My 560SEC had been leaking coolant and giving me heat when I didn’t want it. Last week I started the repairs for these problems. As the Bosch and Mercedes W126 Monovalve repair kit was no longer available, I have been installing the Klima Design Works monovalve elimination kit. In the first part I removed the W126 monovalve, auxiliary water pump and other hoses. This...
My 560SEC has been having a couple of problems with its cooling system. Coolant has been weeping out of the top tank of the radiator. In addition, the monovalve has failed, causing unwanted heating at idle. The radiator looks either original or replaced very early in the cars life. As these radiators have plastic tanks, I have purchased a new one to replace it....
Over the years my 560SEC has acquired quite a lot of stone chips on the front of the car. I understand the previous owner was in semi-rural Queensland so there may have been some gravel or unsealed roads in there. Today I applied a stop gap fix until I can address the problem properly. Most of the stone chips were in the front panel...
One of the things that had been bugging me about my 560SEC was the missing W126 antenna grommet. Over time, they perish and instead of replacing it, the previous owner had used household sealant. This is an odd bodge as the part is inexpensive and easy to fit. The household sealant was making the SEC look like a real jalopy, and while that might...
The W126 was the first Mercedes to feature plastic cladding. I’m not sure this is the best feature of the W126, but it started a trend that would continue for many years. The W126 cladding is attached to the car with a series of clips and consists of eight peices (four on each side) along the line of the bumper bars. The cladding...
Once I got the air conditioning working on the 560SEC it was apparent the auxiliary fan was not working. As can be seen in the wiring diagram below, the W126 SEC auxiliary fan can be triggered either by high coolant temperature or by refrigerant pressure. The diagram is for 1986-1990. In 1990, the W126 went to a dual fan setup. The fan can...
When purchased, my 560SEC did not have working climate control. Not only did the A/C not work, but the heater had a mind of its own, occasionally bursting in to life and turning on full heat. Curiously for a car that has been in Australia since the early 2000s, the car had not been converted to R134A. My first step was to see if...
I discovered at the MBCNSW Dyno day that my 560SEC was running dangerously lean. Lean enough to cause damage to the engine. While I was in the USA for work, I went to the Mid Florida Auto show. I met Pierre Hedary there (who runs an independent Mercedes workshop), who suggested that I should start by testing my fuel pressures and that he had...
The MBCNSW held a tech day at a dyno equipped performance shop today. I was keen to attend as I wanted to understand how much power my ECE 560SEC is making. Geting dyno time independently can be expensive, but through the club day it was very affordable. The tech day was held at SR Performance at Wolli Creek. On the Dyno, the following cars...
It was just announced that the NSW 60 day logbook ‘trial’ has been made permanent. This is great news as its a really good system. The two minor drawbacks – the amount of paperwork and the size of the plates. The plates are tiny and really ugly. They are so small that they don’t line up with the mounting holes of nearly any car. ...
One of the things I noticed when I first changed the oil on my 560SEC was the dent in the lower oil pan. Presumably it hit a curb or rock at some point. It was also leaking. the dent was likely too small to interfere with the oil pump, or oil pickup but I wanted to be sure. The M117 lower oil pan...
A common feature of Mercedes cars from the mid 70s through the mid 2000s is the self-leveling rear suspension. This system is standard on the wagons, but was commonly specified on the higher end sedans too. Mercedes-Benz Australia was particularly keen on the system fitting it to coupes and even mid size saloons. The system ensures that even with a heavy load in the...
All W126 models have an insulation pad under the bonnet to protect the paintwork and reduce engine noise. Over time, the W126 bonnet insulation degrades and starts crumbling down onto the engine. At this point most owners simply remove it. I own two W126 models with the remnants of their insulation pads. A few months ago, I purchased W126 bonnet insulation to...
My 560SEC had a problem where it would emit a puff of smoke after idling. This was rather embarrassing taking off from the lights. It did give me the advantage of keeping people back who got too close. My assumption was that it was cause by old valve stem seals. As the seals get old, they get hard and allow a small amount of...
The Timing chain replacement is almost finished on the 560SEC. The new chain is installed, guides fitted and valve stem seals replaced. I stopped by the workshop to pick something up that I had left in the car and I was able to see it almost done. The photo shows the new chain in place with all new guides. They are a much...
When I last used my 560SEC before Xmas, I noticed a rather large puddle of petrol underneath it. I’ve not driven the car since as it is rather dangerous to drive with such a leak. I had assumed it was probably fuel hoses. Many cars run on E10 rot their hoses. I purchased a few of the relevant hoses so I would only have...
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