1998 v70 pcv fail after 6 month

jiarui6 · Post by **jiarui6** » 17 Dec 2025, 23:13

Hi everyone, I’m looking for some advice regarding a PCV issue on my 1998 V70.

I bought the car about eight months ago. It has around 450,000 km, but overall the condition is very good. Knowing that the PCV system is a common weak point on these cars, I replaced the entire PCV system shortly after buying it. The original system was not clogged at the time, but the hoses were already very brittle. I made sure to use part that not URO. After the replacement, everything worked as expected and the system was pulling proper vacuum at the oil filler cap.

My daily commute is quite short, usually only about 5–7 km. Throughout the summer and fall the car had no issues at all. However, once temperatures dropped below about -15°C, I noticed something concerning during a routine engine bay check. There was a large amount of oil around the oil filler opening and on the plastic engine cover, and some of it had even run down onto the exhaust manifold. At first I assumed the oil filler cap seal had failed, so I cleaned everything thoroughly.

As temperatures continued to drop and recently reached around -30°C, I kept driving the car for commuting. After each drive, I would again find a significant amount of oil pushed out around the oil filler cap. This never happened during the summer or fall. I then performed the glove test, and with the engine warmed up, the glove was being inflated. This suggests the PCV system is no longer functioning correctly.

My question is whether there is anything I can do as a temporary mitigation (since I catch it soon enough). For example, would longer highway drives help clear moisture or ice from the system? Replacing the PCV again is not particularly expensive, but I realistically cannot do that kind of work outside in -30°C winter conditions.

Any insight would be greatly appreciated.

Post by **abscate** » 18 Dec 2025, 04:32

Did you check the block passage for crud when you did the Pcv? If there is a lot of stuff in the port facing forward from the block it’s a sign the oil pan has to come down and the port needs cleaning

-30C …. That’s too cold for this polar bear… bdub might be willing to come up ftom NC though…..

Post by **abscate** » 18 Dec 2025, 04:40

The outline of the port cleaning is detailed in this awesome post by Mike alder

viewtopic.php?f=1&t=55413

Post by **jreed** » 20 Dec 2025, 06:11

I've got a 97 855 so this suggestion may not be applicable to the 98 V70... you could check the PTC orifice is clean and that the little heater built into the PTC is connected and functioning.

Post by **scot850** » 20 Dec 2025, 16:15

Is your car still fitted with the plastic flame trap or has it been removed completely? It fits in a little unit just behind the throttle body. They can get plugged up if not cleaned. Most throw them away. I think I still have a bunch in a bag somewhere that I got from a clearance sale.

Neil.