Performed Coolant Refill Via Vacuum This Weekend

A few months ago, I dropped the engine from my father's 996 to have preventative maintenance (including LN IMS bearing install) performed by a local Porsche mechanic. While the engine was being worked on, we completely removed both radiators and flushed them with water (inside and out), and let them air dry for several days. In addition, we removed two of the coolant hoses that run parallel w/ the car on the passenger side of the car. Since the coolant was drained from several areas of the car at different times, I do not know exactly how much was drained. With the engine back in, and all hoses re-connected, this weekend was perfect for using a UView vacuum for the coolant refill. According to the owners manual, the capacity of the system is 5.95 gallons. As per the instructions, I pulled 26 lbs of vacuum and verified there were no leaks. In a container, we poor 6 gallons of coolant and let the system suck the coolant. Much to my surprise, I see the coolant reservoir/overflow tank reach the max mark with a lot of coolant left over. Turns out, only 4.5 gallons went in! Knowing the engine was removed and most, if not all of the coolant was drained from it (heads were not removed), the radiators were completely removed along w/ hoses, do you think there could have been 1.5 gallons left in the system? I'm worried there may be air pockets. Should I drive w/ the reservoir pin in the open position? What, if anything should I have done differently? Here are some non-related pics. (You know, we don't have enough IMS threads this week... bahahahahaahah.)

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Nice work. My experience with this awesome tool. 1.) you need to have the heater on high and fan on low during drain or fill, this will include more of the heater core hoses and loop and coolant. 2.) the car should be at an angle at some point, either up or down. The long hard lines from front to rear are u shaped, and thus trap a significant amount of coolant. If the car was always level, some coolant might still be there. 3.) you can use the uview to draw vacuum and suck more of the coolant towards the block, and then drain via the plug again. repeatadly. 4.) some of the coolant is hiding in the block, evne though you drain it, there is some in the oil cooler, some in various passages that simply do not drain without engine tear down. 5.) when filling, it is best to place the bucket above the engine bay, on a stand or ladder or something. this is even spelled out in the detailed manual that you can use the aid of gravity to fill. 6.) it is important to prime the filling hose prior to the start of filling. and it is also important the bottom of the filling hose never sees air or is moved, as that could cause air bubbles that enter the system. 7.) to get even more coolant out you can remove the heater core hoses. If I were you I would drain it again and then refill, ensuring you follow the above steps and get at least 5 gallons drained before you refill. When I've done this before it is pretty easy to get 5 gallons out of the system, and when I've tried really hard I've been able to get about 5 + 3/4's out. Or you could just drive with the bleeder open for a week, which is safe to do, but just be religious about the coolant level, never driving too far without checking it and always keep an extra gallon mixed in your trunk and be prepared to camp out while the car cools down so you can top her off.

Followed your suggestions and was able to drain and refill five (5) gallons. Initially, with the car at an angle (rear lower than front), we drained approximately 3.5 gallons. After repeatedly drawing vacuum, thus more coolant to the block, we drained another 1.5 gallons. That was key. We also disconnected both radiator hoses on the drivers sides.

looking good now. RMS and AOS replaced? how did the IMS look on inspection?

Zero grease in bearing. Here's the shop that performed the engine work. Lots of photos and explanations of work. Dad and I only did the grunt work. LOL 1. http://rennsportkc.com/996-engine-time/ 2. http://rennsportkc.com/996-ims-upgrade/ 3. http://rennsportkc.com/996-ims-upgrade-part-ii/

Great job! Certainly no air in there now... but be sure to drive with the bleeder for a day or two, and do a couple blips above 5k rpm on a warm engine to purge any remaining air. Since you followed the steps above, there is likely to be 0 air or additional coolant required. I like to run with the level about 2/3rd's full, or just below the max mark, which sometimes requires drawing a small amount out after the fill procedure using a turkey baster or equivalent.

Thanks for the pics and info.

I hav e been driving with the bleeder valve open for the two weeks after getting my car back. I had to pour a bit over 1 qt of distilled water to keep the tank topped off. I recommend using the HVAC dispay to check coolant temp. Higher than normal numbers indicate air in the system.

Looking at these pix is giving me second thoughts about doing the IMS work myself in a home garage setting, it's going to be a royal pain without the ability to raise the car sufficiently high off the ground without at least a scissor style lift, but should I spend upwards of $3-4K getting a scissor lift and engine/transmission stands that I will hardly use again for minor work, don't have the space to store, and could just pay a shop under $2K for the labor?

Don't be afraid. You can do this with normal jack stands and an inexpensive floor jack. IIRC I did mine with the car raised just 19" on 3 ton jack stands and a $70 transmission jack. It is certainly MUCH easier if you have access to more tools and a lift, but if you are patient and clever, it is not as hard as some make it out to seem.