Self inflicted coolant problem

[graham33]

Hey......

I thought I'd fit a thermometer in the coolant so I could monitor the temperature!
I saw at the top of the head tank what I thought was a little breather hole! So I tried putting in the thermometer sensor in there – It wouldn’t fit so I slightly enlarged it with an 8mm drill bit – popped the sensor in and drove home.

All was good on the way home the temp gauge didn’t move from it’s 11o’clock position and the electronic gauge told me it went up to 90 degrees C.
When I got home I noticed some coolant on the floor – So I thought DAM ! That obviously wasn’t a hole then…..and sealed it up with sealant.

But a few days later I was driving about and the temp gauge in the car went right up and past the 11 o’clock position – So I stopped and had a look at the coolant header tank – It was empty, so I took the cap off and then a massive whoosh of air – the coolant came straight to the top and then a ‘bubble releasing’ noise was heard – the temp gauge had dropped back down, but when driving it rose again so I repeated the cap off a few times and then it seemed to settle, But obviously this wasn’t right so I took it to the garage – one when they had just done a head gasket, and they ‘bleed’ it for me. Happy!

Until I drove it and it was exactly the same.

My question after this long winded explanation is: Is that a small bleed hole at the top and should I un-seal it.

I think I will leave well enough alone in the future!

If nothing else works I think I will bleed it myself with the fact sheet off this forum.

Thanks

[Muzorewa]

Oh dear. Another cooked engine

[scanner]

All was good on the way home the temp gauge didn’t move from it’s 11o’clock position

As has been said many, many times - IT NEVER DOES (unless you have fitted a Mason Alarm).

Until

But a few days later I was driving about and the temp gauge in the car went right up and past the 11 o’clock position – So I stopped and had a look at the coolant header tank – It was empty, so I took the cap off and then a massive whoosh of air – the coolant came straight to the top and then a ‘bubble releasing’ noise was heard

happens.

This

and the electronic gauge told me it went up to 90 degrees C.

was presumably telling you what was really happening.

As to the rest I have no idea - I just leave things alone.

[francophile1947]

There is no breather hole in the header tank that I am aware of If there was, it would not be possible for the system to pressurise.

[westonwarrior]

what you can try is a stainless steel screwin the hole you made big enough to cut a thread but not too big as to split the header

this is how the lca alarms are fitted and should give enough of a seal
then bleed it again making sure it gets hot enough to open the stat

[Doone]

It does sound as though there is air in the system.

There is a 'vent' in the top of the header tank that will vent if/when the cap lifts. This vent should have a rubber 'overflow' pipe attached to it.
It's not really a hole and there is no hole as standard.

Unless it was due to Haydn's modified 'low coolant alarm' (and has been removed), there should not be a hole in the header tank.

[haydn callow]

What you thought was a hole and you drilled larger is in fact not a hole at all...what you have done is drill a 8mm in your tank and of course it will no longer pressurize the system....You need a "new" 2nd hand tank then a proper bleed and hope thats o.k...
However I suspect you have cooked your cylinder head.
If you really want a temp gauge ...contact me.

First get Bongo fixed.