Engine Coolant Flush & Fill Procedure for 3.5L
So I did a flush and fill on my 2010 SE this last weekend, and between the missing/incorrect info in the Haynes/Chilton manual and my lack of experience in doing a F&F on a vehicle mfg'ed in the last 10 years, I'm surprised I got it done without screwing anything up. So I figured I better try to make good use of some of that hard-earned knowledge I gained this weekend by trying to impart it upon my fellow Challenger owners here on CT.
I realize the number of people who could actually benefit from this thread is probably pretty small since it is going to be specific to the 3.5L engine that came in the 2009 and 2010 Challenger SE/SXTs, but all I could find when I searched around before the maintenance for a 3.5L specific write-up for this, I couldn't find one. They were all specific to the Hemi's, which is a little different from the 3.5L if you haven't noticed.
And while we're on the topic of which engine this will be focused on, let me just state for the record that if your Challenger is 2011 or newer and has a V6, then this write-up is NOT for you. You have the 3.6L (aka Pentastar) that Dodge replaced the 3.5L with beginning in 2011. So if you plan on doing a F&F on yours, this write-up won't make much sense when it comes down to the details and pics and such because you have a completely different motor.
Anyway, let's get on with the show...
Since the Haynes/Chiltons manual for these model LXs already has the F&F procedures written up, I will just copy and paste them in here to save time and effort. However, as I found out the hard way, not all of the steps they list are correct, and there is some info missing in other areas about what to do or what to expect. So I will point those out and try to fill in the blanks where necessary with the manual steps, and hopefully that will give anyone reading this enough knowledge to get the job done if they choose to do it themselves.
So here's the first page in the manual that applies to us here (pg 1-27):
That one covers the steps to drain the original coolant out of the engine, as well as flushing the system out to get rid of any remnants of that old coolant and the crap it can leave behind if left in the system too long. The drainage steps can be followed all the way up until Step #7 where it references drain plugs. You can forget about removing any drain plugs to completely drain the engine, as there are none on these last few year model 3.5L engines evidently. And even if there were, you wouldn't be able to get to them because of the exhaust manifolds. So forget about drain plugs and keep going with the next steps.
The next page from the manual is the one that details flushing the system (pg 1-28):
As you can see there, one of its steps is to remove the thermostat and reinstall the thermostat housing before doing the flush.
The section that deals with the thermostat and thermostat housing is in section 3 (pg 3-4):
Now that section is the one that strays the farthest from reality when it comes to what you will encounter in your Challenger's 3.5L. First of all, your thermostat is not swaged as the manual states, so you won't have to worry about any of that part if you replace the OE one with a new one from the local auto parts store (which I recommend doing since you already have it out and won't want to go through all the trouble to remove it again later to replace it when it starts to f-up on you). Also, your thermostat housing has a rubber gasket built into its base (as does the thermostat itself), so disregard any talk about replace the gasket on the housing or scraping the block clean before re-installation of new gasket and thermostat. None of that will apply to your 3.5L's thermostat, which is actually a good thing IMHO.
One other thing about the thermostat housing that the book does not say anything about is that yours has a small tube coming out of the bottom of it that goes down to the oil cooler that is integrated with your oil filter housing. And before you can get that thermostat housing loose, you will need to crawl up under your car and remove the hose clamp holding the coolant line to the bottom of that housing, and then you will need to wiggle it up and out to allow the thermostat housing to be removed completely. Removing it is a little tricky, but re-installing it is downright frustrating because of that oil cooler tube that you will have to get back into the correct position before anything will bolt up.
And one last thing I want to point out before we leave the thermostat section and go back to the fun part (pg 3-19):
As you can see, there is the torque specs for the housing bolts for re-installation. I'm only including that so no one can accuse me of leaving information out of this thing. You won't be able to actually use it when you reinstall the housing because there is just no room to get a torque wrench down in there to torque the bolts. I suppose you could remove the power steering pump and a/c compressor and then maybe you'd have enough room to torque those bolts, but that's not even close to being worth it. They are only supposed to be 105 in/lbs, which is about 8.5 ft/lbs. So just tighten them with a wrench until they won't turn any more and you'll be fine.
Speaking of specs, here is the page from the first section which lists the fluid volumes for the car (pg 1-30):
As you can see there, it states you will need 11.1 quarts of coolant to replace what is in there. While that might be true if you had access to those imaginary drain plugs, I'm here to tell you that you will not be able to get all of the water you use to flush the block out of the block, especially if you use their method of doing it, so you won't be pouring 11.1 quarts of coolant into the engine to refill it. At most, you will only get about 9 quarts to go back in it. And remember, you're supposed to mix the coolant with distilled water at a 50/50 ratio. So if you buy one gallon of concentrated antifreeze, then all you'll need is a gallon of distilled water you'll be good to go. Or you could buy two gallons of the premixed 50/50 stuff and just pour it all in without worrying about mixing it correctly. Either way, that's about all you'll need, not the full 11 quarts.
So now you have the knowledge necessary to go tackle this yourself...NOW GO DO IT!!
Seriously though, the factory pour only has a useful life of 5yrs/100K miles, so if you are over either one of those, you need to change it NOW! Take it from me, as mine was over the year limit by a full 13 months, and once I pulled my expansion tank off to clean it, I saw why it has a life span which should not be exceeded. Mine had started turning into some sort of gelatinous goo down at the bottom of the tank, very much like chocolate pudding actually. It also started to solidify into what can only be described as sand-like material. There was so much of that in my system that it clogged the filter on a funnel I was using to empty the jugs out I was using to collect the old coolant. That was very unnerving to say the least!
I took some pics during my whole process, and I'll create another post in this thread and attach them to it for visual reference on some of this stuff. Especially the crap coming out of the car that was being replaced, that stuff was nasty gross. It has to be seen to be believed.
And with that, I will wish you good luck and say, "May the Schwartz be with you!"
So I did a flush and fill on my 2010 SE this last weekend, and between the missing/incorrect info in the Haynes/Chilton manual and my lack of experience in doing a F&F on a vehicle mfg'ed in the last 10 years, I'm surprised I got it done without screwing anything up. So I figured I better try to make good use of some of that hard-earned knowledge I gained this weekend by trying to impart it upon my fellow Challenger owners here on CT.
I realize the number of people who could actually benefit from this thread is probably pretty small since it is going to be specific to the 3.5L engine that came in the 2009 and 2010 Challenger SE/SXTs, but all I could find when I searched around before the maintenance for a 3.5L specific write-up for this, I couldn't find one. They were all specific to the Hemi's, which is a little different from the 3.5L if you haven't noticed.
And while we're on the topic of which engine this will be focused on, let me just state for the record that if your Challenger is 2011 or newer and has a V6, then this write-up is NOT for you. You have the 3.6L (aka Pentastar) that Dodge replaced the 3.5L with beginning in 2011. So if you plan on doing a F&F on yours, this write-up won't make much sense when it comes down to the details and pics and such because you have a completely different motor.
Anyway, let's get on with the show...
Since the Haynes/Chiltons manual for these model LXs already has the F&F procedures written up, I will just copy and paste them in here to save time and effort. However, as I found out the hard way, not all of the steps they list are correct, and there is some info missing in other areas about what to do or what to expect. So I will point those out and try to fill in the blanks where necessary with the manual steps, and hopefully that will give anyone reading this enough knowledge to get the job done if they choose to do it themselves.
So here's the first page in the manual that applies to us here (pg 1-27):
That one covers the steps to drain the original coolant out of the engine, as well as flushing the system out to get rid of any remnants of that old coolant and the crap it can leave behind if left in the system too long. The drainage steps can be followed all the way up until Step #7 where it references drain plugs. You can forget about removing any drain plugs to completely drain the engine, as there are none on these last few year model 3.5L engines evidently. And even if there were, you wouldn't be able to get to them because of the exhaust manifolds. So forget about drain plugs and keep going with the next steps.
The next page from the manual is the one that details flushing the system (pg 1-28):
As you can see there, one of its steps is to remove the thermostat and reinstall the thermostat housing before doing the flush.
The section that deals with the thermostat and thermostat housing is in section 3 (pg 3-4):
Now that section is the one that strays the farthest from reality when it comes to what you will encounter in your Challenger's 3.5L. First of all, your thermostat is not swaged as the manual states, so you won't have to worry about any of that part if you replace the OE one with a new one from the local auto parts store (which I recommend doing since you already have it out and won't want to go through all the trouble to remove it again later to replace it when it starts to f-up on you). Also, your thermostat housing has a rubber gasket built into its base (as does the thermostat itself), so disregard any talk about replace the gasket on the housing or scraping the block clean before re-installation of new gasket and thermostat. None of that will apply to your 3.5L's thermostat, which is actually a good thing IMHO.
One other thing about the thermostat housing that the book does not say anything about is that yours has a small tube coming out of the bottom of it that goes down to the oil cooler that is integrated with your oil filter housing. And before you can get that thermostat housing loose, you will need to crawl up under your car and remove the hose clamp holding the coolant line to the bottom of that housing, and then you will need to wiggle it up and out to allow the thermostat housing to be removed completely. Removing it is a little tricky, but re-installing it is downright frustrating because of that oil cooler tube that you will have to get back into the correct position before anything will bolt up.
And one last thing I want to point out before we leave the thermostat section and go back to the fun part (pg 3-19):
As you can see, there is the torque specs for the housing bolts for re-installation. I'm only including that so no one can accuse me of leaving information out of this thing. You won't be able to actually use it when you reinstall the housing because there is just no room to get a torque wrench down in there to torque the bolts. I suppose you could remove the power steering pump and a/c compressor and then maybe you'd have enough room to torque those bolts, but that's not even close to being worth it. They are only supposed to be 105 in/lbs, which is about 8.5 ft/lbs. So just tighten them with a wrench until they won't turn any more and you'll be fine.
Speaking of specs, here is the page from the first section which lists the fluid volumes for the car (pg 1-30):
As you can see there, it states you will need 11.1 quarts of coolant to replace what is in there. While that might be true if you had access to those imaginary drain plugs, I'm here to tell you that you will not be able to get all of the water you use to flush the block out of the block, especially if you use their method of doing it, so you won't be pouring 11.1 quarts of coolant into the engine to refill it. At most, you will only get about 9 quarts to go back in it. And remember, you're supposed to mix the coolant with distilled water at a 50/50 ratio. So if you buy one gallon of concentrated antifreeze, then all you'll need is a gallon of distilled water you'll be good to go. Or you could buy two gallons of the premixed 50/50 stuff and just pour it all in without worrying about mixing it correctly. Either way, that's about all you'll need, not the full 11 quarts.
So now you have the knowledge necessary to go tackle this yourself...NOW GO DO IT!!
Seriously though, the factory pour only has a useful life of 5yrs/100K miles, so if you are over either one of those, you need to change it NOW! Take it from me, as mine was over the year limit by a full 13 months, and once I pulled my expansion tank off to clean it, I saw why it has a life span which should not be exceeded. Mine had started turning into some sort of gelatinous goo down at the bottom of the tank, very much like chocolate pudding actually. It also started to solidify into what can only be described as sand-like material. There was so much of that in my system that it clogged the filter on a funnel I was using to empty the jugs out I was using to collect the old coolant. That was very unnerving to say the least!
I took some pics during my whole process, and I'll create another post in this thread and attach them to it for visual reference on some of this stuff. Especially the crap coming out of the car that was being replaced, that stuff was nasty gross. It has to be seen to be believed.
And with that, I will wish you good luck and say, "May the Schwartz be with you!"