I raised this question simple because, in Nissan original B15 service manual it say as follows.
Checking Fluid Level
NIST0012
Check fluid level, referring to the scale on reservoir tank.
Use “HOT” range for fluid temperatures of 50 to 80°C (122 to
176°F).
Use “COLD” range for fluid temperatures of 0 to 30°C (32 to 86°F).
CAUTION:
_ Do not overfill.
_ Recommended fluid is Genuine NISSAN PSF II or equivalent.
Refer to MA-13, “Fluids and Lubricants”.
WST032
Checking Fluid Leakage
NIST0013
Check the lines for improper attachment and for leaks, cracks,
damage, loose connections, chafing and deterioration.
1. Run engine between idle speed and 1,000 rpm.
Make sure temperature of fluid in oil tank rises to 60 to 80°C
(140 to 176°F).
2. Turn steering wheel right-to-left several times.
3. Hold steering wheel at each “lock” position for five seconds
and carefully check for fluid leakage.
CAUTION:
Do not hold the steering wheel in a locked position for more
than 15 seconds.
4. If fluid leakage at connectors is noticed, shut off engine, then
loosen and retighten flare nut.
Do not overtighten connector as this can damage O-ring,
washer and connector.
5. If fluid leakage from power steering pump is noticed, check
power steering pump. Refer to “Pre-disassembly Inspection”,
ST-21 (QG18DE), ST-24 (SR20DE).
6. Check rack boots for accumulation of power steering fluid.
why does it say
CAUTION:
Do not hold the steering wheel in a locked position for more
than 15 seconds.
By they way. thanks all for you valuable replys.