Engine Bay detailing

M. Lawson

True Classic
I am wanting to do a bit of detailing on my engine bay. So to those who show their vehicles regularly or those who are just particular about having clean bays, what is your preferred method for getting all the grime and dirt out of your bay?

My vehicles engine has not been cleaned in a VERY long time and could use a good scrubbing.

Thank you -
 
I drove my car 2,000 miles last year, and other than at the beginning of the driving season and then once more right before a mid-August car show, I did not do anything in the engine compartment other than wiping off water from overall car washing.

While recommissioning the car in the years I have had it before I started to drive it regularly, I have been manaically obsessive about sourcing the best components and properly finishing and assembling them so that NOTHING in the engine compartment leaks. Funny thing, when you eliminate leaks, everything stays remarkably clean.

I find that the most important part of cleaning is to have as many different kinds, types, lengths, and varieties of brushes as your budget allows. Labels on all sorts of cleaners will have you believe that all you have to do is spray on and hose/wipe off, but OF COURSE that is wishful thinking on our part and marketing hokum on their part. There's no getting around it, to clean you gotta scrub, and you need loads of brushes to get in all the nooks and crannies.

One more handy item when cleaning an engine compartment is compressed air. Any proper engine cleaning will require lots of cleaning fluids/solvents/soaps, and lots of medium and high pressure water to rinse and help force off the grime, so every square inch of the back of the car will be drenched. The air comes in handy when you want to get the residual water out of the nooks and crannies.
 
I know it sounds radical but I removed the motor out of the 77 to better clean things up.
 
I used a variety of degreasers, such as simple green, awesome, purple power, etc.. I really like the spray foaming degreasers. Spray it on and let it work for a couple minutes; then spray wash it clean. As long as you don't spray directly into the coils of the alternator or distributor, you won't have any issues. That being said; I do spray and clean both of those, I just don't drench them or spray them directly. My car has the rain tray deleted, so it looks a bit gungy due to some bolts/brackets being rusty. I tend to clean my bay every other trip to the spray wash.
 
If you don't have compressed air you can use a yard blower to get rid of excess water, I use my Stihl backpack blower to dry the car after a wash, gets into all the nooks and crannies. I don't know how the hand held ones would work but the 200+mph 4" stream of air that the Stihl puts out works great, even at getting maple seeds out of the engine cover.
 
I'm in the process of cleaning my engine compartment in preparation for putting the engine back in. I made a first pass with strong detergent and a pressure washer followed by a 240mph, 900 CFM backpack blower. That got quite a bit off. My next pass will be foam degreaser followed by the above.
 
I don't plan on pulling the engine until I have a rebuilt to put in or if something requires me to...but if/when I do pull it out the engine bay will be getting a full scrub and refresh.

I know it sounds radical but I removed the motor out of the 77 to better clean things up.
 
I have a leaf blower that I used to use to dry my car.....got a lot of weird looks from the neighbors. lol. If I need to, I can use my work facilities that would allow me to use a pressure washer, degreaser and compressed air...but the car has to run reliably to get it here. HAHA!

If you don't have compressed air you can use a yard blower to get rid of excess water, I use my Stihl backpack blower to dry the car after a wash, gets into all the nooks and crannies. I don't know how the hand held ones would work but the 200+mph 4" stream of air that the Stihl puts out works great, even at getting maple seeds out of the engine cover.
 
This is kind of what I figure on doing. I just wasn't sure how sensitive some of the components may be if I accidentally sprayed them....

I suppose I could cover some of the items with plastic bags or tin foil....?

I used a variety of degreasers, such as simple green, awesome, purple power, etc.. I really like the spray foaming degreasers. Spray it on and let it work for a couple minutes; then spray wash it clean. As long as you don't spray directly into the coils of the alternator or distributor, you won't have any issues. That being said; I do spray and clean both of those, I just don't drench them or spray them directly. My car has the rain tray deleted, so it looks a bit gungy due to some bolts/brackets being rusty. I tend to clean my bay every other trip to the spray wash.
 
One suggestion from experience, if you use a "pressure washer" (any high force water stream) on the engine/trans. Believe it or not, some water makes it way into the engine and/or trans. I assume it is through seals/gaskets that leak. If you did not have any seals/gaskets that leaked, then you would not be cleaning it like Dan said. So there are leaks and those can go both ways. Therefore plan to change the oil and gear lube after a pressure wash. I've learned this the hard way more than once (I'm a slow learner sometimes).

If available, a steam cleaning machine works wonders. It combines the pressure stream with boiling hot water (steam). And cleaning solutions can be induced through them as they stream.

Regarding which products work better. Everyone will have different experiences due to many variables at play; type of grime being removed, climate where it is used, application techniques, etc. For me none of them are that great frankly, but I've had decent luck with "Purple Power". If left sitting wet on a painted surface long enough (like several days) it will damage the paint, so rinse well (but this is also true of all the similar products). Oddly it happens to also be one of the lesser expensive ones on the shelf, and easy to find at many big-box stores. But as I said, none work that well and scrubbing is needed as Dan and others noted.
 
One other thing to watch out for with pressure washers is rubber or plastic components and paint. A high pressure nozzle can slice through that stuff like a knife. I found that a "fan spray" nozzle worked pretty well once the degreaser had a chance to work and I did not have to worry about damage.
 
some people are going to cringe at what I have done a few times but it cleans well.

I have an air blow gun that has a suction line that I drop into a gas can and it spray's a nice mist of gas/air and cleans very well. (MAKE SURE there are no ignition sources at hand as I think it would turn from a cleaner to a flamethrower.)

but it does a nice job of cleaning
 
Actually I will back up Rod in the use of gasoline as a cleaner. It is the best degreaser I've ever used. I really isn't that dangerous if you have any common sense and decent judgement. But now that I think about it, if we had those things then we would not be fooling around with Fiats would we. o_O
 
I do same as Rod, it depends on situation, but diesel works better than benzin(gas?) sometimes. Also use diesel instead of WD40 or that kind of stuff.

Diesel has to be degreased..with gas haha
 
In the past I used diesel fuel for cleaning parts because it is less flammable (safer) than gasoline. But in recent years the US regulations have changed diesel fuel formulations (and prices) and it does not clean very well anymore. Now gasoline works better than the US version of diesel for cleaning. I'm not interested in diesel engines so have not bothered to learn what has changed or why it doesn't clean well now. Plus it costs more than gasoline in my part of the country. I think it is different throughout Europe for diesel fuels than here.

I've heard about using "oven cleaner" to clean parts. Anyone ever try it? I'm not sure it is a good idea, can't be good for many types of materials. But you never know.
 
I use brake cleaner for cleaning up oily/greasy/nasty areas. When I cleaned my engine bay with the motor out I first used simple green and water and then used brake cleaner for final cleanup. I also rip out that damn fire wall insulation, it's usually ripped, ugly, oily and generally looks like someone just stuffed a dirty rag up against the firewall. With no scientific reason whatsoever, I think it makes just as much sense to put insulation in the spare tire well instead. The gas tank pocket insulates the driver side of the firewall.
 
In the past I used diesel fuel for cleaning parts because it is less flammable (safer) than gasoline. But in recent years the US regulations have changed diesel fuel formulations (and prices) and it does not clean very well anymore. Now gasoline works better than the US version of diesel for cleaning. I'm not interested in diesel engines so have not bothered to learn what has changed or why it doesn't clean well now. Plus it costs more than gasoline in my part of the country. I think it is different throughout Europe for diesel fuels than here.

I've heard about using "oven cleaner" to clean parts. Anyone ever try it? I'm not sure it is a good idea, can't be good for many types of materials. But you never know.

Try Kerosene instead of the diesel, works good and doesn't smell as bad I've also heard that it evaporates and doesn't leave a residue like gas and diesel, gas and diesel smell to bad for me.

Super cleaner is the degreaser I have settled on, I keep it handy in a garden sprayer.
 
I use brake cleaner for cleaning up oily/greasy/nasty areas. When I cleaned my engine bay with the motor out I first used simple green and water and then used brake cleaner for final cleanup. I also rip out that damn fire wall insulation, it's usually ripped, ugly, oily and generally looks like someone just stuffed a dirty rag up against the firewall. With no scientific reason whatsoever, I think it makes just as much sense to put insulation in the spare tire well instead. The gas tank pocket insulates the driver side of the firewall.
I don't know about later models but the 74s came with insulation in the spare tire well.
 
Try Kerosene instead of the diesel
Where I live kerosene isn't common and therefore rather expensive. That would be very different in areas where it is used for things like heating, etc. and therefore much more affordable. But I agree it does clean well. I believe it is a more refined level of diesel fuel so has similar properties but cleaner (hence the better smell). Paint thinner is another similar example; good cleaner with similar properties but more expensive than fuels. A friend of mine can buy thinner in larger quantities at a low cost so he uses it for all his cleaning needs. Most petroleum based products are just different levels of distillation, with other things added.

You also mentioned "Super Cleaner". Is that the one that used to be called "Castrol Super Clean"? If so, I found it to be about equal to "Purple Power", depending on intended use. Both work O.K., and as I noted I use Purple Power, but honestly none of them are really great (however as good as any of the non-solvent/non-petroleum 'degreasers'). Where I shop Purple Power happens to be much less expensive the Super Clean, but than can vary a lot.

I read a article that supposedly tested several degreaser products. They compared them for certain cleaning tasks, environmental concerns, safety for human contact, cost, etc. The winner was "Oil Eater", but it was a old article and did not include some current products. I tried a sample of it and found it to be about equal with the ones mentioned above. But it isn't widely available in my area, and the places that do offer it have rather high mark-up so the cost ends up being considerable.

I found some 'trigger sprayer' bottles at Home Depot that are designed for chemical use (I think it says 'acid safe' on it). They work well for degreasers without breaking down and leaking or not pumping. But a garden sprayer designed for chemicals is a good idea and would require refilling less often...not to mention saving your finger from fatigue.

By the way, these type of degreasers work well in the ultrasound cleaning machine also. Better than regular soaps and safer than solvents (the machines say not to use flammable products in them). If you buy cleaners specifically labeled for the ultrasound machine they are really expensive.

On the subject of 'cleaning products'. One that has gone from a good working option to absolutely useless is Berryman's Carb Cleaner/Dip. They now have a couple versions and I've tried them all (there are few regulations on such chemicals here, more on that later). None did a thing even after soaking for days. The old version would have dissolved the carb if you left it in that long. This did not soften even the lightest of dirt. Frankly water works better.

Speaking of product availability and regulations. I came from Calif where it is impossible to buy most good chemicals. Now I'm in Nevada where they allow all other states to dump their nuclear and toxic wastes onto the nearby land. So they aren't very strict on what you can buy or how you dispose of it. But things aren't cheap here either.
 
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