[ChrisSound]

Just after some advice post thermostat replacement.

I put it all back together and filled up the coolant to just beyond max expecting the system to suck some fluid instantly when I pumped the hoses by hand...nothing happened coolant level stayed the same.

I then fired up the engine and let it idle and coolant was dropping from the small pipe into the coolant res, it seemed to heat up ok and the thermostat kicked in and started sending hot fluid through the big pipe which was nice. However even after all this the coolant level didn't drop much at all.

Is this normal? It is still sitting above max as we speak.

Its a 156 2.0 by the by.

 

[keithyboy]

You might have an airlock somewhere. Is the heater pumping out warm air?

 

[FoxtrotOscar]

Take it for a quick drive, keep an eye on temperature, then check the level again. There is a bleed screw o/s top of the rad, but unless you completely drained the coolant (by removing bottom hose for example) it's unlikely you'll need to touch this. Check the level again when the engine is completely cold.

 

[ChrisSound]

Didn't check the heater really.

FO Will take it for a spin and see what happens. I thought it should be ok as I only removed the hoses near the thermostat. Will report back, ta.

 

[ChrisSound]

Well, mind is slightly as ease now. Just been for a spin, coolant res is now sitting at 'max'. However the temp gauge is reaching 90 then dropping to 70 over and over again, never stayed on 90, I drove for 10miles.
Is that normal?

 

[Ralf S.]

It sounds okay.

The coolant level might drop overnight once the system cools right down.. but if the temperature gets to normal and stays there (the temp' drop is the thermostat opening and letting cold coolant in.. it should then heat up again and repeat the cylce) and the fan comes on if the temp' gets to 92C or thereabouts, and the heater works, then it's job done.

You can get some coolant out of the header tank, if it's over "Max" by sticking a cloth in there to soak it up a bit.. but be careful if you use paper towels.. they disintegrate and clog the header tank!


Ralf S.

 

[davealfa11]

Well, mind is slightly as ease now. Just been for a spin, coolant res is now sitting at 'max'. However the temp gauge is reaching 90 then dropping to 70 over and over again, never stayed on 90, I drove for 10miles.
Is that normal?

just keep eye on level you might have an air lock in system
id get on motorway and cruise at 70 for a few mile then let it cool off then check levels

 

[FoxtrotOscar]

Normal; it's just the thermostat opening and closing (ie doing its' job). Bear in mind the ambient temperature is quite low at the moment, which makes it more obvious.

 

[ChrisSound]

Cheers, FO. I thought that might be the case but this is the first time I've done any work on my own car so want to make sure I haven't ballsed it up.

 

[davealfa11]

Normal; it's just the thermostat opening and closing (ie doing its' job). Bear in mind the ambient temperature is quite low at the moment, which makes it more obvious.

thats why i suggest motorway run

 

[David156]

The temperature should stay even and not drop and rise, the thermostat is not an 'on/off' switch it should be a gradual opening or closing so keeping temperature at 90.
When the engine is cold it is fully shut, slightly warm and it may be open a fraction gradually fully opoening when at normal temp.
I would say you have a faulty stat was it genuine?
Did it rise and drop temp before you changed it??!

 

[ChrisSound]

I got the stat from Jamie Porter as Alfa Workshop so I think it will be genuine.

Before the change I'd never seen the needle rise above the 70 marker, changed today it rose to the 90 marker dropped to 70 then rose again to 90. Then when I drove it, it was repeating that cycle.

 

[David156]

Sounds as though you have replaced one problem with another!
Next port of call would be a faulty temp sender, maybe it can only read those two temps and has a 'blank ' in between causing the needle to drop all the way down to 70 again.
Does it jump from 70 to 90 or is it a nice gentle rise? If it does rise steadily then ignore the temp sender idea, and I would still bet on faulty stat.

 

[davealfa11]

i would seriouslly take it for blast on motor way nd let it cool check levels then take it out again ,and re[port back

 

[ChrisSound]

Nice gentle rise.
Think I shall be taking it for blast 2moro and see what happens.
Will report back.

 

[alid1]

If it's a facet thermostat, then i'm not suprised your getting irregular reading. Your temp should get to 90 degrees and stop there.

 

[davealfa11]

If it's a facet thermostat, then i'm not suprised your getting irregular reading. Your temp should get to 90 degrees and stop there.

beg to differ there alfas dont take average reading of temp ,they are actually real time,so as therm opens temp will go higher then drop

 

[alid1]

beg to differ there alfas dont take average reading of temp ,they are actually real time,so as therm opens temp will go higher then drop

I agree with you to some level. When the stat first opens you can expect a decrease in temp due to cooler fluid entering the engine,however it should not fluctuate up/down irregulary once at 90 degrees.

 

[mo 156]

I have the bouncy bouncy on my dial, 3 garrages have checked and said it works perfectly.
do the pipe test - forgotten which pipe! but hold it, if it gets warm slowly, stat stuck open. if it suddenly gets hot, thats the stat opening when engine gets up to temp, as it should.
knowing the pipe name would help...

 

[alid1]

I have the bouncy bouncy on my dial, 3 garrages have checked and said it works perfectly.
do the pipe test - forgotten which pipe! but hold it, if it gets warm slowly, stat stuck open. if it suddenly gets hot, thats the stat opening when engine gets up to temp, as it should.
knowing the pipe name would help...

Coolant inlet hose to radiator