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2006 DF175 Overheat Alarm at Idle problem
Part 2
This past spring problem #2 suddenly reared its ugly head the dreaded over heat alarm.
This came about after the engine rebuild (see Part 1- oil loss).
With about 20+ hours on the rebuilt engine, I ran a couple hours out to the tuna grounds for a day of tuna fishing. Arrived at the location we wanted to start fishing, pulled back to neutral to deploy rods --- when the overheat alarm goes off. In watching the engine temp through the engine interface on my GPS, I could watch the temperature fluctuate with RPM changes.
Rev the engine up a bit and alarm stops, back to idle and temp starts running up again.
Mechanic got very frustrated in trying to track down and find the reason for the problem. With the rebuild we had installed a new water pump impellor. We were getting sufficient water pressure to the by-pass valve. As this is a potential problem area, he had checked this to see if it was working properly. Checked the thermostat not the problem. Nothing plugged up, just not enough water getting to the head to keep it cool when idling.
NO TECHNICAL SERVICE BULLETINS FOUND!!! This is going to create a big problem.
Mechanic knows a former Suzuki worker that is now working as a mechanic in the Seattle area. What he found from this individual is disturbing. Evidently Suzuki is aware of a problem in the oil pan for engines built in the 2006 to 2008 (approximate date range).
Besides being the oil pan, the water and exhaust ports are built into this piece. Cooling water is pumped up through a tube that meets up with a fitting in the bottom of the oil pan. This is the spot where the by-pass valve is located and the source for the water flows through a passage to the engine head.
On the port side of my DF175, one of the two freshwater washout ports is located on the cover plate. Upon removal of the cover plate, you are looking at the wall between the water passage and the internal built-exhaust port. (See Photo)
This is one known location where corrosion eats through this wall and dumps water directly into the exhaust port, not allowing sufficient water at low RPM to cool the engine cylinder walls, thus the engine then overheats. With a higher RPM there is enough water pressure (in my case) to still cool the power head.
I suspect, at this point, there are potentially two reasons. The original castings left the walls of these ports too thin and therefore heat and water corroded the wall out. Other parts of the oil pan were apparently powder coated to deter corrosion, and these places on the oil pan were not. The engine above the oil pan is coated as well as the internal part of the lower unit below it.
Turn oil pan upside down and it is full of corrosion. I believe the mechanic told me Suzuki fixed this problem with the new oil pan he installed. By the way he was also advised to replace the water tube from the pump to the oil pan. Evidently the crimps in the tube can corrode causing pin holes to develop. This ended up being a lot more expensive repair than need be for me. IF there had been a TSB on this known problem, when the engine was apart earlier, an inspection could have been performed and parts replaced. As it ended we spent a lot of time to find the problem and then had to pull the power head off a second time in order to replace the oil pan.
Hope this is a helpful analysis. Art
Part 2
This past spring problem #2 suddenly reared its ugly head the dreaded over heat alarm.
This came about after the engine rebuild (see Part 1- oil loss).
With about 20+ hours on the rebuilt engine, I ran a couple hours out to the tuna grounds for a day of tuna fishing. Arrived at the location we wanted to start fishing, pulled back to neutral to deploy rods --- when the overheat alarm goes off. In watching the engine temp through the engine interface on my GPS, I could watch the temperature fluctuate with RPM changes.
Rev the engine up a bit and alarm stops, back to idle and temp starts running up again.
Mechanic got very frustrated in trying to track down and find the reason for the problem. With the rebuild we had installed a new water pump impellor. We were getting sufficient water pressure to the by-pass valve. As this is a potential problem area, he had checked this to see if it was working properly. Checked the thermostat not the problem. Nothing plugged up, just not enough water getting to the head to keep it cool when idling.
NO TECHNICAL SERVICE BULLETINS FOUND!!! This is going to create a big problem.
Mechanic knows a former Suzuki worker that is now working as a mechanic in the Seattle area. What he found from this individual is disturbing. Evidently Suzuki is aware of a problem in the oil pan for engines built in the 2006 to 2008 (approximate date range).
Besides being the oil pan, the water and exhaust ports are built into this piece. Cooling water is pumped up through a tube that meets up with a fitting in the bottom of the oil pan. This is the spot where the by-pass valve is located and the source for the water flows through a passage to the engine head.
On the port side of my DF175, one of the two freshwater washout ports is located on the cover plate. Upon removal of the cover plate, you are looking at the wall between the water passage and the internal built-exhaust port. (See Photo)
This is one known location where corrosion eats through this wall and dumps water directly into the exhaust port, not allowing sufficient water at low RPM to cool the engine cylinder walls, thus the engine then overheats. With a higher RPM there is enough water pressure (in my case) to still cool the power head.
I suspect, at this point, there are potentially two reasons. The original castings left the walls of these ports too thin and therefore heat and water corroded the wall out. Other parts of the oil pan were apparently powder coated to deter corrosion, and these places on the oil pan were not. The engine above the oil pan is coated as well as the internal part of the lower unit below it.
Turn oil pan upside down and it is full of corrosion. I believe the mechanic told me Suzuki fixed this problem with the new oil pan he installed. By the way he was also advised to replace the water tube from the pump to the oil pan. Evidently the crimps in the tube can corrode causing pin holes to develop. This ended up being a lot more expensive repair than need be for me. IF there had been a TSB on this known problem, when the engine was apart earlier, an inspection could have been performed and parts replaced. As it ended we spent a lot of time to find the problem and then had to pull the power head off a second time in order to replace the oil pan.
Hope this is a helpful analysis. Art
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