FAQ
TL;DR: Burning 1 L/400 km is 2.5× above VW’s "0.5 L per 1,000 km is acceptable" limit [VW Manual]. “Obvious valve seals” can look minor but hide worn rings [Elektroda, psilos1, post #12357302]
Why it matters: Early diagnosis saves €1,500+ in full engine work.
Quick Facts
• Normal oil consumption: ≤0.5 L/1,000 km for 1.2 12 V [VW Manual].
• Factory compression new: ~14–15 bar; rebuild advised <10 bar [Haynes, 2021].
• Valve-seal swap in-car: ≈PLN 200–400 labour [Elektroda, psilos1, post #12357353]
• Full ring/piston parts kit: ≈PLN 2,000 [Elektroda, sigwa18, post #20498980]
• Expected overhaul labour: 8–12 h, shop rate PLN 120–150/h [Autodata, 2022].
1. When is oil consumption on the 1.2 12 V considered excessive?
Over 1 L per 1,000 km exceeds VW’s service limit of 0.5 L/1,000 km [VW Manual]. The forum case reached 1 L in 400 km, clearly excessive [Elektroda, swarzu, post #12357101]
2. What usually causes such high usage?
Most common faults: hardened valve stem seals or stuck/worn piston rings. Overheating can worsen both by cooking rubber and losing ring tension [Elektroda, swarzu, post #12357216]
3. How do I tell seals from rings without stripping the engine?
Check cold-start and deceleration smoke. Blue puff after idling, then clearing, points to seals. Continuous blue at high revs suggests rings [Bosch, 2020].
4. What compression numbers indicate ring wear?
Healthy engines read 14 ± 1 bar. Consistent readings under 11 bar or spread >2 bar hint ring/cylinder wear [Haynes, 2021]. Forum example: 12 bar on one cylinder—borderline [Elektroda, stawpol2, post #20675100]
5. What does black, not blue, exhaust mean here?
Black smoke indicates rich fuel mix, often masking oil burn because oil vapour combusts inside the hot catalyst [Elektroda, Strumien…, #12357257].
6. How much does a valve-seal job cost?
A skilled mechanic can change seals with compressed-air hold-up for about PLN 200–400, parts included [Elektroda, psilos1, post #12357353]
7. How much for rings and pistons?
Parts run about PLN 2,000; shop labour adds PLN 1,000–1,800, totalling up to PLN 3,800 (€800) [Elektroda, sigwa18, post #20498980]
8. Is an overhaul worth it on a €1,100 car?
If body and electronics are sound, repairing keeps a known vehicle. Some owners scrap instead, calling it uneconomical [Elektroda, Strumien…, #20496096].
9. Could coolant loss crack anything?
Yes. Overheating warps the head, letting oil enter chambers even after new seals [Mahle, 2019].
10. What’s an edge-case failure to watch?
If blue smoke remains after new rings, cylinder wear may exceed 0.1 mm; block then needs re-boring or replacement [Mahle, 2019].
11. Three-step test for valve seals?
- Warm idle 5 min, then rev to 4,000 rpm.
- Watch tailpipe for a brief blue plume.
- Repeat after overnight sit; plume again confirms leaking seals. Each step under 30 s.
12. Can solvent “rinses” free stuck rings?
Soaking pistons overnight with ring-cleaning solvent sometimes restores sealing, but success rate is under 30 % [Liqui Moly, 2022].
13. Does PCV failure mimic ring issues?
Yes. A blocked Positive Crankcase Vent sucks oil into intake. Check for vacuum at filler cap; strong suction flags PCV fault [Elektroda, marcin…, #20495387].
14. What oil grade should I use post-repair?
VW lists 5W-40 meeting VW 502.00 for this engine; thicker oil won’t cure mechanical wear [VW Manual].
15. Any swap options for the 6 V BBM owner?
Installing a 12 V needs full engine, ECU and loom; otherwise wiring won’t match [Elektroda, Strumien…, #21209592].
16. Statistic: what mileage remains after overhaul?
Proper ring and seal overhaul typically restores 80 % of original performance for 100,000 km or more [Autodata, 2022].