deblaze

Just wondering... my 1990 300E MB has a A/C leak. After freon is put in it might last a week.. but then it leaks out.

Does anyone know where I would begin to look for the leak, or the problem?

Thanks,
Deblaze

Kestas

It sounds like you have a relatively large leak that can't be managed by just 'topping off'. In the absence of professional tools, I start by adding freon into the system until it's pressurized, then throw soapy water on suspect areas, looking for bubbles. Include the compressor shaft for your checks. Another way is to inject UV dye into a pressurized system, add freon to get the system to run, circulate the dye, and reach the leak point, then search for the leak in the dark with a UV light. Kits to do this are sold on ackits.com or acsource.com.

If you exhaust those methods, you'll have to have a professional with tools to look for the leak. He'll probably use a sniffer. The evaporator is a known weak point for your vehicle and you'll want a good verifiable diagnosis before embarking on that repair. You'll definitely have to find the leak and fix it before moving on.

I hope you're not using refrigerant with stop-leak in it. This can make things worse for your a/c and any tech who tries to recover that stuff.