Diagnosis thoughts/possibilities

I own a 1996 Tacoma 2.7 4 cyl. 4X4
2nd owner purchased in 1999, and now have 153K
on it. No problems whatsoever, other than catalytic converter,
and usual stuff...brakes, oil changes, starter contacts.
Great vehicle, and my third Toyota truck.

The "problem":

About two weeks ago, had an oil change. Technician indicated that
radiator flush was in order. Honestly, its probably been 5 years since
I last did that. The next Saturday morning I noticed "Halloween" orange
coolant on the drip pans...lots, and the radiator was leaking big time.
I ordered a radiator, and in the meantime did repeated water flushes of
the existing radiator and block. After repeated flushed got to a point
where we had near clear water retuning from the block.
At no time did we ever overheat, at least according to the gauge.
Never over 1/2 scale which is where it always runs.
My son, a Honda tech, installed the new radiator, and I have run a 50
percent coolant ever since.
The overflow level is not changing and is stable, so no "drawing" of
coolant from there if there is internal leakage.
No "white smoke", or no apparent contamination of the oil in the pan.
Running 5W-30.

All three belts also changed at time of radiator installation.
Vehicle has developed a slight "hum", which I think may be engine
related. Hum apparent at 60 mph. Also, does not quite have the power as before, but perfectly driveable, and no problem starting. Heater works fine.
Power issue is very subtle.

My thoughts:
Check compression.
Monitor oil consumption.

Paranoia here, or really got something going on?
Likelyhood of subtle head gasket leak?
I understand that the early 2.7's were not as reliable as 22R or 22RE.

Opinions please:

Steve

 

Sooooo what exactly is the problem, not the same power??? i'd say paranoia. did you use Genuine Toyota Super Long Life Coolant (pink fluid)??

 

I had nearly the exact same problem with my 99 Tacoma 2.7 at 150,000 miles. Turned out to be a blown head gasket. Had nearly no symptoms except for the loss of power and orange coolant. Recommend having a compression check done.