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Little and constant coolant consumption...head gasket? head crack?


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Hi Guys,

I stopped the TR6 for doing some works.

I want to take advantage of this stop for solve one little but annoying problem; the constant consumption of coolant from the expansion bottle, about 0,5 liters every three months of sporadic use, weekends basically.

The engine has been rebuilt 5 years ago with new pistons, block liners, reconditioned new head (the original was cracked between valve seats), valves, guides, water pump, radiator, hoses... all the necessary.

The cold compression test from cylinder one to cylinder six in bar it's: 12-11.8-11.7-11.9-11.5-10

The cylinder six is the lowest.

When the engine it's hot, i don't see the water boiling, temperature it's good, engine run well.

At the engine start i don't notice smoke or something like this.

What can be?? Head gasket?? Crack on the cylinder head?? How to determine??


In the expansion bottle, from the beginning i have regularly this floating black deposit, not too much, in the expansion bottle internal side (picture below).

post-13363-0-20641300-1483998911_thumb.jpg

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That is really not much loss. Could be coming from any number of places, most likely external. If it only comes out under pressure (when the engine is hot) it may evaporate straight away. Could be a weep from hose joint(s) the water pump seal core plug or radiator core. Also, as the TR6 doesn't have a true sealed system, some evaporative loss from the expansion bottle will occur, though possibly not as much as you mention.

 

If the engine runs well and shows no evidence of water in the oil (beyond what might be expected from condensation) then I'd be inclined to check that all the hose clips are tight and check the water pump tell-tale hole for any signs of leakage. Also the heater valve.

 

Nick

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That black stuff in there looks likean oily residue.

which indicates HG, most likely at he rear

 

Butt, as Nick says,that aint much wata

 

ye say,

 

the constant consumption of coolant from the expansion bottle, about 0,5 liters every three months of sporadic use, weekends basically.

 

 

if its just this much, then it could be doon t,evapouration,

engine heat, normal evaporation sequences, or even thirsty wee beasties, :blink:;)

 

there is a wee wol in top of cap, plus, the hose wont be a tight fit in the cap

moisture will get oot thru thee,s

 

I be moer worried about the blak residue int bottle

bung in a bottle of K Seal, see if that stops the blak stuff

 

M

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  • 1 year later...
Hi Guys,
I stopped again the TR6 for doing some works and fit a stainless steel exhaust system.
After the removal of the exhaust manifold, i found the exhaust port of the cylinder 5 without normal black deposits but with some white deposits and basically clean.
This can be related with the low but costant coolant consuption of my car, a misfire or what do you think??

 

post-13363-0-93289600-1527022138_thumb.jpg

Edited by Tr6PI
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Hi Matteo,

have you got a boroscope/camera on a stick.

If so remove #5 spark plug and have a look at the crown of the piston.

If should be black (ish) - it ot looks clean then there is your leak.

 

Roger

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Hi Guys,
I stopped the TR6 for doing some works.
I want to take advantage of this stop for solve one little but annoying problem; the constant consumption of coolant from the expansion bottle, about 0,5 liters every three months of sporadic use, weekends basically.
The engine has been rebuilt 5 years ago with new pistons, block liners, reconditioned new head (the original was cracked between valve seats), valves, guides, water pump, radiator, hoses... all the necessary.
The cold compression test from cylinder one to cylinder six in bar it's: 12-11.8-11.7-11.9-11.5-10
The cylinder six is the lowest.
When the engine it's hot, i don't see the water boiling, temperature it's good, engine run well.
At the engine start i don't notice smoke or something like this.
What can be?? Head gasket?? Crack on the cylinder head?? How to determine??
In the expansion bottle, from the beginning i have regularly this floating black deposit, not too much, in the expansion bottle internal side (picture below).

 

 

 

Hi Guys,
I stopped the TR6 for doing some works.
I want to take advantage of this stop for solve one little but annoying problem; the constant consumption of coolant from the expansion bottle, about 0,5 liters every three months of sporadic use, weekends basically.
The engine has been rebuilt 5 years ago with new pistons, block liners, reconditioned new head (the original was cracked between valve seats), valves, guides, water pump, radiator, hoses... all the necessary.
The cold compression test from cylinder one to cylinder six in bar it's: 12-11.8-11.7-11.9-11.5-10
The cylinder six is the lowest.
When the engine it's hot, i don't see the water boiling, temperature it's good, engine run well.
At the engine start i don't notice smoke or something like this.
What can be?? Head gasket?? Crack on the cylinder head?? How to determine??
In the expansion bottle, from the beginning i have regularly this floating black deposit, not too much, in the expansion bottle internal side (picture below).

 

 

Hi TR6pi! when your replacement cylinder head was fitted, did it have valve seat inserts fitted? Because if it was not pressure tested it should have been! When inserts are put in a TR6 Cylinder head you are very close to the water jacket and porosity can be a problem through the cast iron. The same applies if you use bore liners in the TR6 block. There is a company near me that vacuum seals castings and my local engine machine shop sends him quite a large number of castings per annum for this treatment.

 

Bruce.

 

Bruce.

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For the weekend i will source a borescope and see what happen to cylinder n°5, thanks the the suggestion.

Regarding the cylinder head, considering that the original was cracked between valve seats, i'd bought a complete reconditioned head about eigth years ago in UK whit inserts in the exhaust valves for unleaded fuel but honestly i don't know if they made a pressure test before and more important after all the machining work... the same for the block liners.... a big trouble now to check all this aspects....

Probably if i pressure test the coolant circuit at cold it will be OK, it's when all it's at the operating temperature to see what happen, what do you think??

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