I own a 2009 Bavaria 47C with a D2 75F. When I bought it 3 years ago a pre-purchase inspection picked up that the turbo charger was seized. The previous owner was very surprised and said he never took it over 2000 rpm. We negotiated a price reduction of AUD $5,000, which was what the mechanic quoted. After I took possession he replaced the turbo. I now wish I had asked him to leave the old turbo in a box on the boat.
The engine has run without fault since I have had it and I didn’t know I had a problem until I came across these two forum threads on turbo waste gate seizing issues.
YBW and Cruisers
It appears that there is a common problem with these motors that the waste gate seizes up if the motor is not run at wide open throttle (WOT) occasionally. I am like the previous owner and never run above 2000 rpm.
I decided to check and put a spanner on the waste gate arm as described on the forums linked above. My waste gate was very hard to move and would be effectively seized as the air operated diaphragm would not have the power to move it. It had about 200 hours on it since being replaced three years ago.
I decided to remove the exhaust mixer elbow to give access to the waste gate to free it up. This was easy enough to do. I was concerned about getting the exhaust hose off given limited space and hose length. I undid the clamps, carefully broke the seal around the hose with a screwdriver and put some dishwashing liquid in between hose and elbow. A push on the hose at 90° saw it pop straight off.
I then discovered that the turbo was seized. I didn’t want to replace seized turbos every three years so Googled to find out how to dismantle them in order to attempt a repair.
I found very little information on how to disassemble them and no exploded view diagrams. I decided to give it a go and post my results here to aid others in the same position.
There are a few posts on YouTube describing how to remove them but hey seem to then hand them over to turbo specialists.
I removed the turbo to my work bench easily enough. The turbo is basically in two separate parts held together by a clamp. The main part has the clean air intake compressor, shaft and bearings and the exhaust turbine. The turbine sits inside the exhaust housing and mates up on a flat flange with a locating pin. The two parts are held together by a clamp.
When I undid the clamp I could not separate the two parts as they were seized together. The waste gate was extremely hard to move with a large spanner for leverage. There was a fair bit of soot and hard carbon built up. I decided the carbon need to be removed to enable the two parts to be separated.
I used domestic oven cleaner spray foam, paint brush and small bottle cleaner brush to clean around the turbine blades. I wore safety glasses and latex gloves. I gave this treatment a few goes and let it soak overnight. I was conscious of not letting the oven cleaner drain down along the shaft to the seals so left it positioned to drain away from them.
It cleaned up quite well, but I was still unable to separate the two parts. There was no gap between the turbine blade tips and the turbine housing, so I gave this are some more oven cleaner without success. I then held the turbo by the exhaust housing slightly off my bench and tapped the turbine shaft with the handle of a screwdriver and it popped off. I then did some more chemical cleaning around turbine blade tips. There was some solid hard carbon inside the turbo housing, and this required chipping it off with a screwdriver.
I re-assemble the turbo when the carbon was removed to give clearance for it to spin freely.
I worked the waste gate arm with a spanner and used WD40 and silicon spray to soak down the shaft whilst working the arm. This took ages buts I eventually got it free enough to move freely when tipping it upside down and back.
I also gave the exhaust mixer elbow a dose of oven cleaner and a bit of scraping with a screwdriver. This was not fouled as much as I was expecting and there was no corrosion evident.
I looked at getting new gaskets for the re-install and was hesitant to pay AUD$60 for a flat metal gasket on the mixer housing to turbo face. I thought the mixer elbow has an expensive gasket on one side and a hose with clamps on the other side. No pressure difference. I also thought that these parts are easy to get to so decided to clean up all gaskets and apply a film of Permatex high temperature gasket maker to them.
Re-assembled easily enough and test ran with no leaks.
I was concerned that this could seize up again and should be part of my routine maintenance. Running WOT with a potentially seized closed waste gate would over pressure the engine and potentially cause problems. I decided I needed more instruments to give me comfort in doing this occasionally to clean the turbo and exhaust elbow.
I installed a turbo boost gauge, in the engine bay for now. There is a small ~4mm diameter hose running between the compressor outlet and the diaphragm that actuates the waste gate arm. Remove this and install new hose with a T piece going to a manual turbo boost gauge. I also installed a coolant temperature and oil pressure gauge to check engine conditions, particularly when I run it at WOT occasionally. The three gauges are in the engine bay for now as I can’t get myself to drill holes in the boat at the helm just yet. Exploring options of camera to tablet via Bluetooth or just lift the engine cover and have a quick look like I do now.
The whole job was easy enough, but I would have liked to see photos or diagrams of a disassembled turbo before I started.
All up costs- oven cleaner AUD$6, gasket maker ~$20 to repair a seized turbo vs $5,000 to replace it three years ago.
Instruments were non VP and cost about A$60 each. With hose and fittings under $200 for three instruments.
