By on July 29, 2009

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.

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17 Comments on “Piston Slap: Steam Clean Lincoln Town Car Engine?...”

  • avatar

    I’m almost always “old school” all the way but in this one area I reluctantly had to give in modern realities.
    Yup. Steam cleaning today is absolutely a no-no.

  • avatar

    Up until at least the 2000 model year, Ford trucks used to have a really nice graphic in the owner’s manual, which showed the owner all areas of the engine compartment that could withstand water, as well as those that needed to be protected from it. Being a bit OCD about the cleanliness of my vehicles, I miss having that information.

  • avatar
    Gardiner Westbound

    I steam jennied many a motor in the days when you could see pavement on either side of the engine block. I wouldn’t even think about it now.

    I last did a Gunk and garden hose cleaning about 10-years ago. Spent an hour first taping plastic bags over vulnerable items, there are lots of them. I’m not sure the results warrant the effort and risk.

  • avatar

    try this, the results are amazing and it’s really easy:

    1. cover negative battery terminal, spark plugs, and anything electronic that is exposed, like the alt. with a plastic bag or the like.
    2. spray simple green judiciously over entire engine bay.
    3. rinse with low pressure water after about 2 min.
    4. let dry.
    5. spray entire engine bay liberally with armor all.
    6. let dry.

    that’s it. results are quite impressive for how little actual work it takes.

    I only have to cover the battery terminal on my car, since everything else is shrouded, or underneath.

  • avatar

    I use ctowne32’s method but for the “#4 let dry” phase I start the engine and allow it run for awhile with the hood up. The heat from the engine will get rid of any water that might have gone to a bad place. No problems to date on either of my vehicles, both of which are over 8 years old.

  • avatar

    ctowne32 : 5. spray entire engine bay liberally with armor all.

    Looks great, but turns everything into a dirt magnet. I don’t do that anymore.

    JMII: good point. I forgot to mention to close the hood and let the engine run until all the pooled water dries up. VERY important.

  • avatar
    Daniel J. Stern

    Here’s another vote for ctowne32’s method, minus the Armor-All. Simple Green (or one of the d-limonene-based “Citrus Orange Scrub” type compounds) does a great job cutting the grime, and its residue (there will be residue, and you will smell it) smells much less grotty.

  • avatar

    I hate a dirty engine. My cars are 9 and 5 years old and i clean them each twice a year and have no problems. I just use the regular spray on Gunk engine cleaner and hose off. Then start it and let it run awhile. This tends to make the rubber air intake hose a chalky gray, so i wipe it down with a rag and Armor All. I’d never do a steam cleaning though

  • avatar

    I gave up on the Gunk and garden hose method years ago. I never had good luck with the electronics, and that was before the modern electronics. I covered all the important stuff as well as possible too. I now use a rag moistened with a greased lightening or simple green solution and it seems to work pretty well. The main point is to catch valve cover gasket leaks and the like early, to avoid getting a sloppy motor in the first place.I would never spray my BMW motor with water. Too expensive if something goes wrong. Instead of armor all, try detail spray, Much less attraction of road grime.

  • avatar

    Three more items:

    After washing, a leaf blower works real well in the drying department. But I’d still run the motor to get the belt and accessories (like the alternator) 100% dry

    I’ve never covered the battery any more than the stock cover(s) on the terminal. Or no covers at all. Never had a problem.

    Make sure to wash the REST of the car afterwards, as your fenders, bumper, windscreen will look pretty terrible after all is said and done.

  • avatar

    I’m with BMWfan. A little damp-wiping to feel good about yourself, and that’s enough.

    With so many electronic sensors, circuit boards and connections – not to mention pullies and bearings – I can’t imagine how aggressive applications of water or steam can possibly do any good for the engine bay.

    As a car dealership employee some 20 years ago, I pulled my wheels into the shop one quiet Saturday afternoon to hose ‘er down under the hood. When the service manager saw me, he asked me if I was “(expletive deleted) bound and determined to make sure that thing never runs again”.

  • avatar

    What do you spray back on the engine bay metal, like shock-tower seams etc, to discourage under-hood rust after you’ve stripped off all the oil?

  • avatar

    I probably shouldn’t tell this because it will hurt service-part sales, but…

    Like all Panther-based vehicles (CV,GM,TC) this vehicle has an extension shaft connecting the steering column to the lower intermediate shaft (which is the shaft mounted to the steering gear, and as you move up the assembly from gear to column, has a rubber disk-isolator, a black tube and a golden-coloured Zn-plated shaft, then the U-joint of the extension shaft – appx under the brake reservoir – then thru the dash panel).

    Two things that would be like “crossing the streams in Ghostbusters” (a very bad thing):

    1. Don’t powerwash the u-joint that is just above the mid-point connection between the two shafts (else you will blow water and soap under the o-rings, foul or remove the bearing grease, and cause the u-joint to sieze over time;

    2. Don’t powerwash the seal cap on the lower i-shaft where the golden shaft goes into the black tube (else you will foul the grease in the sliding system at the shaft-tube interface and cause stick-slip, i.e. creaky noises when you steer, or go over bumps, and have increasingly stiff steering as the u-joint freezes-up).

    This is not academic advice, but is based on real-world field experience – these shafts are Swiss-designed and made, are extremely durable and robust, but there are even some usage profiles (and actions like powerwashing) which they can not indefinitely and repeatedly withstand.

    Otherwise, happy spraying.

  • avatar

    By all means, pour water on Ford’s modular motor. The coil packs LOVe to get wet. Then they crap out and cost you $200 each to replace.

    DO NOT spray water around the engine bay of your Lincoln!!!! When I sold Fords, our detailer used to wash the engines, and sure enough, the customer drives off in their new used vehicle, only to come back because the engine isn’t running right. Replacing those coil packs used to come out of my gross profit. Don’t do it!!

  • avatar

    Funny you should mention this. I just bought a 2005 Town Car two weeks ago and I was astounded to find instructions in the owners manual for power washing the engine! Right there at pages 260-61; I’m looking at it right now. It says “Engines are more efficient when they are clean because grease and dirt buildup keep the engine warmer than normal.” (really?)

    Then it has a line drawing of the engine compartment with three areas shaded that should be covered: the battery, the air filter box and the thingie sitting atop the left wheel arch that I believe is some sort of computer. The instructions are “Spray Motorcraft Engine Shampoo and Degreaser (ZC-20) on all parts that require cleaning and pressure rinse clean.” That’s it, except for cautions not to spray a hot engine or an engine that is running, and a warning to “take care when using a power washer to clean the engine. The high pressure fluid could penetrate the sealed parts and cause damage.” Wait, didn’t you just recommend using a pressure washer?

  • avatar
    Lug Nuts

    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.

  • avatar

    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.

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