Fact or Myth: Oil changes on old cars?

I have a 77 toyota celica that has'nt had an oil change since who knows when. I have been told a couple times that if a car has'nt had an oil change in a long time and you do change it it could mess up the engine. I know it may seem odd but it has happened on a previous celica I had. Any thoughts?Fact or Myth: Oil changes on old cars?
A friend once told me he bought an old bronco and the former owner told him the same thing. He said he changed it anyway and some how jacked his car up. I guess the theory behind this is that the sludge and junk got lossened up. I really dont know if this is possible or not. But i have ';heard'; it is. But I have also seen nothing to verify it. If you are concerened perhaps you could ';flush'; the engine out. or drop the oil pan and clean it out. I have owned several old vehicles. What i did when i brought them home is flushed the engines out. Basically I did two oil changes on them.Fact or Myth: Oil changes on old cars?
Sounds odd.....





Now changing automatic transmission fluid can cause problems, but not engine oil.
Fact- oil draws moisture. Fact-oil turns acidic with age. Fact-acidic,water laden oil will eat-away any metal it touches. Fact-your finely spec'd engine will endure this corosive environment for only so long before it fails. How long depends upon your driving habits. Be assured that the long er you continue to ignore the facts ,the greater your heartbreak will be .
from all i have learned about autos, i would say it is the other way around. the longer the oil is in there the dirtier it gets. the viscosity can also break down. in time all this can harm your engine. in my opinion the condition of the oil is even more important in older engines due to the normal wear. the celica was probably just coincedence. good luck.
Not true. It's not good if you use synthetic oil at this point but regular oil should be alright.
i had a 1979 chevette that hadnt had a oil change in 2 years, i changed the oil when i bought it and it ran for 200k more miles. (chevettes run forever for some reason) maybe its a toyota thing, but ive never had a problem or heard of any such issue.
Change the oil and filter.Repeat a few times every month or so. Then change as normal.
I disagree with this one.


But you should post this on the mythbuster's web page.


good idea for a show.
I remember back in the 60 - 70's


the concept to only add oil


and change the filter..


it wasn't until a major overhaul was it discovered the sludge settlement in the engine and in many cases blockage of the tiny oil passages causing the brake down at the cost of repairs $1 - 2K it only makes sense at the 3 -4 K to use a engine flush (kerosene) and change the oil filter


In your case of a new used car I would suggest a monthly routine of engine flush drain and new filter for several months


but always use the flush (kerosene) at oil changes.
The sludge in the bottom of the oil pan probably gets disturbed and clogs the oil pump suction line.Use a light viscosity oil and a thick media filter to prevent this in the future.I busted an engine bearing on a Chevy Citation for the same reasons.You might try cleaning the pan before the oil change including the oil pump suction line.What about an emulsifier(Sludge Dis-solver) before the oil change?I used one once and a mechanic told me it could prevent the oil from sticking to the metal,so use it carefully.I use Castrol oil and a Fram filter for every oil change and haven't had any problems since.I also do oil changes every 3,000 miles.(More frequent changes prevent sludge build up.)Alternately,change the oil,using the lightest viscosity,drive it 500-1000 miles;change it again and slowly increase the interval between changes.
No, it will not hurt the engine. You really should change your oil more often.
sludge/thick oil can mask worn rings and loose bearing clearences so changing the oil may reveal how tired the engine was... not the new oils fault