Here is a thread for people looking to track a pesky exhaust smell inside the vehicle. While this is only one of many dangerous exhaust leaks its extra lethal as it can catch the vehicle on fire!
What we are looking at here is the exhaust crossover (Traverse Tube) pipe found on most all V8 Mercedes from 1986-1991. You don’t see this problem much with the older v8's as there was no cat. converters to deal with and most of the manifolds were dual outlet. With the introduction of the cat. converter in 1986 the v8's got a crossover tube (Shown) to direct the drivers side bank into the collector with the primary converter.
Basically if you hear an exhaust leak and smell exhaust fumes in your cabin have a look here. It’s on the back side of the motor. Should anyone be looking for one go to the website on the photo.
Take a close look and you will see the climate control system vents in this same area! This vent/drain is for condensation run off from the air conditioning however exhaust gases can get sucked into your climate box very easy if the drain/vent is older and there is a gap in the seal! If you smell exhaust gases thru the vents you will want to check ALL of the exhaust connections around there such as the collector flanges, manifold gaskets and seams of the primary converter.
I recently bought a '89 420 SEL and I am having the exhaust smell inside the cabin. I read your comments and was wondering if you could tell me other possible areas where I could look for a leak. Pics would really help. This is my first Mercedes, so I am not only new to the site, but also to the car. Any help would be appreciated
IGE2467 wrote: I recently bought a '89 420 SEL and I am having the exhaust smell inside the cabin. I read your comments and was wondering if you could tell me other possible areas where I could look for a leak. Pics would really help. This is my first Mercedes, so I am not only new to the site, but also to the car. Any help would be appreciated
Some of the most comen leaks are usually easy to spot if you know where to look. I have attached some photos of diffrent areas that are known to leak.
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What is to give light must endure burning -- Viktor Frankl
Small exhaust holes in the pipe and center muffler can be filled in with a welder by someone who has welding skills. The original equipment exhaust system has VERY thick dense steel that takes well to filling in. You can buy time in doing this however its important to check them each oil change.
Genuine Mercedes-Benz exhaust systems are VERY expensive. To replace the system from the cat back could cost in excess of $800! The converters found on these older W126 Mercedes are considered to be at the top of the food chain in terms of Platnium and Uridium. You could get in exess of $400 + if you smelted all of the Platnium and Uridium out of these babies! Back when they were made these metals were lower in cost and as you know Mercedes did not skimp when it come to doing things. I buy OE used converters so if you have any and wish to sell them I will pay $20 for the small one and $40 for the big one. Smelting is not easy... And having an unfortunate smelting experince could cause one to have a platnium tally wacker! LOL (Austin Powers - Goldmember)
I also want to let people know that bad trunk seals, holes in the trunk and excessively rich mixtures can also cause quite a bit of exuast gas to build up in the cabin. This can be amplified when the vehicle is running with windows are down, standing and moving slowly in traffic. Having no converters will no doubt increase these build ups.
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What is to give light must endure burning -- Viktor Frankl
You also have to make sure that the connections at each end of the transverse tube (to the left and right exhaust manifolds) are secured with the ring clamp and have a copper washer in between the connection. I can't stand these transverse tubes !!