08 Boxster Cooling Sys

[vza]

OK....so to the next project. 08 Box Recently took it out for a drive engine overheated needle normal then suddenly pinned to right. Shut down immediately let it cool drove it home where it overheated again....shut done immediately. Then....the temp gauge stopped working(didn't move anymore) replaced the coolant temp sensor ....now it moves but the car never warms up(let it sit for 1/2 hr needle gets between 10-11 o'clock) No hot air blows from the air vent with temp thermostat on high. What gives ?? Stuck closed thermostat? Was going to drain the system ....planning on replacing thermo and water pump BUT wanted to do a compression test to even see what health the engine is in before spilling $$$. Can't get it to operating temp for the compression test. Thanks Vince

[JFP in PA]

Sounds like you may have a bad stat that is jammed open, which is better than jammed closed, which is probably what triggered your overheating event.  Pull the stat and look at it, if it is open, that is your culprit. 

[vza]

Will do. So if its jammed open water will be circulating thru the whole system and taking longer to get to operating temp? V

[JFP in PA]

Yes.

[vza]

Not many resources replacing coolant for 987. Would it be the same as a Cayman? 987 has no drain plug as in a 986. Thanks V

 

[vza]

Happy Holidays all!! Going to fill coolant sys with vacuum tool. Some say pinch 2 lines going to filler cap in trunk....others don't mention it. Also.. what to do with bleed valve open or closed during vac process. Thanks V  

[JFP in PA]

Merry Christmas!

 

There is no reason or need to pinch any hoses while using the vacuum filling system, and the bleed valve should be left closed during the process.  Simply mix the coolant with distilled water in a 5-gal bucket, drop the pickup tube to the bottom of the bucket, pull about 24-28 inches of vacuum on the system, then slowly open the valve to allow the coolant to be drawn in.

 

One of the biggest advantages of the vacuum system, besides speed and completion of a fill without any air pockets, is its simplicity. About 4-5 min after opening the valve to let the coolant flow, you are done.

[vza]

Ummm... after 4-5 min open which valve. Air bleed valve?

Edited December 26, 2021 by vza

[JFP in PA]

Because it is both the most common, as well as the best vacuum fill system, I will use the Airlift system as an example:

 

 

Here is a video of how to use it on a Boxster:  Uview instruction video

[vza]

Well of course its never that easy. Attached my vac.tool(its a knockoff from ebay) Somehow I can't draw vacuum on the coolant sys. I'm I missing something here? Did same in video except going off the expansion tank in engine bay. All hoses reattached and clamped, valve nice and tight in expansion tank. I removed the tool and attached shop air and plugged suction hole and it drew vacuum......it just doesn't work when attached to expansion tank. I had my compressor up to 120psi and just shut it down and connected to venturi. Should I have left it on so it would just kick in while connected to venturri.....didnt think I needed that much compressed air but maybe thats what my problem was. Thoughts?

 

 

Edited December 27, 2021 by vza

[JFP in PA]

Depending upon how big (capacity) your air compressor is, it may take some time for the vacuum to develop due to the volume of air it has to remove. Ideally, you need about 90 PSIG of pressure to make the system operate correctly.  The only other possibility is something is open in the cooling system; if you have a cooling system pressure tester, it might be a good idea to try pumping the system up to around 18 PSIG and see if it holds.

 

When we use the Uview unit, it starts to pull vacuum pretty quickly once the compressed air is started.

[vza]

Yeah I figured as such....2.5 HP 20 Gal. I'll give it another go, see what happens. Like I said I did it with the compressor off, so it definitely fell well below 90PSI while connected.    Thanks V

[vza]

Just for peace of mind after a potential mistake.... I introduced some compressed air thru the overflow tank to force out residual coolant when Flushing. Four hoses were disconnected at the time and coolant came rushing out. Now I'm reading you can damage head gaskets and seals and so on if you over pressurize...considering the system was open(disconnected hoses) I'm assuming I didn't cause any serious damage. Thanks V

[JFP in PA]

First of all, you should never apply high pressure air to any cooling system; your Boxster’s system was designed to see a maximum of 18 psig pressure, anything higher could blow out seals and gaskets anywhere in the system, and even fracture the end tanks on the radiators. .  This is exactly why cooling system pressure testers use hand operated pumps and not compressed air. Bad idea.

[vza]

Ok...well now I know better. With all your experience and knowledge....what do you think ? considering the system wasn't closed. Any damage? Thanks V

[JFP in PA]

If it was open when you applied the pressure, probably not, but the only way to know for sure is to close up the system and either see if it holds vacuum or pump it up with a true system pressure tester to 18 psig and see if it leaks down.

[vza]

Ok thanks. Leak test done....gasket out of place on newly installed Water Pump, holds pressure now. Will move onto filling with coolant. V

 

Edited January 4, 2022 by vza

[vza]

Did the best I could adding coolant with vac sys. I wasn't able to completely remove air from the hose when priming it with coolant so some air got in the system. (air bubble in coolant pick up hose)I ran the car at idle for half hour got a blinking light for low coolant kept revving and adding coolant with the bleeder valve open couldn't get the light to stop. Another thing .....my temp gauge didnt budge and heater is blowing cool air. Then my AOS failed....bellowing white smoke. Ugh.