Steamy exhaust ??

Steamy exhaust ??

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Discussion

Pistoner

Original Poster:

9 posts

3 months

Tuesday 25th May
quotequote all



I’ve noticed today of this very thing smoke/steam coming from my exhaust?
I’ve been for a 30 minute motorway drive and still this happens?

Anyone have any ideas of what this could be ??
Hopefully you can see the video.
Thanks

sherman

8,925 posts

183 months

Tuesday 25th May
quotequote all
You understand how an internal combustion engine works right and you will see more exhaust gas on a cool still dayscratchchin

It could be head gasket, oil or water going places its not supposed to

Pistoner

Original Poster:

9 posts

3 months

Tuesday 25th May
quotequote all
I might be completely wrong but I thought:

A head gasket would cause a thicker ‘cloud’

Think it’s worth getting it checked ?

OllieJolly

294 posts

84 months

Tuesday 25th May
quotequote all
Looks like steam to me.
Is there a chance you accidentally filled up at the water pump, instead of fuel pump?

Pistoner

Original Poster:

9 posts

3 months

Tuesday 25th May
quotequote all
Haha fortunately not olly.

paintman

6,546 posts

158 months

Tuesday 25th May
quotequote all
Burning a gallon of petrol or diesel produces - amongst other things - a large quantity of water.

This is visible as steam from the exhaust on cold/cool days & the liquid that drips from the tailpipe.

A lot of it condenses inside the cold engine & inside the cold exhaust.

If the engine & exhaust don't get hot enough to boil it off it will appear as mayo in the oil filler cap & is the main reason why cars that only do short journeys go through exhaust systems faster than those used for long journeys.

If you aren't losing any coolant then it's entirely normal.

Pistoner

Original Poster:

9 posts

3 months

Tuesday 25th May
quotequote all
Thank you!

I will check my coolant levels.

I do 25 miles a day so not a huge amount that’s why I chose the petrol engine.

Wouldn’t Mayo on the oil cap be a head gasket ??

paintman

6,546 posts

158 months

Tuesday 25th May
quotequote all
Pistoner said:
Thank you!

I will check my coolant levels.

I do 25 miles a day so not a huge amount that’s why I chose the petrol engine.

Wouldn’t Mayo on the oil cap be a head gasket ??
No.

If you aren't losing any coolant then you don't have HGF - at least not as far as a coolant leak is concerned.

As I've said many times before I wonder how many have had their trousers pulled down for unnecessary work by the unscrupulous claiming that mayo is a surefire indicator of HGF.

Scrump

14,750 posts

126 months

Tuesday 25th May
quotequote all
Pistoner said:
Wouldn’t Mayo on the oil cap be a head gasket ??
It could be. As already mentioned it could also be condensation due to short journeys and the engine not getting properly not.
The Mayo is water mixed with oil so all it tells you is there is some water in the oil, it doesn’t tell you where the water came from.

GreenV8S

28,871 posts

252 months

Tuesday 25th May
quotequote all
Pistoner said:
Wouldn’t Mayo on the oil cap be a head gasket ??
It's normal and common to have condensation inside the oil filler. There's no reason to assume that's a problem unless you have some other symptoms.

Head gasket failure will often lead to combustion gases or oil in the cooling system. If you see contamination in the coolant, that's a sign of trouble.

Pistoner

Original Poster:

9 posts

3 months

Tuesday 25th May
quotequote all
Thank you all for the replies!

No Mayo on the oil cap and the coolant looks fine.


Scrump

14,750 posts

126 months

Tuesday 25th May
quotequote all
Looks like it is all good then. thumbup

Forgot say earlier, welcome to PH.

Pistoner

Original Poster:

9 posts

3 months

Wednesday 26th May
quotequote all
Sorry couldn’t reply yesterday as I was new.

Thank you though!

Just a little update….no smoke this afternoon which is good.

Although there is a little water in the exhaust….normal I’m guessing ?

E-bmw

6,207 posts

120 months

Wednesday 26th May
quotequote all
Yes, when you burn any hydrocarbon the biggest by-product is water, which due to the temperature of combustion is steam.

Pistoner

Original Poster:

9 posts

3 months

Wednesday 26th May
quotequote all
Thank you e-bmw.

Think I’m just paranoid because my last car had a knackered dpf filter. Even though this is a petrol lol

sherman

8,925 posts

183 months

Wednesday 26th May
quotequote all
Pistoner said:
Thank you e-bmw.

Think I’m just paranoid because my last car had a knackered dpf filter. Even though this is a petrol lol
lf you have a dpf problem with your petrol engined car just let us know rofl

Pastie Bloater

694 posts

131 months

Wednesday 26th May
quotequote all
Nothing to worry about
petrol + oxygen = carbon dioxide + water vapour

Pistoner

Original Poster:

9 posts

3 months

Wednesday 26th May
quotequote all
Pastie Bloater said:
Nothing to worry about
petrol + oxygen = carbon dioxide + water vapour
🙏 thank you

Huff

2,725 posts

159 months

Wednesday 26th May
quotequote all
In quite large quantities too - burn one gallon of petrol, you get about two gallons of water from combustion (the extra is the bound oxygen from the air) - delivered as vapour

Given that steam at 100degC is c 1300x the volume of the water that generated it - you soon see why,at idle,on the right kind of cool humid or cold day - you can see gallumphing amounts of water vapour out of the exhaust- that diminishes once the whole exhaust system gets warm enough.

Nothing to worry about. And if the car is new to you, good idea to keep half an eye on coolant and oil levels anyway -over the first 3-6000miles, say,after which you'll get a feel that watershouldnt need attention, and oil, probably not much at all. ATB

Pistoner

Original Poster:

9 posts

3 months

Wednesday 26th May
quotequote all
Huff said:
In quite large quantities too - burn one gallon of petrol, you get about two gallons of water from combustion (the extra is the bound oxygen from the air) - delivered as vapour

Given that steam at 100degC is c 1300x the volume of the water that generated it - you soon see why,at idle,on the right kind of cool humid or cold day - you can see gallumphing amounts of water vapour out of the exhaust- that diminishes once the whole exhaust system gets warm enough.

Nothing to worry about. And if the car is new to you, good idea to keep half an eye on coolant and oil levels anyway -over the first 3-6000miles, say,after which you'll get a feel that watershouldnt need attention, and oil, probably not much at all. ATB
Thank you ! It is new to me 2 weeks old ! 2018 Audi A4 saloon.
Short journeys I find it shows more water obviously where the engine isn’t warm enough to clear it. Is this common on both fuel types or just petrol? Never noticed it before on my 2015 diesel.