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Thermostat versus sensor


Valherald
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Hi all

I have just gone to replace the thermostat on the 1147 1965 Herald, firstly I found there isn't one fitted, so, fitted one to very quickly find out why there wasn't one fitted!!

 

I now understand that the early 1200's didn't have a temperature gauge installed so this one has had a modified thermostat housing installed with a temp sender unit in the top, trouble is, the gauge intrudes so much that the housing wont go back on with a thermostat in there!

 

Anybody had a similar issue? I'm wondering if there is anywhere I can get a shorter gauge to fit or alternatively, if I install a standard housing, would I have to install a later water pump housing to get a gauge on or is there any other way?

 

As always, many thanks in advance for any advise.

Regards

 

Garypost-1692-0-15996400-1501100946_thumb.jpgpost-1692-0-79082100-1501100981_thumb.jpg

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Ah. Usually an electric gauge is fitted which uses a shorter sender. 

 

The capillary gauges are really nice, as they are accurate and easy to check. 

 

So I think I would be either fitting a later housing, or drill and tap the one you have.

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Thanks Clive, ah, I see, I wondered how it could work with that length of probe, that explains how others work! I think I will try and stick with the Capillary if I can, although the easiest option appears to be to install an electric one!!

Many thanks, much appreciated.

Gary

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Is there a spare tapping in the rear o/s top of the cyl head, will it fit in there.

 

if you go electric you are liley to need a voltage stabiliser and stabilised gauge with sender gtr108

 

if you manage to find an older moving iron gauge that are not stabilised you need sender 121997

 

you cant mix the two systems

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Thanks Pete, I have these two but not sure if either are in the correct location? I'm thinking the one under the manifold is too low, the other is nearside rear, would that be any good?  

 

Also, I may have had a bit of luck as a few months back a friendly fellow Herald owner gave me a few old spares, lo-and-behold, I have a later pump housing which is tapped at the top. It dousnt look like too much of a job so if these taps arnt any good, that may be my best option if the sender fits. Any tips on cleaning the dried up crud in the replacement housing? anything I could soak it in?

 

Many thanks

Gary

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none of those the 1st is a drain plug , and too low to give you the high  temps.

2nd is the blank for the oil feed to the rockers

 

if its anywhere some have a plugged tapping on the top surface of the head near the rear end alongside the rocker cover 

...or not .

 

as for cleaning  soda blasting, washing soda, plumbers acid,  sand paper , wire brush ,  brute force and your best mates tooth brush

 

Pete

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Ha Ha, thanks Pete, funny you should say that, I only threw a toothbrush away this morning so have retrieved it from the bin!!

 

I'm wondering, just for interest, if the blank you speak of is where my heater pipe is attached?

 

Many thanks for the cleaning tips,I think that's the way I will go, most cost effective as i'm lucky enough to have the other housing, fingers crossed its ok!

 

Thanks for the help 

 

 

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Early Heralds with a temperature gauge had the sensor in the top of the thermostat housing; you need the correct one or it will protrude too far and the bonnet will snap it off; a right-angled spade terminal will help keep it shorter.... later cars used the screw-in aperture to the front of the waterpump housing; if there's a blanking bolt in there it can be hard to remove. I don't think any of the other plugs or ports around the engine will give you a correct reading as far as the gauge is concerned as both the others take their readings from the hot water coming in at the top of the radiator.

You used to be able to buy a Ford Fiesta housing that had the top screwed port and took more modern sensors but they're harder to find these days. The alloy one I had was open in both ports and I was able to fit a temperature sensor in one and a switch for an electric fan in the other and this is the simplest option.

 

 

 

 

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Thanks Colin

That's another option as until your post, I wasn't sure about the electric sender option! Also, I wondered why the later pump housing had two tapped threads so thanks for clearing that up for me, with the electric fan output as well, may be worth me installing the later housing as I have one and if it all comes off reasonably easy (after Pete's warning of shearing!)

 

Many thanks

Gary

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  • 3 weeks later...

Problem solved

The spare pump housing works a treat once cleaned up (a bit of luck having that lying around), engine warms up much quicker now that it has a thermostat, as expected. Also have a spare sensor hole if I come to need an electric fan now.

 

I do have a problem with water loss now though so am getting some temperature rises on a run, is it right that a bad fitting rad cap can cause issues? I seem to have pressure leaking out of the cap which makes a sound similar to a stuck horn and the only place I can see water coming out is the overflow pipe?

 

Any thoughts?

 

Many thanks

Gary

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there are two depths of cap  a shallow/short one wont seal against the filler seating

 

and caps have two valves the big sprung one to open and let expansion out  must compress when fitted to the filler and in the centre a smaller sprung disc to open and allow air  back in 

 

semi sealed systems have an addition fibre or similar seal to seal the bayonet cap to the top of the filler , so on contraction the coolant gets sucked back of of the overflow bottle

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  • 2 weeks later...
On 7/26/2017 at 4:30 PM, Valherald said:

Hi all

I have just gone to replace the thermostat on the 1147 1965 Herald, firstly I found there isn't one fitted, so, fitted one to very quickly find out why there wasn't one fitted!!

 

I now understand that the early 1200's didn't have a temperature gauge installed so this one has had a modified thermostat housing installed with a temp sender unit in the top, trouble is, the gauge intrudes so much that the housing wont go back on with a thermostat in there!

 

Anybody had a similar issue? I'm wondering if there is anywhere I can get a shorter gauge to fit or alternatively, if I install a standard housing, would I have to install a later water pump housing to get a gauge on or is there any other way?

 

I missed this first time around. This is a problem we in the US have long faced, since temperature gauges were always installed for cars destined for the US market. I know you're set now, but there was / is an alternative to swapping out water pump housings.

Back in the day, the proper style of thermostat was readily available; nowadays I believe the only real options are NOS or good used ones. What is needed is literally a thermostat with a flat top. Typically these were of the bellows type, and it's what was originally installed, as opposed to the typical modern thermostat with its extra height. Here's an image I grabbed of the 'net of a typical Smiths brand thermostat.

bellows-thermostat-crop.jpg

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Thanks Andrew, I wonder if they can still be purchased! I would have further investigated but have now gone down the long routed avenue and replaced the pump housing etc (luckily had a free of charge spare given to me). 

Appreciate the additional information for future reference.

 

All the best to you

Gary

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