Chicane5

Hey all - 2006 C4S Cab (6MT) here, 108k miles. New to me since October last year.

Other than burning through a bit of oil, which needs topping off now and again it appears to be solid. That is until recently...

I started noticing damp patches on the garage floor when pulling out in the morning, clear fluid with a slightly oily consistency. Patches were pooling in the middle, toward the front of the car.
I kept an eye over a few weeks, no warning lights, abnormal engine temp or anything else. Then one morning when topping off the oil, I noticed the coolant level about an inch below minimum - I wondered if it could be related to the fluid leaks from the front so bought some Porsche Pink coolant from Pelican, mixed about 400mls 50/50 with distilled water and topped it off.

Drove it for another week or therabouts and then had to go to Europe for two weeks. I got back at the weekend and noticed there was a small patch of coolant on the floor, more or less underneath where the coolant tank sits.
Topped off with another 1200ml of 50/50 mix, although it never seemed to get to the midline between min/max - after a second or two the level would go back down to about an inch below min. I hesitated to top off any more coolant so let it be.

Last night I did my usual commute - about 40mins up the 405 Freeway in LA, then had to get gas and take an urgent call so pulled up to the pump and talked on the phone ~10 mins with the engine running. When I got out there was a long puddle leaking out, and was able to go under and get some video of exactly where the leak is. You can see the drips coming out every few seconds, then stop, then more drips.

When I took the pic of the coolant tank, the flash showed up lots of white chalky residue in the engine bay surrounding the tank - boiled off coolant?

Any suggestions what is going on here would be much appreciated.

Video:

HLCinCOU

I'm not completely sure I understand where it's coming out. At one point you say it's toward the front of the car, but then you say "under where the tank is" which is at the rear. Couldn't tell from the video which end I was looking at. That pic, however, looks like it's coming from up front, which makes me think it might be the same thing that happened to my 2012 C4S Cab. Also the residue around the cap makes me think there could be similarities. So here's what happened in my case:

I had just taken delivery; it went on a truck halfway across the country. After the first drive it leaked a bunch from the front passenger side. Luckily I have a CPO so I had it towed to the dealership. They said they could not find any leak, but that the pressure cap was not releasing pressure; they replaced the cap and said it was good to go. It was not; I drove it home and it leaked more out from the same spot. I took it back and they found the leak; it was at a junction where a hose meets a plastic piece on its way to the front radiator. They had to order parts in from Germany; there were three part numbers, which I didn't look up but assumed to be a hose, a junction, and the plastic thingy, to use the technical term.

Since then I have seen no leaks. However, the coolant level is persistently low when the engine is cold. Just a bit...maybe half inch below the min mark. When hot, it's between the lines. I saw residue around the cap but didn't know if it was new or old. So I cleaned up the area and topped off the coolant so it was midway between min and max, with the engine cold. The next time I drove it, when it cooled down the level was again a half inch below min and there was new residue around the cap.

The above is a factual description which I think is accurate. The following is purely speculation:

I'm thinking maybe you have a bad cap that's poorly regulating the pressure in your coolant system. That may account for random blowoffs that leave that residue, and could also cause failure in other parts of the system, like the junction that failed in mine. Just eyeballing it I'd guess the same part failed on your drivers side (mine was the passenger side). If so, I'd probably replace the cap and the three parts that form that junction. Obviously opening it up and actually visually determining where the leak is would be helpful. But wherever it is I'd probably replace the cap too.

As I said, half of that was an accurate description of a sample-size-one experience I had, and the rest was rank speculation. So take it for what it is, but I hope it's at least a bit helpful. Good luck!

lowbee

So this sounded like the new cap isn't doing its job properly ?

Chicane5

Thanks! Thats very useful info. Sorry - to clarify, in the video the leak is coming from the front, where you can see is just behind the front wheels. The one and only time I have seen fluid at the rear of the car, it was definitely coolant since it was pink in color, a small puddle.

Every other leak has been clear fluid from the front - from that same place as in the video.

doclouie

Looks like condensation from the air conditioner. Mine drips tons in the heat of the summer.

HLCinCOU

Well, maybe...guess it sort of depends how you look at it. The cap is keeping the coolant level stable. Yes, it's below the min line when cold. But having measured the topping off, it's keeping it about 12oz lower than the min line; in a roughly 8-gal system I don't think that's an issue. Previous cap wasn't releasing pressure at all, which caused other coolant system parts to fail. I understand the original caps had a number of pressure related problems and that they redesigned the replacement part at some point to deal with that. I've read other threads where people had similar results with the new ones (stable levels but reading a bit low) so I'm inclined to think that it's doing what it's supposed to do and it's just an issue where the new part just behaves a bit differently than the old one.

HLCinCOU

Oh yeah, this is a good point that I maybe didn't think of because 500 people told me that's what my coolant leak was (it wasn't).

Reading back over your original post, you did say it was clear; coolant should be pink, smell sweet, and feel a bit different than water (a bit slick, a bit higher viscosity). If it's just water, then yeah that's probably just A/C condensate. Although I do think that's supposed to be dripping out of a little tube in that same area as opposed to a random place on the bottom plate.

Qwksnke

Or windshield washer fluid leak which these cars are known for. The reservoir is in the fender behind the left front wheel.
Very common for the washer pump to start leaking. Around a 30 dollar part to replace I believe

swingwing

There’s a coolant leak in that there engine compartment. Looks to me like your coolant reservoir has a crack in it, indicated by the chalky white residue around it. I recommend you replace it along with the cap. A pressure check will tell the tale.

The fluid coming from underneath front of car doesn’t look like coolant to me, rather like normal condensate from the AC system, or possibly from the windshield washer fluid reservoir. Pretty easy for you to confirm though - coolant feels oily, unlike water.

pdxmotorhead

Just did the tank on mine,, shop says the keep them in stock. Very common. He said hes seen them in as little as 3 years.
He also said while there are parts he goes external for, the tank is not one of them. OEM only..

FWIW the BMW's use a tank made very similar and they are notorious for breaking and cracking

I plan on pulling mine when I get my tig back in my garage and doing a stainless or Aluminum one.

Hella-Buggin'

The one in the front is just condensation from the climate control system.
The rear looks like maybe the expansion tank is leaking and splattering everywhere.
They crack about every five years for me.