# Why should I keep the engine running?



## VZSS250 (Jan 8, 2008)

Hi guys,

How come there is all this talk about running the engine during or after an engine wash?

Seems strange that people keep mentioning it without say what the purpose is! :lol:


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## MuZiZZle (Apr 18, 2011)

My guess is heat


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## The Cueball (Feb 8, 2007)

2 reasons I do it...

Firstly to make sure I haven't f***d the engine up...

Secondly to help dry it off...

:thumb:


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## TOGWT (Oct 26, 2005)

I'm not sure I'd want to put my hands into an engine that running, I would prefer to guard against water ingress by protection, although initially running the engine to warm it up will help a degreaser to work more efficiently


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## james_death (Aug 9, 2010)

*What The Cueball and TOGWT Said...:thumb:*


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## The Cueball (Feb 8, 2007)

TOGWT said:


> I'm not sure I'd want to put my hands into an engine that running, I would prefer to guard against water ingress by protection, although initially running the engine to warm it up will help a degreaser to work more efficiently


Neither would I :doublesho

Engine off when cleaning/degreasing

PW on low setting to remove the above

Engine on for 3-5 minutes to help dry

Engine off, final wipe down

No hands near moving parts or when the engine is on...

I don't see the point of covering up specific parts with bags etc, as engines can work, and are designed to work when wet...so as long as you are not aiming a powerful PW at any elecs for a period of time, you should be fine (and obviously blasting water into the air filter)...

Well, I have been so far in 15 years of cleaning them! (touch wood!!!!!) :lol:

The question came up on the XKR site I am on, and we had someone shouting about how he would never, ever be so stupid to allow water into the engine bay, it would kill the engine straight away, and we were all idiots....

Then the big grills/air vents on the bonnet were pointed out to him, where - guess what - water gets in, and falls straight onto the engine :wall::wall::wall:

:lol::lol::lol:

The Jeep is getting a snorkel fitted, so the local river will be getting used to clean it's engine very soon :driver::driver::driver:

:thumb:


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## Bratwurst (Jan 23, 2009)

In agreement with CB here. If my notoriously badly made and badly waterproofed Mini can take it anything can...
Only thing I disagree with is the PW on low thing... not saying it's not safe, just I'm too chicken *hit to do that with mine as I don't have adjustable pressure in my PW, so it's a slow running open hose for me.


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## John @ PB (Aug 25, 2010)

You'll use less water with a pressure washer than a hose and also remove more grime. 

Clark pressure washed the Enzo engine last week and it was absolutely fine so there's little reason not to use a pressure washer on any modern engine.

Just use common sense, don't soak anything and cover any exposed electrical connections and intakes. 

Best to work on a cold engine, then, after rinsing, start the engine to ensure everything is fine and also to speed up the drying out.


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## [email protected] (Apr 28, 2011)

The Cueball said:


> 2 reasons I do it...
> 
> Firstly to make sure I haven't f***d the engine up...
> 
> ...


Same


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## james_death (Aug 9, 2010)

On the whole you would be fine washing washing engine bay and no starting worries just some cars are more susceptible and then you dont even need to be in the engine bay.

The only real fault with the mk2 micra is that even with the bonnet closed if you really really soak the bonnet area it gets water ingress and is a swine to start....:lol:


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## Dingo2002 (Apr 4, 2007)

I thought that engines and their electrical components and water were absolutely fine! Something to do with them running low voltage DC? The main issue is with water ingress into the filters or up the exhaust pipes hence the need for snorkles on 4x4's that are going to cross rivers  (snorkles being for the filter obviously)

I PW'd mine at the weekend and didn't bother covering anything. Obviously I used common sense and didnt blast any exposed electrical items but everything got covered in water at some point.


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## pete79 (Feb 13, 2007)

I done a golf years ago and it wouldn't start after,fired up after a bit though could have been cause it was on it's last legs anyway


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## Matt_Nic (Apr 15, 2011)

The Cueball said:


> The question came up on the XKR site I am on, and we had someone shouting about how he would never, ever be so stupid to allow water into the engine bay, it would kill the engine straight away, and we were all idiots....
> 
> Then the big grills/air vents on the bonnet were pointed out to him, where - guess what - water gets in, and falls straight onto the engine :wall::wall::wall:


He's may be not as stupid as you think he is. While I dont agree with him that as soon as an engine is wet it's ruined, water ingress into the engine bay can and very often does do it more harm than good.

An example of "those big vents" you mention being a hazard - the mk1 MR2 was renowned for the rain water dripping through the airvent straight on to the alternator which in time would knacker that up.

Many cars with bonnet vents actually have rain/drip guards under to direct water away from components.

Other hazards of hosing down an engine are are electrics such as plugs, if they're not really pushed fully in and water gets in the spark plug wells you could end up with arking which will cause a misfire. There's various fuse boxes and wire connections in most modern engine bays these days. The backs of the headlights are often not every water proof, the pulley's for various engine driven components are exposed and can degrade if repeatedly exposed to water directly & cleaning detergents.

I'm not saying you shouldnt clean an engine bay, but you should know what you're doing when you do it.

This is the same as mine btw, theres some totally exposed electricals at the top left side so I wont be hosing it down. The bonnet seals it from natural water ingress, with the bonnet up, no seal = water where you dont want it.


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## justina3 (Jan 11, 2008)

pete79 said:


> I done a golf years ago and it wouldn't start after,fired up after a bit though could have been cause it was on it's last legs anyway


early vw,s are very prone to water damage I done a polo last week which a customer had washed the engine, the ht lead hold water in there casings not something you can see as i have seen them before went straight to it, still damaged the coil pack and the ht leads.

Back a few years back one of the biggest alarm warrenty claims was water ingress into the siren and brain, these days most alarms split the siren and mount the brain inside the car but we still get our fair share of faulty wet chicken sounding sirens

still i am not moaning its all work for me:thumb:


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