i did a complete drain of my cooling system. I removed the engine drain plugs. is there any thing I should know about refilling. I am afraid once the thermostat opens, I am going to get a big rush of coolant into an empty space. any tricks??

I know to have the heater calling for heat.

Also how much coolant does an s4 take. I have 2 gallons, and I bet that may be about 1/2 of what I need.

Just don't want to have come this far and make a stupid mistake...

thanks

 

There may be better ways, but I fill up the block before installing the thermostat as pictured below.

Running the water pump dry for any length of time is really bad for its seals, AFAIK.

(Pet friendly type green coolant.)

 

I'm interested in tips & tricks on this also. I believe that my post-TB/WP overheating is due to an air pocket.
Was not overheating before the swap. I forgot to turn the heater on the first time after refilling and overheated. Turned the heater on and thought I had it whipped because no overheating on a test drive. Then it overheated again.
I swapped the thermostat and inner seal. No overheating on test drive. But next time out it overheated again and blew the lower radiator hose off the fitting. Pressure testing the system after refill showed a possible bad coolant tank cap, but no overheating on first test drive after that refill. Next drive, guess what? Yep, overheated. Swapped the coolant tank cap this week. Still overheating. Arghh.

So, refilling tips and air-pocket elimination techniques appreciated.

 

As I remember the system takes about 14 litres of coolant which is about 3.5 of your puny US gallons [that is about 3 Imperial gallons] !

I find the trick to successful filling is to run the motor without the pressure cap at idle and let the motor warm up with the heater controls fully engaged, you will invariably see the level drop in the header tank [top up as required] and when the motor has reached 80C [thermostat open] start to burp the system by giving the main top hose [from the thermostat housing] a series of two handed hefty squeezes and watch the level. The coolant should not boil unless you have a latent problem but obviously take care- you may need some industrial gloves to protect your hands.

rgds

Fred

 

The thermostat isn't air-tight. The block will fill well enough.

My "trick" is to remove the small hose from the top of the radiator. Fill through the overflow bucket until it dribbles out and then replace the hose. I'll over-fill the bucket a bit to 3/4 full as there'll be air in the system.

The first time you run the car it'll purge itself. Then top it up.

There are no weird air bubble problems with these cars.

 

I agree with Glen no weird or special bleed and burp needed on a 928...944s however did have a bleed screw due to the reservoir being mounted lower. Porsche 928 has the small hose from near the top of the thermostat housing to constantly bleed off any residual air.

 

Ive done it both ways. the block takes about 1.5 gallons alone, the rad and everything else about 3 gallons. I use G-05 and 50% distilled water.

 

My understanding is the same that the system and s self burping. The procedure I was told from Sean was to fill the system with the engine off, until it fills the bottle. Start the car, turn the heater on and with the bottle cap off keep filling as it needs it. Come up to temp and shut the engine off. Let it cool down and refill the bottle and you are done. To make sure that the system is full keep a track of how much liquid you put in. And make sure you put in 3.5?? US gallons. I use G-05 and distilled water 50/50 mixture.

 

If you are overheating check the connections to the fans. When the car is overheating make sure both the fans are on.

 

You need one of these: http://www.ebay.com/itm/Porsche-928-...f4f7d6&vxp=mtr

Owners have over filled on an oil change and put power steering fluid in the P/S res.

 

Timely thread since I'll be doing this soon.

I also plan to flush distilled water through the heater core.

I don't agree or disagree since I've said the same thing over the years based on hearsay posted / talked about since the dawn of time.

However......when I think about it. Does this only apply to pumps that have been exposed to coolant? Otherwise any pump sitting on the shelf for any length of time is suspect.
Is there is a risk of any pump stored in a really dry area to "go bad" before it is even used?

Or are we talking about the pump to block gasket "drying out" not the internal pump seals?

 

In my opinion, the pump bearing is not supposed to see any coolant. The bearing is supposed to have a seal to keep the coolant out of the bearing. Once this seal is compromised, the chances of the bearing going bad are increased and the pump should be replaced.

 

If the pump is stored and the impeller is static it should not do any harm unless we are talking about a really long time [i.e many years] in which case the material of the seal face likely will harden because it is not flexing and then ti is no use as a seal.

Running the pump with no liquid will do the seals no good whatsoever. The seal [presumably a lip seal] relies on the coolant to lubricate the seal face when in motion and if run dry it will simply tear the seal face in no time, however, who runs a motor with no coolant? In such circumstance pump failure is acedemic.

Regards

Fred

 

You've got something else going on in there. The 928 cooling with the exp fill tank at the rear of the engine bay is one of the easier systems to fill. The Sean method works fine. Fill the exp tank, let it sit for 20 min then fill again, let it sit a bit, fill again(coolant will fill through the block and to the pump), then turn on the engine and heater on hi. Let the engine warm normally, I tend to burp the lower hose a few times by hand but you don't need to really. Just warm up normally and keep filling the exp tank every so often. Once you are near the top, you can rev it a bit to purge out any small bubbles along the way, but it's pretty self burping.

I think you have a problem in the thermostat or water pump area. When I did my TB/WP I had no troubles with the cooling system to start with. Now I'm having some issue but it's not overheating, just not staying where it used to run. I think mine is a sensor fault.