Vacuum Coolant fill system

[dgcantrell]

Ok folks... I'm getting really frustrated with getting ALL of the air out of the coolant system on my 944. I used to be able to do this without an issue but now it seems I'm not, to quote Toby Keith, "as good as I once was"... LOL I recently saw a vacuum refilling system for the 944's (and possibly for Audi) that will allow you to pull a vacuum on the system (this is helpful to determine if the thing is leaking also) and refill the coolant without having to go through the bleeding process. Does anyone know where find one?

I found some of my problem (a cracked hose nipple on the coolant reservoir) but it's still running a little warmer than it ever did. I'd like to get the vacuum kit just to check for leaks more than anything. The AC Condenser may be come of the issue on mine too. It's damn near beaten to death from almost 30 years of driving. I have a fin-comb that I hope to comb out the closed up portions as perhaps there simply isn't enough air flow getting to the radiator behind it.

Still, I'd love to snag a vac coolant fill system to make it a heck of lot easier.

[v2rocket_aka944]

1) make sure all connections are tight
2) fill water tank with water, until whole radiator/engine system is full
3) jack up front of car and start engine with bleeder screw open
4) let it run to temperature and keep adding water as necessary...
5) shut it off, put it on the ground, run it again and add water until solid water stream comes out the bleeder screw
6) shut bleeder screw, turn off car

[Arizona_928]

^^^
Doesn't get better then that.

[dgcantrell]

I've done all of the above many many times before. There's a 12mm in the console under radio right now.. LOL I did have a small crack in the coolant reservoir that I found last week. I've replaced it and I'm not loosing coolant any more. The past couple of days, I've not gotten any air out. I'm leaning toward the A/C condenser is just blocking too much air flow.



I still want to get one of the vacuum coolant fill things though.

[djnolan]

For better cooling, have your radiator back flushed with soda water and run only the minimum concentration of antifreeze.

[dgcantrell]

I've taken it out and flushed the hell out of it.. I've even run straight water it in from time to time last year when I put a new thermostat in it. I'm almost certain it's the stupid A/C condenser blocking air flow now.. If temps are below, say, 40F, it's fine.. Above that and it gets warm, as in touching the top mark on the normal operating range on the gauge. It never ever ran more than halfway before. I guess the heater core putting out the excess heat is just enough to keep it at the temp I'm used to seeing on the gauge.. It's not overheating, mind you.. Just running a little warmer that it ever did before.

[Arizona_928]

have you upgraded to the late radiator fans?

[djnolan]

I have similar issues. Do you have the belly pan installed? It helps with the flow of air through the engine compartment. Do you have the 70C or the 80C thermostat? Do you have the cast or tubular exhaust header, tubular possibly helping with heat dissipation? Are you seeing a large drop in oil pressure at idle?

[dgcantrell]

It's an 87 so it does have the cast iron exhausts but does have the updated fans. They are working fine. The belly pan is installed. I can't remember what temp the thermostat is that I put in it but it was the same as the one I pulled out of it when I changed it last. It's just never run this warm before and I've had it apart many many times (broke two timing belts over the years due to idler pulleys going sour). I don't drive it near as much as I used to but it is my backup daily driver and I drive it about 3 or 4 times a week. I'm almost certain now that it's due to almost 30 years and 270K miles of debris slowly bending the fins of the lower part of the A/C Condenser to where it's starting to restrict air flow to the radiator. I'm going to see if I can comb it out this week to see if the cooling improves.

[v2rocket_aka944]

You'd be surprised at the amount of stuff, birds, rocks, coyotes, etc that gets stuck in the condensers.

Maybe this is your excuse to get an upgraded condenser... I don't make them anymore but Griffith's does.

[dgcantrell]

I'd really like to get my AC going again at some point. It's not working and has no R12 in it anymore. I was thinking of doing the R134 update on it at some point. But since I'm going to be downing it to address some rust issues soon, that has been put on the back burner for the time being.

[djnolan]

Are you saying it is running at the 100C mark on the gauge? If so I would suspect a bad thermostat. Sensors and Gauges - Information, Troubleshooting, and Testing

Here is one I hadn't heard about before: When Porsche changed the water pump on later 944s, the depth of the snap ring groove from the thermostat sealing surface changed. This required the use of a different thermostat and thermostat sealing ring. If you get the wrong thermostat it can cause cooling problems. This is described in COOL-07.

Water Pump Information and Replacement

[dgcantrell]

It doesn't always run up that high. It usually runs just above the low mark. But on a hill climb of a couple or three miles it will get up there close to and sometime touch the upper mark. It never did that before.

I made sure the thermostat was correctly sealing when I changed it out 4 or 5 years ago when I had to replace the cam tower gasket. I went head and did a full timing belt replacement at that time too.

Like I said, in the winter when the temps are below 40F and I have the heat on, it does not get near the top mark on the gauge. The cooler air and the additional cooling effect of the heater core probably make up for the lost airflow caused by the gummed up AC Condenser.

I'll get it combed out this week. Heck, I might even just remove it for the time being to test my theory. There is no refrigerant in the system so.

[djnolan]

A 70C thermostat might give you a little more temp/time reserve for a short burst on the throttle.