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Tried posting this yesterday with a photo but for some reason it never showed up? I'm in the process of changing the AOS on a new to me 2003 C4S and found a bunch of coolant pooled up on the drivers side of the block near what looks like it might be a knock sensor? I'm changing the AOS because the PO had bypassed it because of a broken nipple where the coolant line that runs toward the passenger side of the AOS connects. No idea how long ago this bypass happened and the car still has a slight coolant leak which could be water pump (changing that and the thermostat also) or maybe a bad reservoir cap (seeing some white crust around the cap anyone have the replacement part no?). Also changing a bunch of coolant hoses and vacuum lines during this AOS change. I'm curious if this could be old coolant from when the AOS broke just not evaporating, or if it's coolant from the possible bad cap somehow, or if there's another possibility I should be trying to track down while this is all apart? As a side note I found the connection to the changeover valve under there completely broken which should be responsible for my P0413 code and also have to change out the wire from the starter which is totally corroded.
PS if anyone has any hints on getting the AOS 5mm bolt closest to the rear of the car back in I would appreciate them, took forever to get it out...
Part #: 996-106-447-04 Water cap (blue). There are many places to buy such as Warehouse 33. Cap needs to be tight...repeat tight...ask me how I know... "Bad cap" leak should drain down near the exhaust on the drivers side and wouldn't pool "up on the drivers side of the block", in my opinion.
Interesting that someone would just disconnect a bad AOS!
Didn't he mean disconnected the coolant lines at the AOS ? Not all the other hoses.Oh , how I wish you could just disconnect it !
The other potential leakage item at the top of the engine (different area I know) is the Heat Exchanger.
If you specifically ask the 996 guys (I am 986) ,they may say in a warm climate it is O.K. to do a bypass with the coolant to the AOS.The Boxster has no such coolant connections because(?) the AOS is in a much warmer location on the 986 compared to 996
"if anyone has any hints on getting the AOS 5mm bolt closest to the rear of the car back in I would appreciate them, took forever to get it out... "
Try 1/4" drive 'wobble' extensions in every conceivable length, different depth 1/4" drive sockets.
Does anyone have any idea if coolant evaporates or not though? Also I'm guessing the heat exchanger is the blocky square thing over towards the passenger side? Does it leak often and if so from where?
Ceaned up one puddle before I thought to take a picture
The oil/coolant heat exchange unit located on the back right side of the engine has a set of O-rings underneath for both oil and coolant. My understanding is that to replace those is an engine out job. 18, 19 and 20 here http://www.autoatlanta.com/porsche-p...section=104-00
Thanks for the heat exchanger parts diagram, it's completely dry over on that side so I'm still a little stumped. Do those puddles look to anyone like coolant could have pooled up there a couple months ago and the water evaporated? The only thing I can think of is when the AOS nipple broke a lot of coolant shot over that way although I have no way of knowing when that might have been, it was a california car so it could have been running with the aos bypassed for a bit. The only other thing I noticed that really odd dealing with coolant is that as I was changing the water pump I knew to watch out for some bolts that were longer so I took great care to lay the bolts out around the new pump in the same order I pulled them out and even marked the new pump where the two longer bolts were supposed to go, then when I went to reinstall them the two longer ones bottomed out? I had to research on here where they were supposed to go and then reinstalled them in the two holes with the metal sleeves ( 7oclock and 4 oclock IIRC) and they seated fine. This is driving me crazy as I can't see how the bolts were could have come out of the holes I thought they did. I'm feeling like a crazy person as I was very careful while taking them out like 99.9% sure. Although I don't see how that would relate to the coolant up top but might relate to the overall coolant leak.
Most likely old coolant spill. The only coolant line close to that is the AOS one going over the left intake manifold. As long as that hose is not leaking, there should not be other coolant sources there.
That thing is such a mess I cannot see how you are going to tell what is what. If mine looked like that, I would back it into the driveway and soak that whole area with degreaser or engine cleaner and with a garden hose (not nozzle) flush that whole area, rinse, repeat, rinse, repeat. Finally, when things have cleared up, take a leaf blower or shop vac and dry it up. I have been there and done that. As long as you don't absolutely flood the area with water it will turn out okay. I also covered the alternator and removed the belt, air box already removed.
Why are the wires cut to the thing on the left of the picture?
Broken wires go to the changeover valve which explains the P0413 code. I changed out the valve and spliced the wires as I couldn't find a part number to buy a new plug and wire, so should be good to go there. Also got a new Starter wire as it was corroded but that seems to be a common problem as there were lots of posts related to that, curious if putting shrink wrap on the new one would extend its life any...
Coolant evaporates, if it didn't it would never dry up...poor a small amount in a pan, leave it outside, it will dry up. Is it magic that makes it disappear or science?
04-16-2017, 03:37 PM
Coolant pooled up on block
