When to flush coolant? Coolant Expansion Tank Question
 

Just looking for a bit of advice here:

1. Is there anything else I should change while replacing the coolant expansion tank? I also have an updated coolant tank cap.
2. Should I flush the coolant or would it be acceptable to refill with existing coolant/add distilled water? Something tells me I should hold off on flushing the coolant till I do something more invasive like change hoses, etc.

Thanks

Ahsai has a great writeup for getting all the coolant out and refilling. Only requires removing a couple hoses and the drain plug. If your water pump is original I would do that too.

https://rennlist.com/forums/996-foru...pump-tips.html

You do not have to completely drain the coolant system if your coolant is not that old. Remember, Porsche considers the coolant lifetime, but it is a good idea if you care about the car to do a coolant flush and refill if the coolant is over 3 years old. Since your job is the coolant expansion tank:
Car/engine stone cold
Remove expansion tank cap
Get a large roaster type aluminum pan and slide it under the engine as a drain pan
Open the coolant drain plug on the bottom of the engine and start draining
Once the level drops below the coolant tank, reinstall the coolant drain plug. You don't have to drain it all for this job.
Replace coolant expansion tank...a PITA job because you will probably have to lower the engine
Get one of those remote clamp removal tools for the spring clamps on the coolant tank hoses
Once the new tank is in and fitted, fill the tank to somewhere between the min/max line with a fresh 50/50 mix of Porsche coolant and distilled water
Leave the coolant cap off/or loose and start the engine. Watch the coolant level in the tank...it might drop a little bit
Once the engine starts to get warm fully tighten the coolant expansion tank cap and manually open the burp valve on top of the coolant expansion tank
Go for a short drive and get the engine up to temp
Then go home and park. Leave the burp valve in the up position and let the engine cool down.
Check coolant level again, add some if necessary. I leave the burp valve in the up position for at least 4-5 heating/cooling cycles to ensure the coolant level is stable and no air is in the system.
Anytime I'm working on the coolant system, I always replace whatever amount I drain from the car with a fresh mix. Just seems like a good idea.

Replace your AOS and your starter/alternator Y-cable while you are at it. Also replace all vacuum hoses for the SAI system as you will have access. Replace your water pump if it has not been done. Also replace the plastic coolant connector near the alternator with a metal one as they get brittle and snap off.

The water pump was replaced at the end of 2012, so the coolant is older than 3 years. Appreciate the input Joe!

AOS was replaced about 30k miles ago, so I don't think it's necessary to that just yet. The Y cable and and vacuum hoses sound like a good idea! Replaced that connector when I had to do oil filler tube. Thanks!

I read the water pump should be replaced every 4 years as PM. So maybe now's a good time to tackle that anyway.

Huh? I think I'd rather change cars before I'd change the water pump every 4 years

Well, depending on your luck and how long it's been since you changed your pump...you may not have a choice soon. Good luck!

https://rennlist.com/forums/997-foru...xcellence.html

This sentiment has been echoed by my reputable mechanic.

Replacement ever 4 years seems very inefficient and quite wasteful. I've not had any issues with bearing noise, leaking, or signs of damage.

I'm probably going go through with a flush, and replace with Porsche fluid.

Water pumps has already been replaced. Thermostat might be a good idea, as it was replaced in 07.

I'll take a look at the hoses in the area and figure out what I should replace.

Bumper removed and radiators cleaned last month. :)

Sounds good, if you're going to drain/refill, I'd def suggest at least changing out the main hose coming out of the bottom of the tank. It has a plastic connector that over time dries out and gets weak and will leak. IIRC, it's part#: 99610685006

For those debating the water pump, it's super easy to access and swap out -- not sure what the hesitation is to change periodically given the bearing does wear out and if it fails, it's blades can shear off and get lodged in the pipes or worse, in the engine. Sorry, but i have no problems spending a couple hundo and an afternoon swapping it out every 4-5 years vs way more trouble if neglected. Coming from BMW, the coolant systems in german cars designed for far more mild climates is just not something I leave unserviced. My $.02.

That's fine its your car and you can wait for symptoms. But if the impeller blades come off, just make sure you check to see that you have all the pieces accounted for. Hasn't happened to me, but if pieces are lodged in parts of the cooling system, my understanding is that it can cause localized hot spots that may not show up on thermostat and cause some serious damage.

Or you could just change it every 4 years. Like JL said, I just don't think it's worth saving a few hundred bucks every 4 years. But I guess you can always flush the coolant to get all the pieces out if it does happen. Your car your call.

Just a couple of notes of the coolant. I believe the cold coolant fill line is the min level, it should expand when engine gets up to temp. Slakker has indicated you can also add some water wetter. I put in a bottle, not sure if it did anything...I just had some laying around. Getting the clamps off, the clamp removal tool personally did nothing for me, channel locks were more useful in my experience. I don't know how people remove the tank without lowering the engine, if you can, you should probably be shade tree tech on the side. I think you will want lower the engine as much as you can - there are threads on how to do this. If you're as clumsy as I am, this might be helpful.

https://cimg3.ibsrv.net/gimg/rennlis...408296774f.jpg