mikeborden

History,
Installing the third radiator and using the Airlift to make sure all air gets out of the system.

What's it doing.

When I start the vacuum process, the needle goes up to about 20lbs and then all of a sudden it looses the vacuum and it seems(actually i'm pretty sure this is happening) to be pulling coolant through the other line but as mixed air and coolant. So it's a mist.

What I have done.
1. To make sure it wasn't the addition of the third radiator I plugged the original hoses back up that go to the third radiator. I then did the vacuum again and basically got the same results.
2. I emptied out more of the coolant again and then attached the hoses back to the third radiator and started the process over. I got over the 20lbs this time and started the fill process. However,the manual says that sometimes you can repeat this process and I did but it started doing the same thing as described above, get to 20lbs loose vacuum and start sucking coolant.
3. I've used several adapters and made sure that the gauge had a good seal. Man what a pain in the but!
4. I've unconnected and reconnected the new hoses that go to the third radiator.


What I'm thinking about doing.

1. Don't put the bumper on, but at least put on the fan shrouds and stuff and start the car. Get it up to temp and see if there are any leaks where I added the third radiator. If there are, fix them. If not, button it up and take it to a mechanic to make sure there are no leaks, cause if there is a slight one, that's not good.
2. Put it back together and take it to a mechanic---really don't want to do that.

My Questions.
1. Is there anyway to add pressure and hopefully find the leaks? probably a bad idea, but if it is say so.
2. Could there have been a leak before this and it just wouldn't get up to the correct pressure but not have any leaks that actually leaked out coolant?
3. Could this be a sign of the expansion tank going?



Additional note.
Before this adventure, there were no leaks that I knew of. No puddles anyway and didn't notice the reservoir going low. I also checked to make sure there was pressure on the hoses a couple of times when the engine was hot, and it was. That was out of curiosity by the way. The car didn't over heat or anything to this point. I just wanted to add the third radiator cause I wanted the additional cooling for when I'm in heavy stop and go traffic and I live in the hot south.

Any suggestions?

Devil Boy

I'm confused about your step 2. I'm not sure why you would need to fill and then repeat the vacuum. That sounds like a waste and an unnecessary step.

Does your air compressor have enough oomph to bring the vacuum down? I have to open and close the vacuum valve several times to draw down the vacuum into the green because I only have a small 2-gallon air compressor. It doesn't have enough volume to do it in one swoop. I have to do it in several increments. Open the valve - draw down the vacuum a bit - close valve and wait for compressor to build up pressure - repeat.

I would think that the important process to the vacuum procedure is that the vacuum holds once you've closed off the valve. If you close the valve and your vacuum leaks, then you have to troubleshoot and find the source of the leak.

mikeborden

I only did this because it looked like I didn't get all of the coolant back into the system that I saw in the bucket that was drained.


Anyway,
I think my problem was mostly from the system being almost full to begin with. When I did the third radiator, I only lost a gallon, if that. I put in distilled water into the third radiator before I put it on. So, the system was basically full except for maybe a gallon or so, if that.

What I ended up doing was bring the car up to temperature while the front end was apart. When it came up to temperature, I checked all of the connections to make sure nothing was leaking. I also checked to make sure there was pressure on the hoses. I didn't see any leaks, so I put the front end back together. After it cooled down, I topped the coolant tank back up with more coolant. I then brought the car back up to temp and checked again for leaks and haven't found any yet.

I haven't gone for an actual drive yet, but plan on doing that today sometime and check everything again.

I will keep an eye on the level of the coolant over the next few days to make sure everything is ok.

Thanks for the help!


Mike

Macster

Reads like what you did was to create an air bubble (or several) in the new radiator and upon lowering the pressure this bubble was then able to push along some coolant and that's the source of the mist.

If you break open the cooling system in the middle so to speak, you are better off draining it completely then using the air lift system to lower the pressure in order to refill the system.

slicky rick

Have the airlift system and mac is right that its better to vacuum a completely drained system. However p, as you have indicated, you did mot fully drain and actually saved on coolant by filling up the third rad with water and probably connecting the hoses as fast as you can to the existing rads to minimize coolant loss. Simply open the burp valve and let the car idle and when hot rev to 5 to 6k rpm a few times. This should carry the bubbles out of system to the burp valve. This was what i did and never had a problem with the cooling after diying the third rad

Spoddle

I recently added a third radiator and used an airlift tool to burp the system. It took about 30 minutes to get 25lbs of vacuum. During the 30 minutes it spit quite a bit of foamy coolant, never a constant stream.

You may want to clamp the over flow tube on the coolant tank to see if it helps build pressure more quickly.

Rotmilky

What year is your 911? I didn't seem to catch that.

I ask, because I replaced the water pump in my 05 last year. When I pulled a vacuum with my airlift to refill the system after the water pump replacement, I don't think I hit 20. Vacuum was good enough fill the system, but it wasn't what it should be. Outside of water pump issues, I didn't have any kind of leaks. I just assumed that it was a bad gauge.

A few weeks later, I found the coolant reservoir leaking. There was a crack in it in a place I couldn't see. I happened to have the car really hot and noted that there was a stream of coolant shooting out of the reservoir. As it turns out, as the coolant reservoirs age, they tend to crack. Quite a common problem on the older 997s.

So, it's possible that your reservoir could have a crack. Just a guess at this point...but my airlift behaved the same way as yours when I had a crack in my reservoir.

USMC_DS1

+1... there's a leak somewhere within the coolant system if the airlift cannot hold pressure at a constant level. The reservoir is the the most likely component.

mikeborden

I'm not sure if you and the other person you quoted is towards me, but the reservoir could be a problem. At this point, after driving a 40-50 miles and topping the reservoir off, I haven' seen any leaks coming from there. However, over the next few days, I'm going to check to make sure there is plenty of coolant there.

I have done the burping process and have gotten it hot enough for the burp valve to automatically open. The only thing I haven't done is a hard run. I wanted to make sure there are no air bubbles and there is plenty of coolant before I do that.

That will be coming up soon though.


So far though, just tooling around and a couple of regular highway trips, the third radiator doesn't seem to make that much of a difference. Of course, those are just some short term observations and the temperatures of cooled off a bit here. The temps are supposed to get back into the lower 90's later in the week, so we'll see then. I also try to take it for a hard run and see how that goes.

Mike

Petza914

You can't use the dash gauge as the criteria for whether the 3rd radiator is making a difference or not - in the 997, the coolant temperature guage is more like an idiot light than a true gauge. Once the car is warmed up, they'll always point straight up to the 175 nunber. Not sure why Porsche did this, but the oil temperature gauge is a true gauge and you might see that you're oil temp is a bit cooler with the 3rd radiator, which is just as important.

I think maybe with Durametric you can see actual coolant temperature, but if it's capturing the info from the same sending unit that the gauge is using, maybe not - I'm sure someone here will know.

mikeborden

I knew that and that's why I have an OBD reader to see my live water temps.

And from those numbers, I am seeing about ~199 on the highway, which was about the same without the third radiator. My Oil temps look to be about the same as before as well, ~210, maybe a little cooler. These are just short term observations and the only difference so far is the Oil seems a little cooler.

I installed the third radiator to add a little capacity during my commute of stop and go traffic on the way to and from work in the 90 degree heat during the summer time. I'll have some more observations during the week since I'm at work now and it's supposed to warm back up.

Thanks for the input!


Mike

USMC_DS1

OP, besides filling up your coolant the airlift tool is designed to detect leaks in the coolant system... aka air pressure cannot be sustained. It's critical to have a sealed and pressurized coolant system otherwise the engine will not be cooled properly which could lead towards engine damage. Here's a long but insightful read from a Porsche Specialist who rebuilds engines. http://www.hartech.org/docs/buyers%2...20part%205.pdf

FWIW, leaks from the coolant reservoir are known to be difficult to detect visually. We had another forum member, Rotmilky, who dealt with the coolant reservoir issues. Under the right conditions: hot summer temps with stop and go traffic the coolant would leak out from the back of his reservoir. Visually detectable once the tank was removed and inspected from the back. https://rennlist.com/forums/997-foru...997-1-a-2.html

Also consider that the airlift tool itself may have a leak. Make sure to wet the rubber adapters and that a proper seal is formed when the airlift is seated on the reservoir tank. One way to test/verify that the airlift is working properly... try it on another vehicle. I knocked out two other cars(wife's Lexus and son's Tundra) when I was flushing the coolant from the p-car. Helped to get more proficiency with the airlift tool.

Regarding the benefits of a 3rd rad... here in TX I've seen upwards of ~25-30*F oil temp drop under extreme temps(110*F ambient) and driving conditions(canyon runs mainly in 2nd gear). Dropped from 275*F to ~245*F max. In typical 100*F ambient DD I'm seeing 210-225*F oil temp. FWIW, I've also added an FVD extended oil pan and switched from MB-1 to Motul Xcess.

mikeborden

This is what I'm kind of looking for with the third radiator. I was in some stop and go traffic a few weeks ago and noticed my Oil temps getting over 225, and I'm hoping that this will help keep at or below that.


Thanks for the info!


Mike

USMC_DS1

99*F ambient today... oil temp was right at 225*F after some mixed driving that including high revs in 2nd gear and hard acceleration through surface level streets and some hwy.

slicky rick

Water temps should not change mike. The thermostat keeps it at that same level regardless of how big cooling capacity is added. Oil temp is the real beneficiary here. Whereas before i would see noticeable oil temp movement from 90 to 115, third rad now keeps oil temps at around 87 to 95. Fairly constant... Gives a feeling of confidence the engine is well protected..