How To Clean Your Imperial's Engine Compartment

Imperial Home Page -> Repair -> Engine -> Cleaning

Tip from Norm:

Well, one thing I noticed when I got my 64 Imperial convertible back was that the engine compartment was fairly dirty.So, I got out the hose and the de-greasing juice and went to work. First, I cleaned the outside of the carburetor with "Berryman's Carb and Choke" cleaner-works great. Then, I put the air cleaner back on and sprayed the whole compartment with de-greaser. I do not bother to cover up anything. I just let the stuff sit for a while and then turn the hose on it. Comes out pretty clean. Of course, I avoid spraying places like the Alternator or the Distributor, that's just common sense. On the tough spots of caked on grease, the Carb cleaner does wonders.

After the hosing I do two things: One, start the car so as to evaporate all the left over water. Two, wash and wax the car.

Follow-up question from Tim:

What do you mean by "de-greaser"? How do you spray it on -- does it come in a spray bottle or what?

And, for the benefit of those of us who have no common sense about cars, what else should we avoid spraying? :-) Battery terminals, for example? My own engine compartment rivals the Aegean stables, but I've been afraid to try to clean it for fear of damaging something...


From Norm:

My de-greaser I mean any type such as "409", "Simple Green", etc will do.

>...what else should we avoid spraying?  Battery terminals...

Nope, I do those too. Of course, I don't concentrate on it, but it gets rinsed off as well. I do periodically remove, clean and re-attach battery and terminals anyway. I once kept a car with its original battery for 9 years in New York City by removing the battery every 2 months, rinsing the case and cleaning the terminals. I used to check the water level every 2 weeks. For those who may be interested, it was an "Exide" battery that came on my 79 Volvo when new.

I do avoid spraying directly in to the Alternator or the Regulator or the Distributor. Note that I have been doing this to my cars ( this one for over 12 years) with no ill effects and they start right up immediately after spraying. Newer cars, too.

IMPORTANT: The only precaution I take is to re-lubricate the hood hinges and hood release mechanism right after a de-greasing treatment.

From Bob:

I've had a few years experience with a (sort of) new degreaser/cleaner - Castrol Super Clean. It's water based and, according to the directions, can be used for everything from engine cleaning to cleaning carpets or pre-spotting laundry - suitably diluted of course.

I've used it on several greasy engines and parts with great success - it's powerful stuff. It sells for about $7/gal. and I put it into spray bottles. Be careful on or near paint - it will dull (and probably eventually remove!) paint.

I like it much better than Gunk and similar petroleum-based degreasers and TSP, which I also used for a long time.

From Rob:

I always put a baggie over the carburetor & try to cover the distributor too to avoid getting them wet.

Tip from Ross:

As for cleaning the engine compartment, the best way, bar none, is to disassemble the whole shebang and do each individual piece separately.  Short of that, I like to do the underside at the local carwash (late at night when no one around), the car driven up on ramp stands and just have at it from underneath with the pressure washer from the transmission forward, ideally hitting everything from four angles; no higher than the valve covers. Of course, I already soaked it with CASTROL Super Clean, full strength or diluted by one third depending on the component before driving up there.  Use a paint scraper and wire brush or two with long handles to get the worst of it.  Next time, I start from the top down, at the house, in excellent light:  first one engine side, then the other.  From the front, and, most difficult, from the firewall . . . using bristle brushes and low power rinse water, moving the wiring where possible or shielding it. Cover the electrical components and carburetor.  Finish by using best quality aerosol can paints after driving 50 or so miles. (EASTWOOD is one source).  Keep all exterior surfaces covered!   Photograph and copy out all decals in full, they usually don't survive the quick-and-dirty described above.

Tip from Robert:

I once wasted my money having the repair shop do a steam clean. They didn't screw anything up, but it's a real easy do-it-yourself. I like to use Gunk engine degreaser (white can) for the heavy duty work and sometimes use Gunk foamy engine brite (blue can) for routine clean up. Spray it on, let it soak, hose it off. Repeat as needed. Take the air cleaner off, use aluminum foil to cover the top of the carburetor, and the distributor. No need to get carried away making it airtight, just enough to keep the water out. If you're in the commercial car wash, avoid using the high pressure rinse near wiring, vacuum hoses, etc. It's been my experience that high pressure rinsing doesn't really remove any more grease, grime, and dirt than normal pressure rinsing. To get the accumulated gunk off the frame, lower engine, trans, floor pans, etc the best bet it to SOAK it with degreaser and let it sit for an hour before rinsing. Aside from being nicer to look at and less agitating to work on, a freshly cleaned engine compartment is a great way to figure out where the leaks are really coming from. As for no start or rough idle after a cleaning, I've never given myself a no start condition, but I can imagine it if you get carried away with the rinse cycle. Keep the water away from the carburetor, distributor, and relays. Keep the pressure down when rinsing the wiring. Rough idle after a good cleaning is dependent on engine temp, air temp, rinse water temp, engine sealing and state of the wiring. The temp considerations generally amount to the thermostatic choke getting 'confused'. Temp and sealing add-up to moisture in the carburetor and/or in wiring connections. If your car runs rough on wet or humid days it will run rough after a good cleaning. Just crank it up and let it idle until it dries out.

Tip from Mike:

If you are having problems with your car starting after you have cleaned it, try and spray a can of "Ignition Dry-Out" spray! Bought at any local parts store, you spray this stuff all over the spark plug wires. I guess that it's non-conductive (?), and eliminates arcing. 

Tip from Bob:

What is easier and less of a mess is to take your car to a local do-it-yourself car wash. The hot water and detergent there are very efficient in removing dirt, grease and grime. If you live anywhere except the sunshine belt, it's also a great way to remove road salt, etc. from under the wheel wells. Most mechanic types will tell you to cover electrical things like the distributor, carb intake (after removing the filter housing, of course) and any connections to electrical accessories, although I've NEVER done that and the only problem I've had is condensation in the distributor causing trouble starting. I simply remove the cap, stuff a clean, dry rag inside and/or spray with WD-40. After a few cranks, it starts right up. I don't suggest spraying directly into generator windings, etc. but the rest of the engine will clean up surprisingly well.

Tip from Greg:

To clean engines, I spray on diesel oil, let it sit, then wire brush the most stubborn crud. Most of the crud comes off with the first application of the diesel. To get the residual diesel oil off, I then spray the engine with solvent. Let the engine air dry after application because solvent is combustible. I use large sheets of card board under my lift to catch the crud and when they get dirty I replace with new. It works well for me.

I don't like to use any water or sand blasting near or around my engine, there are just too many parts that can be affected or damaged. I watched a guy clean a big radial airplane engine with a water hose and detergent, after he finished the job the engine wouldn't run. He had inadvertently got water into the magneto, which now required a tear down and cleaning. My neighbor had an engine for his Dodge minivan rebuilt by professional mechanics. After about 4,000 mile the engine lose oil pressure. Upon tare down he determined that the "professionals" has sand blasted the valve covers during the cleaning process. The sand had become trapped inside the valve cover baffles and gradually worked its way into the engine bearings. A complete rebuild was needed and my neighbor had to threaten the mechanics with a law suit to get justice. I like to use petroleum based products like diesel and solvent for engine cleaning, keep the pressure washers for the outside of the cars body.

Tip from Zub:

I have found the local co-op store has their own brand of household grease cutter. A very large bottle of this yellowish greenish cheap cleaner, 1 liter is a $1.50 or so. It works wonders. It even washes the grease off with cold water. Its made for the home so the paint stays put.

Tip from ?:

I like Gunk brand engine cleaner and degreaser products. With enough cans, patience, rags, and a garden hose, you can get your motor and  surrounding areas very clean and dry. A pressure washer helps.  Repeated applications are generally required. If you've had nasty  leaks for long periods of time you'll also have a ton of road dirt stuck to the oil. In this case, scrapping some of the thicker spots  w/ a putty knife is helpful.

Tip from Bob:

Everyone is cleaning their engine for the upcoming shows, right? I just tried a new product, on the recommendation of my local (small) parts store - Castrol Super Clean. The label says "3 times stronger than Simple Green". I was a little put off because they only had it in gallon jugs - about $9. Anyway, it worked well on a grungy Toyota engine (not my car!) and didn't tear up my hands too much - all my rubber gloves have melted. I used it both in a spray bottle & with a brush - cuts the grease and washes off with little residue. Didn't even use a quart, so there's enough for the 440 - is isn't very dirty anyway.  This cleaner also works well on carpets.

Tip from Kerry:

Another good engine cleaner are spray on oven cleaners. They eat through the gunk and leave a dry, non slimy finish. They do, however, remove paint also and are nasty on your skin. Wear goggles and rubber gloves. You can usually find it for about a buck a can on sale. I buy it by the case. You may still have to do some scraping but it is much less messy.

Tip from Mark:

Go to your local auto parts store, buy a can of Gunk engine degreaser, mix it up with a liberal amount of old engine oil, and squirt some right in your eye! I hate it when that happens. No, seriously, folks, for those of you who are considering cleaning under your engine, get a pair of safety goggles that wrap ALL THE WAY AROUND the sides of your eyes. I made the (stupid) mistake of using some that I use for other purposes that do not wrap completely around, and a little drop of degreaser/oil found its way into my eye - almost! Enough to burn pretty good. Not fun!

Tips from Dick:

You can't do a good job of cleaning an engine without taking some parts off. For one thing, you must avoid getting any water or solvent in the distributor, and if you just start spraying around in there, you'll cause yourself problems.

I think your best bet it is to take it to your local carwash outfit and ask them to "detail" the engine for you. This won't restore the peeling decals or tired paint, but it will make it look MUCH better, and then you can buy the right paint from the auto parts store and with a little careful masking, you can make it look almost new. You'll need the right engine color (ask someone else, I'm color blind - but it looks like Teal to me), plus gloss and semi-gloss black paint, and rattle cans work just fine. As for the decals, they are out there, check the IML vendor list, or contact Year - One. The pie plate on the top of your air cleaner is a tough one, if yours is at all savable, try to clean it up carefully while preserving the decal. You might be able to make it look pretty good, and then spray clear Krylon over it (available at your local Home Depot). Your hoses and other rubber parts will look much better if you rub them with some lacquer thinner soaked into a cloth - but be careful with this stuff, it eats paint! And don't inhale this stuff, it is a cheap high, but it isn't good for you! Stop short of removing the writing on the hoses.

Lacquer thinner also does a good job on wiring, it will restore much of the faded colors on the wires. Remove your battery and clean the white residue from the tray, then wire brush the rusty areas down to bare metal, then paint it with Rust-Oleum gloss black enamel (also from your friendly local Home Depot) - use brush type enamel, to avoid getting over-spray on nearby items. Wash your battery with "Joy", water and a brush (out of the car) until it looks new and shiny, and after you re-install it, put a light film of Vaseline on the cable ends and post tops to keep the crud from re-forming.

The underhood pad is probably ready to turn to dust. You can try vacuuming it gently, but don't get carried away or it will rain down all over your nice clean engine. If you are going to remove and replace it, spread a tarp or something over the engine and fenders before you touch it.

Question from Greg:

The shop that is currently finding the leak in the a/c on my '61, also does steam cleaning of engines. Is steam cleaning engine area a good idea or will it do more harm than good on already brittle wires, etc.?


From Dick:

I have both a pressure washer and a steam cleaner. The steam is much more effective for old crusty crud and congealed grease, but it is very hard on painted surfaces (peels off the paint) and will find its way into anything, no matter how hard you try to seal it up, so if you drive it into the steam cleaner, I'll bet you a buck that will be the last time you drive it for a while. (Everything, I mean everything, will have moisture and condensation in it!). You'll also want to be prepared to repaint everything under the hood, and replace all the decals. After the mid-50's, the wires are pretty tough, although you may lose the harness wrapping. Earlier cloth covered wire will disintegrate to bare copper and shreds of cloth wrapping. Even the better pressure washers (say over 1500 PSI, heated 200 degree water with detergent) will produce some of the same problems. The toy ones they have in the "quarter in the slot" places are usually not too aggressive, and while you will also probably have trouble getting it to run again afterward if you wash the engine, at least it won't do any permanent damage. I'd recommend a mild pressure washer for the engine compartment, and then if you are willing to get under the car with a can of black "Rust-O-Leum" after it's done, have the chassis steam cleaned. If you are just going to let it rust after cleaning, better let it be, the grease, tar and remaining undercoat is protecting the metal under there.

From Lee:

I've had a number of old engines cleaned at the local car wash [they call it steam cleaning but I'm pretty sure no one uses steam anymore...just water] and never had a problem. Just make sure they cover all the parts that can be damaged from the water. It does a decent job of removing just enough grime so you can see how really filthy the engine compartment has gotten.

From Bob:

I took my '66 in for steam cleaning about 4 years ago - the advertised cost was $35. They offered to do the whole chassis for $45, so I had it done and nothing strange has happened since then.

From Bill:

I personally wouldn't do it on that old a car, they like tender loving care.

From Steve:

While working on aircraft all day, when it comes time to "de-grease" an engine we use mineral spirits and compressed air. Snap-on makes a tool that is merely a blow-gun with a clear plastic hose which gets submerged in a 5 gallon jug of mineral spirits. The suction of the outgoing air draws the spirits up the hose and out with the air. Just make sure to catch all the drippings in a pan or with plenty of rags. Any spirits left on the engine evaporate in about 10 minutes.

Question (1966):

I would like to detail the engine and engine bay area. To include: cleaning, painting, and new hoses and wiring. In order to do this properly and restore the area to a like new condition, would pulling the engine be required? If so , are we talking a monumental task? And finally, if the engine is pulled, would this be an ideal time to rebuild the engine? The engine has approx. 88,000 miles on it.


From Paul:

As you're doing all the wires and hoses, you may as well get that engine out of there which would make it alot easier to 'spruce-up' the engine & bay.

And as long as you've got it pulled, you (if you've got the desire & funds) may as well do the rebuild

From Rodger:

Paul is right in what he said about taking out the engine. In order to do the job right you will need to ID every connection and take a few dozen pictures. And then take off everything. Window washer, see it, you move it for the task. Then after you take the part off the car you zip lock bag the pieces with info in every bag. Before you re-install the pieces you clean and re-paint every part.

From John:

You can do a tremendous amount without taking out the engine. I usually remove everything off the top of the engine including carburetor, wiring, hoses, alt, compressor, all brackets and valve covers (if they will need bead blasting or are a different color), then clean and wire brush everything before painting, using newspaper, tin foil, plastic bags, etc to cover things you do not want to paint. The fan and radiator should also be removed to give more room to work and to be painted out of the car. I have done several details like this and it does a very nice job as long as the extra care is taken to avoid overspray while working in the close quarters of the engine compartment. Fender wells can also be done in the same manner if you can find the matching color in a spray, or you can get some paint mixed at the auto paint store, purchase the reducer, and use the sprayer/bottle available at places like Home Depot.

From Chad:

While doing the body-on restoration of my 1966 Galaxie 500XL I pulled the entire front end off up to the firewall (fenders, inner fenders, engine, radiator support) so I had only 2 frame-rails sticking out. It was much easier when I cleaned everything and installed the new suspension and brake lines. I would suggest removing the engine if you are capable, and using a power washer with some degreasing solvent like super clean by Castrol or simple green. It all depends on how detailed of a job you plan on doing. After I had cleaned everything I could paint everything off of the car which provided a much more desirable result. I would say that the more you leave on the car the harder it will be.

From John:

Pulling the engine would make the job a lot easier, but at 88,000, if well cared for should be far from needing a rebuild. I've had engines go over 200,000 & still run well

This page last updated November 21, 2003.  Send us your feedback, and come join the Imperial Mailing List - Online Car Club