2nd gen AWD coolant super flush

[Tremelune]

Welp. I'm midway through my first coolant flush and thought I might document it a bit in case someone is staring like I was. I'm more or less following this procedure, with the added step of adding Prestone AS105 flushing fluid for a couple of days:

https://www.youtube.com/watch?v=s--5ft5YiHg

I looked up a couple of DIYs and write-ups, but there weren't many pictures, and nobody seemed to have an AWD. Accessing the drain bolt or lower radiator hose is damn-near impossible unless you remove the fan shroud and attack from above. So, off comes the airbox, and up comes the shroud. I disconnected the wires from the airbox, but if you start the car like that, I've read you throw a code...so...I reconnect them before starting the car.



Once you get the shroud off, way down in the abyss is a little plastic drain bolt. At the bottom is allegedly a 3/8" nipple and a valve for it. I tried to get some fuel injector hose around the nipple and it was not possible. I then tried to get a super-flexible hose around the nipple and it was not possible. I wound up squeezing a glossy postcard under the nipple and down through the car. It worked pretty well, though it did not stay on once I started the car.







I thought about leaving the thermostat in, but realized it would take more time to heat the motor up between flushes than it would to remove the thermostat, so I pulled it. The bolts were a real pain. It is very, very hard to get a socket on there...It's like you need a half-deep 13mm socket. I wound up using a box wrench and a universal joint...



Seeing as it was still full of Dex-Cool, I assumed the worst, but the fluid that came out doesn't seem too bad. The gloves are in there to prevent splashing...That proved futile. I still plan to flush the system fully and put Prestone AS2100 "universal" coolant, but at least there's no sludge or dark rust.



I didn't remove the engine block drain bolts because they look intimidating. I'm scared I'll strip one or won't get them back in tight. I think I may do it on the final go though, since I can only get ~2gal of fluid out per flush, I want to be pretty close to 50/50 when all is said and done.

I put the airbox on loose, resting on the body and radiator, making sure the fan wasn't hitting the hoses or anything, and went around the block with the front and rear heat blasting. The rear heater didn't seem to blow warm, which is a bummer, but I can't remember if it did before I started flushing...To be honest, I'm not bothered either way...It's not a particularly great feature of the car. The front does enough.

My second attempt at a paper funnel failed, so I just wound up spluttering coolant mostly into the drain pan underneath, but it was sloppy and dripped on the car and is yet another coolant flush that couldn't be done cleanly and it drives me crazy. Anyway.

3-4 flushes and trips around the block, and here's what's coming out of the car:



Probably would have been faster if I pulled the engine drain bolts, but alas...The last thing I did was fill the system with two bottles of the flushing solution and water and went for a spin. I'm gonna leave it in the car for the next two days and drive it periodically. I'm hoping the system is clean, but hey, might as well give the flush a try.

[Thedivingpirate]

Thanks for the write up!!

[Tremelune]

This "super flush" is turning into a real mediocre flush. Frustrating.

I tried to get those drain bolts out, but it seemed impossible. It was hard getting purchase with a universal joint. They seem to be 9/16" (between 14mm and 15mm). In the end I gave up, fearing I'd never get them back in. So. I flush, I flush, I flush...This is what came out after I did the 36-hour soak:



And here are some crappy shots of the drain bolts, possibly the only ones that exist (I couldn't find any on the internet!):

[Tremelune]

I was hoping to get the system to the point where you could drink the water coming out, but that doesn't look like it's gonna happen. Since I'm only getting about 1.5gal per flush, it's slow going. These final flushes are all distilled water (about 5gal worth total)...then I'm going to add 1.5gal of concentrate, do one final flush, and add another gallon of concetrate. Mathematically, that should get me to around 50/50 with the 4.3 gallons that the system holds, erring on the low side since I' not sure if anything is going through my rear heater core. Blarg. The coolant I'll be using is now Prestone AF2000 concentrate.

I kinda wish I'd gone through the effort to set up a sump pump system as described at the bottom here:

http://www.sancarlosradiator.com/VoltageDrop/flush.htm

https://www.youtube.com/watch?v=ZBA3guw3nJ4

[kennysmoke]

I was hoping to get the system to the point where you could drink the water coming out, but that doesn't look like it's gonna happen. Since I'm only getting about 1.5gal per flush, it's slow going. These final flushes are all distilled water (about 5gal worth total)...then I'm going to add 1.5gal of concentrate, do one final flush, and add another gallon of concetrate. Mathematically, that should get me to around 50/50 with the 4.3 gallons that the system holds, erring on the low side since I' not sure if anything is going through my rear heater core. Blarg. The coolant I'll be using is now Prestone AF2000 concentrate.

I kinda wish I'd gone through the effort to set up a sump pump system as described at the bottom here:

http://www.sancarlosradiator.com/VoltageDrop/flush.htm

https://www.youtube.com/watch?v=ZBA3guw3nJ4

I ALWAYS premix the coolant and water before dumping it in the radiator... not sure if it's necessary or not, but my uncle who is an old school mechanic beat it into my head when I was a young buck and I've always done it this way.

[Zebediah III]

A capful of liquid Cascade dishwasher soap, the rest of the system is water. You don't need any super duper high tech stuff. If some Cascade remains it won't hurt anything.
Do not refill into a hot engine, let it cool. Take it on a good long drive and get it hot before draining.
Once it's cleaned out (however many times it takes) run water without the Cascade through it. This may take a couple of days and half a dozen short drives and cool down cycles, but be thorough. Drill a tiny hole in your thermostat (outer rime beyond the big round opening) to let air past the closed thermostat.

[Tremelune]

I may have gotten a bit dramatic in my frustration. In the end, the stuff that came out wasn't that dirty, and the system as it sits is way cleaner than it was. All and all I'm satisfied. The final touch was adjusting the resevoir cap:



Good times.

[MI_Ghost]

I ALWAYS premix the coolant and water before dumping it in the radiator... not sure if it's necessary or not, but my uncle who is an old school mechanic beat it into my head when I was a young buck and I've always done it this way.

If your are using concentrate that is the recommended procedure. The 50/50 premix should not be used this way as it further dilutes the coolant.

When adding coolant after flushing there is approx 2-2.5 gallons of water left in the block if it has not been drained by removing the plugs. Use the concentrate without added water to get to the recommended 50/50 mix.