Piston Slap: Steam Clean Lincoln Town Car Engine?
Frank A. writes:
This is not a question about mechanical malfunctions exactly, but more about the avoidance thereof. I’d like you to give us your advice on engine cleaning. Clearly, it’s not a matter of putting a baggie over the carburetor and sticking a hose in there anymore!
The engine in my ’03 Town Car is looking dingy, but I don’t want to do anything prejudicial to the, I guess, thousand or so computers under there. I’ve noticed that practically all the shops in my area that used to advertise steam cleaning have quit on it, so that makes me think even the pros find this tricky nowadays. What do you think?
Sajeev answers:
While not as important as regular oil changes on the inside, having a clean shop under the hood is a great idea. Clean engines make visual inspections and repairs easier, keeps moving parts (like belts) alive longer and might even run cooler than dirty ones.
That said, the idea of steam cleaning an engine died for all the right reasons. Underhood electronic connectors are fairly waterproof, but not water vapor proof. You can cause all kinds of temporary electrical shorts by steam cleaning an EFI-controlled engine.
The solution? There are several: to get a really dirty motor clean, get a bottle of foaming engine cleaner from a parts store. Don’t use on a hot motor, but a warm one helps cook off the grime: shoot the cleaner anywhere you see caked on gunk, using a toothbrush to break it free. Use Simple Green (or equivalent) on the rest of the motor, avoiding the belt and cooling passages on the alternator. Let soak for 5-10 minutes, while you scrub the ugly spots. Wash it all off with a garden hose, don’t go crazy with water pressure, either.
Once the motor is clean, do the occasional touch up at your local coin-op car wash, using their “hot” engine cleaner. That stuff works wonders, even leaving a low-luster shine to boot. It’s cheap and keeps your neighbors from silently judging you.
Bonus! A Piston Slap Nugget of Wisdom:
Take off any and all plastic engine/radiator shrouds, so you clean all the areas that need to be seen when it’s time to get something fixed. While you’re in there, check all vacuum lines, the PCV valve and anything else that normally needs attention after 5+ years of service.
[Send your technical queries to mehta@ttac.com]
More by Sajeev Mehta
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If it's really cruddy, liberally spray good-old engine degreaser onto the motor while it's cold (excluding the air cleaner), let it sit for 10-15 minutes, gently spray it off with a garden hose, then take the time to wipe down and soak up any pooled water with rags. For the final touch, after drying most everything off, wipe down the hoses and wires and just about anything else you want using a rag lightly sprayed with WD-40. The results generally look great. If it's not very cruddy, then just use rags lightly sprayed with WD-40 to wipe off the dirt and oil. Never use a pressure washer or steam cleaner if you value the wiring harnesses and the myriad electrical connectors.
As some of you know I have been involved in detailing cars including engine compartments. My reccommendations are: Use a hose not a pressure washer. Too much force with a PW could hurt something. Most electronics are at the top of the engine so they don't get wet when you go thru puddles. Use your hose on the lower half of the motor and run a small stream on the top. Wrap in plastic anything you know to be electronic/senstive to water. Use a cleaner like Gunk to do the work for you, that's why you won't need a PW. Simple Green - be aware that SG can stain aluminum and most engines are aluminum or have aluminum parts. SG does make a formula that's for use on aircraft but it may be hard to find. If you rinse right away and get all of it you will probably have no problems, but it's risk. So I use Gunk or a similar product. Run the engine afterwards. With these simple precautions I have never had a problem yet.