Oil in coolant and intercooler, how fucked am I?

[DasWagen]

For reference, my 1.8T has 101K miles on stock turbo; 30K tuned. The water pump seized so it just got a third timing belt, service and coolant 4K miles ago. I had little faith in the car after that, so I paid to ship it across the country just days ago.

Oil in Intercooler
Was swapping for Apikol SMIC. Found oil residue on intercooler outlet and a small puddle of oil came out of the inlet. I know some of this is from the PCV system, and my car just bounced around on a trailer for a week, but still, it seemed worrisome. I haven't put in the Apikol SMIC to avoid gumming up the new core. oil was clean
My turbo is old but hasn't given any other cause for alarm. Pictured is what dripped out. There is more but removing that elbow is a bitch.



Oil in Coolant
This has been an issue for fucking ages. In May (5K miles ago) I replaced the oil-to-water oil cooler, expansion tank, and flushed twice with rad-flush. 14 fills with DI water later, and the coolant drained cleaner but not clear. A lot of oil sediment came out in the first half of flushes, but not later on. When I replaced the timing belt less than a thousand miles later, I also swapped the coolant flange (was seeping slightly) and the valve cover gasket. I have been watching this for a while; usually, my oil level won't drop by a detectable level, and always drains clean, but it is currently low.


This engine's valve train looks fantastic, as does the rest of the car, but a bad turbo and head gasket would really suck. Thoughts?

[Ol Dirty Noodle]

Sounds like you’re head gasket fucked due to overheating caused by the water pump seizing

[DasWagen]

Sounds like you’re head gasket fucked due to overheating caused by the water pump seizing

Water pump seized well after I started having dirty coolant. So the order is a bit off, but I wouldn't be surprised if they're related

[Audummy]

When you mentioned DI water did you mean distilled or deionized? Hopefully it's distilled. Deionized water should never be put in any vehicle or much of anything else for that matter. It will naturally try to find it's ion balance and suck minerals out of whatever it comes in contact with. How do I know this? Some clown at work decided it would be good to put it in all of our chilled loop systems. Multiple clogged passages due to the stripping of minerals mostly from what became sacrificial aluminum and leaks out the wazoo in short order proved our point that it wasnt a good idea. Hundreds of thousands of dollars in replacement parts and multiple flushes later the damage has been corrected and all is well with regular old DISTILLED water and glycol.

[Charles.waite]

Oil in the coolant could just be a bad oil cooler. I had that a while back and a new cooler and gasket solved it. Give that a go before you start tearing into the engine.

[a4bradsd]

Does anyone have a photo of what Oil Residue in the coolant looks like???

I am working on my 2002 A4 1.8T 115Kmiles myself (1st time) and replacing many parts in the coolant system. I posted photos in post https://www.audizine.com/forum/showt...er-Corehttp://.

Flushing the heater core there was a light brown residue sediment that I clearly determined it was heavier than water and surely not oil. I was thinking this is oxidized coolant that has accumulated, but don't really know.

I am replacing the Oil Cooler only because there was a slow leak at one of the coolant hoses and the nippled was partially corroded away. I bought an aftermarket Uro brand Oil Cooler at a 10th the $210 price of the dealer part. I am just now getting around to putting everything back together but having some 2nd thoughts about installing the much cheaper after+market oil cooler.

I never had a chance to pressure test the coolant system before the heater core hose snapped while driving. I have thought about pressure testing the old oil cooler that has been taken off just out of curiosity, but not really necessary since I am replacing it.

[old guy]

Does anyone have a photo of what Oil Residue in the coolant looks like???

Here's a severe case. This was from a defective oil cooler.

[Charles.waite]

I put a Dorman brand cooler from Napa in my b6 and as far as I know it’s still working fine for the PO. Held up for 2 years under my ownership, I just had to retighten the nut holding it on after a heat cycle due to the oring settling in.

[PSI NRG]

Oil in the intercooler/piping is pretty normal. Especially if you're still on the OEM K03 at that mileage. Check shaft play on the turbo and if that checks out, go through your PCV system and make sure it's up to par.

[DasWagen]

Does anyone have a photo of what Oil Residue in the coolant looks like???

I am working on my 2002 A4 1.8T 115Kmiles myself (1st time) and replacing many parts in the coolant system. I posted photos in post https://www.audizine.com/forum/showt...er-Corehttp://.

Flushing the heater core there was a light brown residue sediment that I clearly determined it was heavier than water and surely not oil. I was thinking this is oxidized coolant that has accumulated, but don't really know.

I am replacing the Oil Cooler only because there was a slow leak at one of the coolant hoses and the nippled was partially corroded away. I bought an aftermarket Uro brand Oil Cooler at a 10th the $210 price of the dealer part. I am just now getting around to putting everything back together but having some 2nd thoughts about installing the much cheaper after+market oil cooler.

I never had a chance to pressure test the coolant system before the heater core hose snapped while driving. I have thought about pressure testing the old oil cooler that has been taken off just out of curiosity, but not really necessary since I am replacing it.

The reisdue you posted def didn't look like anything I had in mine. Nor did it reeally look like what Old Guy shared. I guess I shoul've taken some good pics before ripping the head off . My car also never had a history of coolant leaks nor needed a top off.

What happened for me is that I'd get a slim amount of oil like this
on the first drain followed by an unlimited amount of orange/brown sediment which would never stop comming out flush after flush. This sediment would dry in the hoses if you let it but was slimy if you touch it wet, such as in the tank. I could brown a coolant tank in a month

[A1EK]

This is a common issue.

To determine the problem first check your dip-stick and see if there is any emlusified oil in your engine, if the oil is normal with no brown sludge then the issue is more than likely just your oil cooler. If no smoke comes out the exhaust and no loss of power then happy days.
There is rubber seal that sits on the oil cooler and can leak if not correctly fitted or just shrinks over time. The Rubber O -ring is only £2 and the oil cooler you can buy for about £25 and is easy to fit. You need to ensure that you correctly torque the locking nut to prevent the issue happening again.

The tricky bit is flushing out your coolant... let me know how you get on with the above then I will advise on flushing.