The Triumph Dolomite Club - Discussion Forum

Hi chaps, i have a capillary temp gauge fitted and i have noticed that when up to temperature, just now and again it will jump up ten degrees from say 80 to 90 degrees, hover there for a bit and then back down to 80 where it will stay for a while before doing it again.

This gives me the impression that there is air in the system...Or the head gasket is knackered, so not very happy with that prospect!

Additionally, how much water should there be in the header tank?
I checked the other day and there was a bit in the bottom....I then over filled it and it's obviously started coming out as you would expect!

Cheers as ever o'wise ones!

Shaun

If you are using the standard coolant reservoir bottle it should be half full - there is a special procedure for refilling / topping up the coolant on sprint / tr7.which when reading the procedure its a bit of a faff, but stops you getting a air lock.

Paul

Cheers Paul.....What is it then you tease?!

I thought you fitted a header tank Shaun?
It was certainly discussed in your project's thread.

I can't find a photo of the completed under bonnet layout (but I have just skimmed through said thread)….



Ian.

Hi Ian, it has got a header tank...



This why I'm asking if i have a head gasket problem...

shaunroche wrote:Cheers Paul.....What is it then you tease?!

Shaun

I'm up in Glasgow all week - I will scan the document at the weekend and send it to you, ring you later tonight.

Paul

Okay I see.
You have retained the weak link of a Dolomite's cooling system .
The level remains fine in this tank whilst coolant merrily escapes from the engine.

By definition the tank Dolomites use is neither a header tank or an expansion tank.
A header tank is connected to a bleed from the highest point (or points) of the engine and
has an outlet connected into the bottom radiator hose (some early headers were connected to the top hose but this was superseded).
An expansion tank is connected in such a way as to gather coolant should the pressure build up sufficiently to open the pressure cap
(and said coolant is drawn back as the pressure drops).


You have an electric coolant pump. Do you have a thermostat?
How does the radiator bypass work?
How is the heater plumbed?

If I was in your position I would fit a proper header tank even though it means draining the cooling system and replumbing work and expense.
I would do this because I know from experience bleeding a cooling system with one is easy and reliable,
set the heater to hot, pour coolant into the header tank until the engine is full,
run the pump for a minute or so (to expel air from it) then top up the header to the required level.



Ian.

The photos have gone for some reason but this old article from 2010 does explain the filling procedure
viewtopic.php?f=13&t=13259&p=128593&hil ... le#p128593


Also.
There is an illustration of how an electric pump should be plumbed in here….
http://sideways-technologies.co.uk/foru ... entry96300




hope this helps,


Ian.

Hi Ian, I'll get back to you when I get in, but it's like this diagram, but without the bottom feed from the header tank.....

Carledo wrote:Camera flash error.... I think! Best I can do for now!



I've added flow arrows in the hope that it makes more sense!

Steve

Shaun I have peered at your diagram .

You should have a hose from the top RH spout of the radiator connected to the thermostat housing.
It should not be blanked off because it is the radiator vent.

If you had a header tank with an outlet to the bottom hose you probably will be able to get by without the top RH hose
because you will be filling the cooling system through the header tank, meaning the radiator is filled from the bottom up.


I think a Vauxhall Vectra (petrol) has a suitable header tank for your preferred position on the bulkhead…...




Ian.

sprint95m wrote:Shaun I have peered at your diagram .

You should have a hose from the top RH spout of the radiator connected to the thermostat housing.
It should not be blanked off because it is the radiator vent....

Ian.

Hi Ian, that makes a lot of sense.....there is a little spout on the driver's side of the top of the rad as you say...If i connect that to the blanked off port of the thermostat housing, can I retain the current, standard expansion tank ie with just the one hose going to it and not a second coming from the bottom then?

Never used an alternative tank than the std setup. The only issue is that caps aren't always what they say pressure wise.

Jeroen

shaunroche wrote:

sprint95m wrote:Shaun I have peered at your diagram .

You should have a hose from the top RH spout of the radiator connected to the thermostat housing.
It should not be blanked off because it is the radiator vent....

Ian.

Hi Ian, that makes a lot of sense.....there is a little spout on the driver's side of the top of the rad as you say...If i connect that to the blanked off port of the thermostat housing, can I retain the current, standard expansion tank ie with just the one hose going to it and not a second coming from the bottom then?

Yes probably.

If you post a diagram or photos showing the heater's plumbing I will give a more definite answer, Shaun.




Ian.

sprint95m wrote:

shaunroche wrote:

sprint95m wrote: .

Yes probably.

If you post a diagram or photos showing the heater's plumbing I will give a more definite answer, Shaun.

Ian.

The heater is just a simple in/out mini rad with a manually​ switched fan on it replacing the the big Dolomite heater matrix....




As an aside, I've also ordered a new 13psi header tank cap just in case....

Your heater plumbing is fine Shaun.


I don't see a radiator bypass in your diagram though.
It is not possible to use the Triumph system, despite what a lot of Stag EWP conversions have,
because until the thermostat opens you have no circulation within the engine,
so during warm up the pump just spins…..shortening the pump lifespan (which if you have a Davies,Craig pump
is very short anyway) and doing your engine no good as well.




Ian.