Catastrophic Coolant Leak After Impact

[SkyBlue04A4]

Greetings Audinauts, my 2004 A4 Cabriolet suffered an impact to the front bumper, off center to the driver's side. She now cannot hold coolant; if l pour some in, as soon as the level reaches the lower radiator hose it will immediately drain to the lower lip of the bumper pretty much exactly in line with the location of the impact, before spilling over to the ground. There are no obvious points of failure i can see but i'm hoping with your help we can pinpoint the leak. The leak seems total and happens whether the car is on or off.

I can't seem to find where to add photos to this thread ): any advice on how to do that would be great. Maybe bc this is my first post? Idk. I wanted to post a diagram and offer the numbers of the components close by the source of the seeping coolant. Specifically, there is pooling where the lower radiator drain hose seems to connect (securely, to my untrained eye) to the radiator. Radiator itself looks dirty but not warped as far as i can tell.

I am a novice at auto mechanics and diy fixes, but i do not want to give up on my baby. I will figure out how to provide photos so you guys aren't driving in the dark but thank you anyway in advance.

[Puddin Tane]

I can't seem to find where to add photos to this thread ):

When posting or replying, click on the "Go Advanced" virtual button to the lower right of your text input field. That takes you to a more complicated text editor that has an "attachments" button in the top row, with a paper clip symbol. Clicking on that will open a complicated upload dialogue box you can use to insert images into your text. It's very wonky but if you're at all computer savvy you should be able to figure it out.

Another way: do you have your own website or an account with a file-sharing website? If so, use the "insert image" function in the basic text editor (looks like a little framed picture]. First upload images to your website etc., then use "insert image" to paste those links into your message text. This is a better way because your image appears full size instead of a "thumbnail" people need to click to really see.

[MoRbiD]

You can check the parts page for the cooling system over here
That might give you some idea.

[EuroxS4]

Sounds to be like it needs a radiator or a lower coolant hose.

[MoRbiD]

sounds about right.

[MarioR34]

Hello ,

Hello , My car started to leak antifreeze, it always would drop to a minimum level of antifreeze because of old rubber seals , so i changed all this thermostat and rubbers , i didn't need to change thermostat but i did .

https://prnt.sc/PmTaFAWzn4Bn

Later, I still learned that she was leaking in other places, so I changed the part of the plastic under number 28 and all the rubber seals and the screws , only then antifreez stopped leaking, maybe these guidelines would help you.

https://prnt.sc/BLLxrZRo1gbQ

I paid all of that new OEM parts less than 150 euros.

[Turbo510]

I suspect a cracked radiator. 19 year-old cooling system plastic is not very robust.

[Puddin Tane]

Everybody responding forgot to ask what engine your car has, what transmission (automatic or stick), and whether or not it's quattro. It was assumed you have a 1.8 liter four cylinder engine powering a quattro drivetrain, so that's what they're showing you. If you instead have a 3 liter V6 OR front wheel drive, this is bad information that's just going to compound your problems. You gotta say.

so i changed all this thermostat and rubbers , i didn't need to change thermostat but i did .

https://prnt.sc/PmTaFAWzn4Bn

Just so you know, the part Mario shows here is not the thermostat. It's the coolant temp sensor on the lower radiator hose, accessed from under the car. The thermostat is part #3 in the 7zap exploded diagram and not likely to be your problem. The other part he shows with the other link is the infamous coolant flange at the back of the head (not your problem). But again, all that only matters if you have a 1.8t quattro car.

It sounds like you're strapped for money and need to dive into mechanicking to deal with this yourself. If so, here's the next thing to do:

1) you need to raise the front of the car so you can get under it. Since you can't start the car, that means a jack and two jackstands. Never ever get under a car that's only supported by jacks. You could die. Put the car in Park or first gear and engage the parking brake. In your owner's manual, research the jacking points for raising the front of the car. Those are the go-to spots to put your stands. Wherever you put them, make damn sure the car can't slip off. Shove on the car hard from several directions to make sure it won't budge.

2) Under the car there should be a plastic belly pan that completely conceals the underside of the engine compartment. This has to be removed so you can see what's going on. YouTube is your friend. Search for "2004 Audi A4 belly pan removal." It's easy.

3) Now get under the car and, while watching where the damage is, have an assistant pour G12 coolant 50/50 pre-mix into the coolant reservoir. You will see exactly where the coolant is leaking, which you interpret using an accurate diagram for your cooling system. Or just take pictures indicating where and post them here. Most of the regulars are Audi A4 geniuses who will immediately know what's going on.

[Mike Tries]

3) Now get under the car and, while watching where the damage is, have an assistant pour G12 coolant 50/50 pre-mix into the coolant reservoir. You will see exactly where the coolant is leaking, which you interpret using an accurate diagram for your cooling system. Or just take pictures indicating where and post them here. Most of the regulars are Audi A4 geniuses who will immediately know what's going on.

This is a great way to get started in figuring out the problem. You may note that Puddin Tane emphasized the G12 coolant point. Be sure to note that and buy the right coolant. Don't go mixing random coolants in there or anything. Apparently, different coolants can react with each other, or components of your coolant system, and do some real damage if left alone.

[SkyBlue04A4]

When posting or replying, click on the "Go Advanced" virtual button to the lower right of your text input field. That takes you to a more complicated text editor that has an "attachments" button in the top row, with a paper clip symbol. Clicking on that will open a complicated upload dialogue box you can use to insert images into your text. It's very wonky but if you're at all computer savvy you should be able to figure it out.

Another way: do you have your own website or an account with a file-sharing website? If so, use the "insert image" function in the basic text editor (looks like a little framed picture]. First upload images to your website etc., then use "insert image" to paste those links into your message text. This is a better way because your image appears full size instead of a "thumbnail" people need to click to really see.

IDK why this forum continues to be so buggy for me, I have no idea this thread even posted, much less than I was getting responses. I am now using a laptop to try and improve the UI/UX, and because it was the only way I could figure out how to add photos, which I just did in a thread I posted an hour ago. Wish I had seen this sooner! Thank you for your info!

[SkyBlue04A4]

You can check the parts page for the cooling system over here
That might give you some idea.

I've seen a similar schematic! I wanted to post it but this forum was impossible to use on my phone and I'm still working out the kinks on my laptop. Thank you for your reply! My Audi is an '04 and the diagram I found for that coolant system is a little different, but if they were more or less the same I'd say the source seems to be among numbers 1, 2, 30, 31, 32, and in the worst case 37.

Might you know how to tell whether the radiator is involved (versus the problem stemming from the other numbers which I am assuming will be easier cheaper fixes)?

[SkyBlue04A4]

Sounds to be like it needs a radiator or a lower coolant hose.

I'm really really hoping it's not the radiator. How might I try and determine which of the two? Thank you for your reply I wish I had seen it sooner!

[EuroxS4]

I'm really really hoping it's not the radiator. How might I try and determine which of the two? Thank you for your reply I wish I had seen it sooner!

If the car took a hit I would 100% put my money on the radiator. Pull the bumper. Your going to have to either way to change it. My gut says cracked end tank on radiator. Also wrong coolant in the car. That's asking for a problem. Just because auto parts store says universal don't mean jack when it comes to these cars.

[SkyBlue04A4]

Hello ,

Hello , My car started to leak antifreeze, it always would drop to a minimum level of antifreeze because of old rubber seals , so i changed all this thermostat and rubbers , i didn't need to change thermostat but i did .

https://prnt.sc/PmTaFAWzn4Bn

Later, I still learned that she was leaking in other places, so I changed the part of the plastic under number 28 and all the rubber seals and the screws , only then antifreez stopped leaking, maybe these guidelines would help you.

https://prnt.sc/BLLxrZRo1gbQ

I paid all of that new OEM parts less than 150 euros.

I really hope it is a seal that needs replacing...! Thank you for your reply!

- - - Updated - - -

I suspect a cracked radiator. 19 year-old cooling system plastic is not very robust.

*Gulp* ... how might I investigate a cracked radiator...? What should I look for, and where?

- - - Updated - - -

I suspect a cracked radiator. 19 year-old cooling system plastic is not very robust.

*Gulp* ... how might I investigate a cracked radiator...? What should I look for, and where?

[SkyBlue04A4]

...all that only matters if you have a 1.8t quattro car.

Your frankness and wisdom are very welcome. First reply that made me stop and pay real attention.

It sounds like you're strapped for money and need to dive into mechanicking to deal with this yourself.

What gave it away?

If so, here's the next thing to do:

1) you need to raise the front of the car so you can get under it. Since you can't start the car, that means a jack and two jackstands. Never ever get under a car that's only supported by jacks. You could die. Put the car in Park or first gear and engage the parking brake. In your owner's manual, research the jacking points for raising the front of the car. Those are the go-to spots to put your stands. Wherever you put them, make damn sure the car can't slip off. Shove on the car hard from several directions to make sure it won't budge.

2) Under the car there should be a plastic belly pan that completely conceals the underside of the engine compartment. This has to be removed so you can see what's going on. YouTube is your friend. Search for "2004 Audi A4 belly pan removal." It's easy.

3) Now get under the car and, while watching where the damage is, have an assistant pour G12 coolant 50/50 pre-mix into the coolant reservoir. You will see exactly where the coolant is leaking, which you interpret using an accurate diagram for your cooling system. Or just take pictures indicating where and post them here. Most of the regulars are Audi A4 geniuses who will immediately know what's going on.

1. The stock jack that came with my vehicle almost split my finger like a grape. I respect the power of a ton coming down on me and appreciate the attention to safety on your end.

2. The belly pan! Wait, the belly pan? I can see clear through parts of my engine bay to the ground below. Is it common for vehicles to be missing a belly pan? I will look into it though! anything to gain visibility without having to do intricate removals.

3. I'm still looking for my exact make/model diagram... but now that I'm comparing I think the one MoRBiD provided might be the best bet.


You're the man, Puddin. Thank you I will get back to this thread with an update

- - - Updated - - -

This is a great way to get started in figuring out the problem. You may note that Puddin Tane emphasized the G12 coolant point. Be sure to note that and buy the right coolant. Don't go mixing random coolants in there or anything. Apparently, different coolants can react with each other, or components of your coolant system, and do some real damage if left alone.

Gotcha Mike, thanks. I am using G12 50/50 and if I put anything else in there it's water. ... actually ok so it's 50/50 coolant for sure but more and more people are saying I'm using the wrong kind so I don't mean to brush you off. Need to confirm the G12-ness of my coolant.

[SkyBlue04A4]

If the car took a hit I would 100% put my money on the radiator. Pull the bumper. Your going to have to either way to change it. My gut says cracked end tank on radiator. Also wrong coolant in the car. That's asking for a problem. Just because auto parts store says universal don't mean jack when it comes to these cars.

Are you calling out my coolant because you saw my duplicate thread? If so, damn... whwere do I buy the right kind?

Cracked end tank on radiator. Has an ominous sound to it... and removing the bumper is the only way to figure that out?

[EuroxS4]

Are you calling out my coolant because you saw my duplicate thread? If so, damn... whwere do I buy the right kind?

Cracked end tank on radiator. Has an ominous sound to it... and removing the bumper is the only way to figure that out?

You can load the parts cannon and changed anything you'd like without diagnosing it or inspecting it upclose. It's your time and money.

[Turbo510]

coolant...whwere do I buy the right kind?

Zerex G40 pink/violet is what I use now. G13 compatible, easily available at AutoZone, O'Reilly, etc.

[Puddin Tane]

Wait, the belly pan? I can see clear through parts of my engine bay to the ground below. Is it common for vehicles to be missing a belly pan?

Yes, and it's no big deal IMO. Some people even prefer it that way because its absence keeps everything cooler under the hood. Its most important function is keeping spray and splash out of the engine bay when driving in wet conditions, but man that thing aggravates me when doing oil changes! I leave mine off.

Why the panic that it might be the radiator? Because you've priced a Genuine Audi radiator? Nissens makes very good, reasonably priced aftermarket radiators for these cars ($120 for a 1.8t). I haven't worked on my A4s radiator, but radiator replacements in general are pretty easy and don't require lots of special tools. The biggest biggy here is putting your front bumper and fascia in "service position." Again, YouTube is your friend. You're gonna need those jackstands, dude. Old rusty second hand ones are as good as new and cheap as dirt. Go to a flea market or second hand store.

PLEASE STATE ENGINE DISPLACEMENT, TRANSMISSION (MANUAL OR AUTO), AND DRIVETRAIN (QUATTRO OR FWD) FOR YOUR GODDAMN CAR

[kwilson]

I recently replaced my 1.8T radiator and didn't even need service position. I just pulled the bumper. It took me maybe an hour at a somewhat leisurely pace. Of course I've taken bumpers off a lot, so I knew what I was doing.

OP, if you have a cab, your front end is put together a little different than the sedans. Similar concept, and not too hard to figure out. Just FYI in case you are following instructions for a sedan.

[walky_talky20]

PLEASE STATE ENGINE DISPLACEMENT, TRANSMISSION (MANUAL OR AUTO), AND DRIVETRAIN (QUATTRO OR FWD) FOR YOUR GODDAMN CAR

LOL. Puddin has totes been holding this in since post #2.

[Puddin Tane]

LOL. Puddin has totes been holding this in since post #2.

Post #8, but yeah. Glad you liked it.

[Turbo510]

I installed a Nissens on my 3.0 and it fit perfectly, and not that tough of a job either. I may be mistaken, but I don't remember removing even the bumper cover. I had only two minor complications: (1) the transmission cooler lines are secured to the radiator with one screw each. The accessibility was not ideal, but also not related to the Nissens part. (2) I could not get the bottom radiator hose back on using the supplied O-ring. I gave up and re-used the original O-ring and have never had any leakage.