80 votes
Accepted

Top off gas with old oil, is that bad?

It's a BAD idea! The oil is contaminated with impurities that will not do the fueling system on your car any favors. Further, it's bad for the environment because your car is NOT designed to burn ...
jwh20's user avatar
  • 12.1k
28 votes
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proper oil for 1940's era aluminum ford engine

Per @Eric Urban's suggestion, I found the Technical Manual for the M4A3 tank published in 1942. That tank did use the aluminum Ford GAA 18L V8 engine which produces 500 hp at 2600 RPM! It says: ...
Zach Mierzejewski's user avatar
27 votes

Is it alright to top off with oil instead of changing after 3000 miles?

You should generally go by the manufacturer's instructions, the car's handbook should specify the change interval - but I don't know of any modern car with that low an interval. Therefore you should ...
Nick C's user avatar
  • 28.7k
27 votes

Seized engine due to being run without oil

Yes, it could go that far ... it really depends on the condition of the oil and the engine when the oil dropped, but yes it absolutely could go that far. As a side note ... If she was able to get it ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
23 votes
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Switching engine coolant with similar properties oil

There's a very straightforward answer to this question: Water has a much, much higher capability to transfer heat than oil. Even if you were able to overcome the safety and design issues brought up ...
dwizum's user avatar
  • 1,144
22 votes

What does exhaust smell on oil and transmission dipstick mean?

First of all you're not smelling CO (carbon monoxide) as that is an odorless and colorless gas. What you are likely smelling are combustion byproducts and that is not at all uncommon in the engine ...
jwh20's user avatar
  • 12.1k
21 votes
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How low does the oil level have to get to trigger the low oil light?

The approximate answer for the cars that I have driven that take the standard 5-6 quarts is "about 2 quarts low". Maybe more, maybe less. Normally, you'll notice the light come on when taking a ...
JPhi1618's user avatar
  • 13.2k
20 votes

Why has my car burnt through all the oil?

If it is burning it's oil, the oil is getting somewhere it shouldn't do - and changing the plugs and coil will make no difference to that! As the oil smoke is coming out of the exhaust, that suggests ...
Nick C's user avatar
  • 28.7k
15 votes
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Why don`t we use extremely thin oils in engines

Thin oils tend to have a very poor shear stability, especially when they are hot. The function of the oil is to protect and lubricate the engine and ancillaries (i.e. turbo chargers). In certain ...
Steve Matthews's user avatar
15 votes
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What's the black knob near the oil pan?

If your engine is the 2.7 litre, then that is the oil filter. You can see this in this video detailing how to do an oil change on the 2.7 litre engine. The oil filter may just need tightening a little,...
HandyHowie's user avatar
  • 25.2k
14 votes
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How do I troubleshoot the source of oil in my coolant?

Number one answer is always Head Gasket. The reason is that there are oil and water passages in close proximity, being separated by a gasket (which might just be flimsy paper or rubber, but is often ...
Jim W's user avatar
  • 1,935
14 votes

How do I tell if I screwed up my oil change?

Here's a "tip to make sure I got everything right" for the future. One that I use myself, and taught my Auto Tech students as well: The very first thing is to take off the oil cap, and place it over ...
SteveRacer's user avatar
  • 12.4k
14 votes
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Is it necessary to replace an oil filter every oil change?

You need to change the oil filter every oil change. In fact some of the longer lasting oils like Amsoil suggest you change your filter out at normal change intervals if you don't use their filters. ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
14 votes

Is it alright to top off with oil instead of changing after 3000 miles?

The 3000 mile oil change interval is a US-specific consumer deception so widely practiced that it has become accepted wisdom. It creates enormous revenue for dealers and garages. Outside the US, most ...
ajay's user avatar
  • 141
13 votes
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If you change your oil with synthetic can you never safely go back to using conventional?

This is a myth. A lot of old-school mechanics and non-chemistry educated people repeat this false myth. When changing from synthetic to regular oil, there is not anything special that you need to do ...
cloudnyn3's user avatar
  • 3,333
13 votes
Accepted

Why are recommended oil weights lower for many newer cars?

Two words, fuel economy. Using a thinner oil allows manufacturers to eek out a little more fuel economy. Thinner oil flows a little easier and has a little less resistance. To use the thinner oil, ...
vini_i's user avatar
  • 16k
13 votes
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Does engine oil get old and go bad?

Short answer .... NO !! Now this is one of those seriously contentious topics that people will chime in from all walks of life, experience, and voodoo. I will speak [yell] my piece, and put on my ...
SteveRacer's user avatar
  • 12.4k
13 votes

Top off gas with old oil, is that bad?

All modern cars scavenge blow-by including oil vapour and a mist of droplets. This is good for upper cylinder lubrication and does extend ring and bore life. If you have to, you can install a catch ...
mckenzm's user avatar
  • 416
13 votes

Top off gas with old oil, is that bad?

Aside from the numerous reasons not to do this to your car I would like to offer you a solution to your perceived problem. Don't take the old oil back to the store. At least not right away... Your ...
MonkeyZeus's user avatar
  • 1,187
13 votes

Does a, “5% oil life remaining” dash message mean low quality or low quantity, or both?

Realistically, it doesn't mean either. The life expectancy is just that, how long you should be able to continue to use the oil which is in there. There is nothing wrong with the oil. It will ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
13 votes
Accepted

Oil Pan Flap? What does it do?

The flap allows oil to move freely in one direction and slows it down going the other. The free direction of flow is usually towards the oil sump pickup. This helps ensure there's a ready amount of ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
12 votes
Accepted

Is an "oil life indicator" a reliable indicator for when to change the oil?

To the Mechanic suggesting 3000 mile changes, that recommendation has changed considerably. Several articles and studies have been done disproving the necessity of the 3k change. On any vehicle in ...
Eric's user avatar
  • 136
12 votes

How can an oil plug just fall out after three months and 3,000 miles and the car has just 35,000 miles on it, 2014 Ford Escape

It definitely could have worked it's way (the drain bolt) over the three month period from the previous change. The cause would be an improperly torqued oil drain bolt. It wouldn't be the first time....
DucatiKiller's user avatar
  • 32.9k
11 votes
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Okay to add new oil to old?

Mixing new with the old will cause you absolutely no issues. As long as you are using the same weight oil, it will mix up and you'd never know it. Continue to change your oil at the specified interval ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
10 votes
Accepted

Do air filters purify air better with age?

I don't have any empirical evidence for this, but would say no for two reasons: An air filter will collect more dust, dirt, and debris until it gets so full that it starts pushing the older dust, ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
10 votes

High oil warning in Mercedes B class diesel

Unless you recently added oil or had it serviced, I would be concerned. I would wonder what is raising the oil level. Do you have any signs of engine oil mixing with coolant? Does the oil have a tan ...
mikes's user avatar
  • 19.9k
10 votes

I've got oil in my coolant but no coolant in the oil - Ford Triton V10 Motorhome

If it has an engine oil cooler, that is most likely the problem, a faulty oil cooler, some are made into the radiator, others have heater hoses running to a remote oil cooler, and a few I have seen ...
Moab's user avatar
  • 7,990
10 votes

How can an oil plug just fall out after three months and 3,000 miles and the car has just 35,000 miles on it, 2014 Ford Escape

I had exactly the same experience with a chain oil change shop. It's one of the reasons I stopped using any outside mechanic for anything short of things I can't handle due to specialized tools or ...
cdunn's user avatar
  • 9,296
10 votes

2011 Jeep Liberty ran without oil, did this cause my engine to blow?

Your oil pan didn't rust I would just like to point out that your oil pan can't just rust out. It is made of material that doesn't rust. So when you had a hole in your oil pan it more than likely ...
DucatiKiller's user avatar
  • 32.9k
10 votes

Oil Cooled vs Water Cooled

I am assuming that by cooling you are referring as to which Engine cooling systems are better in particular scenarios... Oil-cooled: Traditional Oil-cooled engines are most commonly found in passenger ...
Jay Vyas's user avatar
  • 101

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