explosive water

[mints53]

I've just seen this, it sounds like you may have discovered the cause but I had exactly the same problem a little while ago, just after fitting a new radiator cap.

 

On examination the rubber seal that is loaded by the spring onto the flange in the rad neck was oversize and when fitted would make a seal on the diameter of the neck or at least cause a significant resistance to flow. That is until it has lifted far enough to uncover the hole in the neck leading down to the expansion bottle. At this stage I guess the pressure is higher and so the flow out much more violent. I trimmed the rubber seal to the same diameter as the steel and it did not happen again. I've driven many miles subsequently without overheating or needing to add coolant.

 

I hope this is useful

 

Andy M

[dpb]

hi there. thanks for your comments.

 

I had tried two different radiator caps during all the trials and tribulations, so pretty happy they were not the cause. (the original one and a new one).

 

Now working up the courage to strip the head off. Unfortunately it seems to have rained every day for a fortnight, and I want to keep dry when doing the job.

 

cheers

Dave

[keith1948]

With regard to heater not working, I have recently dismantled a heater matrix with a view to repair. Not recommended I might add. But anyway the design of these is terrible. At each end is a box that feeds the heater pipes. The far end box opposite the feed pipes was virtually full of sediment and would not really have been removed by flushing with a garden hose. I would recommend that if the heater matrix is blocked a new one would be advisable. The heater tap might also be blocked.

Re overheating, I have a multi blade plastic fan on my 4A and the car has never overheated even in nearly 40C temperatures in France.