1989 300te...first hot day of the year. A/C problems. I now remember this from last year: When the car isn't in motion, the a/c does not blow cold. Driving...just fine, but when at a light,etc., warm air. In layman's terms: What, where do I look, what do I do?

I would suspect that you are slightly low on refrigerant. Are you running R12 or R134A? Does the auxiliary fan come on at idle when stopped?

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1989 300CE

The fan should not come on at idle when stopped UNLESS one of the sensors call for it. I would suspect that MBZMan's suspicion is correct.

Low charge will also cause this. Leaking pod for blend door will start to open and let heat through also at idle.

From what he describes I don't think it's a pod problem, but it's easy enough to pull the glovebox liner and check all the pod hoses to make sure they will hold a vacuum. That's a hard thing to do since all your fingers are crossed while you're trying to test them. If the problem does turn out to be a pod, it's a 15 hour job to remove the dash and replace them. Don't even DREAM of replacing only the leaker, replace ALL of them.

If I was to replace the vacuum pods I would probably change out the evaporator even if it was not leaking. It is something to consider if you are going to have to remove the dash to access the pods.

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1989 300CE

NO! NO! NO! Don't EVER disturb one of these evaporators unless it IS INDEED leaking!

Contrary to popular belief, all of them do not fail. They have a terrible reputation, but that means probably a 20% failure rate. Disturbing one that is not leaking is asking for trouble.

The evaporator in my '88 300E has been in there since they built the car around it in 1988 and it is still as tight as it can be. I did a podectomy and had the dash out in 2004 and left my non leaking evaporator alone.

If it ain't broke, don't fix it!

I agree, why spend time (labor) and money that appproaches what the car is worth? My W124 evap leaks a little, I just vacumn, oil shot/dye and recharge every year. I may do the cliplight superseal Auto. This product is getting rave reviews at all the HVAC stores I visit. (google cliplight superseal).

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1993 Mercedes Benz 300D 2.5 205K (ex wife's)
1984 Mercedes Benz 300SD 320K (SOLD)
2004 Mercedes Benz C240 75K
1995 GMC Sierra 2WD 5.7L 188K
1983 Mercedes Benz 300SD 239K (SOLD)
1987 BMW 325i 220K (SOLD FOR SALVAGE)

609 Certification

I was under the impression that failure rate of the evaporator was more like 50%. Personally, I would NEVER use any type of sealant in an A/C system. You are better off fixing the leak than destroying the rest of the components with those band aid products. If it sounds too good to be true then it probably is.

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1989 300CE

Read the cliplight description, reviews, it will not ruin anything. it runs free until it finds a leak then it seals it. (freon must hold in system for more than a couple of days, can not seal big leaks). This is not some cheap stuff sold at auto stores, only available to certified HVAC techs. Not cheap, superseal auto is about $45 a can.

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1993 Mercedes Benz 300D 2.5 205K (ex wife's)
1984 Mercedes Benz 300SD 320K (SOLD)
2004 Mercedes Benz C240 75K
1995 GMC Sierra 2WD 5.7L 188K
1983 Mercedes Benz 300SD 239K (SOLD)
1987 BMW 325i 220K (SOLD FOR SALVAGE)

609 Certification

I am a Free Enterprise guy and feel that laws should not be interjected that inhibit private business. In the case of these refrigeration system miracle fixes in a can I think I could bend my principles and let them outlaw the JUNK!

Not only will these products (it pains me to use a term as legitimate as "products" to describe this junk) very easily DESTROY your refrigeration system, but they will DESTROY a refrigerant recovery/recycle machine. These machines cost the shops THOUSANDS of dollars. Because of these miracle leak cures, anyone who owns a recycling machine (I own two of them) is scared to death of their machine ingesting some of this junk and being destroyed.

It is HIGHLY ILLEGAL to work on an a/c system without recovering the refrigerant before hand. As a result, once these chemicals are in the system you will play heck finding a shop that will touch it. I know, I KNOW! You don't need a shop, you will take care of it yourself! What about the next poor person that ends up driving around in that car sweating himself/herself to death?

PLEASE! DO NOT USE ANY LEAK PRODUCTS!!!!!!!!!!!! You can very easily end up regretting it.

All that said, there are two general types of magic leak fix "products." There is a seal sweller and there is the cryo type that will seal or try to seal such leaks as you would find in an evaporator. The seal sweller is not as harmful, almost benign, but it would not fix an evaporator leak anyway. The type of sealant that WOULD fix an evaporator is the type that can destroy your a/c system and some poor guys recovery/recycle machine.

Have a heart! These guys with their shop machinery are just trying to make a living, putting beans on the table and shoes on the baby like everyone else.

Don't fall for the sales pitch of these Snake Oil Salesmen selling this JUNK!!!! Oh silly me, I forgot, it says on the can that it won't hurt anything! I'm sure that no one in the history of commerce has ever made misleading statements on their packaging or in their sales pitch.