Idle time before shutting off diesel?
From : ro
Q: i just bought a 2002 ram 2500 with a 5.9 cummins. can you tell how long you should idle down the engine by just looking at the temperture gauge just below 190 degrees is where it wants to say after a couple minutes. thanks ro .
Replies:
From : trey
demon wrote its not so much the water temp you want to cool down its the turbo. you shut off a hot turbo right after its been worked hard the oil flow stops immediately. the oil left will coke do that all the time and your turbo will be hooped in no time. are tehre after market kits to keep the oil and water flowing through the turbo after the engine is shut off for a set amount of time i have seen systems to keep teh engine running for a while but with no air flow the engine heats up until the fan-clutch kicks in so i dont know how well they cool the engine and turbo. .
From : nosey
trey wrote jim wrote you need an egt gauge. when the temp is 350 or below post turbo its safe to shutdown. a few minutes of slow driving will easily get it this cool but stopping after a long pull uphill will require several minutes of idling to cool it off. without a gauge theres no way to tell. egt... exhaust gate temp exhaust gas temp. .
From : jim
you need an egt gauge. when the temp is 350 or below post turbo its safe to shutdown. a few minutes of slow driving will easily get it this cool but stopping after a long pull uphill will require several minutes of idling to cool it off. without a gauge theres no way to tell. on wed 11 aug 2004 221316 -0700 ro jolin@whidbey.net wrote i just bought a 2002 ram 2500 with a 5.9 cummins. can you tell how long you should idle down the engine by just looking at the temperture gauge just below 190 degrees is where it wants to say after a couple minutes. thanks ro .
From : tom lawrence
where the 1250 degree limit comes in. if i want to know what it is after the turbo just subract about 300 degrees. not exactly... on a stock truck the post-turbo temp is usually somewhere around pre-temp minus 10f per pound of boost. i have both pre and post-turbo gauges on my truck and this is a workable rule of thumb. however when i get on the fuel pre-turbo temps can be as much as 500f above post-turbo... even higher if im on a hill with low rpms. and on deceleration particularly after a long pull ive seen pre-turbo temps lower than post-turbo. the point here is that egt reading post-turbo arent very accurate and if you want to monitor what your engine is really doing the thermocouple needs to be in the manifold as you suggested. .
From : tom lawrence
its also a good idea to have the turbo removed so you do not drop metal shavings into the turbo when you drill the hole. you could but this is a lot of extra work. a technique that works well is to tape off the exhaust with duct tape and poke a hole in the center so that the exhaust isnt completely plugged. with drill in hand wearing gloves and a face shield or at least safety glasses start the truck and drill the manifold. all the chips will blow back at you instead of falling into the manifold. once you drilled through shut the truck off. when tapping fill the flutes of the tap with grease. this will catch the metal chips and keep them out of the manifold as well. .
From : demon
its not so much the water temp you want to cool down its the turbo. you shut off a hot turbo right after its been worked hard the oil flow stops immediately. the oil left will coke do that all the time and your turbo will be hooped in no time. i just bought a 2002 ram 2500 with a 5.9 cummins. can you tell how long you should idle down the engine by just looking at the temperture gauge just below 190 degrees is where it wants to say after a couple minutes. thanks ro .
From : greg surratt
on wed 11 aug 2004 221316 -0700 ro jolin@whidbey.net wrote i just bought a 2002 ram 2500 with a 5.9 cummins. can you tell how long you should idle down the engine by just looking at the temperture gauge just below 190 degrees is where it wants to say after a couple minutes. thanks ro the idea behind the cool down is for the turbo and has nothing to do with the water temp. i usually dont cool mine down when using it as a daily driver. i say that because when i get to work it has usually been idling in traffic for about 10 minutes as i creep along. when i come home it works very little for the last 4 blocks as i creep through the 25 mph residential/school area i live in. otoh when im towing the fiver im pretty religious about giving it at least three minutes after i pull off the freeway. greg 98 3500 qc 4x2 cummins isb auto 3.541 driftwood with leather and all the heavy duty options. 89 nu-wa champagne edition 34 foot fifth wheel. .
From : demon
ya what those guys said is right on. an egt gauge will tell you for sure. the bung for the sensor should be put within 4 of the turbine in the exhaust pipe. that gauge will keep you from melting out pistons and other fun stuff too. trey wrote jim wrote you need an egt gauge. when the temp is 350 or below post turbo its safe to shutdown. a few minutes of slow driving will easily get it this cool but stopping after a long pull uphill will require several minutes of idling to cool it off. without a gauge theres no way to tell. egt... exhaust gate temp exhaust gas temp. .
From : epltoy
ya what those guys said is right on. an egt gauge will tell you for sure. the bung for the sensor should be put within 4 of the turbine in the exhaust pipe. that gauge will keep you from melting out pistons and other fun stuff too. you can get everything you need at genos garage. http//www.genosgarage.com/ i put in the tranny temp boost and egt gauges with the a pillar mount. love it. everyone who sees it want one. bill .
From : andy
i have my temp sensor in the exhaust manifold. give a nice quick and accurate reading. gauge needle almost follows the rpms perfectly. ya what those guys said is right on. an egt gauge will tell you for sure. the bung for the sensor should be put within 4 of the turbine in the exhaust pipe. that gauge will keep you from melting out pistons and other fun stuff too. you can get everything you need at genos garage. http//www.genosgarage.com/ i put in the tranny temp boost and egt gauges with the a pillar mount. love it. everyone who sees it want one. bill .
From : demon
thats interesting. where exactly how do you get an accurate reading from all the holes i have my temp sensor in the exhaust manifold. give a nice quick and accurate reading. gauge needle almost follows the rpms perfectly. ya what those guys said is right on. an egt gauge will tell you for sure. the bung for the sensor should be put within 4 of the turbine in the exhaust pipe. that gauge will keep you from melting out pistons and other fun stuff too. you can get everything you need at genos garage. http//www.genosgarage.com/ i put in the tranny temp boost and egt gauges with the a pillar mount. love it. everyone who sees it want one. bill .
From : andy
drill and tap a hole in the rear part of where all six ports come together. the rear is the standard location. do not try to drill directly in the middle where the depressed area is. there is a divider there that keeps the front 3 separate from the rear 3. the two halves come together where the manifold attaches to the turbo. when you start the truck youll see about 250 degrees in a about a second or so. this gives a more real time temp reading. when pulling a hill the temp gauge will climb faster than the tach. and the boost gauges. this is where the 1250 degree limit comes in. if i want to know what it is after the turbo just subract about 300 degrees. thats interesting. where exactly how do you get an accurate reading from all the holes i have my temp sensor in the exhaust manifold. give a nice quick and accurate reading. gauge needle almost follows the rpms perfectly. ya what those guys said is right on. an egt gauge will tell you for sure. the bung for the sensor should be put within 4 of the turbine in the exhaust pipe. that gauge will keep you from melting out pistons and other fun stuff too. you can get everything you need at genos garage. http//www.genosgarage.com/ i put in the tranny temp boost and egt gauges with the a pillar mount. love it. everyone who sees it want one. bill .
From : trey
andy wrote drill and tap a hole in the rear part of where all six ports come together. the rear is the standard location. do not try to drill directly in the middle where the depressed area is. there is a divider there that keeps the front 3 separate from the rear 3. the two halves come together where the manifold attaches to the turbo. when you start the truck youll see about 250 degrees in a about a second or so. this gives a more real time temp reading. when pulling a hill the temp gauge will climb faster than the tach. and the boost gauges. this is where the 1250 degree limit comes in. if i want to know what it is after the turbo just subract about 300 degrees. its also a good idea to have the turbo removed so you do not drop metal shavings into the turbo when you drill the hole. .
From : jigger
manual says 2-5 minutes... 5 minutes is under full load uphill or long hiway towing... city 2 minutes or so m. tom lawrence wrote ... the point here is that egt reading post-turbo arent very accurate and if you want to monitor what your engine is really doing the thermocouple needs to be in the manifold as you suggested. on aircraft you measure egts and chts on a per cylinder basis... considering the cost of their overhauls the owners / operators tend to be rather concerned with whatever best practices will help them maximize the time between overhauls... .
From : grumman581
tom lawrence wrote ... the point here is that egt reading post-turbo arent very accurate and if you want to monitor what your engine is really doing the thermocouple needs to be in the manifold as you suggested. on aircraft you measure egts and chts on a per cylinder basis... considering the cost of their overhauls the owners / operators tend to be rather concerned with whatever best practices will help them maximize the time between overhauls... .
From : trey
jim wrote you need an egt gauge. when the temp is 350 or below post turbo its safe to shutdown. a few minutes of slow driving will easily get it this cool but stopping after a long pull uphill will require several minutes of idling to cool it off. without a gauge theres no way to tell. egt... exhaust gate temp .
From : tom lawrence
thanks for the information tom. it is my understanding that cylinder #6 runs the hottest. would it be better to mount the thermocouple close to that cylinder yes #6 typically runs hottest but i dont think theres a large variation in temperature between #1 and #6... maybe 50f or so when running 4-digit egts. nevertheless because of that temp. difference many people will put the thermocouple on the back runner of the manifold just above the turbo flange. this will measure the egts from cylinders 4 5 and 6. personally i have an ats exhaust manifold and they cast a boss for a thermocouple just after #3 so thats where my probe is installed. again i dont think its a huge differential and any location on the manifold beats a probe installed in the downpipe. .
From : mac davis
on wed 18 aug 2004 050944 gmt tom lawrence tnloaswpraemnmcien5g@earthlink.net wrote thanks for the information tom. it is my understanding that cylinder #6 runs the hottest. would it be better to mount the thermocouple close to that cylinder yes #6 typically runs hottest but i dont think theres a large variation in temperature between #1 and #6... maybe 50f or so when running 4-digit egts. nevertheless because of that temp. difference many people will put the thermocouple on the back runner of the manifold just above the turbo flange. this will measure the egts from cylinders 4 5 and 6. personally i have an ats exhaust manifold and they cast a boss for a thermocouple just after #3 so thats where my probe is installed. again i dont think its a huge differential and any location on the manifold beats a probe installed in the downpipe. i think in most cases it isnt the actual tem youre monitoring but the fluctuation of temp under different conditions... like the water temp gauges that dont have degrees on them when my brother & i were doing some trucking in the bad ol days we took notes on what the normal needle position was of all the gauges in the doghouse panel on the 1st trip... when we got back we rotated all the gauges until our normal reading was straight up so we could check several gauges at a glance... i guess now everything is digital and has warning buzzers bells and computers... mac .
From : john a mooney
tom lawrence wrote where the 1250 degree limit comes in. if i want to know what it is after the turbo just subract about 300 degrees. not exactly... on a stock truck the post-turbo temp is usually somewhere around pre-temp minus 10f per pound of boost. i have both pre and post-turbo gauges on my truck and this is a workable rule of thumb. however when i get on the fuel pre-turbo temps can be as much as 500f above post-turbo... even higher if im on a hill with low rpms. and on deceleration particularly after a long pull ive seen pre-turbo temps lower than post-turbo. the point here is that egt reading post-turbo arent very accurate and if you want to monitor what your engine is really doing the thermocouple needs to be in the manifold as you suggested. thanks for the information tom. it is my understanding that cylinder #6 runs the hottest. would it be better to mount the thermocouple close to that cylinder .
From : tbone
on wed 18 aug 2004 050944 gmt tom lawrence tnloaswpraemnmcien5g@earthlink.net wrote thanks for the information tom. it is my understanding that cylinder #6 runs the hottest. would it be better to mount the thermocouple close to that cylinder yes #6 typically runs hottest but i dont think theres a large variation in temperature between #1 and #6... maybe 50f or so when running 4-digit egts. nevertheless because of that temp. difference many people will put the thermocouple on the back runner of the manifold just above the turbo flange. this will measure the egts from cylinders 4 5 and 6. personally i have an ats exhaust manifold and they cast a boss for a thermocouple just after #3 so thats where my probe is installed. again i dont think its a huge differential and any location on the manifold beats a probe installed in the downpipe. i think in most cases it isnt the actual tem youre monitoring but the fluctuation of temp under different conditions... like the water temp gauges that dont have degrees on them when my brother & i were doing some trucking in the bad ol days we took notes on what the normal needle position was of all the gauges in the doghouse panel on the 1st trip... when we got back we rotated all the gauges until our normal reading was straight up so we could check several gauges at a glance... i guess now everything is digital and has warning buzzers bells and computers... that is the prime advantage of analog over digital you dont actually have to read them just a quick scan is all that you need. -- if at first you dont succeed youre not cut out for skydiving .