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Looks like I have the dreaded intermix. See photos...


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99 C2. 145000 miles.

Replaced water pump 2000 miles ago.

Murky coolant. Drained, run and filled 3 times with distilled. Color wont change. Lots of little pieces of black plastic too. I assume from the old impeller. Never got to see what it looked like, so I dont know how bad the impeller came apart, or if it did at all.

My AOS has a slight oil leak and spark plug tube number 2 has a slight oil leak.

Could either of those cause intermix?

From what a I read replacing the AOS is a serious PITA.

Anyone recommend a indy shop in Bellevue, WA?

Sad sad sad sad. :( :( :( :(

post-73335-0-05874400-1346537882_thumb.j

post-73335-0-97414900-1346537899_thumb.j

post-73335-0-40367400-1346537911_thumb.j

Edited by doublesnaggle
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I don't see an intermix, I see cloudy water. Intermix between coolant and oil gives you something that looks like lumpy hot chocolate, usually with drops of oil floating about.

photo1.jpg

Suggest recharging the cooling system with distilled water and a cooling system cleaner, run it for a bit, drain it and then flush it at least twice with clear water. I'll bet the second water flush comes out clear.......

Edited by JFP in PA
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Thats the exact step Im at. Used two small jugs of flushing cleaner as recommended. And Im on my 3rd flush of distilled. The color is exactly the same as the first drain. The water in that flask has a very slight sheen to it also. I think Im catching an intermix issue right at the very beginning. No?

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Thats the exact step Im at. Used two small jugs of flushing cleaner as recommended. And Im on my 3rd flush of distilled. The color is exactly the same as the first drain. The water in that flask has a very slight sheen to it also. I think Im catching an intermix issue right at the very beginning. No?

If you are having an intermix issue, it has to be very slight. Two suggestions to contemplate: (1) Have the cooling system pressure tested, even very small leaks show up in these simple tests. (2) Get a small bottle of UV dye for engine oil (Uview, the people that make the Porsche vacuum filling system sell it) and add it to your oil. Run the car for a day with just water in the system, and then pull a sample of the coolant and check it with a UV light to see if it glows. If it is a very small oil transfer, it will still light right up as the dye is very sensitive.

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I have the uview vacuum filler. I can vacuum test it correct? Or is the pressure test better?

Great tip on the UV dye, thank you thank you!!!

Im just not sure what to do. I got the car for a really good price. At the time I bought it, I didnt know that 03 and up had so many improvements. I cant quite afford a GT3. Plus there are no GT3 cabs or targas.

So I can keep dealing with my 99 issues or trade it in on an 03. My logic works like this. If I get an 03, that will eat 10+k. If I keep my 99. It will eat 3k, if I get the new clutch/rms/ims/aos. If I was a millionaire I would have a new GT3. If I was broke I would be very happy with any 911. I hate having options.

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Either pressure or vacuum will work; take the Uview unit vacuum down as low as you can get it and then cut off the air flow and see if it will hold that vacuum level for at least 30 min to an hour. If it does, you probably don't have a leak. You may want to put a small hunk of masking tape on the Uview's dial as a reference point during the test.

Uview is not the only firm that makes the UV dye, several companies make it as well. We get the Uview product in six-packs of 1 oz bottles that cost a little less than $3 per bottle.

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You won't know for sure until you properly test but I don't think you have intermix. Intermix looks like gooey pancake batter as JPF stated. You just have cloudy water. No way to tell for sure until you do a proper test but I don't think it's a slamdunk you have intermix.

AOS is only a PITA because you have to drop the transmission. This is why people sometimes get AOS and IMS done when they do a regular clutch job, etc.

Edited by ferrugia
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Your leak test looks good; I would tend to agree that the system is tight.

Having done a couple clean outs after non fatal intermix (oil cooler failures), it takes a lot of time, system cleaner, and hot water to clean out a system properly. You may just be seeing crud from the cooling system because someone used the wrong type of coolant at one time and the system is mucked up, or the car had an earlier non fatal intermix that is still coming out.

The UV dye will tell the story, if it does not show up in the coolant, there is no intermix.

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Ok. Sounds good jfp. Its funny, there is a guy in the Honda Aquatrax forum that has a similar name.

Anyways, Ill put the dye in.

Ive been trying to think of a sure fire way to flush the system. What if I pull the water pump and the thermostat and use water pressure to forcibly run the entire cooling system until it runs clear? Has anyone tried that?

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  • 8 months later...

Besides the UV dye test (I called the local dealer and they had never heard of such a thing, nor the largest auto parts store), is there anything else I can do to determine if what I am seeing on my car is intermix? I don't have the milk chocolate thick goo as others have posted, but it is also not pink or green as standard Porsche coolants are. Reason why I am asking this is because of some occasional puffs of white smoke on initial startup after the car sits for a while, but only comes from the passenger side muffler. I thought it was AOS, but removing the oil filler cap was as easy to remove as if the engine was not running, all I got was some wind noise (breather/sucking air in) and a very slight (almost minimal) change in RPM (definitely not rough idling). Here is what my expansion tank looks like:

post-10928-0-60953200-1368210253_thumb.j

post-10928-0-91708700-1368210262_thumb.j

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Besides the UV dye test (I called the local dealer and they had never heard of such a thing, nor the largest auto parts store), is there anything else I can do to determine if what I am seeing on my car is intermix? I don't have the milk chocolate thick goo as others have posted, but it is also not pink or green as standard Porsche coolants are. Reason why I am asking this is because of some occasional puffs of white smoke on initial startup after the car sits for a while, but only comes from the passenger side muffler. I thought it was AOS, but removing the oil filler cap was as easy to remove as if the engine was not running, all I got was some wind noise (breather/sucking air in) and a very slight (almost minimal) change in RPM (definitely not rough idling). Here is what my expansion tank looks like:

First of all, several companies make the cooling system UV dyes, including Airlift (see below), who makes the Porsche vacuum coolant refilling system:

B483906.jpg

Secondly, you definitely have the signs of an intermix issue in that tank. From your description of the exhaust smoke, you may have a cracked head.

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Pathway forward: Get a leak down test run on the bank that the smoke comes from. Pressure test the entire cooling system. This is not going to heal, it had to be properly diagnosed and fixed.

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And to fix, it entails replacing heads (assuming that in fact it is a cracked head), correct? Will research into leakdown tests (TDC or not, engine cold or not, how much pressure should be use, for how long, readings, acceptable leakdown numbers, etc).

And to think I got the car 7 weeks ago and only put 600 miles in it....

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And to fix, it entails replacing heads (assuming that in fact it is a cracked head), correct? Will research into leakdown tests (TDC or not, engine cold or not, how much pressure should be use, for how long, readings, acceptable leakdown numbers, etc).

And to think I got the car 7 weeks ago and only put 600 miles in it....

Not necessarily, the head may be repairable, but that can only be determined once the problem is isolated and actually visually inspected. Leak down tests determine the percentage of pressure that is being lost at TDC using compressed air and special tool:

http://en.wikipedia.org/wiki/Leak-down_tester

Usually, and depending upon the general condition of the engine (miles, etc.), something in the 10-15% range is considered normal. Often, when a head is cracked, you seen very high leak %, and often get lots of compressed air into the cooling system causing anything from bubbles in the coolant to a water geyser at the surge tank. Similar results can also be had by pressurizing the cooling system with another specialized tool to around 20 PSIG and then see if it hold pressure for 15-30 min. If the cooling system does not hold pressure, it is going somewhere..........

Sorry to hear that the car is a recent acquisition, but this is why having a proper pre purchase inspection done before money changes hands is so important on these expensive vehicles. A good PPI would have caught this.

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Don't be too discouraged.

At a good indie shop shop you are looking at maybe half the cost of a used engine to get it fixed.

If you are at all automotive mechanically inclined or know someone who is, don't be afraid of dropping the engine and pulling the heads.

It's not as hard as it may seem.

Take it in steps, like JFP said, first things first is to assess the situation before going crazy.

You might be one of the lucky few that just needs a new oil cooler and a good flush of the coolant system, which will not be that expensive.

Whatever you do though, don't drive it until it is fixed.

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Don't be too discouraged.

At a good indie shop shop you are looking at maybe half the cost of a used engine to get it fixed.

If you are at all automotive mechanically inclined or know someone who is, don't be afraid of dropping the engine and pulling the heads.

It's not as hard as it may seem.

Take it in steps, like JFP said, first things first is to assess the situation before going crazy.

You might be one of the lucky few that just needs a new oil cooler and a good flush of the coolant system, which will not be that expensive.

Whatever you do though, don't drive it until it is fixed.

While an oil cooler is always a possibility for an intermix issue, one element in this case points in a different direction: Puffs of white smoke from one bank after sitting for a bit. That sounds more like some coolant getting into the combustion chamber on one or more cylinders; I know of no way an oil cooler can fail and do that.

As he will be pulling the plugs in that bank to do a leak down anyway, I'd be looking for one or more plug that looks "steam cleaned", which would be a give away for a coolant drip. If this is found, you could bore scope the cylinder for more confirmation, but one or more clean plugs and a leak down should tell you where you are.

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The crack I had in my head, at the inner exhaust valve spring seat on cylinder #1, which is basically the same place on the casting as cylinder #6, is one of the most common. And it will not show up on either a compression test or a leak down test, that s unless it has gone much farther than mine or most of the cracks at that location that I have seen. These cracks don't involve the cylinder compression areas. A cracked sleeve will. The crack I had just let oil and coolant move between the oil system and the cooling system. I had extensive intermix in both directions. When running ther is oil pressure that can force oil through the crack into the cooling system. Then when the engine is hot and turned off the cooling system is pressurized and coolant can be forced through the crack into the oil system.

I never had smoke from the exhaust from the intermix. The only way I knew about he problem was when the coolant warning light started flashing.

I had the crack fixed in my head and the car has run fine for four years and 23,000 miles. I did pick up a new in the box 1-3 cylinder head a couple of years ago "just in case" that I am now selling if someone needs it. The dealer sells them for $3,200, I am asking $1,800 or best offer. One of these days I am going to post it on the various sites and eBay to sell it. Just haven't got around to listing it a lots of other parts I have accumulated.

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Update: took the car to the local dealer and the shop manager took a look at the expansion tank and he claims it is not intermix and most likely it is that the PO used some non Porsche coolant. He said this after looking at the coolant expansion tank and smelling it, he says their is no oil residue at all (I agree, no oil upon visual and tactile inspection). Car will be vacuum flushed and pressure tested on Tuesday. He also claims that it is not a cracked head as the temps do not rise quickly and the car runs fine when warm. He claims that the white smoke is from when they recently overfilled it with oil. I checked the oil level last night, using the dipstick, and it is in fact still overfilled as confirmed by the dash oil level measurement (all bars lit).

Of note, the huge puff of white smoke was one time only, then the other two times when smoke came out, it was 1/10 of the first large puff. He claims that this is further proof that it is excess oil from the overfill being burnt. I am keeping fingers crossed that the cooling system holds pressure (I will be there to visually confirm the results...) and that the new clean coolant remains that way for a very long time.

I'd like to take a minute to thank you all for your replies and guidance. Will report back next week after coolant flush and pressure test.

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Update: took the car to the local dealer and the shop manager took a look at the expansion tank and he claims it is not intermix and most likely it is that the PO used some non Porsche coolant. He said this after looking at the coolant expansion tank and smelling it, he says their is no oil residue at all (I agree, no oil upon visual and tactile inspection). Car will be vacuum flushed and pressure tested on Tuesday. He also claims that it is not a cracked head as the temps do not rise quickly and the car runs fine when warm. He claims that the white smoke is from when they recently overfilled it with oil. I checked the oil level last night, using the dipstick, and it is in fact still overfilled as confirmed by the dash oil level measurement (all bars lit).Of note, the huge puff of white smoke was one time only, then the other two times when smoke came out, it was 1/10 of the first large puff. He claims that this is further proof that it is excess oil from the overfill being burnt. I am keeping fingers crossed that the cooling system holds pressure (I will be there to visually confirm the results...) and that the new clean coolant remains that way for a very long time.I'd like to take a minute to thank you all for your replies and guidance. Will report back next week after coolant flush and pressure test.

I sincerely hope I'm wrong for your sake, but sorry, but this does not look like "the wrong coolant", it looks like an emulsion mix:

IMG_0074.JPG

Which this definitely is:

photo1.jpg

We have also seen cracked heads that never over heated.

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Dropped the car off at 730am today, but at 2pm the service manager said he had not taken a look at it and will do so tomorrow. Fast forward to 4pm and the car is on a lift and the coolant has been drained from the engine and now waiting to get drained from the front (this is what the mechanic told me, I thought it was all just one system...). Handed them my LN Engineering oil drain plug to replace the OEM one when they go and adjust (for the second time!) the oil level. More updates as they become available to me.

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