Get the gunk out; a little pressure and the right products key to a clean engine compartment
by Tom Jackson
Perhaps some of you, like myself, have been wary of “steam cleaning” the engine on your truck. Blasting high-pressure water under the hood never seemed wise to me. But engines do get dirty, and after 24 years the V-6 / 2.8L gas burner in my Chevrolet S-10 was looking pretty grimy.
I wasn’t concerned about the looks, but trying to find sensors, ports, vacuum tubes and other small components in this black hole was getting harder every year.
After a chance encounter with the people at Gunk during last year’s SEMA show, though, I decided to give engine cleaning a shot.
I did an interview first, with Larry Beaver, vice president of technology at RSC Chemical Solutions (parent company of Gunk) and Aaron Martin, director of marketing; this to assuage my paranoia and to make sure I didn’t do anything stupid.
Beaver and Martin had good answers for all my questions and fears. It turns out I’m not the only one who has these concerns and misconceptions about “steam cleaning.” The process is not technically steam cleaning, but degreasing and rinsing with a pressure washer.
“Spray, scrub and rinse, that’s about as simple as it gets,” Beaver says. “Most people are needlessly worried about pressure washing their engines.”
The only thing you need to cover is anything that has a vent hole or an intake that opens to the air—anything with unobstructed entry to the engine, Beaver says.
Most new engines don’t have these openings, but older and antique cars and trucks do. If that’s the case, cover the hole or port with a zip lock bag, snap a rubber band around it and you should be fine.
You don’t have to cover the alternator or battery, but if you have any sensitive electronics, or a distributor cap, you could cover those just in case. It doesn’t have to be hermetically sealed, Beaver says. It just has to keep the water stream from going down into it.
Beaver also insists that the maximum pressure you should use from a pressure washer is 1,500 psi. We found a 1,600 psi model from Snap-on, and sure enough their experts concurred, nothing stronger should be used to clean an engine.
Pressure washers in this category can be had for about $150 ($99 on sale sometimes). And while these aren’t strong enough for commercial cleaning purposes, they’re just about right for other automotive cleaning applications and they do OK for light duty chores around the house. I used the Snap-on later to clean a brick patio.
Use the right product
Gunk has a variety of engine cleaning products in spray cans, ranging in price from about $4 to $9. I used the Gunk Engine Degreaser Heavy Duty Gel, and the Gunk Original Formula.
Following Beaver’s instructions I lathered up the engine with the Heavy Duty Gel taking care not to get it on the mat material at the firewall and under the hood. The degreaser won’t hurt the mat, but the fibrous material will hold on to the odor for a while.
Next you let it sit for 10 or 15 minutes and then give all the exposed engine surfaces you can get to a good scrub with a brush.
Beaver recommends a toilet bowl brush. I also used a smaller tile grout brush I found at Wal-Mart to reach hard to get places. And I wore nitrile gloves to protect my hands.
After the allotted wait time and the best scrubbing I could muster, I fired up the pressure washer. Beaver recommends spraying from the firewall forward just to keep the mat material as dry as possible. And I watched with pleasure as thick layers of grime melted away.
I was probably over generous with the degreaser spray the first time. As it turns out one can of the degreaser was barely enough to coat my engine.
You will probably want to use two. And once I had everything rinsed off I could see a few places I missed, mostly nooks and crevices where I didn’t spray thoroughly enough. So my S-10 warranted a second spraying of degreaser and another rinsing. Keep in mind it’s a 1987 model with 220,000 miles on it and this is its first cleaning.
After the pressure washing you simply uncover anything you may have covered up, start the engine and let the heat of the engine dry everything off. If your spark plugs sit in a small recess, a little compressed air here will blast the water out.
Uncovering the truth. My engine doesn’t look new exactly. It’s clean, but the cleaning uncovered spots of rust and blistered or faded paint. At least now I can see it—and do something about it. Nonetheless, the effectiveness of the Gunk was impressive.
I was concerned about residue on my driveway. But there was none of that oily sheen you get when you hose off spilled fuel or oil.
After I rinsed the concrete with the garden hose and let it dry I couldn’t see any stain or any indication that I’d just blasted off a quarter century of grime.
(The grass on the downhill side of my driveway suffered no ill effect either.)
Beaver says that before you spray the degreaser you should putting newspaper under the engine to catch the drippings, then remove the paper before you start pressure washing. I didn’t, but best I could tell, I didn’t need to.
If you live in an area with strict rules about runoff, make sure you follow them. Under no circumstances should you do this where the runoff can reach a storm drain. This is true with any cleaners that dissolve petroleum based grime.
Aside from making your engine look better, there are a lot of reasons you would want to do this.
- As was with my case you can see components and sensors better. That makes maintenance easier, and when you’re topping up or refilling fluid reservoirs (like oil, brake or power steering fluid) you’re less likely to introduce contamination.
- If you’re going to do a rebuild, I’d recommend you clean the engine before you pull it. That will make disassembly easier, save you a lot of time at the parts washer, and likewise lower the risk of contamination. You’ll keep yourself and your tools cleaner too.
- Detecting leaks. If everything from your valve covers to your oil sump is the same carbon black color, it can be difficult to detect small oil leaks. Same with other components. A leak on a clean engine will be detected early.
- Heat transfer issues. A coating of carbon based grime acts like an insulating blanket on your engine. A cleaner engine runs cooler.
- Resale. You detail the interior, why not the engine?
- Take pride in your ride. ‘Nuff said.
Beaver recommends annual cleanings, and I tend to agree. The cost is no more than one Starbucks Latte, maybe two. And it takes less time to do the engine than it does to wash the outside of the truck.
After you’ve cleaned the engine you may want to try other a Gunk product called Engine Protector Shine. It puts a little like-new spif back on the hoses and plastic parts that may appear dry or hazed after cleaning. That’s especially useful for more modern engines which tend to have large plastic covers over the engine block. And it coats surfaces to make it easier to clean them off next time.
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