Correct Coolant, 996 C2 3.4?

[eltax91]

Hi guys

In preparation for the upcoming job of removing my exhaust manifold bolts, i've removed the thermostat housing and some coolant pipes to provide appropriate drilling access.

I lost about 10l or so of coolant during the process. About 5000 miles/ 4 years ago the car had a low temp thermostat fitted at Northway Porsche independent specialist. which included a coolant change. Can i use any old OAT coolant off the shelf, or do i need to shell out for the porsche stuff? Is it any different?

Can anyone clue me in the right direction for what coolant to use to top back up, and the appropriate procedure to fill and bleed the system from the expansion tank? I assume the front rads are still full of coolant so i should just top up and run with the cap off, then drive it for a good run, and top it off?

[Orangecurry]

I don't know the answer specifically, but I've started putting Prestone into all my water-cooled cars.

Why? Because it's supposed to be good and you can use it in everything and mix it with anything.

Oh and I bought a shedload from Tesco when it was on offer.

And it's luminous green.

[Pope]

Watercooled Porsche's since 1997 have been factory filled with 'lifetime fill' coolant - unlike their previous watercooled vehicles that had 2yr coolant change intervals (944/968/928).

I would recommend using the genuine stuff - only because it is all I have ever used at work and have never had issues with it.

Bleeding a 9x6/9x7 can be a tricky process - the radiators and heater matrix are high points in the system that can 'air lock' and cause problems. Porsche released their vacuum bleeding equipment - a few years after release of the cars - to minimise errors

• I WOULD ADVISE A VACUUM FILLING & BLEEDING TOOL IS USED - It is less drama overall - borrow one if you can!!*

However, you can do it without (it's a bit of a rigmarole but what else are you doing?!?) :

You will need to rev the engine to 3k rpm for at least 5 - 7 minutes - it's not a quiet process!!

BE VERY AWARE!! - RELEASING THE THROTTLE BEFORE FITTING AND TIGHTENING THE COOLANT CAP DURING THE FOLLOWING PROCESS WILL RESULT IN A MAJOR COOLANT EJECTION FROM THE HEADER TANK - MUCH DRAMA AND A STEAMY FINISH

THE HEADER TANK CAP IS VERY EASY TO CROSS-THREAD; MAKE SURE WHEN YOU FIT IT, YOU FIT IT CORRECTLY!

Options:
- 1 PERSON JOB: Use a bar or similar to fix the throttle in position - ensure it cannot fall away (see above)

- 2 PERSON JOB: Use the willing person (member of your immediate household #MaintainingCV19rules) to press and hold the accelerator to maintain 3k rpm - warn them: 'do not release the throttle until I signal you to' - usually a tap on the shoulder; you really don't want to see above!!


HAVE SUFFICIENT COOLANT READY
(Genuine Porsche coolant needs to be 50:50 mixed with water to achieve the specified level of protection)

Note: From completely dry; the empty system can hold up to 28 litres!!

- Ignition on; switch heater to hot, fan speed 50%
- Switch off AC (rad fans off)
- Fill the header tank until no more is taken in
- Lift the bleed valve and lock it open (the wire catch stands up on its end and holds the bleed open)
- Fill the header tank until no more is taken in
- Start the engine and continue to fill the header tank
- When the level looks like it is full; get the engine revs up to 3k rpm and hold them there *do not release it!!*
- Fill the header tank until no more is taken in (can be as much as 5 or more litres still to go)
- Close the bleed valve
- Fill the header tank until no more is taken in (sometimes a litre or more)
- Fit and tighten the coolant cap
- Check the heater output:
Warm? - good! - allow engine to idle
Cold? - not good! - keep revs up til it warms up
- Idle 'til rad fans cut in
- When fans switch off; recheck heater output
Hot? - good!
Warm? - OK; lift the revs again; now hot? - good!
- Switch engine off; check for leaks
- Check level when next COLD and top up if required.


The above method was devised after many attempts at a successful bleeding; having already exhausted many different options - including seeing people jacking the car up onto its nose to get air out?!

A VACUUM BLEEDER IS MUCH EASIER!!

HTH

[eltax91]

Like this?

https://www.amazon.co.uk/YUAN-Professional-Radiato...

[Pope]

That's the kiddy; you need to find yourself a container to hold 30 litres of coolant and you're ready to go!

[eltax91]

Pope said:

That's the kiddy; you need to find yourself a container to hold 30 litres of coolant and you're ready to go!

Well I reckon I’ve taken out 10l already. That amazon item is on its way to me for tomorrow. I’ll need to wait for the anti freeze a little while longer.

For the remaining coolant that’s clearly still in the system, is it acceptable to purge it using the vacuum widget, or do I need to drain from the front rads too??

Thanks for the advice this far

[Pope]

Basically you need to ensure you have more coolant than you need in the container before you start. You will purge the filler (removing air) before creating a vacuum in the system; once the vacuum has reached its peak you switch a valve over and the car pulls the coolant into itself - if the filler gets air into it (pipe comes out of the container or you run out of coolant) the process will fail. It also helps to have the container higher than the header tank while you are filling the system. It's a siphon process I suppose. Goes without saying that you'll need a source of compressed air too - the bleeder kit uses a venturi to create the vacuum in the first place.

If the system (car) hasn't been drained enough, the vacuum will pull coolant back into the header tank and the tool wont create sufficient vacuum to complete the process. Sometimes, as the header tank fills you need to remove the drain plug again and dump the recovered coolant in steps - it helps to open the bleed valve (on the header tank) when you drain the system - drain it again with it open if necessary; and leave it open when you use the vacuum tool too.

Edited by Pope on Thursday 28th May 07:26

[996TT02]

G40, and having removed all 3 radiators around 3 times I never had any issue with refilling. I just filled up normally, put the cap clip/lever in the upright position for a short period and used the car, just checking levels and topping up as necessary. It's a Turbo if it makes any difference, no idea. Done years ago all is well.

[eltax91]

Pope. Thanks for all the help and advice. After much faffing to get the rest of the coolant out of the system, I used the vacuum filling tool for the job.

It went up to pressure nicely creating the vacuum. Held it for 40 minutes whilst I had a cuppa and then I started sucking up the 30l I had created in my nice clean bucket.

Car sucked up about twenty litres only but the header tank was up to max. I rather worriedly fired it up (bleed valve open), and it dropped almost immediately to the bottom of the header tank. 500ml topped it up and ran it for a while with the heater on full. When the stat opened it dropped another 500ml. So I’ve now 21l in there.

It got up to 80 degrees. Heater working fine. Air con roads kicked in and it’s behaved just fine. It’s SORN so I didn’t take it for a drive.

Anyone think I’ve got enough in there? I’m fairly sure I got low 20’s out of, but I never measured it so can’t be sure! I’ve read a few articles saying the C2 has 22 litres capacity?

I’ll be taxing it before the weekend, taking it for a decent drive with the bleed valve open and a spare 5l in the Pax footwell.

[Pope]

That sounds fine; 28l would be 'everything' completely dry. Weather due to pick up again to be able to get out too!

[eltax91]

I think I can most/ all of it out. Is the capacity definitely 28l, for a MY00 c2?

Reason I’m fairly sure is I left the stat housing return hose off and used the conical thing from the vacuum kit in reverse, and blew all the coolant out.