Jon Wehrenberg
09-22-2010, 08:34 AM
One of our members had some minor engine work done. It was a simple repair, but it required the removal of coolant. When the work was done the coolant was returned to the cooling system, but there was coolant left over. The POG member advised the repair facility that if the coolant came out, all of it had to go back in.
Apparently that did not happen. The POG member drove the repaired coach about 6 miles at which point his engine was ruined, likely due to a cavity filled with air in the cooling system that the engine's coolant pump could not purge. This happened on an 8V92 and all the damage was related to one bank of cylinders indicating one of the two coolant pumps was likely in the middle of a bubble of air.
An 8V92 senses coolant temps on one bank only so there was no way for the POG member to realize on his gauges that anything was wrong. The repair shop error was very costly and it is likely the POG member and the repair shop are going to be arguing over who pays for the repairs which involved replacing all pistons, rings, cylinder liners, etc.
My reason for posting this is because this week I have been involved in discussions with several folks who have become the victims of shitty worksmanship. This example involving coolant is so important I am posting this to alert everry POG member to recognize and understand what some shops apparently fail to understand. Do not assume a repair shop knows what they are doing because I am hearing too many examples of people that expect professionals to be professional, but instead are not. The cooling system is one area where lousy worksmanship will have very serious consequences.
First, there is no quicker way to shorten the life of any of our coach's components than to expose them to excess heat. In minutes or seconds an engine, transmission, bearings, differential, generator, etc can go from prefect condition to junk if overheated. Our engines are controlled for the most part by a computer system that is biased towards preventing engine damage due to heat. There are only three conditions that will create a STOP ENGINE condition and they are low coolant level, low oil pressure, or high engine temps all of which ultimately are indications of excessive heat or imminent heat damage.
Recognizing that coolant is vital to our engine, if any repairs need to be done to a coach, including changing coolant, make certain the shop refills the coolant system. This is so important it cannot be repeated often enough. Our coolant systems are large and complex so patience and an understanding of the system are two attributes necessary to avoid issues such as our POG member experienced. If the work being done is not a coolant change, then you can help by shutting off all valves to the various heat exchangers through the coach. Isolate the engine so less coolant has to be removed and that if any coolant is left over it means clearly that the engine has an air pocket.
I have changed coolant in my coaches about 9 or 10 times now. It is the single most frustrating task because it requires so much effort to fill the system without air pockets. A repair shop that does not routinely work on motorhome conversions cannot possibly appreciate the difficulty in purging the system of air so it will be up to you the owner to protect yourself from ensuing damage if the system is not properly filled by making the shop aware in no uncertain terms that the amount of coolant removed must be equal or less than the amount of coolant returned to the cooling system.
Apparently that did not happen. The POG member drove the repaired coach about 6 miles at which point his engine was ruined, likely due to a cavity filled with air in the cooling system that the engine's coolant pump could not purge. This happened on an 8V92 and all the damage was related to one bank of cylinders indicating one of the two coolant pumps was likely in the middle of a bubble of air.
An 8V92 senses coolant temps on one bank only so there was no way for the POG member to realize on his gauges that anything was wrong. The repair shop error was very costly and it is likely the POG member and the repair shop are going to be arguing over who pays for the repairs which involved replacing all pistons, rings, cylinder liners, etc.
My reason for posting this is because this week I have been involved in discussions with several folks who have become the victims of shitty worksmanship. This example involving coolant is so important I am posting this to alert everry POG member to recognize and understand what some shops apparently fail to understand. Do not assume a repair shop knows what they are doing because I am hearing too many examples of people that expect professionals to be professional, but instead are not. The cooling system is one area where lousy worksmanship will have very serious consequences.
First, there is no quicker way to shorten the life of any of our coach's components than to expose them to excess heat. In minutes or seconds an engine, transmission, bearings, differential, generator, etc can go from prefect condition to junk if overheated. Our engines are controlled for the most part by a computer system that is biased towards preventing engine damage due to heat. There are only three conditions that will create a STOP ENGINE condition and they are low coolant level, low oil pressure, or high engine temps all of which ultimately are indications of excessive heat or imminent heat damage.
Recognizing that coolant is vital to our engine, if any repairs need to be done to a coach, including changing coolant, make certain the shop refills the coolant system. This is so important it cannot be repeated often enough. Our coolant systems are large and complex so patience and an understanding of the system are two attributes necessary to avoid issues such as our POG member experienced. If the work being done is not a coolant change, then you can help by shutting off all valves to the various heat exchangers through the coach. Isolate the engine so less coolant has to be removed and that if any coolant is left over it means clearly that the engine has an air pocket.
I have changed coolant in my coaches about 9 or 10 times now. It is the single most frustrating task because it requires so much effort to fill the system without air pockets. A repair shop that does not routinely work on motorhome conversions cannot possibly appreciate the difficulty in purging the system of air so it will be up to you the owner to protect yourself from ensuing damage if the system is not properly filled by making the shop aware in no uncertain terms that the amount of coolant removed must be equal or less than the amount of coolant returned to the cooling system.