Car is leaking yellow fluid - what is it?

[Rehan]

I noticed this morning that in the snow underneath my car, there were some drops of yellow fluid..some of the drops were brownish. It looked like it was from the rear half of the car, though I'm not sure of that. The spots are about half way between the left and right sides of the car.

It was very noticeable when I was first took the car out for a drive (20 minutes of city driving), but then I couldn't find any other yellow spots when I tried a little later to figure out where exactly it was.

The car is a 2000 Mazda Protege LX with automatic transmission and just over 100,000 km on the odometer. I had the 96,000 km service on it a couple of months ago (and that included a new timing belt).

The fluid in the coolant reservoir is green and it's at the "full" level, so I'm assuming that wasn't what was leaking.

What else could it be?

[careener]

Neighbour's cat? Just kidding

Could be brake fluid. Check your level.
The colour can range between yellow and brown as in this pic
http://www.dixonmotors.co.uk/images/talkkit/brakefluid.jpg

The only other thing that passes through the location you describe is gas.

Funny timing..the brake line blew on my 626 two weeks ago..

[Nyte]

Someone walked by and had to go? ;)

[Rehan]

I already ruled out the possibility that it was bodily fluids -- no footprints nearby, and the yellow spots were in different places where I had left my car this morning (driveway, and on the street when I was shoveling the driveway). :)

The brake fluid is a pale yellow, but the spots in the snow seemed pretty bright....kind of like the fluorescence of coolant. And the brake fluid reservoir is also full.

If I can't "reproduce" the problem to find what section of the car the leak is coming from, should I just keep monitoring the fluid levels and check to see if any of them are dropping noticably?

[sumfunny]

Rusty water? couldjust be some melted snow that was on some rusty part, just an idea that came to mind when brown was mentioned

[careener]

Rusty water? couldjust be some melted snow that was on some rusty part, just an idea that came to mind when brown was mentioned

Could be.

[Rehan]

Would rusty water be bright yellow, though?

[careener]

Found here http://www.grubbsauto.com/technotes/spots.html

Black or dark brown - Usually found under the engine, these spots are likely to be engine oil. It's not unusual for an engine to leak small amounts of oil over a period of time. However, if you see puddles larger than a tablespoon, you should bring your vehicle to a service center for diagnosis and repair.

Bright green, bright yellow or pink - These puddles are probably formed by radiator coolant or antifreeze leaking from the cooling system. If you notice even a moderate amount of fluid, have the radiator level checked immediately.

Red or pink - If you find these spots under the center of a rear-wheel drive car, a good bet is that this fluid is from the automatic transmission. A small amount is nothing to worry about, but you should consult a service technician if more than a little is found. If your car has front-wheel drive, red or pink fluid that is found toward the front of the car may or may not have come from the automatic transmission. A small amount of the fluid should be checked by a qualified technician to verify its origin.

[actng]

HA! This thread just gave me a very good idea of how to take revenge on a guy...

Just poor some diff coloured liquids under his car. He'll spend $$$$$ just trying to figure out what it is.

[careener]

HA! This thread just gave me a very good idea of how to take revenge on a guy...

Just poor some diff coloured liquids under his car. He'll spend $$$$$ just trying to figure out what it is.


That's hilarious!

[Kenneth]

Have you ever used Rain-X de-icing washer fluid?

It's the only liquid that's bright yellow I can think of.

[Rehan]

Have you ever used Rain-X de-icing washer fluid?

It's the only liquid that's bright yellow I can think of.
Nope. Just regular blue windshield washer fluid.

[Buffdaddy]

CLimb under and have a look.

Could be rostproofing if you've ever had your car sprayed.

Could be oil or lube from a joint.

Smell is a good indicator, tranny fluid smells acrid, sort of like vodka or something...power steering fluid smells almost acidic, fi thats a smell. ..brake fluid is watery and smells very little...oil will still be oily, and smell like oil, lol.

Old school trick is to park over a piece of cardboard box overnight so that you can inspect the fluid the next day.

Honestly you shouldnt have to take your car in (not saying you do) to find out what is leaking you should do some more homework on cars in general....talk about a waste of money for an inspection....to fix it, probably, but to inspect...climb under there and see where its coming from yourself.

Do a process of elimination, check all fluid levels, etc.

I'd say its motor oil, personally, but from that area....hmm....maybe differential fluid but I'm not sure if FWD cars HAVE rear Diffs.

Sometimes oil will leak down along the muffle/exhaust though....which could explain its position.

Check your tranny fluid, although the colour sounds off, some tranny fluid is orange which could LOOK yellow-ish in the snow, or mixing with grease/dust/dirt on its way out the bottom of the car.

Gas is generally easy to tell, because it smells so strong.

In that region of an FWD car I'd guess stray oil, brake fluid or fuel because your oil and fuel lines run to the back of the car, but thats about it.

[MTL-TechY]

HA! This thread just gave me a very good idea of how to take revenge on a guy...

Just poor some diff coloured liquids under his car. He'll spend $$$$$ just trying to figure out what it is.

great idea, lol,
but i guess it may be the antifreeze or brake fluid- really rare on mazda though, or maybe radiator oil-coolant

[Buffdaddy]

OH PS:


A LOT of under-car leaks will only occur under pressure IE when the car is driven.

That would explain why it 'goers away' so to speak, after its been sitting.

It will leak under the pressure of driving, and then drip down for a while after you park (obviously)....as you have said.

run the car in the driveway a while to see if that exposes the uncooperative mechanism, might be easier.

[actng]

So I went to KFC at Yonge and Bloor today for lunch, only to find that they don't serve toonie tuesday! (http://forums.redflagdeals.com/showthread.php?p=1357041) Actually they don't serve any fried chicken, only sandwiches. See thread for more details.

Point is, I had mountain dew to drink with the combo and it reminded me of the "bright yellow" liquid under Rehan's car.

I think an RFDer was jealous that Rehan became mod so he went to PM some mountain dew from staples with grocery gateway and poured it underneath Rehan's car.

[gman]

coolant?

[BuddyGuy]

I noticed this morning that in the snow underneath my car, there were some drops of yellow fluid..some of the drops were brownish. It looked like it was from the rear half of the car, though I'm not sure of that. The spots are about half way between the left and right sides of the car.

It was very noticeable when I was first took the car out for a drive (20 minutes of city driving), but then I couldn't find any other yellow spots when I tried a little later to figure out where exactly it was.

The car is a 2000 Mazda Protege LX with automatic transmission and just over 100,000 km on the odometer. I had the 96,000 km service on it a couple of months ago (and that included a new timing belt).

The fluid in the coolant reservoir is green and it's at the "full" level, so I'm assuming that wasn't what was leaking.

What else could it be?

As weird as it sounds, I found the same yellow liquid underneath my vehicle after it snowed. I thought it was the neighbourhood cats, but this thread has me thinking again.

[jayman2004]

I work in a autobody shop and have had leaks on diferent cars and here is what it can be, coolent,gas,dif oil. or dyi that was put in the ac lines to detect leaks wich showup under a uv light or a black light

[felixdd]

It's radiator coolant. It happened to my family car many years ago.

[Rehan]

It's radiator coolant. It happened to my family car many years ago.
So even if the coolant in the reservoir is green (as I mentioned in the opening post), the yellow spots are from the coolant? How does it change color? :confused:

[jed]

There is no other fluid it could be. Lets list the fluids - gas, oil, coolant, brake fluid, power steering, transmission, and differential. The best thing you can do is like Buffdaddy said and put a piece of cardboard under the car so you can see exactly where its coming from (or put it up on a hoist). Until then we're speculating.

[TTony]

put a cardboard under the car check again

[careener]

So even if the coolant in the reservoir is green (as I mentioned in the opening post), the yellow spots are from the coolant? How does it change color? :confused:

Your original post said the spots were at the back of the car..so it's not coolant..It's probably brake fluid. If you're concerned, take it to a garage. They will be able to identify the issue within 5mins.

[Rehan]

Your original post said the spots were at the back of the car..so it's not coolant..It's probably brake fluid. If you're concerned, take it to a garage. They will be able to identify the issue within 5mins.
I'm not completely sure it was from the back, though. Before I noticed the spots, I had parked my car in the driveway both facing out towards the street and facing in towards the garage. So it wasn't necessarily from the back.

But yeah, I'm planning to do some more 'debugging' and take a closer look at the possibility that it's brake fluid.

[Buffdaddy]

Brake fluid is generally colourless, jusy s you know before hand.

[Nacster]

I noticed the very same bright yellow spots today as well underneath my 2000 Honda Civic Sedan..I would say the spots were located somewhere between the back of the engine to the front dash of the car.. I'm perplexed myself..What could it possibly be :confused:

[Rehan]

Thanks to the snow, I was able to pinpoint the locations of the spots better this morning. Click on the pictures below to enlarge them.

Looking in the direction the car was facing while parked:
http://img184.exs.cx/img184/5152/spots19qk.th.jpg (http://img184.exs.cx/my.php?loc=img184&image=spots19qk.jpg)
(red circles are where yellow spots were; blue squares are where tires were)

Near the right rear tire:
http://img184.exs.cx/img184/930/spots25xx.th.jpg (http://img184.exs.cx/my.php?loc=img184&image=spots25xx.jpg)

In the second picture, I think the spots where pavement is showing (aside from the location of the tire) are also where some fluid had dropped...but I'm not 100% sure.


You can see that the fluid in these pictures is not very fluorescent...but I've noticed the spots to be a stronger yellow at times.

So... brake fluid, probably?


(I got MaD sKiLlZ in MS Paint, yo! :cheesygri )

[gman]

I still think those are coolant of your radiator.

[Rehan]

I still think those are coolant of your radiator.
Wouldn't a coolant leak be only near the front of the car?

[gman]

Wouldn't a coolant leak be only near the front of the car?

I think your coolant was leaking while you were driving to that parking spot. It seems the trace moved along with how your car was turned into the spot. You probably stopped over that big spot before you moved to the final position. Then you turned off the engine.

[Rehan]

I think your coolant was leaking while you were driving to that parking spot. It seems the trace moved along with how your car was turned into the spot. You probably stopped over that big spot before you moved to the final position. Then you turned off the engine.
Nice try, but no. :) The spots appeared after the car was parked there. And I don't get spots dripping off like that while the car is in motion just before bring parked (I've checked in parking lots over the last few days).

[Shaf]

While shovelling the driveway this morning, I noticed similar stains on a lot of people’s driveways! Could it be some fluid that reacts with the metal and snow to create the unique colour?

[ctam]

Happened to the same thing with my parent's car a week ago. We put some newspaper under the car. But didn't found any yellow fluid. Not sure what it was.

The car seemed to be fine. No problem yet.

[Nacster]

I have the same problem as U Rehan only not as much, but exactly the way U described it..I went out a second time to c if it was still leaking..When I moved the car from it's original parking spot I noticed that there were small drops, but not as much as the first time..I actually touched it and it was definetly not oily, or greasy, and it really didn't have a smell to it..This is driving me nuts :confused:

[gman]

May be the car really wants to take a 'leak'. :cheesygri

[peterbrowne]

May be the car really wants to take a 'leak'. :cheesygri
now thats funny!

[kornstar369]

^^
actng
ahahahahah
serious