A

AP90

Active Member
Hi

I was about to depart from Cornwall to London and the temperature needle started climbing toward red.

It has been running fine and given a real workout on the cornish hills with no problems

However I did top up the water today when the engine was hot it took about a pint or so which I considered a top up, have I created an air lock or something strange

Am I missing something here, what is the procedure for topping up, can I put things right once she has cooled down?

New rad, stat a couple of months ago, viscous coupling and water pump changed a bot a8 months ago

Any help would be most gratefully received.....

Thanks in advance

Ash
 
AP90 said:
Hi

I was about to depart from Cornwall to London and the temperature needle started climbing toward red.

It has been running fine and given a real workout on the cornish hills with no problems

However I did top up the water today when the engine was hot it took about a pint or so which I considered a top up, have I created an air lock or something strange

Am I missing something here, what is the procedure for topping up, can I put things right once she has cooled down?

New rad, stat a couple of months ago, viscous coupling and water pump changed a bot a8 months ago

Any help would be most gratefully received.....

Thanks in advance

Ash
Click to expand...
Do you know why you had to top off the coolant and have you had to top it off for awhile?
 
Hi

Well it was kinda based on Keith's advice to check and top up the level every now and then, and I have had the top off for about a month.

As I was intending to do a long journey, just part of an oil and water top up

Thanks for your reply
 
AP90 said:
Hi

Well it was kinda based on Keith's advice to check and top up the level every now and then, and I have had the top off for about a month.

As I was intending to do a long journey, just part of an oil and water top up

Thanks for your reply
Click to expand...

Please explain "the top off" ...

(I know what WSR means), I'm just a little concerned at your meaning :confused:
 
AP90 said:
Hi

Well it was kinda based on Keith's advice to check and top up the level every now and then, and I have had the top off for about a month.

As I was intending to do a long journey, just part of an oil and water top up

Thanks for your reply
Click to expand...
You should look for the source of the leak. It can be a pin hole in the rad or a heater hose or a weepy waterpump. They are all repairable, but all of these leaks can degrade rapidly. When they do, bad things happen. Or it could be the dreaded HGF. Find the source of your coolant loss first. It can take some detective work. Look for signs of leaking on the rad, and check the little hoses that heat the air intake. When they leak, it can be hard to spot. Also look around your themostat housing and under the water pump.
 
Last edited:
Dippypud said:
Please explain "the top off" ...

(I know what WSR means), I'm just a little concerned at your meaning :confused:
Click to expand...

The filler cap on the expansion tank

And WSR, as far as I know there are no leaks, this all seems to been initiated from my warm engine top up today.......seems a bit crazy
 
AP90 said:
The filler cap on the expansion tank

And WSR, as far as I know there are no leaks, this all seems to been initiated from my warm engine top up today.......seems a bit crazy
Click to expand...
Well, to check for an air bubble, turn on your heater at high temp and see if it blows warm or cold air. Cold air means bubble. And replace the cap, if you haven't already.
 
West Slope Rover said:
Well, to check for an air bubble, turn on your heater at high temp and see if it blows warm or cold air. Cold air means bubble. And replace the cap, if you haven't already.
Click to expand...


Ah thanks for that........ there wasn't any warm air coming through.......how do I remove the air lock?
 
AP90 said:
Ah thanks for that........ there wasn't any warm air coming through.......how do I remove the air lock?
Click to expand...
Open the expansion cap and fill the system from the little opening in the heater line (that tower with the plastic cap on it to the left of the plenum housing) or just keep adding at the tank and then take a short drive up and down some inclines and then repeat the heater check until you feel warm air. You may have to add it two or three times and do the heater check if you add it through the expansion tank.
 
Last edited:
Thanks WSR I'll give that a shot tomorrow......

I just wonder what I have done to upset the system, there goes that old adage, if it aint broke don't fix it
 
AP90 said:
The filler cap on the expansion tank

And WSR, as far as I know there are no leaks, this all seems to been initiated from my warm engine top up today.......seems a bit crazy
Click to expand...

West Slope Rover said:
Well, to check for an air bubble, turn on your heater at high temp and see if it blows warm or cold air. Cold air means bubble. And replace the cap, if you haven't already.
Click to expand...


Ah, that's what I thought ... :(

Well done WSR you're a star ... :)
 
AP90 said:
Thanks WSR I'll give that a shot tomorrow......

I just wonder what I have done to upset the system, there goes that old adage, if it aint broke don't fix it
Click to expand...
Replace the cap so you know that it's a bad cap and not pressurization causing the coolant to escape. You may have done nothing, but it has.
 
AP90 said:
Hi

I was about to depart from Cornwall to London and the temperature needle started climbing toward red.

It has been running fine and given a real workout on the cornish hills with no problems

However I did top up the water today when the engine was hot it took about a pint or so which I considered a top up, have I created an air lock or something strange

Am I missing something here, what is the procedure for topping up, can I put things right once she has cooled down?

New rad, stat a couple of months ago, viscous coupling and water pump changed a bot a8 months ago

Any help would be most gratefully received.....

Thanks in advance

Ash
Click to expand...
no topping up wont create an air lock, lack of coolant will either from combustion gasses pushing coolant out or a leak
 
Hoping it's not ta cracked head or anything like that, went through all this a couple of months ago and was just a cooked stat and me letting the coolant level get low, I haven't got the gear with me to strip down the system, I'd like to think is not serious, just mysterious...... here's hoping
 
I hope I have missunderstood, but from your posts, it sounds like you have been running with the pressure cap off?
The pressure cap must be in place and fully tightened down, sometimes they feel tight before they seal.
The viscous might be newish, but if it is Britpart, I'd be inclined to do the newspaper test to be sure it's working well.
 
Hi Keith

Pretty sure I buttoned the cap down well and truly, when I released it at the petrol station there was huge gush of coolant and steam.

Have topped up before and had no problems

I can't get my head round it as its has been absolutely fine until I topped it up yesterday when warm/hot just not sure what I have done, would I have created an air lock and caused the pump to cavitate?

And sorry just remind me, the newspaper test is to allow the system to get hot and then attempt to stop the fan with the rolled up newspaper? If it stops it's bad?
 
Last edited:
Look at the bypass/heater pipe that goes into the head just below the thermostat sealed with an o'ring. And at the other end of it where it comes out of the matrix and passes behind the head in a metal pipe then goes through a C shaped hose to the back of the head. If you have a weep in that it WILL cause an airlock in the system.
 
AP90 said:
Hi Keith

Pretty sure I buttoned the cap down well and truly, when I released it at the petrol station there was huge gush of coolant and steam.

Have topped up before and had no problems

I can't get my head round it as its has been absolutely fine until I topped it up yesterday when warm/hot just not sure what I have done, would I have created an air lock and caused the pump to cavitate?

And sorry just remind me, the newspaper test is to allow the system to get hot and then attempt to stop the fan with the rolled up newspaper? If it stops it's bad?
Click to expand...
Newspaper test is as you describe.
Never a good idea to undo the cap on a hot engine, it's the pressure that stops it boiling, release the pressure and the coolant will boil in hot spots.
Start again with a cold engine, top up, start the engine and continue to top up with the engine idling, ensure you have water coming out of the return pipe from the top of the RAD to the expansion tank as this is where air bleeds out too, I also find it helps to rapidly squeeze and release the main hoses in a kind of pumping action plus a few short bursts of revs. Helps too if the nose & driver side of the car is a little higher than level. When you stop getting air bubbles from the return pipe and the level is good, refit cap and see what you get. (assuming the viscous is OK)
 
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