Interior Update: G-Wagon Center Console

Anyone with an older G-Wagon has experienced a center console with holes and cracks. Seems over time, various switches and modifications have been added and removed to many consoles so there are small holes, screw mounts and missing parts. This was the case with my G-Wagon but there was another problem. The center air conditioning unit had been removed leaving the rear of the center console where it was cut looking pretty shabby. 

I thought about getting a new console, but the price was well over $600. I decided covering it with vinyl like the rest of the car would look better and be less expensive. 

Repaired Underside of W460 Console

I asked Ben at Brent's Custom Upholstery to try. He said it would be pricy and take some time, but he would see what he could do. He started by patching the holes and performed a miracle by using ABS plastic to fix the cut out portion so it had the shape prior to the trimming to accommodate the air conditioning console. 

He then covered the console with padding and finished it off with stitched vinyl that had a nice leather look that matched the seats and doors. I opted for black to keep the feel of the original console. One bonus is the new console isolated more noise from the transmission and engine. 

Covered G-Wagon Console

At about $200 this was a better option for me and a huge interior upgrade to the look of the W460 while keeping the original look and design feel.

THANKS BEN!

OM 617 Turbo POWER

If you are like me, you have probably never driven a 1984 turbo diesel G-Wagon. They are kind of like Unicorns, we like the idea of them, but they were just never made. Why you ask? First of all, there were no G-Wagons sold in the US in the 80's and secondly the turbo diesel G-Wagon was not even built until the 90's. 

ALDA with Cap In Place

The thing was, the power from the OM617 5 Cylinder Turbo in my car seemed pathetic. Why would anyone want to have this? The term SLUG comes to mind. I was getting 0-60 in something like 30 seconds and forget about a mountain climb at anything near the speed limit. So I started digging for more power. Turns out the first thing I tried, adjusting the ALDA, was just the thing I needed. It was easy and did not take long, required no special tools or instruments and WORKED!

The OM617 Turbo has an ALDA that controls the amount of fuel sent to the engine. The ALDA is a simple mechanical device that that measures altitude of the vehicle and the pressure from the turbo intake manifold pressure to adjust the fuel made available to the engine. I could tell mine had not been adjusted since the engine was assembled at the factory because the cap was still covering the adjustment screw. 

My first step was to make sure the pressure from the intake manifold was reaching the ALDA. I started by removing the nut at the rear of the intake manifold with the banjo connecting to the plastic hose and make sure the airway was clear. It had some build up in the nut and the banjo so I cleaned it with a solvent and replaced it. 

The next step for the pressure from the manifold was a cutoff valve. There is a switch on the top of the intake manifold that measures pressure inside the manifold. Too much pressure and the switch connects to ground and causes a bypass valve to release the pressure before it gets to the ALDA so the turbo will not overload. In my case the wires going to the bypass and manifold switch were disconnected.

Just to make sure, I removed the bypass switch connected the hoses tested it on my bench. It worked perfectly. After checking all the remaining hoses I removed the cap from the top of the ALDA.

ALDA Cap Partially Removed

The top of the cap is plastic so I used a sharp razor blade to cut through the plastic on top and a pair of diagonal cutters to cut the metal along the side ring. This reveled a hex lock nut and the adjustment screw. I kept working at the cap until I could get to the locking nut. By removing the locking nut from the ALDA, I was able to remove the remaining part of the metal ring and plastic.   

Once the cover was removed, I replaced the large washer that was under the nut with the locking nut but did not tighten it all the way. With the nut loose, the screw in the middle was easy to turn. Do not force the screw, it will break! I turned the screw counterclockwise about 1/8 of a turn to increase the fuel flow and took the car for a drive. I tightened to hex hut to hold the screw in place. WOW what a difference. Much better acceleration below 2000 rpm and a HUGE improvement once the turbo kicked in. 

I repeated the steps above and adjusted it one more time and got another increase in acceleration and responsiveness. I was careful not to adjust so far that black smoke came out of the exhaust indicating too much diesel to was being provided for the the engine to burn.

The next step was to get the overload bypass working again. I simply installed the bypass switch and reconnected it to the manifold overload switch. Unlike what some other said, I experienced NO LOSS OF POWER by replacing the properly working pressure release switch. Most importantly the engine is now protected from turbo over boost. Even with the overbuilt nature of the OM617A, too much turbo could damage the engine.  

There is a lot of talk on the internet about whether or not to adjust the ALDA. Some even say you should completely remove the ALDA. Others turn the screw all the way out till it stops. I think my results speak for themselves. The car was a slug prior to the adjustment and now it is downright zippy with 0-60 now less than 22 seconds that is almost a 30% increase in acceleration. My feeling is a 30 year old mechanical device could use some adjustment.

One more note: I also performed a Diesel Purge that provided more of a performance boost. CLICK HERE for detail instructions. 

If anyone wants to drive a 1984 300GD Turbo, just take a short drive to Park City and I'll let you take it for a spin. Because unlike the mythical unicorn, they really exist. Warning: after driving the turbo, you will hunting for an OM617 Turbo to put in your W460!

Interior Update: Modified Recaro Seats

Original Tartan W460 Seats

I'm not looking to restore my 1984 300GD. If I were looking to have an original G-Wagon from the 80's, this would not be the car. First of all it was built as a 280GE, now it has an engine from a 1985 300 Turbo and a totally different transmission. On top of that, it was repainted a modern Mercedes Onyx color. I'm looking for a Snow Wagon to be a winter driver here in Park City so a seat upgrade was in order. 

When the 300GD came with two sets of seats, my choice came down to comfort and looks. A set of Recaro racing seats had been installed by a previous owner. He made some custom adaptors that were basically two steel square tubes that ran down each side of the seat. Also included were the original seats with that checkered fabric. They actually looked pretty good but did not even come close to comfort of the Recaro. 

Recaro Racing Seats

The thing is, the Recaro's are racing seats similar to the Recaro Speed series but with larger, and to me very ugly wings on the sides. The Speed Series are designed to accommodate racing restraints that would come over each shoulder and latch between the driver's legs. We may do some off road driving in this car, but there would be no need for racing restraints. Looking them up on Recaro's web site, I could tell the current version of this seat sold for about $900 each. I decided if I could make them look a little less like a racing seat, I would go with the Recaro. The original seats would be bound for an eBay auction!

While I did most of the interior work myself, I was not about to take on the job of upholstery work on the seats. For that I decided to use a local shop in Heber City, UT called Brent's Custom Upholstery. They said they could recover the seats, trim down the wings, remove the plastic rings and fill in the seat restraint holes. They recommended covering the front of the seats with the more durable and breathable leather and use the vinyl for the backs. Turns out this is how most "leather" factory seats are covered. 

Covered Recaro Leather Seats

When covering the old rear seats, I decided to focus on two passenger look rather than three. I had some 1" padding added to add definition to better match the pattern on the front seats and stuck with vinyl to reduce the cost. I asked them to add some ABS plastic to the otherwise metal back of the rear seat and had it covered with HR1307 Harddura. For those not familiar with Harddura, it is a strong vinyl backed with heavy felt that was used as interior floor lining in English cars, mostly Jaguars of 60's and 70's. Since I was planning to use it as the floor covering for the back of the car and under the rear bench seat, it made since to cover the back of the bench seat with the same material.

I already had the lather and matching vinyl so pulled out the Recaro front seats, the back bench seat and installed the original seats so I could continue the rolling restoration. I also dropped off some ceramic heating elements for the front seats to be installed. About 6 weeks later and the seats were done and they looked great. 

The seats are comfortable look fantastic and the rear seats look very much like the W463 seats shipping in the newer G-Wagons. I really like the upscale stitching pattern that Brent's used and it matches the stitching on the doors. While not accurate as an example of a W460, with the interior done, folks can't believe this car was made in 1984. To me it is comfortable to drive and does not deviate much from the original design.  

Slipping in 4th - Transmission Trouble?

Last week after I got the oil changed, I noticed the transmission slipping in 4th when climbing hills. I called my local Mercedes guru Brent Groth and asked what he thought it could be. He had this worried sound to his voice and said, "that is not good." I had the transmission oil changed and a new filter fitted in Burbank just about 6 weeks ago so I was a bit worried. 

I see from records that the previous owner provided that he installed a rebuilt 722.109 automatic transmission from Sun Valley Mercedes Transmissions in December of 2008. That is the same transmission that was used in the 300D from 1957-1981. Checking the records of when the car was built using a European VIN Decoder, it looks like the car was originally fitted with a 720.109 4-speed automatic transmission.

Since I need to have the front and back master cylinder boots rebuilt anyway, I decided to have the transmission looked at. I took the car to a place in SLC called Transmission Man (I'm not making that up), gave Ben all the info I had and asked them to take a look at it. He had his folks look the car over and while they are good at what they know, he asked me to come down and go over it with him. 

We started by looking over the vacuum system and tested the Vacuum Modulator with a hand pump and gauge. With our setup, it would not hold pressure indicating a ruptured diaphragm. The "red" Vacuum Modulator used in the 722.1xx transmissions seems to be hard to find, but we found one at Ecklers and ordered it. 

Once the new Vacuum Modulator arrived, I removed the old modulator and about a quart of transmission fluid drained out from the hole. Once the modulator was out, I pressure tested it again and it held pressure perfectly. My guess was the test rig performed by Ben and me had a leak. Since I had a new modulator, I pulled the pin from the old modulator and adjusted it to have approximately the same length. 

Once the new modulator was in place and I added back the quart of transmission fluid, I used the supplied key to adjust the shift points. Note: The correct way to adjust the modulator is to measure the pressure from the transmission pressure port just next to the modulator, but I did not have the equipment to do that.

I then noticed the vacuum modulator was connected to the VCV vent valve. The VCV vent should vent into the car cabin and not be connected to the modulator. I installed a new T to the hose at the top of the VCV and connected it to the Vacuum Modulator. I purchased an OTC 5613 Vacuum/Pressure Gauge Kit and tested the vacuum coming from the top of the VCV and it was within spec at 15 in Hg and dropped to 0 in Hg at full throttle. 

The result, shifting much smoother but still slipping in 4th. With all of the pressure points going to the transmission good, I've done all I can do without pulling the transmission.

Ready to Travel to LA

I put in a call to Sun Valley Mercedes Transmissions and Marc said he knew exactly what the problem was. Apparently, there is a valve in the transmission that dramatically reduces the pressure when the transmission shifts to 4th. His guess was valve needs to be replaced and said because it has been slipping that a rebuild is probably in order. Brent at Transmission Man in SLC said he could rebuild it but since I'm going to LA this week thought it would be best to let a Mercedes Transmission expert do the work. Brent pulled the transmission and loaded it in the back of my car for the trip to LA.

My Rebuilt 722.109 Transmission

When I dropped off the transmission at Sun Valley Mercedes Transmissions, Marc said he had never had a transmission he rebuilt come back before. He took a look and as he suspected the valve and spring needed to be replaced. After about three days, I came to see him test the transmission. They basically rebuilt it again, cleaned it up, gave me the correct dipstick, washers for the banjo on the dipstick tube and a new Bowden cable. I had to admit the transmission they loaded up in my car looked new. All this for a very fair price!

I loaded the transmission back into my car on my next trip to Park City where the folks at Transmission Man put it back into the car. The guys at the shop did not really know how to adjust the modulator or Bowden cable, but the process of testing the vacuum and throttle taught me how to perform the adjustments. 

Once I adjusted the vacuum modulator and Bowden cable, all is well again. Well except, I'm out about $1000. 

Baby it's (too) Cold Outside... for my G-Wagon

Living in Park City it can get cold so that classic great American song holds true here. We actually love the cold here because this is a ski town and our economy is based on folks wanting to ski on hundreds of inches of snow. That being said the weather is usually pretty good with bright sunny days and highs in the mid 20's to low 30's and with the low humidity, it is very nice in the winter. But once in a while, we get those arctic blasts and the temps can go very low. That is exactly what happened last week when the temp dropped below -12 F. 

My G-Wagon is a 1984 280GE who's previous owner had a 300CD turbo engine put in it. The G-Series of that era could be purchased with the OM617 engine, but none were made with the turbo option until the 90's. But Mercedes-Benz did fit some of the sedans of that period with the OM617 Turbo, an engine that still has a cult following today.

The problem is, at -12 F the 280 dual overhead cam gas engine would fire right up. I know this because we have a 1984 280 SL and as long as the coolant and oil are correct for low temps, no problems starting the car in the winter. Not so much with the diesel, as it has no spark plug to ignite the fuel. Diesel ignites from heat generated when it gets compressed. Glow plugs help, but when it is very cold, the fuel just does not get hot enough so... no combustion.  

I'm not new to diesel as my Kubota tractor has a 3 cylinder diesel and while it is hard to start when very cold, as long as I keep a winter blend of fuel and add a little winter treatment I don't have trouble with fuel gelling. Even then, on the coldest mornings, the tractor is very hard to start.

That is why I was surprised when I had trouble starting the G-Wagon when it was parked outside overnight. When keeping it in the garage heated at 50 there is no problem, but when parked outside overnight and the temp goes below 20, it is nearly impossible to start. Last week, when it dropped below 0, there was no way it would start. I had to tow it into the garage with the tractor and let it sit overnight, only then did it crank up. Yes, the tractor started but the Mercedes would not!

I checked the glow plugs with cables and all are reading .7 OHMs. That is a shame because Bosch 80006 Duraterm plugs are only about $10 each -- that would have been on an easy fix. I also checked the relay and am getting 11V on each of the five wires leading to the plugs and it correctly drops to 3V after the initial warm up. Additionally, the glow plug relay was even staying on longer when it is very cold. To bad because I can fix just about any electrical problem. 

I was beginning to think my plan to use a diesel as a winter car was a mistake. If you ask my wife she will say it WAS a mistake. When I started looking for a G-Wagon I wanted the peppier 280 anyway so now I'm feeling like the 280 would have been a better choice. I was not ready to give up!

Convinced the car was working as it should, I started looking for an engine block heater. For those of you who are not used to being in very cold climates, engine block heaters warm the engine block by either heating the oil or the coolant for easier starts, shorter warm-ups and less friction on the engine. 

Zerostart Engine Block Heater

The OM617 engines shipped to the states were fitted with an integrated engine block heater. So I looked under the exhaust manifold where the OM617 should have the heating element and all I found was a large plug. No heating element. I guess the California cars including my engine donor did not get the heaters.

Mercedes owners are used to great parts availability and you can get a OEM Part #: 606-200-00-94 or 900-203-48-95 for about $120. Turns out there is also an aftermarket unit called the Zerostart PN 310-0105 Engine Block Heater that fits most older Mercedes-Benz engines and you can get it from Amazon for about $45. 

Glow Plug Reamer

Before installing the block heater there were two things I did to make the engine run better that just happen to make a big difference with the cold starting issue:

First I removed the old glow plugs and reamed the chambers. This sounds easy, but took some time. You will need to remove the wire nut from the old glow plug, remove the old glow plug, install and remove the reamer until it does not bind, vacuum out the hole, clean, lubricate and replace the glow plugs. There was quite a bit of carbon build up in the chambers because the reamer was hard to get in the first time. The build up had to dramatically reduce the effectiveness of the glow plugs.

The second thing I did a diesel purge to further clean the carbon from the entire fuel system, including the prechamber. I did this to clean the fuel system and deliver more power. CLICK HERE for detailed instructions on the purge process. 

Those two easy steps helped the car start better in the cold and so far the car starts with no issues even when it is in the low 20's. I'll do a test on the next extreme cold night and report the results. 

Back to the block heater because even though it does start in the cold now, I know there will be those crazy cold days and a preheated engine will start with less wear and tear on engine components even when it is not Arctic cold. 

I attempted to remove the plug to install the block heater. I treated the area around the plug with a penetrating lubricant in advance. Then I put a 19MM hex socket on a 1/2 driver and even with a long pipe could not get the plug loose. Since the reamer and the diesel purge improved things so much, I decided the block heater could wait.  

Update 11/12/15 it was 17 degrees this morning and I forgot to put the cold weather treatment in the G-Wagon. I left it outside overnight and after two tries, it started right up. I believe the diesel purge and the reaming (cleaning) of the prechambers where the glow plugs are installed made the difference. After this latest test, I'm no longer worried about the cold winter of Park City... baby - it's not too cold for my G-Wagon and I've become quite happy with the 300G Turbo.