AirLift won't hold vacuum on drained system.
 

I drained some antifreeze in order to change the o-rings in my oil cooler. I Also changed one of the radiator fans so I was working up front as well. Everything is back together again but now the system won't hold a vacuum. I can't get the Airlift to go aboe 14 lbs. So before I start tearing everything apart again, how should I go about finding the leak? Any hints? :(
BTW, I replaced the tank 6 months ago, so it's not that.

The first place I would check is the seal at the opening of the coolant expansion tank where the airlift adapter goes. I think I had to use the cone shaped adapter as none of the other "regular" ones would fit quite right, even though they were close. So if you are not using the pointy one, that may be the area that is causing you the trouble.

I was able to pull the vacuum and let it sit for about 10 minutes or so with absolutely zero loss of vacuum when I did mine.

If you are sure it isn't the adapter then I would start looking at the areas where you opened the coolant system to see if you can see any air being sucked in, maybe you can spray bottle some water and see if you see any air bubbles or see/hear it getting sucked in?

Steve

Vacuum leaks are usually pretty noisy; try checking around where you worked with a mechanic's stethoscope while pulling a vacuum on the system.

I'm pretty sure the adapter is okay. I used it last time with no problems. I've been meaning to buy a stethoscope for some time now. A good excuse to run up to Canadian Tire to pick one up! Cheers.

I am currently replacing my coolant tank and I was wondering where did you get your airlift pump? I want to make sure I have no air pockets when I put it back together.

i just got it myself and used it for the first time last week.
got it from amazon.

Amazon.com: UView 550000 Airlift Cooling System Leak Checker and Airlock Purge Tool Kit: Automotive

i found it cheaper on tooltopia.com
http://www.tooltopia.com/uview-550000.aspx

but with amazon i get it shipped free and got it within 2 days.

I got mine from Amazon too. Since then ECS Tuning has come out with their own version that is around $43 or so cheaper:

Search SiteSearch Coolant Tool - 003466SCH01 - Coolant Evacuation Tool Kit - ES#2712734

I have never used it so I don't have any input but it looks like essentially the same thing.

Steve

That is a plastic version by another manufacturer; Uview also has one, which is also cheaper: Bottom-line pricing on UView 550500 at ToolTopia.com

Redeye, you can borrow mine if you like.

That's really nice of you I might take you up on that. Tell me did you have any trouble draining your system completely?
By the way what part of montreal are you in?

Well, last year when I had the engine out, it got pretty empty by default! �� This year I didn't remove all the fluid since I was only lowering the level to change the o-rings on the oil cooler.
I'm In TMR. I'll send you a PM.

Just to flollow up, I never found the leak but I suspect that the releif valve wasn't sealing properly, maybe because it had sat empty in my minus 10 garage for a couple of months. I managed to get the vacuum to -26 ( my bad: I hadn't turned the pressure up on my compressor :o) although it wouldn't hold. I Got it filled after 3 tries. Today I ran it while up on jack stands until it got up to temp. There was about 3 drops of coolant that came out the overflow tube but no other apparent leaks. The tank is recent and it comes with the relief valve so I'm a bit surprised that it didn't seal properly. Has anyone else seen this problem?

I don't want to discourage you, but what engine are you working on? Reason I ask is that the only time we have seen cars refuse to hold vacuum, there were only two reasons: (1) A leak somewhere in the cooling system (loose fittings, loose hose clamps, cracked tanks or lines, etc.); or (2) A cracked cylinder head.

On cars with the first case, the leaks were large and obvious. In the second case, the leak down was more gradual.

If it were the latter, wouldn't i see some evidence in the oil? It's a 3.2

Not necessarily, that would depend upon how the head is cracked. As these heads often develop cracks adjacent to the valve spring and seat area, you can get a small crack that opens the water jacket to a combustion chamber. The car will run fine, but if you pull vacuum on the cooling system, air is drawn in from the combustion chamber and the vacuum bleeds off, usually slowly. While this is not an everyday occurrence, it has happened.

When we ran into it, we confirmed an issue existed by running a leak down test and found one cylinder with high leak rates; when we pulled the head and dyed it with a crack finding compound, two small cracks appeared near the spring seat.

As your system is already refilled, I would suggest doing a cooling system pressure test, if necessary with some Uview cooling system dye in it (that won't bother the cooling system at all, but will highlight any where coolant is trying to leak out under pressure).

These cooling system are typically tight under vacuum (we hold them at 25-26 inches for at least 15 min. before refilling the system). You need to track down where yours is losing vacuum as that should not happen.

When I last did the refill, in the summer when I changed the coolant tank it held vacuum just fine. This time, the vac dropped to 0 within 1 to 2 minutes. I will do a leak down test to check this out and post my findings. There's still a shirtload of snow here so I still have a bit of time.

:eek: Or is it just me?

It's just you. :cool: The car is very stable on jack stands. (Otherwise I wouldn't be crawling under it!)

I have it on Jack stands too and it doesn't worry me at all. I would love to get a lift but space is limited.

So I am about to do my water pump and thermostat because the car is running a little hot. The car is fine if I run the ac and the fans kick on and the temp does not climb. If I do not have the ac on and the fans are not running it will climb slowly. My coolant level is fine so I ordered a uview and hooked it up tonight to check the system on a vacuum. So my question is what size compressor are you guys using? I borrowed my in laws compressor and it is a 3 gallon and is pressurized at 100 PSI to start. Once the air starts flowing it will get to 25 psi of vacuum but at that point the air compressor kicks on and jumps back down to 20-18 PSI and will flicker. My system does have fluid in it still. Do I need a bigger compressor that will hold the PSI more or do I close the valve as soon as it hits 25 psi and wait to see if it holds the vacuum?

Thanks!