Do I need to re-apply thermal grease

[sundoe]

I opened my T61 recently to fix the fan. I removed the fan assembly and cleaned it with a blower. I noticed some silvery substance present at the points where the fan assembly touched the processor (and another chip which seems to be the graphics processor). I searched and discovered that it is thermal grease. I had already cleaned the grease off the assembly but not from the processor and the other chip. I have closed the laptop now.

Do I need to add more grease?
I can get the grease but it will take 6-7 days, till then is it safe to use the machine for work? (I could run it on "maximum battery life" power setting to keep the temperature down, for now)
Should I install some software to monitor the temperature, fan status? (tpfancontrol or nhc...)
thanks

[goofyGAguy]

I would install Core Temp and monitor it carefully.

http://www.alcpu.com/CoreTemp

[richk]

Clean surfaces with denatured alcohol. Apply thermal compound (I suggest arctic silver) according to manufacturer's directions.

[moronoxyd]

Do I need to add more grease?

After removing the fan you should ALWAYS remove any grease from the CPU, GPU and fan and apply new one.

Leaving the old one on doesn't work in the long run.

[geohsia]

After removing the fan you should ALWAYS remove any grease from the CPU, GPU and fan and apply new one.

Leaving the old one on doesn't work in the long run.

I second this. part of good contact means you apply the thermal grease in an even spread or a small dollop (rice grain size) and let the compression action spread it out. Either way, making sure there are no trapped bubbles is key. Air is not a good conductor. When you separate the two elements the pulling action creates a mess and pushing the two together you undoubtedly will trap air. You can try to spread it but the best thing to do is clean it off and start it over. I had to do it 4 times in one week because I kept dorking with my fan. Worth the extra hassle.