cylinder head

[swordfishdani1960]

i Have a water leek ,about 200ml a month ,i was thinking it was going into the engine via thru a piston chamber ,i dont have any white gunge round the oil filler cap
when i go for drive say 10 miles stop engine for 10 mins ,go to the expansion tank and there a lot of pressure there when i half turn the cap ,,would this pressure not go into the engine ,if the cylinder gasket was leaking ,there are no leeks any where else

[John_C]

The pressure sounds normal to me. 200ml of coolant a month disappearing may also be okay dependent on the mileage you are doing. Does the coolant still disappear if the car remains static all month?

[busheytrader]

Hi,

The expansion tank on my wedge,whether 2.0L or V8 wont run with the header / expansion tank full to the top. It runs at a level about 35 to 50mm below the filler cap. If I top it up cold, drive for 30 minutes or more, then leave it to cool down, the level stabilises at 35 to 50mm Below the cap again. Could that be the missing 200ml you're looking for?

I've had a head gasket leak coolant in to a cylinder on a different vehicle. Lots of white smoke (steam) blew out of the exhaust pipe, bubbles from the cylinder blew up from the header tank which tried to drive out the coolant with the cap off.

I did have a leaking water pump on my 2.0L engine, via that nice hidden slot underneath the carbs IIRC.

Hope this helps,

Adam

[Hasbeen]

I fitted an expansion/overflow tank to the 7. I was worried as my header tank always settled at about 65mm below full.

I found the one from an 86 Toyota Cressida nicely filled the gap between the radiator & the inner wing on the header tank side. With this fitted the radiator redraws the coolant forced out by expansion at operating temperature, & remains full on cooling.

This has done nothing for the running or cooling of the engine, but makes me feel better.

Hasbeen

[FI Spyder]

The expansion tank runs just above half way as when water expands it forces water out the overflow pipe. Water expands when heated (that's why it's called an expansion tank). That level and the level that sets off the coolant light on the dash is pretty small. Leaking from the open rectangle in the block from a water pump seal is pretty hidden (at least on an FI) you wouldn't likely see leakage from there as it rolls down the side of the block and onto the road. There is the inevitable loss from evaporation (escape of steam) even on our "sealed system" so the occasional (seldom needed) addition can be expected.

[swordfishdani1960]

Thanks Adam ,yep thats whats happening ,am over filling my header tank
am filling to near full so am losing it driving ,yes it is settling down and leaving quarter full , my heater guage is reading half on the scale ,this is due to the warm weather ,no white smoke out the exhaust, runs well its a 1978 ,4 speed 70k on clock

[Beans]

According to the owners instruction manual the level in the header tank should be kept at ±25mm below the filler neck.

A lower level might also be caused by a worn pressure cap, resulting in a lower pressure in the system. And as such some coolant loss.
This will also cause the engine to run slightly warmer, on a healthy cooling system and engine the temperature gauge should read between ¼ and ½ of the scale.

And make sure the level doesn't drop to low as the thermostat will run dry