Cooler line flushes are easy!

[sciphi]

All of you who said cooler line flushes are easy DIY jobs are totally right!

I did a cooler line flush with ST Dex-VI on my 1999 Buick LeSabre today. It has a B&M transmission cooler, which makes things even easier since there's already a tailor-made rubber hose coming from the factory lines to the auxiliary cooler. After draining the pan and refilling with Dex-VI, I put the gallon milk jug in a place where I could see it and cranked the car until the jug was full. Then the pan was refilled and another milk jug was filled with ATF. It was honestly one of the easiest "mechanical" things I've done to my car aside from oil changes.

The degree of difficulty almost made me wish for an "easy" button to press after the job was done.

 

[mechanicx]

Sounds good. I think how hard the flush is depends on how hard it is to get to the cooler line and if you have a trans dipstick. Sounds like you had it made there.

Using milk cartons was a good low-buck way to catch the fluid and get a handle on how much was coming out. Good going with using Dex IV.

You drained it at the cooler outlet line right? When you say crank the car engine till a gal jug filled. I assume you let the engine idle? Did you shify through the gear selector. I always wondered about doing that? I assume you never let more than a gal at a time flush out before topping up, and you went through 2 gals of flush plus the initial refill so about 12 qts? I think that is the full capacity of these transmissions.

 

[ADFD1]

What I do is get two of the exact same 1 gallon jugs and mark them every pint all the way up to 3 qts. I make sure my fluid level is at the proper level before I start. I only get about 2 qts out via the cooler line.

One container is for clean ATF the other is what I drain. Then I refill the car with the exact same amount of ATF from the clean container of fresh ATF. Makes refilling it a lot easier and I usually get the level perfect after the exchange.

 

[sciphi]

I just eyeballed the ATF level in the gallon jugs. The jugs had previously been used to drain the pan via a hand pump, so I had some idea of how much was coming out. I had also looked up the total capacity of the transmission before starting, and had dropped the pan to do some other work. It ended up being about 14 quarts of old ATF by the time I was done. The 14 quarts of new Dex-VI had all disappeared down the dipstick tube, and brought the level to full.

Well, it idled for a few seconds at a time, then was shut down. There wasn't much time to shift gears because it flowed out pretty quickly. Plus the milk jug was lodged in place, so no sudden shocks were in order.

I'm liking the Dex-VI. Smoother, more positive shifts for my transmission in the 20 miles I drove it after flushing.

 

[mechanicx]

Cool so you pumped the oil fluid out by way of the dipstick tube before dropping the pan to more accurately catch what came out avoid the mess I take it?

The way you did it makes a lot of sense and seems to be about the best way. I need to switch out some Dex III for Dex VI on some cars.

 

[sciphi]

Originally Posted By: mechanicx
Cool so you pumped the oil fluid out by way of the dipstick tube before dropping the pan to more accurately catch what came out avoid the mess I take it?



Yes. I bought a $7 hand pump, threaded it down the dipstick tube, and started pumping. Pumping the old ATF out into the clear gallon jugs gave me an accurate picture of how much I needed to put back, and avoided a lot of mess when I dropped the pan.

Not dropping the pan avoids the mess created by a pan drop, and makes the whole exchange almost mess-free.

Thanks for the compliment about "the best way"! This way is pretty good. Yes, it could use a bit of refinement, and won't be the same for everybody. The auxiliary cooler hoses helped me a great deal. Making a flush hose is easy enough with a threaded fitting onto the factory lines or a longer piece of hose in place of an OEM hose.

 

[Donald]

Another alternative if you have no drain plug, is to setup for the cooler line flush, run engine until you see air bubbles (now most of pan is drained), then add the amount drained and continue with cooler line flush. Running until you see air bubbles will not hurt anything as long as you shut it down promptly and don't take a beer break.

 

[Falcon_LS]

I don't really see the point in a drain and refill, and have been doing cooler line flushes for the past 3 service intervals (also replace the pan/filter gaskets and filter whilst I'm at it).

 

[sciphi]

Originally Posted By: Donald
Another alternative if you have no drain plug, is to setup for the cooler line flush, run engine until you see air bubbles (now most of pan is drained), then add the amount drained and continue with cooler line flush. Running until you see air bubbles will not hurt anything as long as you shut it down promptly and don't take a beer break.


I thought the outgoing fluid came from the torque converter, not the pan. At least that's the setup on my car. The cooler lines go from somewhere that's not the pan, out to the transmission cooler, and back into the pan.

I guess it's different for different cars...

 

[Gary Allan]

Sure. The outgoing fluid does typically come from the converter ..which is filled from the sump. The return, again typically, lubricates and cools the rotating mass before returning to the sump.

If anyone is doing a pan drop (assuming you have a pan to drop and a filter to replace and you don't have a drain plug) ..then BY ALL MEANS drain the sump as much as possible via the cooling line to avoid having to deal with a FULL PAN splashing all over the place. NO BRAINER!!

Then refill the sump and do your cooler line exchange.

 

[SuperDave456]

I've done 3 cooler line flushes and pan drops in the past 2 months.
I agree, once you figure out how to do one the rest are easy.