Ugh. New silicone oil in the fan clutch? What a PITA...
Do a spin test, if you haven't already. With the engine stone cold, spin
the fan. It should spin sort of freely. THen run the engine up to full
operating temp, and when you stop the car, spin the fan again. It should
be stiffer. If the engine is really warm it should really be stiff.
I replaced the whole clutch, and after I did I can *HEAR* the fan come on.
This solved all my problems as far as overheating (88 Supra)
Base ignition timing that is too advanced can cause overheating, but you
would probably experience pinging if it is advanced enough to cause
overheating.
Do hachiroku's test to check the fan clutch, or use a hair drier or heat gun
to see if the clutch becomes harder to spin when it is warmed up.
What is the condition of the radiator? Does coolant circulate freely and
are the fins clear of debris and deformations?
Is the fan shroud in place?
--
Ray O
(correct punctuation to reply)
And the underpan?
The fan cowl *should* be a one-piece surround.
Something like this:
http://www.enjukuracing.com/images/OEM%20Fan%20Shroud.jpg
The underpan I was talking about is a plastic pan that attches to the
underside of the car, just in front of the crossbar the suspension is
attached to. It looks like this:
http://www.gdscentral.net/88supra/rockplate1.jpg
On the Supra, anyway, the 'grille' openeing is very small, and the airflow
actually comes in under the bumper. If this pan is missing, the airflow
diverts from the radiator and just passes underneath the car. Probably
good for "ground effects" at thigh speed, but not condusive to air flow to
the radiator...
"Thigh speed"? Reminds me of my college days...