My turn for the Evaporator Party - Page 2 - PeachParts Mercedes-Benz Forum

brewtoo · #16 01-25-2007, 11:02 AM

How much oil should I add back to this system? Replacing evaporator, expansion valve and receiver/dryer.

Bruno_300TE · #17 01-25-2007, 11:31 AM

40ml for the evaporator and 10ml for the receiver/drier. This is for part exchanges. An extra 10ml is added when refrigerant (and some oil) was lost due to a leak. Total volume of the system is 120ml (4 ounces).
Bruno

Kebowers · #18 01-27-2007, 12:20 AM

External corrosion due to mold. Mold will form corrosion 'cells' that will 'eat' right through the aluminum--probably where the 'South has aluminum eating mites' comment came from.

brewtoo · #19 01-30-2007, 10:32 PM

While I have been very impressed with MB engineering, fit and finish as I've worked through this project, there are a couple of things that have been lacking, IMHO. One of them is the AC condensate drains. The originals are delicate foam with springs inside to support them. You can see the remains of one in the first photo. You can also see the consequences of it leaking onto the floor under the mats. I went to Lowe's plumbing dept and bought some plastic tubing, 3/4"ID and 1"OD. See the second photo. The fit is perfect. Be sure to warm the hose up a bit in hot water and installation is a snap. I am confident that this will not leak. Cost was $1.13 total as opposed to about $11 per side for the original foam hoses.

manny · #20 01-30-2007, 11:45 PM

I can't believe that you're bastardizing such a fine car with " Lowes " parts.

Sure give you a lot of credit for your courage, tackling this project.

#21 01-31-2007, 06:58 AM

Quote:

Originally Posted by Smoke124

If it isn't leaking now, it will. I assume you did this effort as a result of insufficient cooling or none at all.

Replace with an ACM evap that has the expansion valve attached.

Replace receiver drier and make sure your pressure switch on the drier is the red one or you need to replace that at the same time. I have an extra on if you wish to purchase.

My water hoses were a bit difficult to disconnect, but I removed battery to get better access and got it. I ended up taking the battery tray out and cleaning and repainting. Ever read the book "If you give a pig a pancake"

Order a oring kit for your heater core and replace the o-rings as an extra preventive maintenance.

Yes take the fan out to help you remove the box.

Leave the seats in place.

Replace all the vacuum pods while you have the dash out.

Get the printouts from the CD for all steps.

Take digital pictures of every screw you remove, because there are probably 6-7 different types.

There is a caution on removing the leg room flap arm so the plastic piece is not broken.

Everything is just like the book says, straight forward and no MB tools or MB 40 hr training required.

Inspect the shifter bushings when you disconnect the speedo from the tranny.

Put a few drops of ATF on the fan motor bearings while it is out.

Replace cabin air filters.

Use a pry bar like a Super bar to release the box from the firewall

You will need to replace the weatherstripping around the evap box. Cannot get this from MB. I went to Lowes. I think I used 3/4" wide and maybe 1/2" thick. I would not use plumbers putty as the sealer as it is not intended for plastic and non-stainless parts (unless you find a less acidic type). I used silicone based caulk - little messy if you aren't careful.

I never found the plug for the center vent dial light, so I cut the wire and reattached.

There are a lot of plugs to disconnect, so make sure you reconnect them all. I had forgotten the cigarette lighter and I had to remove the console again to find it.

I am sure I left something out, but plan well and take your time.

PS I have just completed mine and I think I might have damaged my ignition switch as a result of not removing it per the instructions. See my post on my fan acting irratic.

94 E320 ACC Fan Irratic After Evaporator Replacement

Olin

The first sentence in the quote above is INCORRECT! Not ALL 124 evaporators will leak. Yes, this is most definitely a terrible achilles heel of the 124 MB, but that DO NOT ALL leak or eventually develop leaks. My 88 300E still has the original evaporator and it is still tight. I have had and repaired other leaks and at those times it was difficult to keep from assuming that the problem was the evaporator but it was not.

One time, the expansion valve was leaking and the other time the condensor was leaking.

DO NOT replace a 124 evaporator without CONFIRMING that it is leaking. Use a sniffer and UV dye both. BE SURE!

throne7 · #22 01-31-2007, 11:15 AM

Quote:

Originally Posted by brewtoo

OK, I figured out that to remove the ductwork above, you have to first remove the piece below that goes under the seats. No easy task. The plastic was not brittle at all, though, even after 17 years.

My toughest puzzle so far...the dash would NOT come out. Why? It seems that the guy who replaced my windshield a while back glued parts of the dash in for me. No extra charge.

I did not remove the steering wheel. I was going to but couldn't get the bolt loose. I figured I'd come back to it later but it turned out that it was no problem. I did remove the ignition switch.

I used a bit of compressed air to blow out the heater core so I wouldn't spill coolant in the car.

I've ordered ACM evap w/expansion valve and all new pods and a dryer and pressure switches.

I haven't broken anything. The drain hoses are one thing that deteriorated over time and have to be replaced.

It sure feels like I've gotten up close and personal with this car!

Oh man!!! I hope that when you put your benz back together it will still drive quiet like a benz without the squeaks and rattles that haunts other makes. I really feel sorry for you already.

brewtoo · #23 01-31-2007, 11:19 AM

There will be no rattles. There will be no leftover parts.

Actually, the way this thing is engineered, I think it would be hard for anything to rattle, especially if reassembled with reasonable care.

david s poole · #24 01-31-2007, 01:09 PM

larry,i agree that not all evaporators will leak.mine did but only after i made the mistake of trying out one of the blended refrigerants that contain mostly 134a.3 days after filling with fr-12 mine lost it all .tracked it down to the interaction of 134a with epoxy used to seal the u tubes at the ends.moral----if you dont want to change an evap stick with r12.

brewtoo · #25 02-05-2007, 09:16 PM

A few odds and ends for those who do this job...

Not really necessary to remove the steering wheel. I could not get the bolt loose even with an impact wrench.

Do remove the ignition switch from the column. It's easy. The retaining pin fell out of mine so watch out. You will have a rough time getting the heater box out with the ignition switch in the way.

The A-pillar trim is removed by pulling straight toward the back of the car. The two clips hold it firmly. Replacing it requires attention. I had to remove the visors and lower the top molding to get it back under at the top. Don't worry, the VIN tag that has to be bent forward will bend right back into place after you replace the A-pillar trim.

I used an ACM evaporator. It almost fit. The difference was mostly in the area of the expansion valve...it sat further back than the original. I had to loosen the clamp that holds the low-side pipe and slide it towards the firewall. The inlet and outlet pipes were a bit different. I had to use a bit of sealer in the gaps.

Pay attention when disassembling the heater box. Tons of screws and clips. There's more to it than you would expect and by the time you get to that part of the job you are in a hurry to finally get that damn evaporator out! Just remove everything from the outside of the box and it really will split open so you can get to the evap. Just take it easy and DON'T force anything. The heater core stays in place unless you are replacing it (you can replace the heater core without removing the heater box from the car). As everyone says, replace the vacuum pods. All of my dual-chamber pods were bad; all the others were ok. You can probably not bother with the footwell and diverter flap pods if yours are good. The diverter valve seems to rarely operate and the footwell is not too hard to get to in the car. Certainly do the center flap pod or you will be sorry if you have to replace it later, unless you have the hands of a munchkin. Test all the new pods with a MityVac. Then test them again right before you reinstall the box in the car. Being cowardly, I replaced ALL my pods, BTW.

You cannot take too many photos. I was SURE I had taken plenty but I still missed some things.

Leave the seats in. Put the car up on ramps and it will be easier all around.

Evidently the center vent light wire comes right out of the harness and has no end connector. Some people cut it. I removed the wheel from the center vent and left it in the car.

Be careful removing and fitting the dash and pay particular attention to easing the dash over the defroster outlets on the heater box.

One of the tougher puzzles on reassembly for me was the driver-side lower dash under the steering wheel. A word to the wise...put the black plastic front part in first. Hold your mouth just right and get everything positioned just so and get the fasteners in before anything moves. The passenger side is much easier.

When removing the floor ductwork, there is a secret little tab on the piece that goes under the seats. Gently bend it up to gain just enough clearance to get the two sections apart.

Toss the drain hoses and replace them with clear vinyl hose from Lowe's. 3/4" ID, 1" OD fits perfectly. I just saved you an hour - now you don't have to take the bottom of the case to Lowe's and try all the different ones.

When you drain the coolant, drain about a gallon out of the bottom of the radiator. Disconnect the driver-side heater hose and use compressed air to gently blow the coolant out of the heater core. This will save you from making a mess in the car.

Repair all the broken metal tabs on your AC vents with JB Weld. Reinforce the ones that have not broken yet with JB Weld.

The row of push buttons under the center vent? Remove the rocker switch on the right and the trick is...you remove the little panel by pushing it IN, not pulling it out.

There are FIVE NUTS that hold the heater box in.

Go ahead and remove the wiper for access. It will be easier than trying to get the blower power cable out of the firewall while you are trying to balance the heater box on its way out of the car. If you also remove the blower motor you will be able to see the evaporator to verify the leak and the box will be a bit lighter and a bit easier to remove.

I had plenty of bags ready for my fasteners but did not use the bag-and-label method. I simply replaced each fastener as I disassembled things and I think that is the best way to go.

Replace any burned out light bulbs while you are in there.

Go ahead and buy a little telescoping magnet to pick up those fasteners that get away.

Disconnect the battery and remove it for access to the heater hose on the right. Of course, you were going to disconnect the battery first thing, right? Good.

The panel with the window switches tilts to the side and stays in the car when the center console comes out.

Try to order your parts in advance so there will be no delays. You can forget a lot of assembly details while waiting for parts to arrive. Order the evaporator (w/expansion valve), pods, and drier. I replaced the pressure switches on the drier, too. You can test the pods before you ever take the car apart right through the glove box opening and determine which you need, if you are daring enough not to replace them all. If you buy an ACM evaporator, tell the seller to open the factory box, verify there is no damage and add packing material. Mine first one came with inadequate packing material to protect the evaporator.

I removed the center console first, before the dash to avoid damaging the top of the center console with the two bolts that stick down out of the dash.

No matter how careful you are, there will be times when you have to go back and disassemble what you just put together because something else needed to be assembled first.

When you restart the car, the coolant will be reluctant to flow thru the heater core. I ran the engine briefly up to about 1500 RPM and started the flow.

If you be careful and pay attention you really can do this job. I had the luxury of spending over three weeks on it, off and on. It is not a job I would want to be rushed on. Twelve days of that was spent waiting for parts and then replacements for damaged parts. It is a BIG job, no doubt about it. I had my trunk full of parts and the roof and truck lid covered with parts. It is a very satisfying job, though, and the labor savings are very significant. Replace your evaporator and you will surely feel like you have accomplished something.

I have lots of pics. Let me know if you need a pic of anything.

#26 02-06-2007, 08:38 AM

Quote:

Originally Posted by brewtoo

A few odds and ends for those who do this job...

Not really necessary to remove the steering wheel. I could not get the bolt loose even with an impact wrench.

Do remove the ignition switch from the column. It's easy. The retaining pin fell out of mine so watch out. You will have a rough time getting the heater box out with the ignition switch in the way.

The A-pillar trim is removed by pulling straight toward the back of the car. The two clips hold it firmly. Replacing it requires attention. I had to remove the visors and lower the top molding to get it back under at the top. Don't worry, the VIN tag that has to be bent forward will bend right back into place after you replace the A-pillar trim.

I used an ACM evaporator. It almost fit. The difference was mostly in the area of the expansion valve...it sat further back than the original. I had to loosen the clamp that holds the low-side pipe and slide it towards the firewall. The inlet and outlet pipes were a bit different. I had to use a bit of sealer in the gaps.

Pay attention when disassembling the heater box. Tons of screws and clips. There's more to it than you would expect and by the time you get to that part of the job you are in a hurry to finally get that damn evaporator out! Just remove everything from the outside of the box and it really will split open so you can get to the evap. Just take it easy and DON'T force anything. The heater core stays in place unless you are replacing it (you can replace the heater core without removing the heater box from the car). As everyone says, replace the vacuum pods. All of my dual-chamber pods were bad; all the others were ok. You can probably not bother with the footwell and diverter flap pods if yours are good. The diverter valve seems to rarely operate and the footwell is not too hard to get to in the car. Certainly do the center flap pod or you will be sorry if you have to replace it later, unless you have the hands of a munchkin. Test all the new pods with a MityVac. Then test them again right before you reinstall the box in the car. Being cowardly, I replaced ALL my pods, BTW.

You cannot take too many photos. I was SURE I had taken plenty but I still missed some things.

Leave the seats in. Put the car up on ramps and it will be easier all around.

Evidently the center vent light wire comes right out of the harness and has no end connector. Some people cut it. I removed the wheel from the center vent and left it in the car.

Be careful removing and fitting the dash and pay particular attention to easing the dash over the defroster outlets on the heater box.

One of the tougher puzzles on reassembly for me was the driver-side lower dash under the steering wheel. A word to the wise...put the black plastic front part in first. Hold your mouth just right and get everything positioned just so and get the fasteners in before anything moves. The passenger side is much easier.

When removing the floor ductwork, there is a secret little tab on the piece that goes under the seats. Gently bend it up to gain just enough clearance to get the two sections apart.

Toss the drain hoses and replace them with clear vinyl hose from Lowe's. 3/4" ID, 1" OD fits perfectly. I just saved you an hour - now you don't have to take the bottom of the case to Lowe's and try all the different ones.

When you drain the coolant, drain about a gallon out of the bottom of the radiator. Disconnect the driver-side heater hose and use compressed air to gently blow the coolant out of the heater core. This will save you from making a mess in the car.

Repair all the broken metal tabs on your AC vents with JB Weld. Reinforce the ones that have not broken yet with JB Weld.

The row of push buttons under the center vent? Remove the rocker switch on the right and the trick is...you remove the little panel by pushing it IN, not pulling it out.

There are FIVE NUTS that hold the heater box in.

Go ahead and remove the wiper for access. It will be easier than trying to get the blower power cable out of the firewall while you are trying to balance the heater box on its way out of the car. If you also remove the blower motor you will be able to see the evaporator to verify the leak and the box will be a bit lighter and a bit easier to remove.

I had plenty of bags ready for my fasteners but did not use the bag-and-label method. I simply replaced each fastener as I disassembled things and I think that is the best way to go.

Replace any burned out light bulbs while you are in there.

Go ahead and buy a little telescoping magnet to pick up those fasteners that get away.

Disconnect the battery and remove it for access to the heater hose on the right. Of course, you were going to disconnect the battery first thing, right? Good.

The panel with the window switches tilts to the side and stays in the car when the center console comes out.

Try to order your parts in advance so there will be no delays. You can forget a lot of assembly details while waiting for parts to arrive. Order the evaporator (w/expansion valve), pods, and drier. I replaced the pressure switches on the drier, too. You can test the pods before you ever take the car apart right through the glove box opening and determine which you need, if you are daring enough not to replace them all. If you buy an ACM evaporator, tell the seller to open the factory box, verify there is no damage and add packing material. Mine first one came with inadequate packing material to protect the evaporator.

I removed the center console first, before the dash to avoid damaging the top of the center console with the two bolts that stick down out of the dash.

No matter how careful you are, there will be times when you have to go back and disassemble what you just put together because something else needed to be assembled first.

When you restart the car, the coolant will be reluctant to flow thru the heater core. I ran the engine briefly up to about 1500 RPM and started the flow.

If you be careful and pay attention you really can do this job. I had the luxury of spending over three weeks on it, off and on. It is not a job I would want to be rushed on. Twelve days of that was spent waiting for parts and then replacements for damaged parts. It is a BIG job, no doubt about it. I had my trunk full of parts and the roof and truck lid covered with parts. It is a very satisfying job, though, and the labor savings are very significant. Replace your evaporator and you will surely feel like you have accomplished something.

I have lots of pics. Let me know if you need a pic of anything.

I have not replaced my evaporator, but I went all the way down to it in order to replace the vacuum pods and heater core. This was almost two years ago so I don't remember every detail.

I would suggest, however, that to prevent the problem in bold above, simply lay out the parts in order. I don't mean every little screw, but when you remove a piece, lay it and all the associated pieces at one end of the garage wall or somewhere. Then the next piece and it's hardware are laid down after that until you have a trail of pieces. Then when you go back together, you will put everything back in the correct order.

I have done this with most all major jobs over the years and it helps a LOT to keep from getting something on, only to have to remove it for the addition of another subassembly of some sort.

Also, it is unfortunate that brewtoo could not remove the steering wheel bolt. It is normally it only takes a minute to remove the steering wheel and get it the heck out of the way. ALWAYS, however, disconnect the airbag connector under the right floor mat FIRST. Also, lay the airbag down with the soft portion up. If it were to somehow go off, if the hard part is up, it will be a projectile.

Also, when loosening the steering wheel center bolt, hold the steering wheel with one hand and the wrench or ratchet with the other to prevent putting this load on the locking mechanism.

My $0.02,

brewtoo · #27 02-06-2007, 12:37 PM

Quote:

Originally Posted by LarryBible

Also, when loosening the steering wheel center bolt, hold the steering wheel with one hand and the wrench or ratchet with the other to prevent putting this load on the locking mechanism.

All good points, Larry. Regarding the statement above, I would also suggest first turning the key to unlock the steering wheel, just to be sure the load cannot be transmitted to the locking mechanism.

And that's a good idea on the "trail of parts," too.

brewtoo · #28 02-10-2007, 04:04 PM

OK, time to replace the drier.

I removed the left headlight since, IMHO, it makes it SO much easier to get to the drier, fittings and wires. It just takes a minute to get the headlight out. I also removed the air filter housing so I could remove the intake ductwork.

I replaced both pressure switches.

For those doing the evaporator replacement...be sure to order ALL the o-rings that you will need in advance. I missed a couple.

davidmash · #29 02-28-2007, 05:18 PM

I have a few R134 conversion questions that I have not found answers to in my search of this site.

The coil on my 190 has a leak and it needs to be replaced. My indi recommended that since the coil needs to be replaced and the cost of R12 is going up and up that I might as well convert to 134.

The indi told me that I would need to replace the coil. Dryer/receiver and expansion valve but not the hoses. I was under the impression from some of the things I have read that the hoses need to be replaced with 134 friendly hoses due to the fact that the 134 molecule is smaller than R12. So, do the hoses need to be replaced or not?

Most of the threads I found were a bit dated so I will ask this (I have a feeling I probably should not but what the hell), does anyone know how this will affect the cooling? I live in TX. I saw one thread where someone had a 190 and felt no ill effect as a result of the conversion.

Thanks

brewtoo · #30 02-28-2007, 05:55 PM

I just replaced my evaporator and I did NOT convert to 134. Did not even consider it.

I would think long and hard about converting. The condenser is too small, you will have to be sure that all the o-rings are the green ones rather than the original black ones. It is true about the 134 molecules being smaller but the hoses should be OK anyway, but not the o-rings. You have to be SURE to flush out all the original oil as it is not compatible.

I had a 300E that had been converted and it never did get very cold, although it did start eating compressors after the conversion. I had that one done by professionals. After the third compressor failed, they gave up and refunded my money.

With a conversion you have a good chance of not being happy with the performance. Especially in Texas where you need all the efficiency you can get.

R12 is what that sysem was designed for. You can't beat that wonderful 38-40' air coming out of that AC in the hot summer! 45-50' just ain't the same.

It's not worth the risk, IMHO, of course.