil. Because of leaking(after a year or so) I have replaced the rear main, oil filter adapter, valve cover, head gasket and oil pan gasket. I think it is because of all the switching of brands.
What is considered switching too often? I switch from Amsoil to Le in my cars, I ran Amsoil for 5yr and just started with LE. After 25,000 I'm and some UOA I going to switch to Sheaffers and do the same and compare UOA and then go with the best one. So will all of this switching be bad some people do this quite often including some companies because they buy oil from who ever will sell it to them the cheapest.
if you're concerned about constantly switching, why not use PZ 5w30 winters, 10w30 summers? Here, the price difference between PZ & Chevron is ~$.60/qt. Considering how much $$ goes into the gas tank, not a big deal.
That is what I am leaning twords. However, I have already started on the Chevron Supreme (after using Mobil for 20k miles), and I have a supply of 10W-30 to "use up".
If one is looking for the optimal oil for your application I feel that you must stick with one brand and weight for least several OTI in order to get a feel for the performance and if you are using analysis you need to build a trend with each one. You will not be able to compare oils by switching every other time.
Alternative: since you have a good supply of Chevron 10w30, and there's plenty of time until winter, scrounge around until you find some Chevron 5w30, & then buy a couple of cases. In my area, the Wal-Marts that have no auto service dept. all have Chevron Supreme motor oil. The WM's that *do* have a service dept, have no Chevron supreme oil. Why? [I dont know] I dunno, but it's true here.
Most oils have no compatibility issues. In fact, Mobil 1, Amsoil and Delvac 1 are all compatible with each other and even dino oil. I've never read anywhere that states scientifically that you will have any problems switching. What you might see though is various additive packages clashing causing the oil not to perform as well as it could have. I just made a final switch back to Mobil 1 and I am only running it for about 2-3k miles. I had Amsoil in the engine but the TBN might drop off pretty quick being I am switching brands.
Find a decent synth 5W30. It could be the group III pseudo-synth. I think even that can do 5W30 without VII. Run it all year. The only reason to run 10W30 summer and 5W30 in winter is the worry about the VII in dino 5W30 shearing down. Without VII that shouldn't be a problem. You could probably make up some of the cost difference by extending your drain interval (which you should be able to do with synth)
You guys are getting me worried. I've switched back and forth between M1 and Amsoil for the entire 100k of my cars life. Never anything else, just those two. Usually, it was Amsoil 0w30 in he winter and M1 0w40 in the summer. Just did the same yesterday, was running Amsoil for about 15k during the past winter (two fills) and now switched to M1. Just started UOA's, so I guess I'll see if it affects anything...but seals...now that won't show up on a UOA. [I dont know]
if the oils are constantly changing their additive packages to meet new standards or coming out with "new and improved" versions, isn't that like changing brands as well? i don't think any of the oils we bought today are the same as say we were running in our same cars and trucks 3 or 4 years ago. just a thought.
I'm pretty inconsistent with brand of oil. Sometimes I change it, otherwise I let someone else do it and every place has a different oil from Amalie, Quaker S., Pennz, SuperTech, Valvoline, Castrol....Anyway I have 192,000 miles no issues with any leakage. I usually use 5k miles as a change interval and never had to add. Its typically is down less than 1/2 quart. [ July 02, 2003, 07:25 PM: Message edited by: harper ]
Sounds like a sound theory (leaks with switching) but in practice I really don't think it causes leaks. At least not in my neck of the woods.... Maybe it's more like: some seal materials are worse than others with changing....or don't react as well with differing chemistries. [ July 02, 2003, 07:46 PM: Message edited by: Pablo ]
I try not to make frequent declarations outside my area of expertise, but I've got to hoist the Bravo & Sierra flags on this one. Oil companies change additive packages and/or "reformulate" all the time. Most people take their cars to whatever dealer/quicklube is around...people are very mobile these days so it's not necessarily going to be the same one (or brand of oil) twice. People who change their own oil often buy whatever is on sale at the time. So where is this epidemic of engine seal failures caused by all of this reckless oil brand switching? Guys on this board have done a lifetime of oil brand switching in 6 months with no problems... I think this issue needs to be filed with "PZ-QS causes sludge", "You can't switch an old car over to synthetic", and "I didn't inhale" in the BS folder.
So why do some Dodge Caravans end up burning oil due to bad seals and other not? Maybe sticking not only it the same brand, but the same batch for years? Or is it jumping from brand to brand? I would like to think that when the oil companies change formulations, that they at least make the new one compatible with the old. If I bought a new computer with Windows 2000, I could easily transfer my files, but is the new computer used Mac OSX, it would be more of a challenge. I am still spending more on the Pennzoil of the month than I like, but have not been able to bring my self to switch to whatever Wally's has cheap this week. This board has reassured me about using ST's rather than Frams since I can't find the AC 1177's.
One thing we definitely agree on, it gets COLD in those Pennsylvania winters ! Recommend finding whatever oil you like that is readily available year-round; this is not to say that all oils will be adversely affected by mixing them.
Not open for further replies.