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Car engine cleaning is important for many reasons. A clean engine runs cooler which helps with fuel efficiency. It also helps prolong the life of your engine.

So cleaning the engine the proper way requires best-practice methods, which is what we include in this overview of Car Engine Cleaning Tips.

A Clean Engine will Increase a Vehicle’s Resale Value

Other than the obvious benefits, like a cooler-running engine and fuel efficiency, a major reason to regularly clean your car engine is in the trade-in or resale value of the vehicle.

What would you rather buy? A grime-covered dirty engine? Or a reasonably clean version?

Car dealers know a clean engine will increase a vehicle’s resale value. So the first two items on every resale to-do list is detailing and car engine cleaning.

Unfortunately, since there are many ways that an engine can be damaged, you need to make sure you follow best practices.

Don’t Try This At Home

A word of caution: don’t try this at home if you aren’t comfortable around car engines.

At, we are all about do-it-yourself detailing and reconditioning of vehicles. That’s why we created this website. But car engine cleaning is one topic that you need to be well aware of the potential risk before you try this.

You can really screw-up your car engine if you clean it improperly. Seriously, don’t try this unless you understand how your car engine works and where you don’t want to get water inside it. Car Engine Cleaning Tips

One mistake and your spark plugs will be sitting in water. Or you can inject water into your oil. Or you can force water into your gas. There are so many ways to mess up a car engine cleaning.

Insurance is Always a Good Thing

Professional detailers have experience cleaning car engines. Plus, they’re insured in case they mess-up anything. As with most things in life, insurance is always a good thing.

It doesn’t happen very often, but it does happen. So just be careful. It’s much more costly to bring your car to a mechanic to have them take it apart and remove the water that you sprayed inside it. So you’ve been warned.

Now on to the rest of the car engine cleaning tips.

A Heated Pressure Washer is Preferable

This is one of those tips where most DIY detailers at home are thinking, “Um, well I don’t have a heated pressure washer.” I get it.

But a large number of our readers are also new or fairly new to the detailing business. So I’m speaking to them here. It took me a full year after I opened my first shop before I could afford a hot water pressure washer. But if you can swing it, definitely think about it.

Chemicals are Important in Cleaning a Car Engine

Hot water helps, as does pressure, but chemicals are important in cleaning a car engine. You need the degreaser to loosen up the oil deposits, grime, grease, and dirt. The hot water simply helps the chemicals work better.

Ultimately, you want to use the least amount of water as possible on the engine. Pressure helps, obviously, but heat melts grease and oil. So combining hot water with your degreasing chemicals is a win-win.

Cold Water Works Too

If you don’t have access to either a hot water pressure washer or a steamer, then your next best option is plain-old cold water.

Obviously, a pressure washer is a basic tool of detailing. But I do know excellent, old school detailers, that rely mostly on chemicals and simply use a hose to rinse the engine.

But once again, a hose pumps a lot of water on your engine. Be careful.

If you go the non-pressure route, then you need to use a much higher level of chemical degreasers. Rely on the chemicals to do their job.

And like I mentioned above, putting that much water on your engine for the length of time is takes is inadvisable. Water and your engine are not a good mix, so if you can get a hold of a pressure washer it’s better.

This is also why having a good template from a quality car engine cleaning tips page makes sense.

Wipe the car engine

When Cleaning a Car Engine, Less is More

I would be remiss if didn’t keep reminding you of this on a car engine cleaning tips article. It’s the simple rule that when it comes to water pressure, especially with car engine cleaning, less is more.

Always. Always. Always rely on the chemical degreasers and NOT the water pressure to clean a car engine.

If you haven’t figured it out yet, there’s a theme in this article. It’s mainly the idea that forcing water into an engine is something you don’t want to experience.

So when cleaning a car engine, less is more. Rely on chemical degreasers. Use both water and pressure sparingly. Let the chemicals do the work for you.

Anywhere from 1,000 PSI on up to 2,000 PSI is more than sufficient. Any more than that and you run the risk of injecting water into places you don’t want water in your engine.

Engine Running or Not?

This topic alone could fill several blog posts. For decades, professional car detailers have debated whether to keep a car engine running while you are cleaning it.

PRO TIP: I will address this in more detail below, but yet again, I find myself needing to add our standard disclaimer that we take no responsibility for any damage that you do to an engine. We can only tell you how we did it for years and you decide how to proceed from there.

We Started By Leaving the Engine Running

At both our shops and our mobile crews, our process changed over the years. At first we started by leaving the car engine running. I ran the car engine for about 15 minutes to warm it up. Then I turned it off.

Next, I would cover-up air intakes, electrical boxes, wiring harnesses and spark plugs. With what?

PRO TIP: Buy those big contractor garbage bags from Home Depot or Lowes. The really thick, black contractor clean-up bags. Obviously you can use them for garbage and anything else that you need to toss. BUT, I take one and cut it in pieces and use it to cover the electrical components and air intakes on the engine. It works like a charm.

Next, I applied a generous amount of cleaner/degreaser solution and allowed it to soak for 15 to 20 minutes. Or longer if needed. Just don’t let it dry. Keep reapplying or shooting a light misting of water to keep everything wet.

After the soak, the engine was started. A heated pressure washer on the high heat/steam setting was used to spray the engine clean. We never had an issue with any of the thousands of cars that were cleaning in this way.

PRO TIP: If you try this, make sure you get the engine clean without leaving it running for a long period of time. Even though those garbage bags are thick, they still melt. If you leave them covering parts of the engine, they will melt when it gets hot. This step usually only took a few minutes.

Our Engine Cleaning Process Changed as Degreasers Got Stronger

Even in industries as slow-moving as auto detailing, car chemical companies still attempt to make better products.

That’s why competition is always a good thing.

I started to rethink our engine cleaning process when I began noticing that the degreasers we were buying were showing improved results immediately after application.

So our engine cleaning process changed as degreasers improved. It made sense since we no longer had to apply so much water and steam to clean the engines.

We were still careful to cover delicate electronics and wiring harnesses, but we were able to use a lot less water. 

Your car engine cleaning chemicals make a world of difference. Never go cheap on your car detailing supplies. Even at home. It’s just a bad idea and it makes everything harder.

And if you’re doing this professionally, then set yourself apart from every Joe Schmo who buys cheap cleaners. Do it right and invest in your business. It will reward you with the ability to offer faster, better, service.

Have fun and enjoy the process. You shouldn’t have any problems as long as you follow the tips outlined above and use common sense along with a good safety regimen.

Suggested Pages to Check Out

Detail Shop Liability Insurance Page with Info on Garage Keepers Liability Coverage

1099 Contractors and Other Detail Shop Tax Issues

Go Back To Home Auto Detailing Step-by-Step Page