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I am in the process of installing a center/third radiator in my 981CS and everything went smoothly until the coolant refill. I got the Uview 550000 Airlift kit, suggested by Schnell and reviewed highly everywhere I've seen.
The 981 holds a ton of coolant in the lines being mid engined. I drained the radiators and the engine block, but the uview still spit out nearly a gallon of coolant so far over the course of 5-10 attempts to get full vacuum. I know it suggests a completely empty cooling system, but that seems hard to achieve on the 981. I'm using a fairly small compressor, 2.6CFM @ 90 PSI, but at least the first 30 seconds or so maintain 90+ PSI before dropping. It initially couldn't get over 12 PSI (or inches?) on the gauge, but now can get to 20 or so, presumably thanks to greatly reducing the amount of liquid it is spitting out.
Anyone know if a 2.6 CFM 1.5 HP unit is insufficient or if my woes just relate to still having coolant in the system? Some folks online claim the compressor is fine, but 981 is somewhat unique in having a MUCH greater coolant volume than most cars due to being MR. Thoughts?
You may eventually get there with your compressor, but it really is too small. A friend helped me go through the same procedure and we took a long time to get to 25 (?) psi vacuum even with my 2.5 hp compressor. A big shop compressor would pull that sucker right down.
I think I've probably got the same 1.5HP compressor. I used it with the Uview successfully on multiple cars, including my 987.2 (which should have pretty much the same cooling system as your 981.) Had to wait a bit for the compressor to catch up a few times, but that didn't cause any major issues.
On the Cayman, even after opening the drain plug and disconnecting the lines underneath per the manual I still got some glugging from the cooling system as I pumped it down. I suspect this was residual coolant in the radiators up front, which I don't think drain fully when you disconnect the hoses under the middle of the car. Nonetheless, I was able to pump down and refill the system without problems. I didn't get any significant spitting of coolant out of the Uview when I did it, though, so not sure what's going on in your case. But I don't think compressor size is your problem.
Next time I do the coolant I'll probably pump it down, then repressurize, then drain from underneath again...I'm thinking maybe this'll help get a bit more coolant out.
Thanks guys. Got to 23 PSI just now, so the end is near I think. It has been a process though. It stalls whenever it catches liquid, which keeps going up in PSI thankfully.
Thanks guys. Got to 23 PSI just now, so the end is near I think. It has been a process though. It stalls whenever it catches liquid, which keeps going up in PSI thankfully.
When you say “catches liquid,” is it actually spraying liquid out the Uview? That should not happen.
Really surprised you’re having that much trouble. You sure you drained from all the right places? On the 987.2 there is a metal drain plug and then like three hoses to disconnect, but not sure on the 981 procedure.
When you say “catches liquid,” is it actually spraying liquid out the Uview? That should not happen.
Really surprised you’re having that much trouble. You sure you drained from all the right places? On the 987.2 there is a metal drain plug and then like three hoses to disconnect, but not sure on the 981 procedure.
Yep it is spraying out the hose. I have a long hose into a bucket. I drained both front radiators and the engine block drain plug. I think I'm going to raise the car and pull the plug again.
I did the 3rd radiator install on my BS using the UView vacuum kit and a 2 HP, 20 gal. compressor. I was able to drain 3.5 gallons of coolant out of the car before starting. I drained the radiators, disconnected both hoses in front of the engine and pulled both drain plugs near the front of the engine. I made sure the car was level before draining. I was able to pull 25" of vacuum in one attempt without taking that long. I can't remember if my compressor cycled on or not, it probably did, but tank was at 135 psi before I started. I set the regulator to 95 psi before starting. I did not pull any liquid up through the UView system. When I filled the car, it sucked in a little less than 3.5 gal of fresh coolant. I added the rest of the volume of coolant needed to make up for the 3rd radiator over 2 or 3 drive and check sessions, getting in about another liter of coolant, maybe a little more.
I did the 3rd radiator install on my BS using the UView vacuum kit and a 2 HP, 20 gal. compressor. I was able to drain 3.5 gallons of coolant out of the car before starting. I drained the radiators, disconnected both hoses in front of the engine and pulled both drain plugs near the front of the engine. I made sure the car was level before draining. I was able to pull 25" of vacuum in one attempt without taking that long. I can't remember if my compressor cycled on or not, it probably did, but tank was at 135 psi before I started. I set the regulator to 95 psi before starting. I did not pull any liquid up through the UView system. When I filled the car, it sucked in a little less than 3.5 gal of fresh coolant. I added the rest of the volume of coolant needed to make up for the 3rd radiator over 2 or 3 drive and check sessions, getting in about another liter of coolant, maybe a little more.
There is a bleed valve on top of the engine next to the fill pipe where you attach the vacuum tool. We left that open and drove the car that way for a few miles. Engine cover was off, and loud! Fun. After that close everything up and top off after engine cold next day.
In addition to draining the left and right radiators by pulling the 2 plugs where the 3rd radiator hoses connect, I drained per the WSM at the places shown in the 3 images below. In the first image, I only disconnected the hoses at the ends pointed to by the number 2 and pulled them down to drain the long pipes to the radiators. Make sure the car is sitting level, or aft end slightly down during this step. Close everything up, pull vacuum, refill with coolant. I then opened the air vent valve shown in the 4th image (flip the metal ring up until it stands up vertical) and started the car and let it run for 45 minutes until the radiator fans cycled on and off about 3 times. At that point, I put the heater on full blast for about 5 minutes. Then I closed the valve and shut the engine off, and let it cool until the next morning. That's when I was able to get most of the coolant in that I had to add to top it off. Took a couple more of small additions to finish it off but those were both after driving for an hour or two and cooling down fully to check level first.
BTW, if anyone is going to attempt the 3rd radiator by themselves, the procedure Schnell describes on their website to remove the front bumper is waaaayyyyy more complicated than it really is. It is actually a very well designed modular disconnect from the car, including all wiring harnesses. The only tricky part was getting the damn thing back on and steering the radiator ducts into their guides in the radiator inlets. The center duct was a breeze. The passenger side duct was a pain. I eventually figured out that your arm can be extended up into the almost installed front bumper cover to push the duct up so it guides into place. Highly recommend having someone, anyone who can hold up 20 pounds, there to be topside when you are downside doing this arm-into-bumper task. If you are planning to take this on and want some advice, PM me.
Thanks Okie, very helpful stuff. Surprised none of that was in the diy article. The bumper is definitely easier than it looks. No need to remove the headlights, really, but I went ahead JIC.
To clarify one thing: you can the car 45 minutes with a bunch of coolant drained out? Or was that after you refilled?
Oh, one other thing: I know the Schnell entry says the radiator ducts must be closed in order to be efficient. No other sites selling third rad kits say that though, including BGB and other very reputable shops. It does not really make logical sense to me to need those since the three ducts will be separate anyway. Thoughts on running the normal "open" style ducts with the third radiator? I have the third radiator duct from the 981 GTS already, the question/point of discussion is just the side ducts.
Thanks Okie, very helpful stuff. Surprised none of that was in the diy article. The bumper is definitely easier than it looks. No need to remove the headlights, really, but I went ahead JIC.
To clarify one thing: you can the car 45 minutes with a bunch of coolant drained out? Or was that after you refilled?
Sorry, I edited my post to clarify, yes, you must refill before starting the engine. Never, ever run without coolant in the engine. I was typing while thinking in context of my previous post where I described refilling with fresh coolant.
Originally Posted by PorscheAddict
Oh, one other thing: I know the Schnell entry says the radiator ducts must be closed in order to be efficient. No other sites selling third rad kits say that though, including BGB and other very reputable shops. It does not really make logical sense to me to need those since the three ducts will be separate anyway. Thoughts on running the normal "open" style ducts with the third radiator? I have the third radiator duct from the 981 GTS already, the question/point of discussion is just the side ducts.
I have all three ducts "closed", meaning they all serve the radiators with ducted air isolated from the other areas of the front bumper cover. I think the Schnell DIY used the term "closed" in a somewhat confusing way. What they meant is that each radiator has its own dedicated funnel of air "closed" off so the air can't go anywhere else. I want as much air as I can forced into the radiators and the closed ducts accomplish that. My left/right ducts were unchanged, were already closed. The new center duct that came with my 3rd radiator kit (Rennline supplied but they bought it from Suncoast) was a perfect fit with the center opening of my bumper cover, snapped right in place and connected up to the radiator again by snapping firmly into place. I was impressed by the total package fit/finish and design.
Sorry, I edited my post to clarify, yes, you must refill before starting the engine. Never, ever run without coolant in the engine. I was typing while think in context of my previous post where I described refilling with fresh coolant.
I have all three ducts "closed", meaning they all serve the radiators with ducted air isolated from the other areas of the front bumper cover. I think the Schnell DIY used the term "closed" in a somewhat confusing way. What they meant is that each radiator has its own dedicated funnel of air "closed" off so the air can't go anywhere else. I want as much air as I can forced into the radiators and the closed ducts accomplish that. My left/right ducts were unchanged, were already closed. The new center duct that came with my 3rd radiator kit (Rennline supplied but they bought it from Suncoast) was a perfect fit with the center opening of my bumper cover, snapped right in place and connected up to the radiator again by snapping firmly into place. I was impressed by the total package fit/finish and design.
That's what I figured on the coolant question, just wanted to confirm. Yeah, the closed versus open ducting is confusing to me. My car has the ducts they refer to as "open," shown in this pic: https://1.bp.blogspot.com/-8QWY6R_vx...00/Blog-25.jpg and on top in this pic: https://1.bp.blogspot.com/-uy6hYzv4B...00/Blog-31.jpg. Once the air hits the duct it can only go to the radiator, so I'm not seeing why it would be advantageous to swap. The part of each side duct that goes toward the middle would be unnecessary/not effective since the middle will no longer be blocked off funneling air there, but the opening is large otherwise. I'd like to button the car up before I could get closed ducts in, and assume from the lack of discussion on the issue by any other vendor that it is not a big issue.
04-02-2018, 11:36 AM
Experience with UView coolant system
