16 replies to this topic

[minisilverbullet]

I drained and flushed my coolant over the weekend. 

 

Removed the bottom hose, then put a garden hose into the radiator cap and flushed the radiator. 

 

I then removed the thermostat and flushed the block. 

 

Just so I am clear about the the filling procedure. Do I fill the block at the thermostat housing, refit the thermostat and then fill the radiator. 

Do I then leave the radiator cap off to bleed the system, I guess I need to leave the car to get to temperature so the thermostat opens.

 

 

 

 

[jaydee]

Spi? I usually remove the heater pipe at the back of the thermostat to allow air to escape then slowly fill from the rad cap

Since you have removed the stat housing you can easily fill up from there

Spi engines needs a few more minutes to bleed the system because when you fill they tend to form air bubbles at the opposite side of the cylinder head

[dklawson]

I simply fill the radiator, leave the cap off, start the engine, and monitor the level of the coolant with the engine idling.  The thermostat will open and the fluid level will drop.  When it drops, I top it up again.  I go through these steps as many as 3 to 4 times until the level stays constant with the engine idling at temperature.  Then I fit the cap and turn the engine off.  Excess coolant will be "burped out".  

[CityEPete]

I do it the same as dklawson, someone once said that is bad because you are letting cold water in to a hot engine, what those people think happens everytime they use their car on a cold day I've no idea!

[jaydee]

Thats true but it wont let air escape either nor help the bleeding.

Remeber hes got a late A+ engine so no heater take off at cylinder 4.

[minisilverbullet]

Great, so it seems like there are many ways to skin cat. 

 

I didn't know it was ok to run the engine, without coolant (at least until the thermostat opens). 

[jaydee]

On a new built engine or even after an headgasket replacement, i always first start the engine without any coolant nor water in the system, then turn the engine off and fill up, but thats because otherwise its very likely to leak. 

You're just replacing coolant, so your main concern is the best way to bleed any air lock.

[Dusky]

On a new built engine or even after an headgasket replacement, i always first start the engine without any coolant nor water in the system, then turn the engine off and fill up, but thats because otherwise its very likely to leak. 

You're just replacing coolant, so your main concern is the best way to bleed any air lock.

Out of intrest, how long do you run the engine?

 

I've already ran a fiat 850 engine with a broken waterpump for a minute orso, but that was on startpilot, just to show that the engine ran ( was getting sold after it was tucked away for 20 years, was to be a project car  but dad never got round it..)

[jaydee]

Enough to make the head warm to touch, usually from 30 secs to 2 minutes max (It does not take long as you stop the engine and feel the heat spreading form the engine, espescially when its the first initial start up that you do with a 2k rpm tickover)

Form memory a fiat 850 engine is not cast iron, its an alloy block but i doubt it'll break after a minute unless theres something very wrong somewhere else.

Edited by jaydee, 19 May 2015 - 02:07 PM.

[dklawson]

I have heard of people using Jaydee's method particularly with the BK450 head gasket.  I have never had the guts to try it.

 

I was not suggesting that I start the engine without coolant, after a rebuild I fill the radiator with plain water, then bring the engine up to temperature, filling the radiator each time the thermostat opens and the coolant level drops.  After the break in period I drain the water and repeat the process with the water/antifreeze mixture.

[Anthony30]

Put your thermostat/thermostat housing back on, and refill the system until the water/antifreeze mix to the top of the radiator. Start the car, with the radiator cap off, and the heater on and in the hot position. Leave the car running until the vehicle is up to normal running temp, whilst keeping an eye on the water/antifreze level. The level will go down due to airlocks in the system.

[minisilverbullet]

Well that was that! pretty uneventful, since i had the thermostat out i decided just to fill the block and refit the thermostat then filled the radiator then ran the car up to temp. 

 

had to top it up a bit. 

 

I think it is bleed. Though I couldn't really feel my heater getting hot, though I don't currently have a heater fan fitted and the heater matrix is new. I did remove the pipe form the heater valve and i can see that the valve is opening and closing. 

 

Perhaps I should have left it running for longer. 

[CityEPete]

Are the heater pipes hot, both the flow and the return?

[minisilverbullet]

Are the heater pipes hot, both the flow and the return?

They weren't! but i ran the engine again, I gave the pipes a squeeze for a bit and then they got hot, I guess there was an air lock somewhere. 

[CityEPete]

Sounds like it, just keep checking them and the coolant level,did it drop after you got some heat in those pipes?