I have a 2013 Boxster S with about 95,000 miles on it. I was out driving it hard in the canyons, when the water temperature went very quickly from 194 to 261 with a message to stop driving and add coolant. The oil temperature never rose above the normal temperature level. I immediately pulled over and checked for leaking coolant and checked the filler cap in the trunk to make sure it was not overflowing. All looked ok. Since I was in a remote area I decided to try to limp it down the mountain. The temperature went back down to 194, it went back up once, but never above 261 and the oil temperature never elevated. It went back down to 194 and stayed there as I drove it to my local mechanic about 40 miles. My mechanic said there was a broken plastic tube that went into the water pump. He replaced the tube, the water pump and the thermostat. I'm still having the intermittent overheating issue, he said that there is a large air bubble in the coolant that he cannot get out. He has tried flushing it 3 times, but he said Porsche has a special machine for this because there is such a long path from the radiator to the engine and he does not have one. He said that I either need to take it to the dealer or a shop that owns such a device. Does this sound correct? Thanks.

 

At least on my 987.2, the dash needle is well known to be heavily "buffered" by the ECU. It's not a real reading, and will read 175F even though it could be significantly higher. In that sense, It's good to hear that the ECU still told you that there is an issue, but you can't trust the dash needle that much. A scanner can tell you the actual temp (Foxwell NT530, Durametric, PIWIS, and many others).

I agree, it sounds like you may have air in the cooling system. Yes, Porsche has a machine to help refill the coolant, but you can get a similar device at low cost. I've seen this one recommended by people: https://smile.amazon.com/dp/B09BKV9XZQ - one guy actually bought this and then gave it to his mechanic to do the work on the car. It's a great way to get all the air out and makes filling these cars very easy and reliable.

I actually had my coolant flushed by my shop without this equipment. The guy said it took him a VERY long time to do it, but he succeeded... so it can be done without the tool, but next time I'll certainly give them this tool... it's a cheap and easy way to ensure your car is serviced properly!

 

Yes, but all that is needed is a simple vacuum pump, which most indy shops should have.

Just curious, how much did your mechanic charge you for this work?

 

Haven't received final invoice, but estimate is $1,500

 

My mechanic also used a vacuum fill device to replace the coolant in my 996. Those systems are really worth it - I wouldn’t do it any other way. No bubbles.

 

That sounds like a very fair price.

 

IME you have to drain almost all the coolant out, then use a vacuum fill.


not difficult with a lift, but lots of work, panels to remove, etc.

I would think it a real pita to get air out without the tool, and risking overheating.

Just did this today, installed a 3rd radiator.

 

Well, doesn’t the vacuum tool do both (drain and fill)?

 

I drain first by loosening the hoses, don’t know how efficient the Venturi would be draining 4+ gallons.

 

My advice is to never take your 981 to a mechanic to do work that doesn't have the correct tools to do the job. The AirLIft tool for properly refilling coolant costs less than $100. Also need a reasonably powerful air compressor but that's something any shop should have that works on cars.

The plastic tube that cracked is a known weak link on the engines. I just recently replaced mine when doing some major preventative maintenance work. Car had 51,500 miles on it, the original part looked fine, I saved it as a spare.

 

Can you tell me one specifically you are referring to? "The plastic tube that cracked is a known weak link on the engines"

 

Part number 13 in this image. Porsche part number 9A1-106-026-31. I found it at porschemarinparts.com for $62.73, list price is $90.41.

 

Perhaps I am wrong but I seem to remember that the 981 cars need to be hooked up to PIWIS in order to be properly "burped" of air bubbles in the cooling system after coolant change?

 

PIWIS is not required to successfully refill the cooling system on 981 cars. Use an Airlift vacuum extraction/refill tool properly and PIWIS is not necessary. Before I did it on my car the first time, I talked to two race prep shops that prep 981 cars and they both said they don't use PIWIS for coolant extraction/refill. I believe what PIWIS does is open the disc valves for the gearbox coolers and possibly the cabin heater flow valve. When I start the engine the first time after filling coolant with the Airlrft system I turn the cabin heater on with the temp set to max to make sure the heater core has maximum coolant flow to help move any trapped air through the system. I've done the refill procedure twice with the Airlift tool on various projects with my car and I've never had to top up with more than 24 oz., most of that added the first time the engine goes through a full operating temp to cooldown cycle. It's impressive how well the Airlift system works if you are able to get the vacuum gage to the recommended level. This requires an air compressor with sufficient airflow and pressure capability.

 

^^^^This. I also have performed two drain and fills on my 981CS and used the Airlift with great results. Once for a FF1 engine mount insert that requires radiator hose removal and again for a center radiator installation. I do have a large 60 gallon compressor and was able to pull 25” of vacuum but there are tricks with a small compressor by doing it in stages that should also work. I think that the more complete the drain that the more successful the vacuum fill is and not for a top off​​​​​​. I did leave the top engine cover loose for a few heat/cool cycles and added a few ounces of coolant to make sure I had a complete fill before reinstalling the engine cover and carpet and trim. There is also a air bleed (comfort valve #5 on diagram) which is a network of lines from the tops of the radiators and heat exchangers and high spots in the system to the valve at the top of the coolant expansion tank that vents the air pockets internally to the expansion tank. That control valve can also be manually flipped to an open position and can go through a heat cycle for a more complete bleed……at least that’s my theory 🤔.
Jim