Cleaning a car engine bay.

Cleaning a car engine bay.

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Discussion

Wacky Racer

Original Poster:

33,680 posts

206 months

Sunday 18th October
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As per thread title.

In the good old days in the 70's, I just used to buy some Gunk, spray it everywhere, working it into the engine with a brush, leave it five minutes and hose it off. Usually the car would start, sometimes you might have to dry the distributor off with a hairdryer.

However with modern cars which are full of electrical gubbins under the bonnet, I'm pretty sure this would be an unwise thing to do for obvious reasons.

Is it better to just do a little bit at a time, or just leave it a dusty mess?

Davie_GLA

5,740 posts

158 months

Sunday 18th October
quotequote all
i just do the same but take the time to cover the gubbins you can see with a plastic bag. 10 minutes with the user manual or google will tell you what is important.

I usually try and dust the loose stuff off then use an APC, Prince then use a protectant. It's not perfect but it keeps it looking good.

Don't use a pressure washer, or if you do then bang the power down a bit.

Of course, if you are doing this to look for oil leaks etc then much, much more care should be taken.







Edited by Davie_GLA on Sunday 18th October 19:01

AdamIndy

1,654 posts

63 months

Sunday 18th October
quotequote all
I just spray some engine cleaner all over it, leave a couple of mins then pressure wash the whole lot. I’ve never once had a problem with electrics across probably 15 different cars.

swisstoni

9,776 posts

238 months

Sunday 18th October
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Although I’m a bit of a polisher, my engine bays stay dusty messes.
I’d rather have them dirty and working than lovely and broke.

blue_haddock

859 posts

26 months

Sunday 18th October
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Most cars nowadays you can barely see the engine let alone clean it

Gad-Westy

10,807 posts

172 months

Sunday 18th October
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I don't think anything has changed.

Liberal spraying with degreaser/APC. Agitate with a brush. Hose it off. You can get some good plastic dressings to give it all a nice sheen and a bit of protection afterwards if that's your cup of tea.

Electrical connections are very robust and well sealed these days. The engine bay on my exige for example is pretty much open to the elements so gets totally soaked if I wash it or use it in the rain so personally I don't even bother protecting anything anymore, but don't sue me if your car never works again having done the same yourself. When rinsing, I just use the open end of a hose and try not to aim directly at any connectors but I see people jetwash them and even that doesn't seem to cause any problems. Not brave enough to try myself though!

Chubbyross

1,241 posts

44 months

Sunday 18th October
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To minimize water damage as much as possible when engine cleaning I recently spent £150 on a steam cleaner (the Dupray Neat). It’s a great piece of kit and rather useful around the house too.

trickywoo

8,791 posts

189 months

Sunday 18th October
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You can still do that with modern cars. Maybe put some bags over any big bundles of electronics but it should be ok.

fwaggie

1,608 posts

159 months

Sunday 18th October
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One problem with modern cars is ones that have coil packs that are combined with the spark plug caps.

My BMW 535i F10 has these, and the first time I washed the engine I basically filled up the holes that these go in, about 6" deep. Of course they were old coil packs so the water got past the seals and into where the top of the plug connects, weakening the spark a lot.

Took damn ages for the hot engine to evaporate all that water, and left everything covered with calcium deposits.


Also bought a steam cleaner, $250 or so. At full steam it could run for 30 seconds then it's run out of puff and alternate between little puffs of steam and warm air - could hold my hand in front of it. Heater element is just too pathetic to keep a steady stream of steam going. A decent one is $500 or so.

Johnnytheboy

21,151 posts

145 months

Sunday 18th October
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I tend to use the stuff I use to clean the cabin, eg interior shampoo and vinyl cleaner.

But my engine bays never get that dirty tbh.

hellorent

88 posts

22 months

Monday 19th October
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I always use paraffin for cleaning engine, a lot cheaper than any type of gunk etc.

Evoluzione

4,566 posts

202 months

Tuesday 20th October
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hellorent said:
I always use paraffin for cleaning engine, a lot cheaper than any type of gunk etc.
Yes that's really good for the environment.

SeeFive

8,047 posts

192 months

Tuesday 20th October
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Missus's car. First proper under bonnet clean in 3 years. Removed twigs and leaves from all areas and hit it with a 1 to 10 mix of g101, brushed it about a bit. Rinsed with the lowest pressure setting of the pressure washer from a good distance. Then a good dry off followed by a coat of Auto Finesse Dressle to the plastics.

mercedeslimos

626 posts

128 months

Tuesday 20th October
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Evoluzione said:
Yes, that's really good for the environment.
Don't take a look at the ingredients of most car cleaning products then! Gunk is basically refined paraffin with detergents in it. Many cleaning products I use are terrible for the environment. Hence the Germans won't let you clean the car at home. Also, mine all stay outside in my special valeting shed, lots of it isn't stuff I'd want inside were anything to happen.

hellorent

88 posts

22 months

Tuesday 20th October
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Evoluzione said:
Yes that's really good for the environment.
Correct, similar to Gunk & most probably all the other degreasers out there.

Evoluzione

4,566 posts

202 months

Tuesday 20th October
quotequote all
hellorent said:
Evoluzione said:
Yes that's really good for the environment.
Correct, similar to Gunk & most probably all the other degreasers out there.
No that's incorrect. Proper engine cleaners are water based and emulsify with the oily deposits to turn it into something safe which can be treated and cleaned.
Paraffin is oil which cannot.
It's also flammable, so that along with being toxic to the environment is a pretty stupid liquid to be spraying on an engine. Presumably you just wash it off and let it run into the ground or down a drain? Well done.

hellorent

88 posts

22 months

Tuesday 20th October
quotequote all
Evoluzione said:
No that's incorrect. Proper engine cleaners are water based and emulsify with the oily deposits to turn it into something safe which can be treated and cleaned.
Paraffin is oil which cannot.
It's also flammable, so that along with being toxic to the environment is a pretty stupid liquid to be spraying on an engine. Presumably you just wash it off and let it run into the ground or down a drain? Well done.
Really: http://www.partinfo.co.uk/files/732.pdf lets hope all the gunk users abide by this info, I think you will find paraffin will not
ignite on it's own, it's not like petrol you know.

Edited by hellorent on Tuesday 20th October 23:05


Edited by hellorent on Tuesday 20th October 23:12

colin_p

2,916 posts

171 months

Wednesday 21st October
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You can "put a fag out" in paraffin or diesel without going "woof".






montyjohn

80 posts

45 months

Wednesday 21st October
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Evoluzione said:
Yes that's really good for the environment.
We are talking about small amounts of kerosene here. And let's remember kerosene is a light oil. I'm guessing the chap who said he used paraffin will use 50ml, if that.

If done on a hard standing, and not washed down a drain, it will evaporate fairly quickly and break down in the atmosphere.
If done on soil it will break down in one or two months within the soil.
If it soaks deep into the soil it may take as long as 18 months to break down.
If it washes into a small ditch it will penetrate sediment and then break down.
If it flows into a large water body, if you choose to wash your engine next to a lake it will spread to 0.01mm thick and rapidly evaporate.
If it goes down a sewerage system it will likely contribute to a blockage so avoid this one.

If you are washing engines as a business this will be a real issue (any of the above), as it will accumulate in the environment quicker than it can evaporate or break down. In such cases you will need a bunded site with collection so it can be safely disposed of. Running it through an interceptor would not be good enough.

A small volume every now and again will have negligible impact.

If you use an oil (or any engine gunk type product) then do it on a hard standing (or in a well ventilated garage) and not wash it towards a drain that would be better. The biggest problem you then have is it will slowly degrade concrete, but not noticeable if you don't use a lot of it on a regular basis.