airlock?

[grahamrose]

Hello, please help a new owner in distress!

I have recently acquired a Mk 2 Stag. There was a small leak from the expansion bottle at the hose inlet so I decided to replace the whole thing. I also noticed that the heater wasn't working as per Kingpin's description in the club magazine and I fixed it in exactly the way he described, so thank you very much. The cable had come disconnected at the controls as he predicted and not a fun job to fix.

My problem is that on refilling the system, opening the heater and running up to normal temperature I'm getting huge airbubbles and hot water squirting from the expansion bottle cap, lots of loud fizzing noise followed by all the water in the bottle disappearing when the engine cools down. I've tried refilling but it seems to happen again. Is this something to do with my heater not having worked for years? Not filling it properly? A massive cylinder head blow? The temperature gets up to halfway and stays there. I've only had the car a week and it's all rather worrying!

Can you advise please?

Many thanks

Graham

[DJT]

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Hi Graham, and welcome. Plenty of experience available here so someone should have the answer - I hope.

You say that you have recently acquired the Stag. How much have you driven it? Was it generally OK before you changed the expansion bottle and fixed the heater?

Regards filling the system. The way to do it is to have the heater valve open and top up the system via the plug on top of the radiator. It helps if the NSF of the car is raised slightly. Squeeze the top hose a few times to expel any air and when the rad is full, replace the plug. Then fill the expansion bottle half-way and replace the cap. This should ensure no airlock.

Dave.

[Tdm]

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Following on from what DJT said - try using the "search" facilty button - type -
expansion bottle.....overheating.....air lock... etc etc to access questions & answers previosly raised on such subjects or any other problems you might have.

[grahamrose]

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Hi DJT, thanks

I've only driven locally and probably did 60 odd miles but there were no obvious problems. Temp normal.

I'll try jacking up and filling....should I fill the expansion tank too and replace the cap before running up to warm?

[grahamrose]

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Thanks Terry,

I did a search and can only see a possible non functioning water pump as a potential problem if the heater doesn't work.

Is there a way of testing it without getting the big spanners out?

[V Mad]

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Graham
Welcome to Stag ownership and the forum.

Firstly, make sure you follow the correct procedure for filling the system with coolant and purging the air. Then if the car is then running at normal temperature, you should not have any excessive pressure, nor should you have coolant coming from the expansion bottle. On coolign down, only a small amount is normally siphoned from the expansion bottle, which should then return to the original level (half full).

If you want info on the correct procedure, please ask and I am sure someone will explain.

[DJT]

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grahamrose wrote:

Hi DJT, thanks

I've only driven locally and probably did 60 odd miles but there were no obvious problems. Temp normal.

I'll try jacking up and filling....should I fill the expansion tank too and replace the cap before running up to warm?

Hi Graham,

Re-read my first. It is important to only half-fill the expansion bottle. Any more leaves no room for expansion.

Dave

[grahamrose]

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Hello,

Thank you everyone.

Just refilled as per DJT and as is well. Heater impressively hot, temperature staying below centre on gauge. No bubbles, squeaks or geyser impressions.

I jacked the car NSF as high as poss and watched the bubbles come out. As I filled, the radiator drained into the expansion tank and I realised I should have had the cap on to stop the air escaping and the bottle filling. I squeezed all the hoses including the heater's and watched for the water popping out at the filler plug. Ran the car for 20 mins in the garage and all is well.

Thanks again, very impressed with the rapid and helpful responses!

Graham

[martin]

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Hiya Graham, indeed welcome to the strange land of Stag ownership, it's only a shame this happened to you so early in the experience ! It is a wonderful machine, the first time somebody says something nice about it, and they will,there will issue from your lips a loud YESSS ! Good choice mate, VERY pleased the forum helped, and thrice welcome ! Martin.

[DJT]

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Hi Graham,

Really pleased that it worked as your symptoms were similar to complete water pump/jackshaft failure and I was afraid that someone had sold you a dodgy motor.

Now enjoy

Dave