Tvr 3000m thermostat problem

[chris52]

Hi I have a problem that the thermostat is not opening I've checked the thermostat and that's ok and it opens at 82deg as stated also the pump is new.
Without the thermostat in the car runs fine with good flow through the radiator so I'm assuming its the way I have it plumbed that's wrong having not dismantled the car myself.
I have the pipe that comes from the back of the water pump meeting the the pipe that goes to the base of the thermostat housing on a constant loop with the heater matrix T-ed off to supply hot water to that.
These pipes get hot when the engine is running but the thermostat never opens so the engine just gets too hot and throws all the water out of the swirl pot cap.
Any help would be appreciated.
Chris

[tuscanturner]

There must be a number of different plumbing set ups!! The small pipe under the thermostat on mine goes to the heater and the small pipe on the water pump is blanked off!!
If its been working ok before, it might just be the thermostat not opening fully. Less than a tenner but cheap enough to eliminate.

[chris52]

I have two thermostats one 86 the other 82 but both have the same result.
Plus I tested both in a pan of water with a thermometer in and all was ok with them.
But thanks anyway
Chris

[Cerberus90]

Where do your pipes for the heater run to?
Are all of your rad caps sealing properly? We had a problem with one of ours not sealing fully causing overheating and water spouting,

I found a good picture online for the M series cooling system, it's from the M-fix website.

[chris52]

That's perfect many thanks for your help
Chris

[Adrian@]

Cerberus90 said:

Where do your pipes for the heater run to?
Are all of your rad caps sealing properly? We had a problem with one of ours not sealing fully causing overheating and water spouting,

I found a good picture online for the M series cooling system, it's from the M-fix website.

Chris/Thomas as good as it is, I know we spoke about this Chris... the T pieces bleed and restrictor either within the pipe or fitting as I spoke about needs to be added to that pictorial (for those with using an auto choke it is a must and for those who require heat from the heater too!)

NOTE This pictorial is a M system rather than a Taimar or S, as these use open heater matrix and deflect air through the matrix or not as the case maybe.

Adrian@

[chris52]

Adrian@ said:

Chris/Thomas as good as it is, I know we spoke about this Chris... the T pieces bleed and restrictor either within the pipe or fitting as I spoke about needs to be added to that pictorial (for those with using an auto choke it is a must and for those who require heat from the heater too!)

NOTE This pictorial is a M system rather than a Taimar or S, as these use open heater matrix and deflect air through the matrix or not as the case maybe.

Adrian@

Hi Adrian thanks for the info the other day I did pipe up as you explained. My problem is that the thermostat is just not opening I thought it may have been down to the way I had piped it and misheard what you had said but this is not the case as all is piped up correctly. It may well be the cap on the swirl pot as that seems to start throwing water out when the temp gauge reads about 95 but the thermostat is still closed at this point and as a result the radiator is cold. I have cured the problem temporarily by drilling a hole in the thermostat, this seems to let the thermostat open and the car runs at a steady 90deg fan cuts in and keeps the temperature steady. I will have to look into this a little more when I get chance as I know there must be something wrong, I just don't know what yet.

Chris

[RCK974X]

I've seen that before, where replacement thermostats did not have the small hole like the original. Seems like it's a waste of time, but that little hole allows air bubbles to escape.....

I had that same problem with a replacement stat for my Triumph 2500, it overheated until I drilled a small hole....

Edited by RCK974X on Monday 1st July 07:04

[Adrian@]

A thought..cast impellor or pressed steel impellor on the water pump, as the steel version has no back-plate and this version only thrashes at the water rather than pumping...and have you back flushed the engine from the drain under No4 bore as over time the silt from the engine gathers there and causes hot spots around that bore.
Adrian@
I will mention the steel pipe under the thermostat housing closing up over time (just for info).

[chris52]

Thanks Adrian the Pump is new from burton power this one http://www.burtonpower.com/water-pump-essex-v4-v6-... , I had the engine in bits before reinstalling it and all the waterways were blown clear so should be ok. The steel pipe on theremostat is also clear.
Will have to have a look into it in more detail later. But for now with the thermostat drilled it all seems to be working well.

Chris

[Adrian@]

I really don't know what version Burton's are selling...
Adrian@

[heightswitch]

check also for jiggle pin in stat body, consider drilling 2 1/8 holes through the body to allow a small amount of by pass which helps with any airlocks..

[oliverb205]

This could be obvious, be I assume the radiator caps are on the right way round. The plain cap should be on the header tank and the pressurised one on the expansion bottle. Swapping them over will result in a lot of coolant being thrown out - I know 'cos i once put them on the wrong way round after checking the levels!

Glad the rebuild's coming on well.

Oliver.

[chris52]

Thanks for all the help and advice, the caps are the correct way round. I will get to the bottom of this but will have to wait now as I'm at the Griff Growl this weekend.
Chris

[Adrian@]

Thermostat bleed-by holes...that were, then were not, but still are ...on some, IF you look at the central housing from the top you will see that within the main body there is a small raised nick, turn it over and that nick is a V shaped indentation in the edge of the main body, allowing water to bypass, this serves the same purpose as a bleed-by hole, on others a simple nick in the sprung loaded central part, allows the air to bleed-by (hold the stat up to the light and you can the nick). Different brands do different things.
I would want a bleed-by, if mine did not have one then I would put one in, it need not be a big drill hole (IMHO a 1mm hole would be enough).
Adrian@
Edited after looking at TOOO many thermostats...

Edited by Adrian@ on Thursday 18th July 17:34