Flyntz

Hello all,

New to the forums and posting while on the train to work, so please forgive the poor posting.

I recently purchased a 2000 Boxster S with 70K miles and immediately fell in love with it. As a precaution I went ahead and upgraded the IMS and while doing so they also replaced the thermostat. Things were smooth driving so to speak until about a week later I laid the biggest smoke bomb I've ever seen.

Needless to say I had them replace the AOS. 2 days later my coolant warning light started a slow blink so they topped off the coolant level. Again smooth driving for a day. Yesterday after some neighborhood (house hunting to be exact) driving and then a quick jaunt on the interstate resulted in a huge smoke session that lasted briefly then went away. After parking for 15 minutes , I started it back up and there was a slow steady stream of oil smelling smoke (blue).

My question is this. Can this be expected after an AOS replacement? Am I just burning off the residual oil or is this indicative of a failed AOS install?

Thanks for reading this tl;dr post, any advice welcomed.

-Flynt

sjfehr

What's your oil level like? High oil levels can stress AOS and cause them to fail. It could just be residual oil, as a failed AOS will coat your intake manifold, but it should be readily apparent soon enough if it's getting worse or better. Just be careful, as you can risk hydrolocking your engine if too much oil leaks into a cylinder.

Flyntz

Thank you for the insight. Currently it's at the shop (they're checking the AOS at the moment to see if there is something odd going on) I'll mention the oil level to them, although I would expect an authorized service shop to know about this already. Crossing my fingers things are alright. It's a shame, but I'm a bit gun shy about driving it now. Nothing worse than driving along with the top down in the nice California weather, taking off from a stop light and blasting the neighborhood with smoke.

sjfehr

Hopefully it's something that simple. If the shop overfilled your oil after the IMS replacement and caused two AOSs to fail, it's THEIR problem to fix, not yours.

These engines are amazingly strong and just love to be flogged. Take it easy until it comes up to temp, but don't be bashful after that. 2000 Boxster S with 70k miles should still be highly reliable for years to come. My AOS failed years ago, and I've not been shy about flogging it since.

Flyntz

Well I must say I'm pretty disappointed. Shop called me, they've had a pressure test on it all day, leaking coolant. Looks like a head gasket (they're going to dig into it this morning). Sounds like it's been roughed up previously. None if it caught at time of purchase check with the Dealer shop or the check during IMS install. Consider me deflated.

Macster

There can be some residual smoking after an AOS failure that includes the failure mode that supplies to the engine (via the intake) with some crankcase oil.

But this should be over with after a reasonable road test after the AOS repair.

I'm troubled by the low coolant. But it might be due to a bad coolant cap. You should replace the old one with a new one. Do this with the engine dead cold. Remove the old cap, clean the spigot where the cap threads on and seals of any residue. Make sure the coolant level is ok. Add distilled water if you have to bring the level up some. Install the new cap. Give the inside of the coolant tank a thorough inspection looking for any signs of oil droplets. There should be none. If there are...

If the coolant level drops after this suspect a cooling system leak. A common leak point is the coolant tank, though with a used car the radiators are suspect -- if the previous owner was not religious about keeping the radiator ducts free of trash build up -- and of course to add to the suspect list any hose or hose connection, the water pump, the oil/water heat exchanger, the heater core to name the biggies.

If the oil level is ok, if some reasonable acceptable oil is in the engine, if the smoking continues -- with no other symptoms -- one has to suspect a botched AOS installation or a bad out of the box AOS. There could be other symptoms if the AOS was bad: Rough idle or a too high (or too low) idle speed; maybe some backfiring through the intake; CEL with mixture related error codes.

I'd try to eliminate the new AOS and its installation ASAP with ideally no engine running until the AOS has been inspected and if any issues found addressed, even if this means replacing the unit -- because it is defective or suspected of being defective.

If the oil level drops, if the coolant level drops, or goes up -- for both fluid levels you must be very accurate, precise, and disciplined how you determine there has been a change in fluid level or you will scare yourself silly for nothing -- there is probably (I say probably) something else going on that is allowing either oil or coolant to get into the engine or oil or coolant to intermix.

Flyntz

Intermix for sure. They are going to be looking into the heads to see if there any cracks (or erosions) allowing this intermix. Which means a few grand for repairs if they can even repair it,

Needless to say a heartbreaker. Always wanted a Porsche and this is a nice looking ocean blue Boxster that drove like a dream...for all of a few weeks.

I'm not sure if it comes down to it and I have a need to replace the engine if I'm even going to hang onto it. Thorough disappointment souring my experience. I wish I had known about this forum beforehand. But let me be honest, I'm not sure I would have even known to ask for a check down to this level.

sjfehr

I've never heard of a head gasket failure on these cars. Cracked heads in a few extreme cases, but loose/failed coolant caps and failed AOS are a lot more likely. I'd still point fingers at the shop because the car was running fine before you took it in for the IMS & thermostat.

Flyntz

Well I have news some bad most good. Turns out I had a cracked head. Pictures will be forthcoming. Was able to get it replaced by my local shop European Autotech. Tim and Chris did a fantastic job getting my baby back in shape. Drives great, got the back window replaced, looks new. Finally a good ending to the story.

Macster

Thanks for the update. Glad to read you got the problem resolved. Do you know where the head was cracked?