Nathan Lewis

Hi,

My first post here, I hope its in the right spot. I have a 996 turbo with about 85k miles. I've only had it a few months.

I have had an off and on coolant leak, which I am 99% sure is due to a cracked expansion tank. (I can see orangish waxy substance on the outside of the tank, and what started as a slow leak has totally emptied the expansion tank the last two times I had it out. It took half a gallon of distilled water to refill it.) I have an appt at a shop to get that fixed.

BUT, my question is as follows: I took the car out for a short drive tonight after refilling the tank, to see if it would leak as badly as it did last time or if it had gone away again. (Plus I just missed driving it.) Anyway, under hard acceleration the CEL started blinking for about 5-10 seconds, then it went off. I kept driving because the light went off. I tried one more time to accelerate hard and the same thing happened to CEL blinking for 5-10 seconds then off. I noticed the power seemed to drop off also.

Any ideas if this is related to the coolant problem?

Is it safe to drive to the shop (5 miles away) so long as the light is off?

"02996ttx50

totally safe as long as you're sure its the tank ( which is probably correct given the commonality of failure of them ) so yeah, if you've got coolant in the tank that you can see, and no cel's if even only temporarily? then sure drive it to the shop and swap it out.

rmc1148

Agree they will read the codes, make sure of course the coolant level is up before leaving.

Tuxiemama

boost leak ?

993GT

I'm betting misfires, replace plugs/coils

Nathan Lewis

Thanks for the thoughts. I hope they can read the codes since it is intermittent. When I got home I could go down in the menu to "check" and see the notice. I turned it on again last night to pull in the garage and the notice is gone now. Does that mean the code is erased from memory too?

Nathan Lewis

Oh one more thing, my boost gauge from time to time will momentarily go up to 1.5 bar. Seems like it did it more often in cold air. Is that reasonable for a boost spike? Most of the time it only gets to 0.7 or 0.8. So far as I know the car is completely stock.

"02996ttx50

probably a vac leak check the hoses and easier connections e.g. tug on the ic hoses. y pipe etc. that could be your boost spikes or even wg's being out of whack adjustment wise or a bad n75 but probably something simpler. keep it easy then work your way down the diagnostic list. could even be a cracked check valve at the plenum. i had similar symptoms and thats what the boost spikes were, though i messed with my WG's and replaced my n75, it was ultimately a $20 check valve casing me the consternation.

you may have a soft code stored ( probably ) in the ecu and you'll have to get the codes read.

this has nothing at all to do with the hairline crack you have in your expansion tank causing the coolant leak ( waxy coolant residue outside the tank ) thats gonna need an r&r for sure.

time for the shop. good luck

wross996tt

Do yourself a favor and get Durametric. The codes will be stored and those codes can be read by the Durametric (don't get just any code reader). Flashing CEL's are not good. Without the codes, all of the above are just guessing...we'll be glad to spend your money too...LOL

rmc1148

He's taking it to a shop, don't believe he's a diy sort . Having a durametric is great if you do your own work otherwise?

wross996tt

And we can assess your mental state and whether you are a DIYer via the web...LOL

rmc1148

If he's taking it to the shop for a simple fix like coolant reservoir I am making a guess. But really do not care just trying to help and yes the Durametric is nice to own if for nothing else keeping shop somewhat informed/honest.

wross996tt

just yanking your chain...no harm intended.

rmc1148

I have calluses around my neck from years of chain pulling= all is good lol.

Macster

My WAG is the coolant tank leak is wetting the coils and this can have the coils misfiring.

I have driven my Boxster several miles to the dealer after the coolant tank gushed its hot contents to the ground one day. After letting the car sit overnight the next day I filled the cooling system with with distilled water -- a gallon at least -- and seeing no signs of leaks started the engine and drove the couple of miles to the dealer with the cooling system still fluid tight. The engine never got up to operating temperature in that short of a drive though.

If the CEL is on and the error codes are just misfires and the CEL doesn't blink you are probably ok to drive the car.

But if at the first sign of any deterioration of the engine's behavior shut off the engine ASAP and arrange for a flat bed tow.

Have the coolant tank replaced and I would think the coils and even the plugs -- they are scheduled to be replaced rather often regardless -- replaced at the same time.

Also, I'd flood rinse the engine with a bucket or two of hot water to rinse away any coolant residue or the engine will reek of anti-freeze for a while afterwards.

If you do this be sure you start the engine -- the belt will likely slip initially you can see the volt meter gage reading low (~10) volts -- and let it idle until the meter reads nearer to 14V and then drive the car enough to bring the engine up to full operating temperature and keep it there a while to ensure the engine is completely dry after the rinsing.