Antifreeze smell through a/c??
 

Anybody has any ideas why I could be getting an antifreeze smell through my a/c while in traffic and not on freeway? Temp indicator looks ok and there are no water leaks.
w124 300CE

Seems there has to be a leak somewhere.

My first guess would be that your heater core is leaking. Would not take much of a leak here to smell the antifreeze.

Also, any antifreeze that hits hot metal (like an exhaust bit) will vaporize, and this vapor may be sucked into your vent system intake. Very small amounts would create a strong scent in this case. This would be more noticeable in traffic, because the vapors would not be blown away. Could be a very slow leak, so it is not noticed by checking the level.

Look around very carefully right after a nice hot drive. You may find it. You may even here it hissing.

I just got a UV Dye Leak Detection kit. I got it for AC, but the directions say one of the dyes can be used for coolant. If your leak is very elusive, this would do it.

aris3000

The smell is telltale .... monitor your coolant tank, especially when cold, such as first thing in the morning.

Look under the upper coolant hose. Often the radiator neck becomes brittle and will start as a little leak there. You can sometimes see evidence of the leak as white residue on the black plastic.

Get you head down under as they say and look around. If there are not leaks within the engine compartment, battery area, fuse box area, then explore under the dash.

It is my experience that you do not get that smell unless something is a problem.
Haasman

Csnow, my experience with a/c UV dye leak testing tells me that the dye and coolant light up the same. I was in a situation where I couldn't tell if the UV light was showing an a/c compressor seal leak or green coolant leaking from a blind are near the water pump.

What I'm saying is that green coolant will show up bright with a UV light without dye. Maybe MB coolant behaves the same way.

Interesting. Did not know that green coolant glows under UV light.
That could be very convenient (or annoying as your case shows).

The whole UV thing brand new to me...

In addition to the smell, do you get a slimy fog film on the inside of the window glass? If so, it is most assuredly a leaky heater core.

This is really bad news on the 124 as it is the same job to change heater core or evaporator.

Best of luck,

Good point. Man I hate seeing that film, makes me shudder.

Also, you might try driving the car, getting it warm, park it and open the hood for a short while and then use your nose to see if you can detect the source.

I have almost always found these leaks by just using my hand and reaching under each hose, connection and component I can touch.

Keep us posted,

Haasman

Many thanks guys I'll try to get around it soon and let you know what happens

You probably have the same problem that I had last month when I hit the Arizona state line. There is a small hose under the intake manifold. It is like a small elbow. There was a split on the inside of the hose. This would only leak when the cooling system was under pressure or in my case, overheated. You have to remove the starter and some other patrs to get at this $5.00 part. It takes about 4 hrs of labor. The best way to test for this is to pressurize the system for a few hours to find the leak.

Hope this helps,

Steve

I think I got it all figured out today. After I drove the car in traffic for a long time I noticed that the temp was close to 120 but not redlining.Outside temp was about 40C. After parking the car I noticed something dripping on the passengers side, which was antifreeze fluid. I popped the hood open to see that coolant was slowly coming out of the expansion tank lid. I replaced the lid and hope this works. I will monitor it for a few days and let you all know.

That's scary. Is there any oil in the coolant, or coolant in the oil?

Good luck,

Finally that was the problem guys. A bad expansion tank lid. Replaced that, drove the car all day today and it's been just fine. The temp indicator was just over 80. So I think that solved the problem inexpensively!!!

I'm with LarryBible here!

This is all to familiar to me. You must not have seen my threads around here the past two weeks, lol.

I thought this was my resolution as well. Then I later noticed the car getting warmer and warmer. To make a long story short, I get to go and pick-up my car tomorrow and the head gasket will be fixed, lol.

I'm thinking this is why Larry asked is there any coolant in the oil, or vice versa. I know it feels good to get a "cheap fix" but your car is worth far more down the line, than your emotions are right now in feeling good that you saved some cash.

Have your engine checked out on Monday. Or if you do your own work, put your hood up, turn your heat on as high as possible (full blast) and while sitting in park, gas your car for around 5 minutes. I mean, give it some gas. A loose, or bad expansion tank lid shouldn't cause smelling coolant. Engines are funny, you won't smell the coolant all the time so I'd not get too at ease about it right now. After you gas your car, HARD, for 5-10 minutes, get under the hood and see is any coolant in the oil, or vice versa. Your coolant shouldn't even be jumping-up to the point where your tank lid would even contribute in leaking. That tells me there's some built-up pressure in there and that there's likely a leak in the pistons, either inside or outside.

I'm not trying to scare you, but this is too familiar as I too thought I had a quick, less expensive fix.

Good luck!

You are really scaring me right now!!! Ever since I changed the lid the temp is actually at normal with the a/c on even at standing idle in traffic and there is no smell anymore. Everything looks fine now but I think I'll go ahead and do that.
Thanks.

how would you describe the smell of coolant?

distinctly different from gasoline?