Oil analysis for cars with low mileage

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I have a couple cars that get driven typically only a few hundred miles per year. I'm approaching the 1 year mark and instead of changing the oil, I'm wondering if an oil analysis (with TBN?) will tell me everything I need to know if it's still okay to keep using the same oil? Since it's about the same price of changing the oil vs. doing the analysis, I could just change the oil and filter also (it would be nice to not have to do it though, and also not have to start w/ the lower oil pressure for a split second after the change while it primes).

Would the TBN be the main factor that would tell me if it doesn't contain too much acids, etc. and it's still good to use?
 
A UOA with a TBN might be a good idea because your situation is unusual. E-mail you service provider and ask their thoughts on taking the vehicle for a long drive before taking the sample or sending the sample without the long drive. This would be to identify if moisture is a problem. It would be interesting to see the results.
 
Originally Posted By: CT8
What does it cost to do an oil change VS a uoa with postage etc?


Originally Posted By: kevmor99
it's about the same price of changing the oil vs. doing the analysis
 
try to do UOA for 1 year usage (i assume you 1 year with low mileage) then learn something about the decreased oil life based on TBN, detergent, addtivies and so on. then make a conclusion by urself or share it to us. maybe we can help...
 
A UOA or two will tell you how long you can leave your oil in, for your situation. Once you've done a couple you can maximize your oil use, and in the long run save money. For those that are saying it's a waste of money, well, they're right if you don't use the results wisely.
 
If you're doing a few hundred miles a year then you'll be putting around 10,000 miles in over 20 year. You could run the same oil for 5 years and everything around the car might be falling apart except your engine. Save your money. A UOA will tell you nothing. I bet if you ran the oil for 5 years and did a UOA it'd come back with a TBN high enough for continued use.
 
Originally Posted By: deven
If you're doing a few hundred miles a year then you'll be putting around 10,000 miles in over 20 year. You could run the same oil for 5 years and everything around the car might be falling apart except your engine. Save your money. A UOA will tell you nothing. I bet if you ran the oil for 5 years and did a UOA it'd come back with a TBN high enough for continued use.


I have a truck that sees 800 miles a year. Mostly highway miles and it's always heated up fully before it's parked again. Very easy on the oil. By the second year the TBN is almost depleted. In my situation the oil will never last five years. I think in almost all situations oil is not going to last five years. Oil is cheap engines are not, just change it every couple years. Makes absolutely no sense to push it to five years.
 
Originally Posted By: deven
If you're doing a few hundred miles a year then you'll be putting around 10,000 miles in over 20 year. You could run the same oil for 5 years and everything around the car might be falling apart except your engine. Save your money. A UOA will tell you nothing. I bet if you ran the oil for 5 years and did a UOA it'd come back with a TBN high enough for continued use.


This.

I'm currently at almost 4 years and 1800 miles on my 240Z. I'll change it next spring and I'm not worried a bit. It gets driven sparingly and when it does, the oil gets hot enough to burn out moisture. Also I'm using QS 10w40 from 1973. Also not worried either. Drive on and change it every few years as long you aren't doing short trips and not getting things up to temp.
 
My 900 GLE had 108.000km when I bought it. It had been sitting in a barn for two years. Before that, it belonged to a woman. According to the stickers we found in the engine bay, she had brought the car to the service every 10.000km, just as prescribed. Unfortunately, she had not read the part "or once a year, whichever comes earlier". So there were up to six years between the oil changes...
Engine was toast when we got it. At laughable 102.000km! Usually, Saab B201 will do their first 400.000 without issue.... But then, ususally they don't sludge up as bad as this one. Timing chain tensioner failed (ok, [censored] happens...), but what really struck me was that the camshaft had seized in its bearings. Never seen something like that before.


If I were the OP, I would definitely NOT run the oil for several years. With a PAO-based fully synthetic I might try two years, at most (when an UOA after the first year indicated there was still life in the oil).
 
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If you only go a couple hundred per year your fine...as you can see lots of opinions on this, it would be interesting to see a UOA, as I have vehicles that get little use, I dont go past 3 years now. Found this on a reputable site:

Motor oil changes are usually scheduled based on the time in service or the distance that the vehicle has traveled.These are rough indications of the real factors that control when an oil change is appropriate, which include how long the oil has been run at elevated temperatures, how many heating cycles the engine has been through, and how hard the engine has worked. The vehicle distance is intended to estimate the time at high temperature, while the time in service is supposed to correlate with the number of vehicle trips and capture the number of heating cycles. Oil does not degrade significantly just sitting in a cold engine. On the other hand, if a car is driven just for very short distances, the oil is not allowed to fully heat-up, and contaminants such as water accumulates in the oil, due to lack of sufficient heat to boil off the water. Oil of this nature, just sitting in an engine, can cause problems.
 
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Originally Posted By: Chris B.
Originally Posted By: deven
If you're doing a few hundred miles a year then you'll be putting around 10,000 miles in over 20 year. You could run the same oil for 5 years and everything around the car might be falling apart except your engine. Save your money. A UOA will tell you nothing. I bet if you ran the oil for 5 years and did a UOA it'd come back with a TBN high enough for continued use.


I have a truck that sees 800 miles a year. Mostly highway miles and it's always heated up fully before it's parked again. Very easy on the oil. By the second year the TBN is almost depleted. In my situation the oil will never last five years. I think in almost all situations oil is not going to last five years. Oil is cheap engines are not, just change it every couple years. Makes absolutely no sense to push it to five years.


Good to know.

My '99 sees only 1200 miles per year and always fully heated up. Was thinking of shifting to multi-year oil changes but I think I'll spend the extra $20 and just do annual synthetic oil changes. One thing intriguing me though is the possibility that with very low mileage oil changes, the add packs may not get fully activated until hundreds of miles have occurred. That might be a reason to go 2-3 year OCI's so that the add pack is still working 100% during years 2 and 3. Need more proof one way or the other.
 
If it is driven periodically long enough to burn off any moisture which might have collected, you could easily go another year, maybe two. I had an analysis done on a low mileage car where I put 2000 miles (one tank trips)on it in a three year period, the analysis was very good and was told I could go longer. Alot depends how it is driven.
 
The analysis would be useful for determining an extended oil change an additional year. In your situation, every 2-3 years would do.
 
I'd want TAN numbers as well if this is a vehicle that doesn't get driven much. TAN is a measurement of acidity, as oil becomes acidic over time.
 
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