My '98 Olds Intrigue (3800) seems to take a long time to heat up, and
the heat gauge never gets much above the one quarter mark.
I changed the upper and lower intake gaskets last summer and when I
re-assembled it I put a new thermostat in it.
When I installed the new intake gaskets, I had read that it was
somewhat difficult to purge all the air out of the cooling system after
performing this job, and a way to get around that was to drill a 1/8"
hole in the new stat, which I did, and filled the system -- topping it
off several times until it was completely full.
I noticed it never really develops full pressure in the system, but
the coolant remains full. I have never pressure tested the cap.
Anyway, now that winter's here, I am dis-satisfied with how long it
takes this car to heat up, and with the fact that the temp gauge stays
down around a quarter -- so I was wondering if my having drilled that
1/8" hole in the new thermostat would be enough to compromise the
heating-up of the engine as I described?