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leadfoot · Posted: Mon Nov 15, 2004 10:31 am Post subject: Thermo time switch

Thermo time in the rear coolant flange, can anyone tell me what the thread and pitch are on it as i have a coolant sensor that I'd like to put in it's place and I'm not sure if it will fit.
The other problem I have with the colant flange is this...
there are three outputs
1. small 10mm outlet going to tranverse tube via supplementary start valve thermo switch (the one that trigger a reduction in control pressure for hot start)
2. large output going to heater core
3. large going to heater bypass valve
I have a sensor now in place of the thermo start valve but it never measure above 41degrees yet the number 2. tube that is directly parrallel to this and from what I remember is fed from the same oulet of the head has temperatures consistent with the running temperatures of the head.
Why is this?? am I missing something in the coolant flow diagram or is it possible my transverse tube has a blockage.
The head was boiled less than a year ago and the coolant flange was cleaned at the same time.
Leadfoot

Lizard · Posted: Tue Nov 16, 2004 9:16 am Post subject:

why would you bother putting a coolant sensor in its place when right beside it there is a factory coolant sensor?
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3 928s,

leadfoot · Posted: Tue Nov 16, 2004 12:16 pm Post subject:

The sensor is part of the efi conversion just done, the factory sensor is still running the temp gauge on the console, but I am not registering the correct temperature on the new sensor in place of the old pressure control warm start solenoid. I have a suspicion it's a blockage in the transverse tube line but if it is a staright swap out for the thermo switch then i'd rather put it there and replace the other line with fresh hosing, i'm not sure of the thread and pitch though.
leadfoot

leadfoot · Posted: Sun Nov 21, 2004 4:15 pm Post subject:

Ok so I took the transverse tube of the engine and gave it a good cleaning. As it turns out the the smaller tube that links with the supplementary start valve is just welded onto the main line going to the heater bypass valve and does give accurate reading of the coolant temperature as it warms up.
In fact the maximum temp reading I found was about 40-50 degrees, whereas after modifying the line it now reads from cold to hot, maximum temp is about 90 degrees.
There are to was you could modify the line, one is to cut the small tube just before the bend and drill a hole into the larger tube, but be careful as I drilled mine straight through the other side, DOH and had to cut it off at before the split and run a t-piece to split the line.
BY the way the end of the smaller pipe was chocked full of crud, and this would explain the slow rise in temp as well. Worth cleaning out if you're doing a coolant change. Might explain some hot start problems for some people...
Leadfoot