Easy Coolant Exchange
Having recently changed out my coolant I thought I’d share my methodology with the non-motor head DIY-ers out there. Let me get the disclaimers out of the way before I get started. My method will exchange about 70% of the coolant in the easiest way I could come up with I’m not implying “better” methods aren’t available. But rest assured my method is more than adequate, I’ll even throw out a money back guarantee.Also the details I go into might not completely apply to pre-04 GPs, since this write up is based on my work on an 08 GP.
Before anyone one gets turned off by the length of my post realize a lot of the verbiage is me trying to compensate for a lack of referencing pictures. The process I’m going to step you through is actually fairy easy, I’d give it a difficulty rating of 2 of 5 monkey wrenches.
Stuff you will need:
3 gallons of Dex-Cool 50/50 coolant
Funnel (large)
10mm socket wrench
7 mm socket wrench
Pliers
Garden hose (optional but nice)
Drain pan (5 quart capacity)
3 Windshield washer containers (or some other way to hold 3 gallons of waste coolant)
Car ramps (or some other method to elevate the car)
Wheel chocks
Now that you have all your tools it is time to get your car up on the ramps, then set the parking brake and chock the rear wheels. Before opening any part of the pressurized cooling system ensure it is cool first. For a recently driven car open the hood and let it sit for an hour.
Phase 1 – Draining the radiator
On the drivers side of the car you will need to remove a 10mm bolt on the under side of the bumper that holds the front splash guard, that will give you access to the radiator drain plug. The drain plug is made of black plastic that is hard to see and is located at the bottom of the radiator on the driver’s side. Before opening it remove the radiator cap then locate the actual drain outlet, it is near where you removed that 10mm bolt. It kind of looks like a nipple, and place the drain pan under it. Now simply turn the drain plug counter clockwise until you get a nice stream of coolant, but do not completely remove the plug. Expect to get about 4-ish quarts of coolant to drain out, now it is time to clear any sediment out of the radiator. Take your garden hose and spray some water through the top. NOTE: I never recommend using plain tap water as coolant, but since this water will only be in the car for a few seconds it is no big whoop. Or you could simply pour some water into the radiator if you don’t have a hose available. Just try not to over flow your drain pan. In my experience it doesn’t take much water to get out the fine particles and flakes out of the system, but flush the radiator until you’re happy.
Now is a good time to address how to handle the waste coolant. New coolants do have more chemicals than in years past so you just can’t dump it anywhere. I collected my coolant in windshield washer containers and brought them to my local Haz Mat disposal facility. Some states allow you to use the sanitary sewer for disposal. But don’t ever dump coolant into the storm sewer or into a septic system.
Phase 2 - Refilling and a system flush
First close the drain plug finger tight then completely fill the radiator with new Dex-Cool 50/50 coolant and replace the radiator cap. This is where the funnel comes into play, without it coolant would splash all over the place. Run the car until it heats enough to open the thermostat, now is a great time to place the car ventilation control system on full heat (this allows the heater core coolant to flush). It might take about 10 minutes or so to heat up, the best way to tell if the thermostat opens is by the temperature of the upper radiator hose. When the hose gets to hot to hold, the thermostat is open. This is kind of a key point because the system can’t “flush” with the thermostat closed. Now turn the car off and let it cool.
Please be aware at this point in the process you car is basically ready for use, and you can step back into the coolant exchange at anytime. Just make sure your coolant expansion bottle is at least half full, in fact it would be best to completely read this before driving off.
Phase 3 – Radiator Drain (play it again Sam)
Once again drain the radiator by removing the cap and opening the drain. Now after the coolant is drained, completely remove the drain plug to clean and inspect it paying close attention to the condition of the O-ring seal. Now re-install the drain plug finger tight, it doesn’t need to be monkey-ed. In fact, because ppl generally monkey the $hit out of (everything including) drain plugs they get a bad rep of breaking. Now you shouldn’t need to get back at the drain for a long time, and can re-install that 10mm bolt for the splash guard.
Phase 4 – Expansion container
Now is a good time to change channels a bit and address the coolant expansion/overflow container. Using your 10mm ratchet remove the two nuts holding down the container. Using your pliers remove the spring clamp on the small coolant line that goes from the radiator fill neck to your expansion container. Now pull it all out of the car and dump what ever coolant is in the container. Be aware there is a rear vent on the container that will spill coolant if you let it. By now you will have noticed how nasty this container is. I highly recommend cleaning both the outside and inside of the container at this point. Now re-install the container, ensure the lower hold down is proper seated (or the container will shake around) and replace the two nuts. And of course re-connect the line to the radiator.
Phase 5 – Filling the system
Now completely fill the radiator with Dex-Cool 50/50 coolant and replace the radiator cap. The expansion container is next, but only fill it about half full with Dex-Cool 50/50 coolant. And I do mean half full, there is a “cold” level line at like 20%-ish level but that won’t be enough. The fact is having more coolant will never damage the car, but not having enough coolant may.
You can now start the car and get it off the ramps. Keep the car running and check for leaks while monitoring coolant temperature and level.
Phase 6 – Bleeding the system
Once the thermostat is open you should “bleed” the system of air. The bleeding device is located on the coolant thermostat elbow. To access it you need just need to remove the plastic engine cover, you can now see it on the front drivers side of the engine. It is easy to find just follow the upper radiator hose to it. The bleeder is the little brass device sticking out of the elbow. Before actually using the bleeder I want to explain it. If you look closely at it you will notice the top is slightly smaller that the body. The top of the bleeder is a 7mm hex head bolt (the body is 10mm), by loosening it that will allow coolant/air to “bleed” out from a small hole in the body. It is important to know the entire bleeder is NOT to be removed. Now bleed the air from the system by loosening the bleeder screw. Use your 7mm ratchet and turn the bleeder counter clockwise about one full turn, now wait until you get solid stream of coolant coming out. NOTE: You may need your pliers (or a 10mm wrench) for applying counter torque to the base of the bleeder to get the inner screw to break free. Now, of course, close the bleeder after getting good stream of coolant.
Phase 7 – Miller time
For all intents and purposes you are done. Treat yourself to a cool refreshing beverage. Ideally at this point your system is air free, but realistically it won’t be. After your first drive check the overflow bottle for proper level, expect it to go down a bit. The same goes for the radiator, you need to check it at least once after driving it to ensure it is completely topped off. Seeing lowering coolant levels is actually a good thing because your system is purging air. If it goes lower than the cold level mark on the expansion container you need to add more Dex-Cool 50/50. This flow up is essential because you don’t want to run around low on coolant. That could cause your engine to over heat, lead to sludge build up or possibly component failures.
Speaking of heat, during that first drive keep the heater on full heat (as mentioned earlier) to help with the purging of any air. The question has been asked a thousand times on how to properly/completely bleed a coolant system. To be honest I laugh a bit every time I see the question posted, because the coolant system basically purges itself. We just need to keep the coolant topped off, period end of story, the car will do the rest.
This reminds me of a relevant maintenance tip that in my experience is often over looked. The coolant expansion bottle isn’t sealed and therefore allows a small amount of water/coolant to evaporate over time. It is a pretty small amount (about 1 quart a year), I check my expansion tank level about twice a year and add DI/distilled water as necessary. 50/50 Dex-cool would be great if you have any extra around, please just don’t use tap water.
Now for my observations:
#1 Dex-cool despite its infamous history seems to be doing an outstanding job in my car. Yup I said it.Honestly going into this I wasn’t sure what I would find. But my system was clean as a whistle. Did it have a small amount of metal fines and some dex-flakes (yup I just made that word up), sure. But considering it was 4-year old factory fill I’m more than pleased with what I saw. Even though I didn’t mention it in the write up I did remove the thermostat housing to inspect the system, turns out that was totally unnecessary. There wasn’t even a sign of corrosion or build up any where.
#2 The lower radiator hose doesn’t need to be removed. I know that many people swear by using it as a means to drain the system, but I found the actual radiator drain a much better option. My reasoning is the hose doesn’t appear to be the lowest point in the system nor a trap for sediment.
#3 There is a bunch of information on the inter-web that seems a bit off. Even though I have been doing most of my car maintenance for 20-ish years it had been a while since I last did a coolant change so I did some research. Anyway by chance my local Farm and Barn store had some Prestone coolant on sale so I looked at their web site after buying it. And wow, the video they have posted is a little scary. I won’t pick on every little thing but two items jumped out at me. The first being they were not using Dex-cool coolant for their demonstration vehicle that clearly called for it. Honestly I think the editor realized this because they do a pretty good job hiding the Dex-cool symbol on the fill cap. They used “all makes all models type coolant”, now in theory this may not sound like a big deal. But in the past mixing Dex-cool with any other type coolant was a huge huge problem.The other big item I didn’t like was them pushing the flush solution. In a word no, I’m not putting acid into my car.
Well that is it, if I messed up some where please let me know I’ll be more than happy to update the post so it can be a more useful resource.
Originally Posted by brandonl2000
