[T3] cylinder head temps

Keith Park topnotch at nycap.rr.com
Fri Apr 15 18:14:32 PDT 2022

Good read from Ray!  So let me start with this being a T4, (same should
apply to T3) with a thermocouple spring loaded on the head just above the #1
spark plug,
And using a good Fluke meter (which should be compensated).  Generally the
heads run in the upper 2's to lower 3's, mid 3's on a hot day, but I notice
that on a 70 degree day,
Driving 9 miles home on a secondary road the heads get up to about 325
before the thermostat opens, then it comes down to 280 or so.  It opens in
about 4 miles.

On a 30 degree day, I can be about 7 miles out before the thermostat opens,
and by then the heads are 360+, but once it does open up then they come down
to the upper 2's again,

So, on the cooler day BEFORE THE THERMOSTAT OPENS (the trick part of the
question) the head run much hotter.  Short trips around town when its cold
enough the thermostat may never open and the
Heads will remain hotter.

Never noticed this till I happened to plug the fluke in last fall in the
colder weather, cause I really wasn’t worried about head temps when the
weather was colder but I drove it rather late into 
The cold season and a couple mornings in the upper teens before they salted
us up and took a few readings, and was a bit surprised how hot the heads
would get before the thermostat opened.
Might be something to check on a T3 just to verify it also happens with that
coolant design.


Topnotch Restorations
topnotch at nycap.rr.com
71 Squareback  “Hothe”
65 Notchback  “El Baja Rojo”
93 RX7  “Redstur”
13 Subaru Outback "Blendin"

-----Original Message-----
From: type3-vwtype3.org <type3-vwtype3.org-bounces at lists.vwtype3.org> On
Behalf Of Max Welton
Sent: Friday, April 15, 2022 10:41 AM
To: type3 at vwtype3.org
Subject: Re: [T3] cylinder head temps

Sorry ... better link.



On Fri, Apr 15, 2022 at 8:40 AM Max Welton <max.welton.2k at gmail.com> wrote:

> Ray Greenwood had a good (and long) post about uncompensated CHT 
> gauges a few years ago. I've seen others but Ray seems a pretty reliable
> https://www.thesamba.com/vw/forum/viewtopic.php?p=9488107
> Max
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