Yellow Discharge from Car

Hi all

Anyone any ideas what would cause a yellow widdle-like stain to appear in the snow under the car engine bay? Does the air-con do strange things like this in severe weather (east yorkshire temperatures/conditions)? I think that this has generally been obvious when the car has been moving in deep snow, such that the underside of the engine/sump has come into direct contact with snow.

The discharge does not feel oily. Coolant and screen wash are blue. Clutch/brake fluid reservoir not dropping. Losing oil, but probably burning this after 96,000 mile (and as noted, the discharge does not seem oily!).

Car is Mazda 6 2004.

TIA

Phil

Reply to
TheScullster
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It's probably condensation dripping off the engine - the yellow is caused by soluble residues

Reply to
Phil L

Any cats nearby?

Reply to
The Other Mike

Tom cat, fox, ...

;-)

Reply to
Andrew Gabriel

Rust?

Reply to
stuart noble

Does sound like the product of an animal, and cars are a favourite target.

Grease from torn CV boots - usually black/grey in colour, stuck to wheels if outboard or inboard. Oil mixed with coolant - yellow milky colour, coolant can leak from water pump weep hole at the timing belt end and mix with normal oil leaks. Power steering & ATX - red colour, usually pretty distinct along with the resulting noises when it gets too low.

Check oil-is-oil, coolant-is-coolant. There is an water-to-oil heater/heat-exchanger on most cars around the oil filter, they rarely fail but if they can the high pressure oil will be found in the coolant. Likewise ATX cars with oil cooler in the radiator can suffer cross contamination although most make them physically independent now.

As to losing oil, They All Do That (TM). Generally that is a clogged PCV valve (check it rattles although you have a 4-banger), usual oil pressure sender rear leak, cam cover gasket, numerous seals, oil pulling through valve guides on lift off, pulling through rings.

Oil filler cap milky residue. Not unusual for the underside of the oil filler cap to have a milky consistency, this is condensation being driven out of the oil under the cam cover and condensing in the colder filler cap. Some cars suffer are afflicted worse than others, change the oil if it builds up into a paste and run the engine for longer. Asda had Mobil 1 ESP and similar (true synth, 5w30 etc) going quite cheaply recently - about =A328 a 4L (or is it 4.5L?) bottle and =A37.50-8.50 a 1L bottle for top-up of yourself and the car at that price :-)

If you have a diesel, be afraid, they deposit other things on the ground if they go wrong - followed by an empty wallet, melted credit card and yourself (usually with the wife stood over you carrying a spade).

Reply to
js.b1

Does sound like the product of an animal, and cars are a favourite target.

Grease from torn CV boots - usually black/grey in colour, stuck to wheels if outboard or inboard. Oil mixed with coolant - yellow milky colour, coolant can leak from water pump weep hole at the timing belt end and mix with normal oil leaks. Power steering & ATX - red colour, usually pretty distinct along with the resulting noises when it gets too low.

Check oil-is-oil, coolant-is-coolant. There is an water-to-oil heater/heat-exchanger on most cars around the oil filter, they rarely fail but if they can the high pressure oil will be found in the coolant. Likewise ATX cars with oil cooler in the radiator can suffer cross contamination although most make them physically independent now.

As to losing oil, They All Do That (TM). Generally that is a clogged PCV valve (check it rattles although you have a 4-banger), usual oil pressure sender rear leak, cam cover gasket, numerous seals, oil pulling through valve guides on lift off, pulling through rings.

Oil filler cap milky residue. Not unusual for the underside of the oil filler cap to have a milky consistency, this is condensation being driven out of the oil under the cam cover and condensing in the colder filler cap. Some cars suffer are afflicted worse than others, change the oil if it builds up into a paste and run the engine for longer. Asda had Mobil 1 ESP and similar (true synth, 5w30 etc) going quite cheaply recently - about £28 a 4L (or is it 4.5L?) bottle and £7.50-8.50 a 1L bottle for top-up of yourself and the car at that price :-)

If you have a diesel, be afraid, they deposit other things on the ground if they go wrong - followed by an empty wallet, melted credit card and yourself (usually with the wife stood over you carrying a spade).

seriously... A nice warm place for a cat to hide. Dont discount it check for paw prints around the car. I have a cat and in this cold spell goes straight under the car does its business and bolts straight back inside. I have to physically throw him out for 5 minutes.

Reply to
SS

In message , TheScullster writes

A cat or other animal sheltering under the car using the residual warmth from the engine.

Highly unlikely to even work at much below +10 degrees C let alone sub zero temperatures

Like cat pee then?

NP, now wash your hands

Reply to
Clint Sharp

frozen radiator and or water pipes.

That's classic antifreeze.

Or a cats been under there.

No. Aircon drips condensed water only.

Never seen blue coolant yet. Always yellowy green.

Reply to
The Natural Philosopher

I have a suspicion it oxidises to yellowy green, and indeed certainly would be if it runs down the engine block re oil from cam cover gaskets (which are pretty much designed to leak on those engines).

To OP: In which case check water pump - ie, coolant level in engine, not just reservoir. It is a circa 4hr job. Just the right kind of temperatures to cause the water pump seal to begin to go. Stick a tray under the car and check it regularly, it should taste sweet if coolant... if it is animal based it will taste... different... :-) Ewwwwwwwww.

Reply to
js.b1

Not if it is a diabetic cat.............

Reply to
ARWadsworth

Don't feed the trolls

Reply to
fred

Thanks to all for informative and sometimes entertaining suggestions

Phil

Reply to
TheScullster

Power steering oil is yellow

Reply to
zaax

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