Replacing Coolant with AirLift System?
 

Hi All -- I recently purchased a low-temp thermostat and want to replace the coolant in my 987S, as it hasn't been changed since the water pump was replaced by a previous owner in 2013 or thereabouts. The AirLift vacuum system came highly recommended by others in the Porsche community, so I bought one to make the process go more smoothly.

Well, I have my AirLift system, I have my air compressor, I have my thermostat and coolant... but I have trepidation about actually doing the job, as I've never used a system like this before. Moreover, the instructions included with the system are fairly vague.

I'm sure it isn't a tough job, and once I get into it I'll figure it out... I did once do a top-end rebuild on a 951 engine (and replaced its transmission) in my home garage... but as with any new procedure, I'm cautiously hesitant. Have any of you used this method before? Could you offer me any tips regarding doing the job on a water-cooled flat-six Porsche?

The Air Lift is an awesome tool! You will need to access the expansion tank in the engine compartment to fill your system properly. The earlier 986 cars were a little easier with the expansion tank in the trunk. Just attach the Air Lift to the tank, plug in your air hose, and bring the system down to 25-30 inches of vacuum, close the valves. Let it sit for a few minutes to make sure you don't have any leaks, then open the fill valve from your coolant bucket. (I use a 5 gallon bucket) It fills the system very efficiently.
Good luck.

Thank you for the response. So, how do you know it's reached "25-30 inches of vacuum"? Is that what's denoted on the gauge? If so, when you start the procedure, what reading will it start with before going to 25-30 inches of vacuum?

Yes, by the gauge reading. Your Air Lift may be a bit different then mine. I remember doing some modification to mine. I'll have to take a look at it tomorrow when I get to work. Maybe I'll post a pic of it. I might even be able to come up with a photo in our database with the tool hooked up to a car.

http://i.ebayimg.com/images/i/251653184270-0-1/s-l1000.jpg

This is the kit I have. The modification I made was to drill and tap 180 degrees from the on/off valve and screw in the Filler valve to the new hole. That way, once the system was in a state of vacuum, you simply close the one valve, and then open the other valve to fill. Saves time!

I agree with Dan. The Air Lift kit is awesome! I just used mine for the first time yesterday on my 996. After replacing the water pump, thermostat, and draining all the coolant, filling the system with new coolant using the Air Lift was by far the easiest part of the job. As previously mentioned, once the 25 psi or a bit more is indicated on the gauge, close the valve, detach the hose, and monitor the gauge to see if the system holds pressure. If it does, attach the hose that has a filter on one end, and place that filtered end in the container of pre-mixed coolant. Attach your air pressurized air line to the other end, open both valves, and see your coolant get sucked into the system at a very fast rate.

Yes, that's the system I have as well. Thanks!

I have the cheaper version that is made largly of plastic but still high quality. It isnt very difficult to use, I think the other guys have it covered. One thing to remember is to have all the coolant you need in a single container so that you dont introduce air when switching from one to another

Stupid question, but why not pour it in from the top like it's been done for 100 years?

Because of the heater core and radiator pipes that have high spots, if you don't vacuum fill it you'll get many air pockets.
I use mine daily at the shop....
Dont forget to flip up the vent spring when you fill it

Yeah, but I have never had a problem with bleeding all of the air out...

I get the difference in using one in a shop, if you use it all the time and it saves a few minutes on each job. This is different...

The water cooled p cars are pretty tricky to bleed correctly the old fashioned way . The air lift is not just a time saver, it is a huge time saver

Here is my set up.
http://forums.pelicanparts.com/uploa...1523899432.jpg

http://forums.pelicanparts.com/uploa...1523899476.jpg

I love my Air Lift, it's one of my favorite tools.

JR, if you've ever fought to bleed air out of a stubborn cooling system you'd understand the value. When I had a dealership I had a 2008 Wrangler that had a sloshing sound in the heater core because of trapped air, which was a common issue. I tried every trick to flush it out, nothing worked. 10 minutes with the Air Lift and the problem was gone.

Never had a problem with it. Wrenched on 60 or 70 cars and bikes and never needed one. Neither of the two shops I ran had a need for one. Guess I was just lucky..

you don't need any system to bleed a Cayman, it has a built in system.

fill it, run it, pull the metal tab on top of the coolant tank on the top right of your engine.
https://i.ebayimg.com/images/g/9PYAA...EM/s-l1600.jpg
you will hear the air escape
fill it up, run it some more , repeat

do not drive untill your car's heater produces heat.


You might get some filling done after the first run
but once the engine is warm and reasonably filled up with coolant, don't try to fill it, the hot coolant will just spill through the overflow hole, over your engine.
it's designed to push out in that direction vs spill inside your trunk, you'll notice pretty quick when you hear it surging on opening the coolant filler cap.
So for the last bit of bleeding and refilling you'll have to let it cool down.
But the car is already driveable at that stage, if the heater works, and you pulled the little tab on a hot engine, most if the air will be out.
If it surges at that point, it's already full enough to drive.

It's half an hour work,
15 minutes stationary, 5 minutes to bleed & refill, 10 minute drive
Then an afternoon or night to cool down, and 5 minutes to bleed & refill , done.

^^^If you use that method w/ the factory bleeder you need to park the car on a downward incline then run it with the bleeder open.

...But in full disclosure I use an Airlift. Way more predictable, no chance of leaving any air behind, and way easy.

One word of advice...mix and get all of the coolant you need in a big 5 gallon or larger bucket. Once the Airlift starts sucking up coolant into the system you cannot easily switch between coolant bottles w/ the strainer pickup tube without introducing some air into the system.

works fine on a flat floor. the bleed valve is the highest point..
in fact downward incline makes the filler the highest point.. that don't work well.

Might depend on the car I guess. On my 996 they recommend parking the car nose down. Maybe not so on a Cayman.

Thread his a bout a Cayman.

Regardless of bleed method, the key is that the bleeder needs to be the highest point in the system to help evacuate the air.

I don't think the point of this thread is that an Air Lift is the ONLY way to bleed air out of a cooling system. I would just submit that it is the EASIEST way to refill a cooling system. I love the ability to refill a drained system in less than 10 minutes without any concerns about trapped air or bleeding the system. It's also very neat because you can put your desired coolant/water mix into a 5 gallon bucket and just suck it out of there, no worries about funnels, spills, or trying to mix it up in gallon jugs.

can you in 10 minutes?
What about to the radiators..won't you get pockets there behind thermostats?
I would think at any time that built in bleed valve remains a must after some driving to warm up the engine.

So it's not that big of a time gain.. and not worth investing the money if you don't do this on a weekly basis. which i doubt any DIY porsche mechanic does.

10 minutes tops. You always have to drain the system via drain plug. After that point you close the plug, hook up the Air Lift which will suck out the residual fluid before pulling a vacuum, close the valve to insure the vacuum holds and you don't have any leaks, and then suck in the new fluid until the vacuum is back to ambient. At that point you are done, period, no bleeding or other work.

The manual way typically works fine, I did it for years. But this is faster and easier, and gets the job done right the first time. As I get older and have less free time, that's worth buying a $100 tool. Which I have used a LOT because it's universal, I'll probably be doing my F150 this weekend as it has 75k on the original coolant.