"I'm trying to diagnose some overheating on my '68 2000 (Stock engine,
electric fan). The temp guage usually passes the midway mark, sometimes
approaching, but not reaching the 240 mark, then I shut it down.
Using an infrared thermometer, I measured the following:
Radiator- 205' throughout various locations
Upper/lower rad hose- around 190'
Engine block- 225'
Valve cover- 170'
Thermostat housing- 190-200'
Questions:
1. what are normal temps for the above? Radiator?
2. theoretically, should the thermostat housing register the same temp as
the preset thermostat? (ie 160 or 180, I don't know whats in there)
3. is the engine block temperature really that high?
4. where should the temp gauge register under normal operation?
5. where do I start? new thermostat, recore rad?"
Hi Ritchie,
You did good, very good with your IR thermometer.
To me, another consultant with a degree in A.E. it appears that the temps.
rearward of the thermo housing are what I would call, highish.
[I had to convert to degC to decide that]
For the block to be at 225F [107degC] IMO is too high, and quite a step from
the temps. forward of the thermo. housing.
Also, using the factory electric gauge as a reliable indicator is fraught
with problems.
It seems that the block is unable to pass the heat through to the radiator
effectively.
???Thermostat???
As for the leccy fan, I have mine set to cut in 5degC above the thermo
rating e.g. thermo 85degC, fan cut in 90degC.
My advice to anyone with real cooling concerns, such as you have, is to
connect a mechanical temp. gauge to the engine block, albeit temporarily, to
monitor what is really going on during normal driving.
They can be had for a song usually and because they are independent of
electrickery, they will read all of the time.
What we really need is for someone to do those IR tests on an engine without
cooling issues and do a comparison.
I hope this helped : )
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