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1999 Porsche Carrera intermix questions

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Old 12-31-2022 | 03:23 PM
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Default 1999 Porsche Carrera intermix questions

I currently got oil intermixing in the coolant reservoir but so far from what I can tell none in the oil itself. Im thinking its either AOS, crack cylinder head and hoping not D Chunk Cylinder failure but wanted to know if there is a way to confirm without borescoping as I dont have the place to do it due to weather? Is there anything I can look for while turning the car on or anything like that? No check engine light on. Car seems to start and run fine (not driven other then up and down driveway).

Now if this is the cylinder D chunk failure wouldnt there be intermixing in both the coolant and oil? Also if the car is started wouldnt there be a cloud of white smoke? Or would that be depending on if its a small crack early stages?

As for a cylinder head crack what types of symptoms would I expect to see? Higher coolant pressure and rising coolant when cars on?

I tend to pull plugs and borescope once weather permits and leakdown but for now just trying to get a general idea!

Thanks in advance

Last edited by Johnny-5; 12-31-2022 at 03:26 PM.
Old 12-31-2022 | 08:07 PM
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Originally Posted by Johnny-5
I currently got oil intermixing in the coolant reservoir but so far from what I can tell none in the oil itself. Im thinking its either AOS, crack cylinder head and hoping not D Chunk Cylinder failure but wanted to know if there is a way to confirm without borescoping as I dont have the place to do it due to weather? Is there anything I can look for while turning the car on or anything like that? No check engine light on. Car seems to start and run fine (not driven other then up and down driveway).

Now if this is the cylinder D chunk failure wouldnt there be intermixing in both the coolant and oil? Also if the car is started wouldnt there be a cloud of white smoke? Or would that be depending on if its a small crack early stages?

As for a cylinder head crack what types of symptoms would I expect to see? Higher coolant pressure and rising coolant when cars on?

I tend to pull plugs and borescope once weather permits and leakdown but for now just trying to get a general idea!

Thanks in advance
Old 01-01-2023 | 02:36 AM
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Your intermix is not being caused by AOS failure or d-chunk.....

AOS failure or D-chunk will cause "coolant in oil" and not vise versa because there is no significant oil pressure in the area..

" Oil in coolant" can be cause by failed oil cooler ( not very likely) or cracked head ( very likely) ....and they both can cause both "oil in coolant" and "coolant in oil" due to coolant pressure and oil pressure are both close by these area's..

Since you ONLY have "oil in coolant" , I'm sorry to say but the likely cause is a cracked head...but it's not the end of the world, just send the heads to Len Hoffman he can fix them no problem...

Old 01-01-2023 | 07:31 PM
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Originally Posted by b3freak
Good video thank you!
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Old 01-01-2023 | 07:32 PM
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Originally Posted by Porschetech3
Your intermix is not being caused by AOS failure or d-chunk.....

AOS failure or D-chunk will cause "coolant in oil" and not vise versa because there is no significant oil pressure in the area..

" Oil in coolant" can be cause by failed oil cooler ( not very likely) or cracked head ( very likely) ....and they both can cause both "oil in coolant" and "coolant in oil" due to coolant pressure and oil pressure are both close by these area's..

Since you ONLY have "oil in coolant" , I'm sorry to say but the likely cause is a cracked head...but it's not the end of the world, just send the heads to Len Hoffman he can fix them no problem...
Thank you for the information. Will look into Len Hoffman for pricing
Old 01-01-2023 | 08:51 PM
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I had my heads removed and checked by Len. He then did a refresh and stage 1 port job since I went 4.0.

Long story short, my heads weren't cracked. My intermix was from a failed oil cooler...
Old 01-01-2023 | 09:04 PM
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Originally Posted by e30rapidic
I had my heads removed and checked by Len. He then did a refresh and stage 1 port job since I went 4.0.

Long story short, my heads weren't cracked. My intermix was from a failed oil cooler...
Oil cooler from the previous owner was replaced as they thought that was the case but wasnt so its not that. Reviewing online it appears the crack cylinder head is the main cause but Ill have to tear into it once I have the time to confirm. Its possible it may just be a AOS (wishful thinking) but will see.
Old 01-02-2023 | 03:20 PM
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Originally Posted by Johnny-5
Oil cooler from the previous owner was replaced as they thought that was the case but wasnt so its not that. Reviewing online it appears the crack cylinder head is the main cause but Ill have to tear into it once I have the time to confirm. Its possible it may just be a AOS (wishful thinking) but will see.
No, like I said above, the AOS will not cause "oil in coolant" ..can only cause "coolant in oil" ...

BTW :: UAOS even eliminates this possible failue as it does away with the coolant ( heater) portion of the air/oil separator..
It can do this because it moves the high velocity/low pressure flow area to near the throttle body in a much warmer place...



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