# Possible pitfalls of engine bay washing/detailing



## Suberman (Aug 16, 2010)

Hi guys,

So being obsessed with cleaning our engine bays, just how much risk are we opening ourselves to when we wash our engine bays?

I remember reading a thread here by a member who discovered his EVO 9 had wire rust (i suppose water got into the wiring loom).

Did a quick search. This one. http://www.detailingworld.co.uk/forum/showthread.php?t=217888

Although i've done it on several cars and so far i've only been rewarded with a clean engine bay , it got me thinking the other day, do we risk getting water into our wiring loom (although the wire loom from the factory looks well protected). Is this a possiblity? 

We certainly can tape up the sensors and electrical connections, but what about the wires itself?

What do you think chaps?


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## deano93tid (May 8, 2013)

I think if you use a small amount of water to wash off and don't start the car until it's completely dry I can't see there being an issue.


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## PaulTheo (Sep 26, 2010)

It's always a risk


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## Porkypig (Jun 20, 2012)

Never use a pressure washer, bag up the electric bits and seal with cable ties, use a brush to agitate degreaser, dry it properly, and.... never drive in the rain.... :thumb:


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## Suberman (Aug 16, 2010)

Porkypig said:


> Never use a pressure washer, bag up the electric bits and seal with cable ties, use a brush to agitate degreaser, dry it properly, and.... never drive in the rain.... :thumb:


I've never used a pressure washer. I've always done the following:

Plastic sheet wrapped around:
Alternator
Main wiring loom connection
Over the dipstick

I will be taping up the various sensors connections from now on, but I'm really referring to if the wires get wet, will they rot with time from the moisture?

If so, maybe it's a good idea for all of us to start cling wrapping the length of the wires to prevent this.


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## voodoocars (Oct 20, 2012)

I have cleaned lots of car engines and never had a problem. Obviously on older engines water ingress into electrical components can be a problem but on modern engines its not an issue. Even a pressure washer shouldn't cause any problems unless the nozzle is really close to a vulnerable component.
Several cars have open vents in the engine compartment covers so rain water can get in anyway..
All I ever do is spray with a degreaser then wash it down with a hose or pressure washer. After just run the engine for a while to evaporate the water.


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## srhutch (Aug 2, 2009)

Suberman said:


> Hi guys,
> 
> So being obsessed with cleaning our engine bays, just how much risk are we opening ourselves to when we wash our engine bays?
> 
> ...


If you read that EVO thread it would appear the loom was hacked about by a previous owner, nothing to do with washing the engine.


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## jdquinn (May 19, 2010)

My Alfa 159 manual recommends washing the engine bay now and again to prevent a build up of dirt!. I've only washed the 'bay once and it took a lot of 'will I won't I' internal debate untill I couldn't stand the dirt any longer. A decent coating of engine degreaser lightly agitated followed by a gentle hosing down. Absolutely no issues whatsoever.


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## james_death (Aug 9, 2010)

You dont even have to open the bonnet.

I washed the Neighbours car never went under the bonnet, but some how water got into the engine.


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## Apex (Aug 29, 2009)

Never had a problem, keep the pressure turned down and lance vertical over the engine bay. No getting too close and mop up excess water then start engine close bonnet and let it dry out.


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## svended (Oct 7, 2011)

james_death said:


> You dont even have to open the bonnet.
> 
> I washed the Neighbours car never went under the bonnet, but some how water got into the engine.


Did the same thing. Scared the crap out of me when the car wouldn't start and when it eventually did it went into limp-home mode. Took three days for the car (Renault Clio cabrio) to dry out. Water had found it's way through a small hole at the bottom of the windscreen. Renault dealership wanted £400.00 to replace a 'module under the battery'.


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## james_death (Aug 9, 2010)

A have used surfex HD in a pump spray bottle before spraying the bay, taken a detailing brush to agitate and another pump spray bottle to rinse off.


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## Porkypig (Jun 20, 2012)

svended said:


> Did the same thing. Scared the crap out of me when the car wouldn't start and when it eventually did it went into limp-home mode. Took three days for the car (Renault Clio cabrio) to dry out. Water had found it's way through a small hole at the bottom of the windscreen. Renault dealership wanted £400.00 to replace a 'module under the battery'.


WOW! That is pi55 poor luck dude, makes you wonder what would happen if it ever got rained on!! :doublesho

Like others, I have never had a problem but just use common sense and take each case as an individual, if it's an oldy with carbs etc then chances of getting water in places you don't want would be higher than a modern fuel injection engine for example. If you are worried about it, don't do it. :thumb:

Here's one I did a while back with no water used. Engine degreaser, brushes and alot of rags and polishing. Took hours but was worth the effort.


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## Suberman (Aug 16, 2010)

srhutch said:


> If you read that EVO thread it would appear the loom was hacked about by a previous owner, nothing to do with washing the engine.


Yeah i read about it, i was just wondering if that is a possibility from a perfectly fine loom.

Seems like there are more people without issues that with. So i suppose some common sense and a few preventative measures is suffice.

Thanks to all who contributed. :thumb:


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## Danny B (Apr 14, 2010)

There must be a little risk, But then ask yourselves what happens when you drive in the rain?? You don't wrap electrical components then?


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## Suberman (Aug 16, 2010)

Danny B said:


> There must be a little risk, But then ask yourselves what happens when you drive in the rain?? You don't wrap electrical components then?


But your engine bay doesn't get that wet when you drive in the rain....


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## svended (Oct 7, 2011)

Porkypig said:


> WOW! That is pi55 poor luck dude, makes you wonder what would happen if it ever got rained on!! :doublesho
> 
> Like others, I have never had a problem but just use common sense and take each case as an individual, if it's an oldy with carbs etc then chances of getting water in places you don't want would be higher than a modern fuel injection engine for example. If you are worried about it, don't do it. :thumb:
> 
> Here's one I did a while back with no water used. Engine degreaser, brushes and alot of rags and polishing. Took hours but was worth the effort.


It dried out and all was well. But since then I lightly spray degreaser and wipe round, then dress with 303 Aerospace. You get through a lot of cloths, but I've loads of the damned things.


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## Danny B (Apr 14, 2010)

Suberman said:


> But your engine bay doesn't get that wet when you drive in the rain....


True it may only be drips where as washing is directed


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## Dummer (Jul 28, 2008)

maybe use a steamer?


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## lanciamug (May 18, 2008)

Regarding the corosion of the wiring, the wires are made of copper. Now what are domestic water pipes generally made of? (Connectors, now there's another matter!)


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## Richrush (Jun 25, 2012)

Well I think if you’re sensible with the water you should be ok. Jet washing straight into an electrical plug/connection or around the dip stick, well you are asking for trouble. All of my electrical connectors (04 Honda Civic) have the factory grease still present and this should stop lights spray and mist from entering the electrical components. If you start to jet wash the grease out or get to keen with the brush and cleaner, I’m sure you will get a problem sooner or later. The grease was put there for a reason, after all we drive our cars in the rain at 70mph right? If you’re really that concerned, start the engine or go for a drive to dry it out after cleaning. Happy cleaning!


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## Richrush (Jun 25, 2012)

Suberman said:


> But your engine bay doesn't get that wet when you drive in the rain....


Mine does, there is a bloody great gap between the front wheels and the engine bay:driver:


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## Suberman (Aug 16, 2010)

Richrush said:


> Mine does, there is a bloody great gap between the front wheels and the engine bay:driver:


Take it you're driving a Civic Type R?

They created the gap to save weight mate. :lol:


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## Sheep (Mar 20, 2009)

Take any car with a top mounted intercooler, and the whole not getting stuff wet arguement kinda goes out the window. The Acura RDX engine bay gets covered in water and dirt from the scoop through the grill. I have used pressure washers on engine for years, including a 1988 toyota corolla with a carb, and nothing has happened. New cars have no distributors, otherwise wrap that. Alternators, wiring, connectors, all designed to see moisture. Don't hit anything point blank, and blow dry it once finished. The other problem I see some times is a noisey belt, but it's gone once it's dry.


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## DanN92 (Nov 16, 2010)

Never had any problems on my previous car where I used to clean the bay pretty regular before bringing it to shows etc

Cover electrical components such as alternator and don't point the nozzle directly at any sensors etc..all the engine needs is a light mist of water, agitated with APC such as g101 and rinsed again..can't see this being a problem whatsoever

As said, engine components get wet all the time on a day to day basis...especially with the weather we get

EDIT: If your still weary of using a pressure washer i'd suggest a steam cleaner


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## dillinja999 (Aug 26, 2013)

never washed my engine bay so no problems :wave:


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## Lewis_ (Jun 29, 2013)

I personally totally avoid anything that remotely looks electrical and use a steam cleaner using a small amount of steam at a time and a microfibre to lift away the loosened dirt!


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