Hello, a while back I had an inquiry about the a/c on my 88 300e, 165,000 miles. The a/c starts out okay, but if it's hot outside and I've driven 10 mins. or so....the car temp goes up and the air blows hot. Put in a new blower motor at one shop-didn't fix the problem and so went to a diff. mech. who put in a new fan clutch which didn't fix problem and he referred me to a diff. mech. who supposedly specializes who TOLD ME I HAD TO HAVE the head and head gasket reconditioned because of a 50% loss in compression......BUT that will fix the problem with the overheating and the a/c. I just got home after driving my car without air. It cost me 2300.00 today. This shop charged me $400.00 over their highest quote w/o telling me and w/o blinking an eye and I have to call them tomorrow and tell them my air doesn't work when I stop my car after driving it 15 mins. and restart. I had to revisit this site because I am hoping someone will reinforce my belief that this could be a good car for me. I have owned my car since Nov. and have spent at least 3500. on it. Can you guys reply this time?

 

A 300E is a great car. Any Mercedes will require a good amount of $$$ to get it running up to par, and with proper maintenance, it will last many years. If you are still having problems with the A/C, you should look at the sight glass on the receiver/drier, which is in the engine compartment next to the driver's side headlight. Start the A/C and look for bubbles, foam, or the like. The refrigerant should flow freely and with little or no bubbling (almost invisible). Any bubbling could be a result of a low charge, and you'll need more freon (R12 in the case of an '88). So hang in there and let the good times 'roll'!

 

Thanks for the feedback-I check it again...when all this started there was too much freon in the car. Well, back to the mechanic today.

 

A/C and head gasket have nothing to do with each other. The A/C stopps if the refrigerant is low and the pressures in the A/C system cannot reach the required level to cool the air. What you describe asks more for low level than overfilled refrigerant. Or too much water in the system and you need to have the A/C drained, the dryer bottle changed and a new refill done (probably with R134a sinc R12 is not available anymore (in many locations) If the car is overheating and the fan was not the cause, than you might loose cooling water through the damaged head gasket and this could cause overheating. But bad compression, however, does not necessarily call for damaged head gasket, can also have other (not less servre) reasons.

 

Ok, I got this one! It is the pusbutton unit! The module inside the car that has the temperature dial, 5 horizontal buttons and the fan controls. I had this very thing happen on a 1987 300E and a 1989 300E, replacing this unit solved the problem in both cases.

 

engine compression plus head gasket have nothing to do with the A/C system. There are two different/isolated system. I think you need a new mechanic/technician, who will either know how to fix it or not lie to you. Sorry, but you've been had.
jackD

 

It seems that there were two problems to me. A leaking head gasket and a bad pusbutton unit. An overheating engine will cause the ACC unit to shut off the compressor until the temp cools off. Of course there is always the possibility that the shop(s) Tamara has been to are scamming her, but a simple check of the compression test prior to rebuid and current will prove it. Also, a leakdown test will help verify that the head was indeed reworked.

Assuming (I know) the head gasket was fixed and the ACC problem still exists, there is another problem. In my case(s) the pushbutton unit was switching to Defrost mode on its own as a result of cracks in the PC board. This occurred about 10 min after I started the car on a hot day. I could almost always make it work again (for another 10 min) by cycling the ignition switch.

Tamara, please post, or email the names of the shops you had work on the car and I will research their reputations amongst my friends in the business here in Phoenix.

-Dennis

 

Before throwing more parts ((i.e$$$) at the problem, I would have 2 quick checks done:
1) Check the A/C system for R-12 for charge and pressure. Any competent A/C shop could do that very little money.
2) The ACC Mono valve could also be defective, allowing hot radiator coolant to circulate through the heater core with A/C on.
The heater control you are talking about is over $200.00 (rebuilt) (plus install).
JackD

 

Thanks to all of you for taking time to detail your thoughts about this problem. All of your information has been very helpful and has enabled me to communicate better with the mechanics. At the onset, pressure tests were done on the a/c...and that was okay but there was too much freon in the system.

At this point I know the head needed reconditioning and that the overheating was a seperate problem from the a/c. Although I was traumatized by the bill, I think I did the right thing by my car.

The blower moter wasn't working and I trust the shop that replaced it. But they didn't want to get further into it....Then I was referred to a shop that specialized in Volvo and I shouldn't have been there. They replaced the fan clutch (340.00) which may or may not have been ok-because I understand from my new mechanic this is an electrical part and rarely goes bad. When they realized they were in over their heads they sent me on my way. All in all I was trying to find a shop by referral and was one step away from going to the dealer when I got a referral to Star Service in Mesa. They did the work on the head. The shop supposedly had a good reputation and worked only on MBs so I thought I finally found my mechanic. There is a new owner. I've since heard he does jobs way over quote and doesn't keep the customer apprised which is what happened to me-much, much worse but I won't go into it. This guy actually threatened to tear my car apart because I was asking him what the 600.00 in extra charges broke down to-just a question-I did not provoke him. Oh, and he hung up on me twice (he's like the "soup ****" of auto mechanics if you know who that is). As you can imagine, I no longer deal with him personally and just want my car out of there. I would not recommend him to my worst enemy.

dlafever, the above shop is installing the new starter and I pick up the car today-they mentioned this might be the problem when the relay switch replacement didn't work. Even tho they assured me the new head would fix the problem and it didn't, I still have to pay them. After reading your comments about the PC Board I'm not so sure about the starter but am hopeful: ) I had two referrals when I chose Star, the other is Imports and American Auto in Mesa-if you know anything about them....

I have a newfound respect for the mechanical mastery of my car since discovering this forum and intend to be very involved in its upkeep.

 

If I have read correctly, your A/C is still not working properly. I have another theory to present. It could be the Klima (climate control computer). This little box compares the rpm's of both your engine and your compressor. If it detects a difference it will tell the clutch to disengage until the next ignition cycle. This could be the result of a slipping clutch, bad Klima, a loose or slipping belt, or perhaps even a poorly installed new clutch. There are ways to bypass this function but I haven't tried and thus cannot recommend the process. Make sure that you find a properly trained MB mechanic to look at the A/C. It may cost a little more initially but you'll only have to go once. By the way I would make it my mission in life to tell everyone about that nasty mechanic. If he's so wealthy that he no longer needs business then I feel that it's your duty to spread the word for him! Good luck.

 

I totally agree with DLAFEVER. I had the same thing on an 86 300E I used to own. It was the pushbutton unit. In my case when I turned the AC on, the fan would come on and would blow the outside temperature air, but the AC compressor clutch did not engage. I was able to hotwire the AC compressor clutch and get the AC going. Then I swapped the pushbutton unit from my friend's '90 300E and the AC started working normally. The next thing was the trip to the local junk yard.

 

Ok, I got this one! It is the pusbutton unit! The module inside the car that has the temperature dial, 5 horizontal buttons and the fan controls. I had this very thing happen on a 1987 300E and a 1989 300E, replacing this unit solved the problem in both cases.

...............very impressed. Yes, it is the temp control unit that is causing your problem. This exact thing happened to me last week. Do you here a clicking sound behind your dash?

Ted

 

I thought that clicking was relay logic at work. It only seemed to happen when the ACC closes/opens a damper at the temp. set point on the selector wheel.

BTW, an online parts retailer sells a rebuilt pushbutton control unit for $240 with a $200 core refund. The question is here is, is 'Programa' (the manufacturer) an OEM company for MBs, or some aftermarket outfit? Sounds European.

 

The mechanics called me from their cell phone to tell me what was going on with my car. They replaced the ignition switch; they test drove the car and when they stopped and turned off the car the a/c would not always go on when the car was started back up. They went ahead and threw in the push button control....

I picked up my car and on my way home made a stop to pick up drycleaning... got back in, started the car...no air. I was able to get the a/c back on by restarting the car two...three times.

This SRS light I've read about....can't recall much about it but someone said they wait until the light goes off before starting the car. Since doing that the a/c has come on although there is a delay for the fan when I first start the car.

Shadetree, I'll have to check into the climate control computer, don't know if this comes with the push button control unit. Thanks!

 

First thing, find a new mechanic. Your ongoing saga leads me to believe that these guys are screwing you. Why would they replace the ignition switch? If it was faulty the car wouldn't run at all, no less the A/C! The Klima control is not part of the pushbutton control unit. It is in the engine compartment behind a plastic shroud on the passenger side. It says "Klima" right on it, so you can't miss it. If you're handy, you can replace it yourself. It just pops out and you put a new one in. If this still doesn't help, the compressor might have a bad clutch, or the compressor itself is bad. I wish you the best. Don't let this bad experience scare you away from a great car!

 

They replaced the fan clutch (340.00) which may or may not have been ok-because I understand from my new mechanic this is an electrical part and rarely goes bad.


Hi Tamara,
this is total BS, what they told you. The main blower is belt driven and has a fluid coupling which increases speed when the temperature goes up. It's nothing electrical at all. But one is true the silicon oil cloupling wears with time and milage. But if this part goes bad the radiator temp. goes up in slow or stop and go traffic and comes back to normal (~80 Celsius) as soon the traffic situation is back to normal driving. Any other appearence has different causes

 

Tamara: please do yourself a favor. Find an other competent mechanic for your car. This guy has not done anything to solve your problem and has told you lies after lies and got your hard earned money..
The viscous fan has nothing electric or electronic about it.
The ignition switch has nothing to do with A/C
A valve job has nothing to do with the A/C system.
What you need is a competent/honest mechanic that will listen to you, look at the car and what has been done so far, test your system, sit down and THINK for a moment and come up with THE solution. Throwing parts (i.e$$) at a problem is frustrating and costly
jackD

 

Tamara...

Lets not forget to report all the BAD shops you've been going to the BBB.

Maintenance rules:

#1. Never call an electrician for plumbing problems....i/e if driving a MB, dont take it to Volvo specialty shops.

#2. Parts on MB's are expensive, meaning don't waste your time at "corner" shops or gas stations.

#3. There are lots of members in this forum that live in or about your area, I'm sure someone here can provide references for a reputable shop when you have exhausted any DIY work or T/shooting. Even the BBB can help you locate a shop.

You have 2 fans on your vehicle, one driven by a belt and using a clutch for engagement (radiator fan) and another one in front of your condenser (electric). The electric "auxiliary fan" as its called engages when certain parameters are met. There are quick tests that can be done to ensure a few switches and sensors and relays within the A/C & Cooling system are functional.

Jumping from shop to shop all it causes is aggravation, and the problems don't get solved because most mechanics like to "shot-gun" a discrepancy by slapping parts here and there and not fully troubleshoot the problem, (you will be surprised the amount of mechanics that dont even know how to use an ohmmeter or a fluke). By the time you are done after spending lots of $$$$, that same amount of money could have been spent at the dealer, with OEM parts, with warranty and 9 out of 10....fixed.

Here in Houston, most specialized european shops versus the dealer as far as labor only differs by maybe 5-10 dollars an hour. Tamara, don;t give up on your vehicle, once the problem gets taken care of and as mentioned in another post before, with proper routine maintenance, you MB will reward you with many years and miles of pleasure driving.

Jorge

92 400E (157K)
99 BMW528i Sport Pkg (38K)
86 BMW325e (175K)
85 VW Scirocco (132k)
71 Chev Nova (425K...thats right!..comp @ 55-60, but still drives)
99 Peg Perego Jeep 4x4...(oops, thats my kids bat powered jeep)

 

Hi Jer,
Yes, the Klima control has been replaced-I think I referred to it as the A/C relay switch. I guess the only thing left is the compressor and since the air doesn't work at all now, and only blows hot air, I'm going to the dealer to face the music and hopefully, finally, get this problem fixed. At least the mechanics didn't charge me for the pushbutton control, the Klima and the starter....I know once I get done with this, my car is going to be fantastic-it's just a little hard to be optomistic when the o/s temp is 112 and of course I have so much into it.

 

I am the owner of a new pushbutton unit (free) and the problem still exists but-I never did hear a clicking sound. Just wanted to let you know for future reference. I really appreciated your input and because of your suggestion I asked about this AND have this unit at n/c because the mechanics were baffled and basically said-yes that could be it... I'll say this here again in case you guys don't know it but this forum has been so tremendously helpful, inspiring and all out, mentally life saving I just want to thank everyone AGAIN for their input.

 

.......................Call master mechanic at Mb Autowerks. His fixed the problem with mine. Tell him I sent you. Telephone number is 678-482-6553.

Ted

 

Thank you Ted, I will SAVE the number! Just picked up my car today, it's been in the shop a while. I had taken it to the dealer last week and had it checked out (for the 100.00 diagnostic charge). They recommended: new compressor, manifold hose, expansion valve, receiver dryer...blah blah blah all for 2500. or so. I had one more mechanic referral to see and figured I might as well since I'm so far into it, and he did all that for 1700.00. Soooooo, since November when I bought the car, the grand total for work done on my car has been 5000.00. My new and very, very trusted mechanic has told me, my car is one of the nicest, cleanest MB's he's seen for it's age and said I shouldn't have to spend another dime on it for a while.

Here's a hat's off to my car....after having to shuttle around with other's since mine's been in the shop soooo much....I got in my car and...I had just plain FORGOTTEN how luxurious it feels to sit behind the wheel of the 300e. Finally! And I thought to myself, yeah, don't let 'em kid ya, this was worth every penny.

 

Tamara...

Im am so glad that you got your vehicle back and Im sure the rest of "users" here that have been keeping up with your posts are as well.

Now, its time for you to put a photo or a link to one of your car and a smiley you of getting it back.

Happy driving......