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My coolant light started flashing the other day. So I checked the coolant and it was very low, and it appeared like thick chocolate. I topped up the coolant with fresh porsche coolant and distilled water. Checked it the next day to find the pink color turned hot cocoa powder brown and thick.

So I started reading the forum, and I think what I'm looking at is what poeple are terming "intermix".

Can someone explain what this is, what the causes are, and why it's sounds so devistating to the engine?

Before I rush to the dealer (as it sounds like may be necessary) is there anything I can do myself to try and diagnose and fix the problem?

FWI, the car is a 1999 996 with 180000 miles. It's on its second engine which has 85000 miles. I did a recent oil change and saw nothing unusual - ie I didn't notice coolant in the oil.

Thanks...

Ross

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First stop driving the car and have it towed everywhere from this point forward until you get the problem resolved.

Intermix is a situation that arises typically when the engine has become too hot, and a crack occurs in the aluminum, typically in the spark plug tube area. This causes the oil to mix into the coolant, eventually (rapidly) clogging the cooling system and leading to much much bigger problems if they are ignored. Including engine/car write-off if ignored too much.

There is a small small chance that the intermix is due to a failed oil cooler or AOS, which each run about $200. With that much sludge though you are still looking at a hefty bill to clean up the intermix sludge from the cooling system. And based on your description of the sludge formation I would bet more on the cracked head than the oil cooler or air oil seperator.

Unless you are a very handy mechanic who is comfortable dismantling the engine, it is best to take it to a shop. Hopefully you caught the problem early enough and there has not been any other collateral damage and the engine is still salvageable.

Basically fixing this problem requires removing the engine from the car, removing the heads, having them pressure tested to locate the leak, repaired, and reinstalled.

Then the entire cooling system needs to be completely cleaned of residue. There are miles of coolant hoses in this car, 2 radiators, and from what I understand that part of the job is a big pain in the butt.

Good luck and keep us posted. (but DO have it checked out before you drive it again).

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Thanks very much. I will get it to the shop immediately.

But answer me this, if you would...

With the miles on the car it's truely just not worth that much. And the cost of a head replacement likely goes beyond what I'd be willing to put into a car worth (I'm guessing) $10k. (And that price assumes it's running!)

So the car's probably a write off. That being the case, it's probably time to just trade it in and move on. My question is what will happen if I just keep driving it? (it actually goes fine) Will it die suddenly leaving me stranded, or a slow death blowing smoke and just get worse and worse? If the latter, how much time would you estimate I have to find a 997?

Thanks,

Ross

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Honestly there is no telling how long you have.

There are many possible failure mechanisms. Some are a bit benign (the leaking oil cooler or AOS)

to cracks in the heads or cylinder itself. Antifreeze is nasty on bearings and what not.

It can also fill your cylinders with fluid causing hydrolock.

Sort of a ticking time bomb -- you just don't know how long a fuse you have.

I doubt you'll be able to trade it in. I'm sure this is something that anyone knowledgeable about

996's should be looking for. A 996 with 180K miles isn't worth much. One with intermix issues is worth

practically nothing.

If you plan to move to a 997 -- I'd start looking yesterday.

Mike

Thanks very much. I will get it to the shop immediately.

But answer me this, if you would...

With the miles on the car it's truely just not worth that much. And the cost of a head replacement likely goes beyond what I'd be willing to put into a car worth (I'm guessing) $10k. (And that price assumes it's running!)

So the car's probably a write off. That being the case, it's probably time to just trade it in and move on. My question is what will happen if I just keep driving it? (it actually goes fine) Will it die suddenly leaving me stranded, or a slow death blowing smoke and just get worse and worse? If the latter, how much time would you estimate I have to find a 997?

Thanks,

Ross

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Thanks very much. I will get it to the shop immediately.

But answer me this, if you would...

With the miles on the car it's truely just not worth that much. And the cost of a head replacement likely goes beyond what I'd be willing to put into a car worth (I'm guessing) $10k. (And that price assumes it's running!)

So the car's probably a write off. That being the case, it's probably time to just trade it in and move on. My question is what will happen if I just keep driving it? (it actually goes fine) Will it die suddenly leaving me stranded, or a slow death blowing smoke and just get worse and worse? If the latter, how much time would you estimate I have to find a 997?

Thanks,

Ross

Yes, a car with that amount of miles and an engine with a substantial amount of miles too is not worth much. Especially with a broken engine.

If you are the DIY sort who would be comfortable removing the engine in your back yard, and it is ONLY the heads you CANfix it yourself for about $2500 give or take. Heck if you were in Northern California I might even consider lending a hand since I've done this work before (aside from the intermix cleaning, which is more tedious than difficult), but I am also just an enthusiast, not in the trade.

The dealers are just going to shove you out the door unless you want to buy a replacement engine. They would charge you just as much to drop the engine and repair it, in which case you'd be better off buying a replacement from them anyways. An indy might charge you less, but it is still going to be in the upper thousands range.

Yes it would not make sense to buy a re-manufacturered engine from Porsche for $10,000 on car that's worth just about the price of the car $15-18k minus the repair (in most cases $10,000).

The other option for you might be a used engine, which I've seen go for as little as $4000 for a used 3.4L on ebay (high miles). With removal and install costs on a used engine you are looking at maybe $5000-6000.

With any luck, it will just be the oil cooler or AOS and then a thorough cleaning of the cooling system (about $1000 procedure guessing) and you are back on the road. The oil cooler can be pressure tested to see if it is the culprit. And at around $200 each the oil cooler and AOS are not that expensive to replace while you're in there items.

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As expected, the dealer says "new engine", case closed.

Agree with all the possible scenarios to repair, but not really something I want to get into. So the car will go.

It's probably worth more in parts than anything else, and thus a breaker has offered me $5000. I'll probably take it, unless someone ups him substantially.

It's on ebay here if anyone is interested: http://cgi.ebay.com/ebaymotors/1999-Porsche-911-No-Reserve-/140611098893?pt=US_Cars_Trucks&hash=item20bd13190d

Thanks everyone for your help.

Ross

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Hey Ross,

This really sucks for you, I'm really sorry to hear this.

Blue book says $10,000 for the car in excellent condition with running engine and that many miles.

Even for the DIY'er to fix the cracked head (assuming that is the problem), they are looking at $3000 to repair.

I hope you find a buyer!

Edited by logray

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