Either the above or turbo seals.

20W50 is excellent

for lubing door hinges

Racing oil for high temperatures of engine pushed to the max.

 

I am researching about some racing oils and found this post.

 

I push my car hard and I believe stock oil (no matter what brand) is poor lubricant for performance car.

 

But is always a compromise if you have multipurpose car.

He wasn't using a performance oil nor in a performance engine either!

My vrs is a high mileage 180k, and I found I was constantly topping up with 5/30 oil. (No noticeable smoke). I switched to 10/40 and have been running that for the last 25k. Seems fine  - (uses about 2 pints in 10k), and the local vw specialist who services my car said this was fine. (Would not run 20/50  - my 1969 bedford runs this stuff)

You say the blue smoke started after you replaced some PCV associated components.

Start by rechecking PCV system. Make sure its piped correctly, and the pipes are secure and not kinked, pay particular attention to the manifold vac pipe.

A classic symptom of a failed PCV system is; engine oil leaks and increased engine oil consumption (the latter being a possible cause of blue smoke from the exhaust).

HTH.

Bill.

If you want thicker oil that is suitable to use in winter and addresses compression problems on an old engine, use 5W/50 full synthetic, there are many brands, Mobil1, Comma, Valvoline and others. Flows just as well cold, but does not thin out as much at higher temps, 5W50 has similar viscosity at 100degC as 5W30 at ~75degC. The problem with 20W50 oil is with the "20" low temp rating, not the "50" high temp rating.

 

Nothing wrong with using high "hot" viscosity oils, other than their increased cost and marginally increased fuel consumption, so long as they flow well in a cold engine, and all 5Wxx rated oils flow similarly at cold temperatures. If they made 5W90 oil, you could still use it safely in a turbocharged engine, in fact it would protect turbocharger better on account of thicker film in the bearing. It's the cold flow properties that can be a problem, so do not use 20W rated oils in winter.

 

Below is comparison of viscosity for various oil grades. 

 

Edited 6 December, 201411 yr by dieselV6

If you want thicker oil that is suitable to use in winter and addresses compression problems on an old engine, use 5W/50 full synthetic, there are many brands, Mobil1, Comma, Valvoline and others. Flows just as well cold, but does not thin out as much at higher temps, 5W50 has similar viscosity at 100degC as 5W30 at ~75degC. The problem with 20W50 oil is with the "20" low temp rating, not the "50" high temp rating.

 

Nothing wrong with using high "hot" viscosity oils, other than their increased cost and marginally increased fuel consumption, so long as they flow well in a cold engine, and all 5Wxx rated oils flow similarly at cold temperatures. If they made 5W90 oil, you could still use it safely in a turbocharged engine, in fact it would protect turbocharger better on account of thicker film in the bearing. It's the cold flow properties that can be a problem, so do not use 20W rated oils in winter.

 

Below is comparison of viscosity for various oil grades. 

 

 

 

I don't think that would be a good Idea neither. even when hot that would be too thick.  Oil is not just a lubricant, its a heat transfer too. Lubrication comes from flow not the thickness of it, if its too thick it wont flow so will not remove heat from the components, nor will it lubricate.

 

on the other hand an oil that's too thin wont lubricate neither, Its a balance of how you drive and how hot the engine runs.

5W90 oil, if it existed, would be as thick at 100degC as 5W30 oil at around 70degC, so it would flow just as well as 5W30 at 70degC, i.e. well enough. But it would have much stronger film and lubricate better. Lubrication does come from film thickness, basically by design parts of engine (and turbocharger) do not touch one another, there should always be a film of oil between them. Once the film is pierced/broken, wear occurs.  While turbocharger bearings make sure by design the film is thick even with thin oil (large oil flow through the bearing), the physics of oil film are unchanged.

 

Heat removal rate is indeed proportional to flow and important for turbocharger bearing, but flow rate is forced by the oil pump (within limits, but we are talking viscosities comparable to moderately warmed up to fully warmed up 5W30 engine oil), so oil pressure goes up with thicker oil and down with thinner oil, but flow is similar.

 

All theorethical, of course (no 5W90 oils around), but just to show that 5W50 is indeed a good oil to address compression and wear tolerances problems while keeping turbocharger happy.

 

FYI, below is a graph of gear oil viscosities vs temp, as you can see, at higher temps they all converge, even 250 weight oil is thinner at 100deg C than 5W30 oil at 25degC. 5W250 oil?  :p