bbboy

2 weeks ago I got my A4 1.8 (2001, 76k only) from Audi dealer. Looked at the coolant - brownish; oil- dark; the previous owner must have followed 15k service interval

Got Castrol Syntec 5W40 + filter, Audi coolant (G12) and took it to a mechanic.
Oil was not that bad, now I am worried about sludge - what if I now do oil change every 5k, to kind of flush the sludge?

Coolant - brownish, the mechanic was talking about some anti-leak additives that the guy must have put in...but so far (1 day) I see no leaks of coolant. What could that be then? Mixed (top-up) different coolant?
The mechanic ran tap water few minutes, then we put demi-water, started the car and heater, flushed the water, ran tap water throuh it again, put 50-50 mixture in.

My worries:
1) What if the engine is now fckd because of coolant?
2) What if the engine is now fckd because of long oil change interval?

It's 76k only, but...

K04-S4

Brown G12 means coolant is contaminated and the right thing to do is simply replace it. I wouldn't worry about it as long as coolant temps are reading normal.

Suggest shine a light inside oil fill opening in valve cover and look under oil fill cap for sludge deposits as it will give you a quick indication how bad the build up is. As we know, regular synthetic oil changes are the best sludge defence.

bbboy

I had the coolant flushed and wahsed the cooling system. Temp is between 70-90 C, depending on the driving speed.

I will check the oil cover. Would frequent oil change (like every 4k) help remove deposits?

gary647

I'd like to see some comments on this issue too. I recently puchased a fairly high mile A6, (182k km) and want to switch to synthetic oil. What about an "engine flush" as offered by some oil change shops? I generally shy away from these places as I do my own work, but would like to hear some comments on how these woud work, or not work, to clear out some of the sludge.

K04-S4

The 2.7T should always use synthetic engine oil and nothing else.

A hot oil change is usually preferable than a cold change to maximize removal of suspended particulate.

I've heard mixed thoughts on the "Seafoam Treatment" as some suggest dislodging sludge deposits can cause additional new problems. Inspect inside valve cover through oil fill opening as it should give very good indication.

I've seen 100K KM 2.7T's with nasty sludge problems and 250K motors with nearly zero sludge, it's all up to the owner for supporting regular oil changes along with regular maintenance.

I'd be curious to hear more of the "engine flush" some oil change shops refer to as well. Note that most oil change shops will install a cheap oil filter which I would strongly suggest avoiding.

S4zAudihere

it would be cool to find out more about the oil flush. i seafoamed my parent's TDI, and i did notice a difference, although it didnt smoke all crazy like in the video's. I added it through the fuel line and crankcase then dropped the oil. it was nice and chunky. and i only say nice because the chunky was comming out....
That doesnt sound too right.

Anyway. i'm just scared it's gonna dislodge some buildup and mess up my (fairly new) k04's.