This is a job that is essential due to coolant leaking into the engine oil and vice versa coolant escaping into the combustion chamber. The obvious clue to this issue was an operator complaint of coolant loss. Since we could not detect an external leak all fingers pointed to the EGR cooler. Since this Mercedes MBE 900 diesel engine was a 2006 there is much less hardware and wiring in the way since it’s a non-emission engine.
The front housing is easy to pull off to inspect the inner core where exhaust flows through to the intake system. It was obvious there was problem with visible coolant buildup inside the cooler. At least when we have to buy a part there is no doubt. This unit cost us fifteen hundred dollars but after the original EGR cooler lasted 12 years. To me that is acceptable the cost of the new part will last another 12 years given the past performance of the original cooler. Parts lasting this period of time is what we like to see in a fleet operation.
What I like to see is changes/improvements to the original part. The new cooler had larger tubes installed for better flow to reduce blockage. With any diesel engine there is a very good chance the EGR cooler will fail if the coolant level is allowed to go below the cooler causing air in the system. This causes very intense heat and it would not take very long for the solder holding the cooler bundle together melting down and you’re stuck with an expensive repair that could be easily prevented.
In the video you can see the stainless steel material used to construct the cooler. It’s easy to see why the cost for emission parts is so high. So the best advice that I can give you is keep the engine coolant level up to the normal level. Make sure your truck has a low coolant level sensor that works properly. This sensor will save you a lot of money and down time. The stop engine will come on and you’ll be thankful for that red light on your dash which could prevent you from spending hundreds even thousands of dollars.
So don’t delay when you’re coolant level is dropping on a daily basis. Pressure test the system right away and get the problem fixed before doing anything else. I always advise drivers to carry extra coolant with them when on the road just in case. Water will work if you’re in a pinch but properly mixed coolant is the best way to go.
