nickb524

I've got a '13 c2S with about 60k miles on it. First time I got the error message it turned out to be a bad changeover valve, had it replaced no problem. After about another 1k miles, I now have another Coolant System Error message, this time they're seemingly having a lot more trouble pinpointing the problem and I've been told it's related to a vacuum line. They can't identify exactly where a vacuum line has come loose or frayed to throw this error. So today they told me the next step would be to dive deeper to inspect / replace all of the vacuum lines, and quoted me around $1800 give or take depending on where the issue lies.
I should also note, about 300 miles ago I had a Fabspeed Valvetronic Exhaust System installed. I figured this had to be the problem but they say it has nothing to do with that and everything looks fine in that regard. I think this cost seems absurd compared to other scenarios I've read about on these forums, especially considering its not a giving a bad COV reading. I'm very interested to hear others' thoughts. Has anyone else experienced anything like this? What was your solution?

dannyk304

I've been going through something a little similar - had the code come up and checking through it looked like the COVs I could inspect were fine, etc. It is likely that it may be a failure of a vacuum driven component, not the line nor the COV. For instance, I've noticed my Symposer no longer symposes...or whatever. Therefore, seems like the actual component on the airbox is busted and I will be capping that COV as I don't care much for the symposer and buying a new airbox is unnecessary. Once capped I'll clear the code and if it comes back then I'll need to keep looking. It is possible that the valves that control the exhaust flap are failing - not holding vacuum and that's the issue. But one thin you can do is look at the operation of certain parts - does your heater work - put it up to full blast on high when the car is warm, if it's not blowing hot then at least you know one direction to search. Does your Symposer work? Does the exhaust button actuate the flaps? does your car overheat (engine coolant cutoff valve issue, or even transmission coolant valve issue.) etc. If all these components are working, it could be your vacuum pump - how's your brake pedal? It is pretty annoying that it has to be a scavenger hunt but best insight I can provide that may give you a direction to follow. Good luck!

nickb524

The exhaust button works - mind you- my car didn't have the PSE button, but with the fabspeed valvetronic I have a separate system on my keyring to open/close the valve. Works just fine. The heat works, Brake pedal feels normal. Car isn't running hot at all. Not sure about the symposer, how does one even know if it's working or not? Will look into the vacuum pump.

Catharpin

I would start with plugging the 2 that are easiest to reach and the most useless, the air cleaner flap and acoustic simulator. After that move on to the others. Here is a good post showing locations. https://rennlist.com/forums/991/8002...l#post13043586

IXLR8

I do not know what your skill level is, but you might want to look at page 62 - Vacuum System in that document.

And if I were to replace vacuum lines, I'd do it myself using silicone tubing with a Durometer so that they cannot collapse during vacuum. Those lines last forever and can take heat.

dannyk304

If your brake pedal feels perfectly normal, the vacuum pump is likely fine. you'll know if the symposer is working when you press sport and it gets a bit louder inside the car, or if you're gunning it and break 4000 RPM and suddenly your car starts screaming more. If there is no perceptible change inside the cabin then your Symposer isn't working - could be the COV, could be the line from the COV to the airbox, or the symposer itself is busted. Or the airbox flap - for which I have no idea its actual purpose.