When using a Raytec or any other infared heat measurment device, we have
found that the color and material of what you are measuring has a very
substantial effect on the readings obtained. A black metal object, like the
top tank of the radiator will read 20 degrees hotter F than a silver or
aluminum colored metal surface like a thermostat housing even though they
are the same temperature.
Regards, Greg Solow
----- Original Message -----
From: William G. Lamb, III <lambroving@worldnet.att.net>
To: Stein, Ross <Ross.Stein@kp.org>; Lorne Goldman <gomog@angelfire.com>
Cc: William C.W. Lamb <chip@wmsbrg.com>; Morgan Mailing List
<morgans@autox.team.net>
Sent: Thursday, September 23, 1999 3:30 PM
Subject: Re: Cooling
>
> Ross, et al.
>
> To satisfy myself as to the accuracy of the VDO water temperature gauge
> in my 4.0 Plus 8, I had the water temperature measured at the top and
bottom
> of the radiator near the location of both sensors, i.e. that for the fan,
> and that
> for the gauge, with a Raytek infrared gun. The fan kicks in for a few
seconds
> whenever the gauge reads ~ 99 - 102 C. The actual water temp at the return
> elbow is 93 C. +/- 1. At the same time, the temperature at the top of the
> radiator is ~ 88 C. So... the VDO is most likely reading 12 - 14 C higher
> than actual water temperature. I know this info will come as a relief to
many
> of you. It may also apply to owners of 3.9's since I believe the
thermostat
> housings are the same, but you will need to check the VDO part numbers
> for the 3.9 and 4.0 to see if they are the same.
>
> Regards,
>
> Willie
>
> Land Rover Specialist
> NAS 4.0 Litre Plus 8 (R-11953)
> MSCC # 9096, Morgan 3/4 Owners Group
>
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