Ben8jam

Well despite some minor hiccups everything on my water pump and thermostat replacement was going well. pressure tested the system held at a solid 25 I then proceeded to fill through the vacuum. But when it got to zero I had a full gallon of coolant left. I assume I introduced an air bubble by not priming the tube first which I didn't sadly see in others notes. till after I had already done it.

i'm trying to follow all the varied differing opinions on how to manually bleed the system (on a slope, flat, valve open. no tank open, etc). I left the expansion tab up ran the car till I got to a mild operating temperature, plenty of heat coming from vents, but I'm not noticing any drop in the reservoir tank. It's still close to max.

this was all in preparation for a big annual 996 Club drive tomorrow that I'm sadly probably not going to be able to do with a full gallon of coolant unaccounted for.

can someone please document an excepted procedure to how I can get this last gallon in? I would really appreciate it thank you

allcool

Did you purge/blow out the heater core? Did you drain out a full 6 gallons.

You can try to vac out system again and it might take more in, maybe. Or fill to in between min/max, tighten cap down, leave reservoir bail up. Drive easy till at full operating temperature keeping an eye on temp gauge. Pull car in garage and let sit over night. Don't take off the cap.

When engine/cooling system cools fully to ambient temp it will suck in most of what it needs with in reason. Then do the same thing again, and see if it needs to be topped up a little more once fully over night cooled off.

Maybe after all the cooling system work take a peak under the car to make sure its totally dry. A leak could screw up the vacuum refill.

jmo

theprf

Just pull vacuum again with the airlift. When it starts to spray coolant shut off the air and suck in more coolant.

I think you're about there though.
You can try this...
leave the coolant cap loose
run the engine until the hoses at the front are warm. You can reach under the front and touch the hoses.
Shut off and top up the coolant.

Mike Murphy

My mechanic said the same thing when he changed my coolant out. One approach could be simply to fill the system with water all the way, and then try to pull it back out again.

There is a procedure to get all coolant out at one shot, but it does involve pulling more hoses to get the coolant out of all places.

Ben8jam

I did disconnect the heater core pipes and blew air through it to clear it out. I then undid the main drain blew more air from the reservoir over and over I'm almost positive all the coolant was removed.

but I did not actually measure it. I used 2 5-gallon buckets and they looked both to be well over halfway full. I also poured in a gallon and a half of distilled water and blew that through the system too.

I just now measured all the coolant into jugs and I only have 5 1/2 gallons. So now I am super confused because 6 (original) + 1.5 (distilled flush) should equal 7 1/2 gallons. That means I left 2 gallons in the system and I just don't see how that's possible, I was very thorough with blowing compressed air through the system.

I ran the car yesterday and I checked the coolant when it was hot and it had decreased in the expansion tank. But now that it is cool it is right past the max line. So I can't add any more coolant in regardless

I didn't know I could pull pressure again with the system almost all full with the coolant at the max line Won't it just pull that coolant straight out?

What is the difference between leaving the cap off and pulling the little tab on the expansion tank up? I'd be really concerned about trying to drive the car with The coolant cap off and it sloshing all around in there.

allcool

I think what theprf meant was to just idle the engine in the garage while cap was off, top it off as needed, till radiator tubes got warm, showing you have full circulation. More or less the usual way to fill most cooling systems without vac evacuation method.

Yes you can vac system again even with coolant showing in reservoir. Theoretically if a large air pocket was trapped in system the vacuum should lower pressure enough in reservoir to 'suck out the air thru the coolant since coolant is heavier than air, then coolant will spray out just as theprf said...

With cap off, no pressure will build up in system and air can easily find its way out. This is a way to let system warm up and top off for a system that is very low on coolant and one you don't want to vac out. Don't drive like this. It might take 2 or 3 full heat/cool cycles like this to get system totally filled.

With bail up it connects both top of radiator small tube bleed/vent/overflow/(whatever they are called?) lines together. Allowing system to purge easier. Also iirr it lowers system pressure relief.
I run with bail open most of the year here in SFL. Only downside is the engine doesn't warm up as fast. But in the SFL heat its not a concern for me.

Just like was said above, I think you're almost there if not already there. Keep bail up, cap on tight, drive car with eye on temp gauge(don't let it overheat) You can stop and check fluid level on your drive if you feel its necessary. After fully warmed up to max operating temp, park in a level floor garage, let sit over night, see if coolant drops. Top off as needed. If you fill to max mark when cold it will most likely overflow when hot. Fill to in between max and min when cold.
Done.

jmo

Ben8jam

At cold, the coolant level is right at the max line. I drove it around (under 4k) till it heated up past 180 with the ball valve open. Checking coolant, it had lowed a tad in the reservoir tank (right to bottoms of word MAX). I then let it cool. I opened the tank and the pressure released and allowed the coolant to rise back up to the max line.

Two drives now and the level hasn't decreased any to allow adding more coolant.

I can try to pull a vacuum on it again, but I fear it'll be very messy.

The only thing I can think of is when I did the purge, even though I pushed air through the whole system multiple times, and opened all drains multiple times, as well as the heat core, I somehow left 2 gallons in there. When I did the vacuum pressure test - I was losing some air out of that black hosing that holds the ball valve. I removed all the bolts, gave it a solid cleaning, and screwed it back down, and that solved the problem.

Or if all the coolant was removed maybe when I was pushing air through, that small leak, was enough to bypass 1 gallon of coolant? I also didn't prime the tubing, so pushed in a tube length of air.

But even with the theory i have a gallon of air in the system; the math doesn't add up:

1. 6 gallons green old coolant to start (if it was full, and it was near max line)
2. Drained the green coolant into buckets (but didn't count the gallons)
3. Added 1.5 gallons of distilled water to tank. Pushed through with air and drained into same buckets.
4. Vacuum pulled 5 gallons of pink coolant - had one left over.
5. Poured ALL the drained coolant from buckets (original + my distilled water) into gallon jugs, and I only ended up with 5.5 gallons.

So I should have filled up 7.5 gallons (6+1.5) but only filled up 5.5
So that would infer 2 gallons left in system.
But then I added 5 gallons, which would then mean there is SEVEN gallons in the system, which I assume is impossible.

What the heck?? Am I going to have to drain the entire system again? It was so messy

sublm8

What color is the coolant in there now?

If you did a green->pink change, it should be mostly pink. If there were actually 2 gallons left in your system, it'll be yellowish.

Honestly, I wouldn't worry too much about the specific numbers. I drained/filled my system 3 times, also going green->pink, and the quantities were always a little different and lower than expected. I have 1000 miles on the current fill, it's been fine. You can test the specific gravity with a $5 tester and if you're in range, I'd call it a day.

Ben8jam

It was green, but kinda brown/green. Not cloudy like intermix, but definitely not a clear bright green. Who knows how long it has been changed last. I filled it with pink, though I'd have to drain it to see what color now.

I still don't get the math. I have two empty distilled water gallon jugs that technically should be full. How did I lose 2 gallons of liquid??

Ben8jam

Well holy cow would you look at that. Huge drop in level after sitting a few days. Coolant level has been at max, even after a few full operating temp engine cycles (at idle as diagnosing AC issues). The last one got higher coolant temps and then I left it for two days and did not open expansion tank (except for bleed gasket).

Think i may try and pull vacuum now the level is much lower and see if any more air gaps in there. Let this be a testament to making sure you bleed! It was on max for a week. (no leaks)

Ben8jam

Update 1:

I tried to vacuum pull it again. It would only get to about 15 on the gauge and was pulling fine coolant mist. With compressor disconnected it did slowly fall to 10.

I collected about 6oz of mist coolant.

Looking at my distilled water jugs there are actually 4oz of extra water in them per gallon. So i probably added a few extra cups of distilled water when i added the 5 gallons.

I just topped off the expansion tank to the MIN level, and it only took 1/5th of a gallon. So that'd still put me at just under a gallon short (i actualy had over a gallon of coolant left). I wonder if the Porsche coolant containers are over a gallon as well.

So what should i do next? Should I fill to max (i read somewhere it should be min level at cold).

Or just keep doing this hot cold cycle and hope the air isn't causing issues with cooling.

Ben8jam

Update: Have done a few hot driving cycles. Temps seem okay, but...

forget below, i'm a dummy, the coolant is expanding in the tank.

For the first few drives, the next morning I was able to add small amounts of coolant to get level up to close to max when totally cold.

Issue is now that cold level is not moving, but when back from a run, the hot level is way low in the expansion tank (lower than the neck).

From my understanding it should be HIGHER. I have been driving with the bleed valve open. I have tried (when cold) to pull vacumm on the system again but it just spits out coolant.

My driveway is in a slight incline and I've run the car with engine up, but no change (granted it's not THAT elevated).

Does this mean I still have a bunch of air?

hardtailer

Just drive it and keep an eye on the cold level.
Pulling vacuum will only work if there's hardly any liquid in the system. What you have now is the exact opposite.
What you need now is operating temps and the high revs so that coolant speed in the system is high and any air is dragged along from a dead or high spot to the coolant tank.

996-CAB

Hey hardtailer, I haven't had any issue with my vacuum fill to get the last couple liters in. It works well for me. Just saying.

Ben8jam

So Turns out I am just blind. Coolant is expanding north of the Max line.

Ok so if coolant is way low when hot, then that does mean an air pocket. And the only way to get rid of it is to drive it a lot?

Does the jack up rear end and run it matter? Can I do that while already hot or do I need to do it from cold with expansion cap off? Is bleeder valve open sufficient? Reading a lot of differing threads on it.