5w40 vs 15w40: Which one ensures Longevity, Performance & Value

5w40 vs 15w40 which is Betting big, Prolong the Lifespan of your Engine, and being Suitable for vehicles in the Fluid industry?

While looking for a relevant recommendation for our engine performance, it seems hard to choose from 5w40 vs. 15w40.

Diesel pickup trucks and gas-powered engines rely greatly on such oils. But when it’s about providing reliable protection to our buses and trucks, we must assure that we own the best motor oil.

There is no doubt that your vehicle needs a working viscosity and quick lubrication. And if you can’t judge the best one, then everything will go out of your shot.

On that note, I am going to help you with a conceptual solution featuring 5w40 and 15w40. They are one of the most merging oils you can ever have.

So, to grasp your favorite product between the two beasts, do continue with my article. You will surely meet your confusion and get your choosiest one prevailing a nice experience.

5w40 vs 15w40 Comparison Table

Kinematic viscosity[mm2/s]14.443 at 100 °C and 90.903 at 40 °C15 at 100 °C and 11 at 40 °C
Viscosity Index176143
Low Shear Rate Viscosity12.5 to 16.3 mm2/s at 100g12.5 to 16.3 mm2/s at 100g
High Shear Rate Viscosity3.5 at 150g3.7 at 150g
Temperature Range-25 °C to 35 °C-22F to 122F
Density[g/cm3]848.3 kg/m³848.3 kg/m³
PriceCheck PriceCheck Price
Oil FlowFlowing is good in coldCan’t flow good in cold

Difference between 5w40 and 15w40.

Which one is the best – 15w40 vs. 5w40

5w40 and 15w40 are two uncompromisable engine oils having their own standards. Each of them are qualified in each circumstance. In 5w40 you will get a good flow and fast lubrication of oil.

On the other hand 15w40 resumes a thicker version in cold weather.

Just as 5w40 gives a lower viscosity, so will 15w40. But for quicker lubricants in your engine, 5w40 is a better alternative. Similarly, 15w40protect engines of turbo-charged, light trucks, gasoline, and so on.

What if the price doesn’t support your affordability? And if you are concerned on that part, then there is nothing wrong to choose 5w40.

Because its usual price is less than 15w40. So if you think features are an important consideration along with price, then 5w40 is best on that part.

5w40 Full Synthetic Motor Oil : Main Features

5w40 engine oils can be your best friend if you maintain them well. But before that, we should know the features of this motor oil as a rectifiable use.

1. Inhibits rust and corrosion

Usually, our engines experience premature wear or tear due to rust and corrosion. But don’t worry when you have the 5w40. It performs like an inhibitor and reduces oxidation in oil.

Therefore, your engine can have better performance and long-lasting life.

2. Reduces Friction

The prime feature of this oil is to reduce metal-to-metal contact and friction in the engine. This 5w40 oil forms a protective layer on the machine running part.

By this layer, the metal parts will not contact each other and save from damage.

3. Removes impurities

5w40 oil consists of additives and detergents that help to remove impurities. The running parts of your engine will stay clean in the removal of deposits and others.

4. Acts as a gap filler

The space in the piston and cylinder is not so smooth. On that note, 5w40 will improve efficiency and performance, acting as a gap filler for your engine.

5. Acts as a coolant

5w40 oil has a fantastic coolant feature that keeps the running parts cool and prevents the upper engine from deterioration.

What is 5W-40 oil used for?

5w40 motor oils are a principal source for European vehicles. They own a recommendation for the performance of gas-powered engines.

Moreover, American diesel pickup trucks need such kind of good quality engine oils. So you can use them for both diesel-powered and gasoline-powered machines.

And oil is going to suit the best in any climatic condition.

5w40 oil is used for which cars?

The 5w40 engine oils are well sourcing thinner oils compared to others. They lubricate fast and quickly, which is very important for diesel cars.

As a result, the most appropriate choice to use 5w40 is for diesel cars.

Specification of 5w40 : Modern Contractor Solutions

Kinematic viscosity[mm2/s] : 14.443 at 100 °C and 90.903 at 40 °C

Viscosity Index : 176

Low Shear Rate Viscosity : 12.5 to 16.3 mm2/s at 100g

High Shear Rate Viscosity : 3.5 at 150g

Temperature Range : -25 °C to 35 °C

Density[g/cm3] : 848.3 kg/m³

Price range : $140.02

Thickness : 3.5mPas

Oil Flow : flows at freezing cold.

Top 3 best 5w40 motor oil that is best fit for diesel and gasoline engines

#1. Shell Rotella T6 Multi-Vehicle 5W-40

Check Price On Amazon

Shell Rotella T6 Multi-Vehicle 5W-40 performs efficiently for diesel and gasoline engines within consolidated lubricants. It adds simplicity in use and storage.

Moreover, the advanced additive technology ensures a fully synthetic base exceeding CK-4 performance standards.

The use will exhibit cold temperature flow, which gives an easy start-up of extreme ones. And this heavy-duty engine oil resists breakdown through the heat in continuous protection throughout the service interval.

So guess what? You will get strong oxidation which will minimize the formation of acid with longer engine life. And if you think about oil thickening, that’s also totally budging.

2. Shell Rotella T6 Full Synthetic 5W-40 Diesel Engine Oil

Check Price On Amazon

Shell Rotella T6 5W-40 offers an enhanced fuel economy capability of 1.5%. It will help you to save money on fuel consumption without even compromising durability.

The advanced multi-functional dispersant additives provide a level of protection against sooth, dirt, and contaminants throughout the service interval.

This heavy-duty synthetic oil will resist breakdown through heat and control blocking or poisoning with the low-ash formulation.

Besides, the oil will maintain your vehicle emission compliance and diesel engine efficiency of 5w40 vs 15w40 fuel consumption ratio.

And the best part is, Shell Rotella T6 resists viscosity loss effectively and maintains optimal pressure in your engine.

AmazonBasics Full Synthetic Motor Oil

AmazonBasic Store launches one-quart six-pack full synthetic motor oil of high-quality value. This product can be a great source to formulate your longer drain intervals at a very cost-effective price.

And the entire mixture it consumes helps to prevent build-up which causes rust and corrosion.

The less engine wear in this oil prevents friction and gives a high resistance to viscosity and thermal breakdown.

You will not find a single strip in the liquid that gets extra Warren synthetic properties. While on exhaust emissions, that is also avoidable when you acquire AmazonBasic’s oil.

So, it’s nonetheless certain that this product stands up to your expectations giving relevant features.

Shell Rotella T6 Multi-Vehicle 5W-40Performs efficiently with consolidated lubricantsAdds simplicity in use and storageThe heavy-duty resists’ breakdown through heatExhibits cold temperature flowReduces acid formation and oil thickening
Shell Rotella T6 Full Synthetic 5W-40 Has enhanced fuel economy capability of 1.5%Advanced multi-functional dispersant additivesProtects from sooth, dirt, and contaminantsMaintains vehicle emission compliance Resists viscosity loss
AmazonBasics Full Synthetic Motor OilFormulates longer drain intervals Prevents rust and corrosion causing build-upsGives resistance to thermal breakdown Has Warren synthetic properties Reduce exhaustive emissions

15w40 Full Synthetic Motor Oil: Main Features

You may take the engine oils for granted if you don’t know about their features. Similarly, 15w40 possesses a similar situation. The features it has shown an integral performance and longevity in engines.

1. Minimizes friction and wear

The 15w40 oil does an excellent job in minimizing friction and wear between components. Lubricants on metal surfaces ensure to reduce friction and prevent heating.

Engine bearings like abrasion stay away in the use of 15w40 motor oil.

2. Cleanliness

This motor oil suspends contaminants and makes sure the components don’t adhere to each other. Mainly the detergents mixed with 15w40 remove dirt, and additive dispersants act as a solvent to maintain cleanliness.

Moreover, it prevents sludge from coming to your engine.

3. Cool engine parts

As the oil reduces friction, it also calmly decelerates the heat of moving parts. In this way, the oil lowers your engine’s overall temperature and absorbs heat from contact surfaces.

4. Form a seal

This 15w40 oil plays a dynamic role in combustion chambers, reduces consumption, and works great.

5. Transfer energy

Lubricants are incompressible and work fine as an energy transfer medium. This oil features inevitably to actuate components as a hydraulic fluid.

6. Dampen shock

15w40 performs like a cushion in blowing mechanical shocks. It disperses the energy strikes and absorbs them over a broad contact area.

Moreover, the vital lubricant here resists rupture and minimizes opposing forces.

15w40 Specification

Kinematic viscosity[mm2/s] : 15 at 100 °C and 11 at 40 °C

Viscosity Index : 143

Low Shear Rate Viscosity : 12.5 to 16.3 mm2/s at 100g

High Shear Rate Viscosity : 3.5 at 150g

Temperature Range : -22F to 122F

Density[g/cm3] : 872.5 kg/m³

Price : $155.45

Thickness : 1.39mPas

Oil Flow : Not so cold

15w40 is used for which cars?

Considering the 5w40 vs. 15w40 high mileage, both the oils have the same viscosity and thickness. Though the situation is different in the dead of winter, the lubricants work effectively for functioning your engine.

You can use the 15w40 engine oil in passenger cars, diesel light trucks, turbo-charged diesel engines, gasoline engines, and so on.

Top 3 Best 15w40 best oil

Shell Rotella T – 550045348 5 Synthetic Blend 15W-40

Shell Rotella T5 15W-40 Synthetic Blend is one of the best heavy-duty diesel oil having triple protection. The technology gives all benefits that you can expect from top-notch diesel oil.

This product holds a unique combination of synthetic base oils and advanced additives.

And the triple protection plus will protect your engine from wear, providing long life. Even if it’s at a high temperature, this oil maintains the viscosity control smoothly.

With an exceptional deposit control, this oil protects against oil breakdown in order with a low-temperature flow. Thus, you can reduce your fuel consumption and improve low starting.

Royal Purple’s API-licensed Motor Oil

Royal Purple’s API-licensed Motor Oil combines proprietary additive technologies that optimize engine performance. Also, this premium base oil creates high performance and delivers superior protection.

Gasoline and diesel engines will get prevention of metal-to-metal contact beyond both dexos1 and ILSAC GF-5 specs.

Here the patented additive technology will prevent white sludge and lubrication starvation. This motor oil is fully compatible with mineral or other synthetic oils.

For a quicker and smoother run of your vehicle, Royal Purple’s product can be your wise option. To own your right filter, we must give it a second thought.

Valvoline Premium Blue

Valvoline designs premium diesel oils to provide performance and protection in modern and emissions treatment-equipped engines.

Other diesel engine technology included in this product are- Exhaust Gas Recirculation (EGR), Diesel Particulate Filters (DPF), etc.

Cummins has tested the Valvoline Premium Blue 8600 ES extensively in various engine applications.

American-made heavy-duty diesel trucks can have reliable usage from this oil with a suitable range. The oxidation is breathtakingly outstanding as it supports long oil life in heavy-duty engines.

And for hardworking, heavy-duty trucks, the superior wear protection serves the best.

Shell Rotella T – 550045348 5 Synthetic Blend 15W-40A unique combination of synthetic base oils and advanced additivesHas triple protectionProtects from wear providing long lifeMaintains viscosity controlPrevents breakdown with low-temperature flow
Royal Purple’s API-licensed Motor OilOptimizes engine performance Delivers superior protection Fully compatible with mineral and synthetic oilsGives quicker and smoother run of the engine
Valvoline Premium BlueProvides performance and protection Gives a reliable usageReduces the oxidation Supports long oil life in heavy-duty enginesHas superior wear-resistant properties

What does 5w40 engine oil mean?

A winter viscosity grade of five is all that defines a 5w40 engine oil. Here, the viscosity is more diminutive in low temperatures but holds a hot viscosity grade of 40.

This motor oil keeps the moving parts away from overheating caused by friction. And thus, no oxidation or combustion prevails in your engine.

Properties and specifications of 5w40 oil

  • Viscosity, cSt (ASTM D445)

At 40° : 80

At 100° : 13.7

  • Viscosity Index : 176
  • Phosphorous : 0.1
  • Sulfated Ash, wt% (ASTM D874) : 1.3
  • Density @15.6 ºC g/ml (ASTM D4052) : 185
  • Total Base Number, (ASTM D2896) : 11.8
  • Flash Point, ºC (ASTM D92) : 231
  • HTHS Viscosity, mPa•s @ 150ºC (ASTM D4683) : 3.9
  • MRV at -35ºC, cP (ASTM D4684) : 24,453

Advantages and Benefits of 5w40 :

1. Active cleaning agents

It helps to sludge build-up and enables a long engine life. And by reducing deposits, 5w40 will grant mere cleanliness.

2. Outstanding thermal and oxidative stability

Allows an extended drain interval protection and resists oil aging.

3. Low oil consumption

The oil decreases hydrocarbon pollution.

4. Excellent low-temperature capabilities

It gives fast protection and conquers in extending engine life. Also, it provides a quick cold-weather starting.

5. High Viscosity Index

5w40 has an excellent wear protection performance in overall lubrication. And the term is relevant in all conditions and driving styles, even from mild to severe.

6. What does 15w40 engine oil mean?

We know that ‘w’ stands for winter in engine oils, and 40 indicates the weight. And this oil will thin out to a 15 weight in cold temperatures.

Sometimes you will see there is HD written on 15w40 full synthetic oil, which means heavy-duty. Like the oil circulating in engine parts, the modern oil detergent plays a crucial role.

Properties and Specifications of 15w40 oil

  • Grade : SAE 15W-40
  • Density @ 15.6 C, g/ml, ASTM D4052 : 0.866
  • Flash Point, Cleveland Open Cup, °C, ASTM D92 : 230
  • Kinematic Viscosity @ 100 C, mm2/s, ASTM D445 : 14.6
  • Kinematic Viscosity @ 40 C, mm2/s, ASTM D445 : 107
  • Ash, Sulfated, mass%, ASTM D874 : 0.5
  • Total Base Number, mgKOH/g, ASTM D2896 : 6
  • Pour Point, °C, ASTM D97 : -39

Advantages and Benefits of 15w40 diesel synthetic oil :

1. Dispersancy and control

15w40 diesel synthetic oil gains a soot dispersancy in an excellent range and has complete wear control. source

2. Protection

It gives fast and extended drain interval protection. Moreover, it prevents corrosion and wears simultaneously.

3. Superior formula

The superior formula of 15w40 part synthetic oil helps to reduce sludge and protects the varnish formation.

4. Stability

There are super anti-oxidation characteristics that keep the oil stable in high temperatures.

5w40 vs 15w40 which one is better [5w40 or 15w40]

In a simulation of 5w40 vs. 15w40 hot weather and cold weather conditions, both oils perform the same. They have similar temperatures and viscosity.

It’s nowhere like one thinner and the other thicker. We know the 40 here stands for consistency, which is the same in these two oils.

But this similar grade will always not remain stable like it is on a natural process, especially during the dead winter.

When you start your engine, 5w40 usually conveys a lower viscosity. On the other hand, 15w40 does not lubricate as quickly as 5w40.

Though the operating temperatures are the same in these two oils, the flow is more accessible in the case of 5w40.

Anyway, if you go through a breakdown, it won’t be an overstatement to say 5w40 is better than 15w40.

15w40 vs 10w30-What happens if I use 15W40 instead of 5w30?

Will Synthetic Oil Quite Noisy Lifters

Check Difference Between 5w30 and 5w40. And Can I use 75W140 instead of 75W90?

Buying Guide for a perfect Engine Oil

Though the engine oils work in an acceptable standard, they can vary in general and specific qualities.

Maybe the poor and high-quality oils look the same, but you need to justify which features are important for your engine.

Don’t worry. It’s as simple as a cakewalk to find the relevant one. The buying guide below will help you out more regarding your preferable engine oil.


Your oil’s fluid resistance flow defines viscosity. Several fluid molecules are attracted to one another, and energy is required to pull them apart.

And thus, they can create a flow. While in larger molecules, the attraction is, and so is the viscosity.

So, again will require energy to overcome this molecule attraction and create a fluid flow. Always consider chemical qualities and viscometric behavior while buying engine oil.

Makeup your mind on 5w40 vs    15w40 which is thicker while buying one.

Type of fuel

Before you purchase one, you must assure that on what fuel your vehicle runs. Is it petrol, diesel, or LPG? After determining the type, you can go for your correct engine oil.

API or ACEA classification

One more important thing is to check the label if there is any API or ACEA classification. This kind of ratings gives a determination of your oil’s suitability in various engines. source

In the improvement of technology, the standards also update regularly.


Being a first-timer of buying engine oil, you shall expect a price of $25 to $50 for 5 liters. Likewise, the 15w40 semi synthetic oil ranges from $30 to $60 for 5 liters.

And the price of synthetic oils are most expensive compared to other oils. They usually cost about $40 to $90 for 5 liters.

So, in what amount you are ready to expense on your engine shall be in your requirements as well. And same satiating to 5w40 vs  15w40 price comparison

Frequently Asked Questions

Which is better 5w40 or 15w40?

We all know that honey is a higher viscosity fluid and takes longer to flow. On the other hand, lower viscosity fluid like water doesn’t take time to flow.

Similarly, 5W40 has a low viscosity when your engine is started. And the 15W40 will take time in flowing as it combines a thicker texture.

Therefore, 5W40 will lubricate easily and quickly compared to 15W40full synthetic oil.

Can you mix 5w40 and 15w40?

After a certain usage, you can see that 5W40 vs 15W40 oil consumption holds the same thickness and viscosity. Even if you mix both the oils, none of them will make severe or unsafe contamination.

Moreover, there will be no grudge that one is more concentrated and the other is diluted. In a 40-degree viscosity, both oils perform the same.

But the situation will not be neutral all the time, especially during the dead of winter.

Is 5w40 good for diesel engines?

Turbo Diesel 5W-40 is a great factor in maintaining the outstanding performance of your vehicle. While significantly in higher temperatures, this oil performs better than other high-performance diesel engine oils.

It also ensures to protect your engine and extends the important life. And the best part is, that 5W40 is fully compatible with many other conventional oils.

And if you are looking for a quick and easy lubricant, then this can be a flawless item.

Which is better 5W30 or 15w40?

Considering the quick-flowing capability, 5W30 does a better job. Moreover, it has cold starting properties, which is a crucial source for our convenience.

If you use 15W40, you may have more fuel consumption due to more loads in your engine’s crank. But if you are looking for an adaptable oil for your diesel engine, 15w40 will suit you nicely.

And for gasoline engines, 5w30 is logically appreciable.

What temperature is 15W40 good for?

The widest performance range a diesel engine gains is from 15W40. The starting temperature of this oil is -22F, and the highest temperature is up to 122°F.

It is a suitable temperature that can go well with farm tractors, off-highway diesel equipment, passengers’ cars, and so on.

Oil viscosity drops and gets thinner when the temperature starts rising. Thus a complete success is surely acquirable mainly for road diesel trucks.

Is 5W40 good for summer?

Yes, 5W40 is good for summer because it has a higher viscosity and effective properties. So, the protection against wear is certain for the good engine running in high temperatures.

And most apparently, your car will get a proper running. But it’s not like 5W40 can’t run at low temperatures.

Even if you look for an easy flow during winter, that’s also pliant for this oil.

Is full synthetic oil 100% synthetic?

Full synthetic oils have high refined petroleum base with artificial lubricants. With distilled crude oil in base materials, the synthetic additives make such oils more natural.

As you can see, the whole mixture combines synthetic base and synthetic additives, so it’s 100% synthetic oil.

Also, in some products, other raw materials are used to dissolve modified petroleum components.

Does Hyundai recommend synthetic oil?

Hyundai recommends changing the filter every 3,000-5,000 miles for conventional oil. And for every 7,500 – 10,000 miles, they recommend you use synthetic oil ordinarily.

On a note, the density of 5W-20 or 5W-30 oil is all that Hyundai requires to sit comfortably between the engine parts.

Both in winter summer, they need enhanced durability synthetic blend. But for filtration efficiency, it won’t be a perfect choice for your engine.

When should I use 15W40 oil?

15w40 is a heavy-duty diesel engine oil that you can use for complete success in over-the-road diesel trucks. Furthermore, you can use this oil for off-highway diesel equipment, farm tractors, and passenger cars if you want.

The turbocharged diesel engines or gasoline engines are greatly compatible with 15w540 oils. But what the manufacturer recommends, always use it at that time.

For the warm climate, you should use 15w40, and for the cold climate, 10w30 is preferable.

What is the best 15w40 oil to use?

Among all 15w40 items, Royal Purple 15w40 is the most prominent motor oil you can have to increase fuel efficiency. It also helps to boost the performance of your engine as heavy-duty diesel oil.

But if you are searching for an affordable oil, go for Shell Rotella T6 Synthetic Diesel Motor Oil 5W-40.

It’s nowhere less than any good quality engine oil. And the synthetic lubricants have the same viscosity in both products.

What happens if you use 15w40 instead of 5w40?

Both 15w40 and 5w40 have a viscosity of 40 degrees. But when it’s the dead of winter, everything doesn’t remain usual, and the changes can vary. While starting your engine, 5w40 will have a lower viscosity other than 15w40.

In short, 5w40 gives easy and quicker lubrication in cold temperatures. If you use 15w40 instead of 5w40, you may not get a similar appliance of smooth flow of oil.

Can I put 15w40 in my petrol car?

The main purpose of 15w40 is to enhance the performance of diesel engines. Moreover, there are extra additives that are particular but not detrimental to gasoline engines.

As I mentioned before, 15w40 is quite thicker than 5w40. And there will be no problem if you want to use it for your petrol car. Even petrol cars adapt with thicker oils compared to thinner oils.

Can you put 15w40 in a 5w30 engine?

Putting 15w40 in a 5w30 engine will increase the fuel consumption of your engine. That is because your engine’s crank will get overloaded but won’t blow off.

Your engine will cause wear rapidly due to insufficient oil flow. And the moving parts will be lagging in exhibiting good performance.

Also, remember that the synthetic additives here can damage your catalytic converter being out of range.

Is 15W-40 oil only for diesel engines?

15w40 oil suits best with diesel engines. The diesel engines have an oil formation of additives that the gasoline engines can’t catch.

But there is nothing necessarily bad even if you use 15w40 on gasoline engines.

While typically, people most often use this oil on diesel engines to boost their vehicles’ performance. And a complete success in over-the-road diesel trucks is sure to be noted so far.

Does diesel oil damage gas engines?

Diesel oil is always not a successor for gas engines. It would be best if you put them in a higher temperature and higher oxidation rates.

But the sulfur deposits, fuel soot, acids, and other deposits are usually not found in diesel oils. And thus, your automobile engines don’t find a relevant option to turn on.

The reason is, diesel oils fail in some critical areas when you use them on gasoline engines.

Will 5w40 hurt a 5w30 engine?

On a pitched note, I will recommend you choose 5w30 for an extensive engine power next to 5w40. Or if you find it too expensive or unavailable, there will be no problem if you choose 5w40.

Moreover, it will not cause any hurt or damage to your engine parts.

But make sure the oil pressure is not heavy so that your engine gets a soothing flow of oil.

What oil is thicker 5w30 or 5w40?

5w40 is thicker than 5w30. The viscosity range of 5w30 is 9.3 to 12.5mm2/s. At the same time, the viscosity range of 5w40 is 12.5 to 16.3mm2/s. It means the 5w30 has more viscosity than 5w40, and it’s a sign of more thickness in the oil. So, according to the viscosity range, 5w40 is thicker than 5w30.

Which oil is thicker 10W40 or 15W40?

Motor oil grade represents operating temperatures, and the weight of oil is cold. When the temperature rises, viscosity or thickness will also rise at the same time.

Coming to 10W40 oil, it is a thicker option in the cold in comparison to 15W40. But there will be no change in the viscosity of both when the temperature is high.

Again, 15W40 attempts to be heavier than 10W40 with more shear resistance if you see it in a cooler condition.

Which oil is better 20W50 or 15W40?

It is best to use 15W40 for your new engine, which takes 15W40 effectively. But if your engine wears down 300000 miles that takes 15W40, then 20W50 will be the king for usage.

Because here you get thicker lubrication, and it sticks to your bearings. And the rest of the moving parts around makes your engine not wear out as fast.

Moreover, the 20W50 is a bit heavier than the 15W40 and consumes more oil.

Final Verdict on 5w40 vs15w40

In a juxtaposition of 5w40 vs 15w40, the article must have got the shot that you are looking for. What type of viscosity, ability, and thickness you want you must go for that one. In this imperfect world, it’s hard to find the perfect item but not impossible. Rather it will be best if you get the true mint of engine oil with a real recommendation.

Likewise with low viscosity and good lubrication 5w40 wins the crown. Though 5w40 lacks somewhere, 15w40 fills on that part, and the same goes for the other.  And on a comparable note, this engine oil handles better than 15w40.

So what about giving it a second thought? Not being late, grab your perfect engine oil and serve your engine the best.

Similar Posts