Help please: coolant pipe temperature query

[Matt&JoyBongling]

My coolant alarm went off today. When I opened the bonnet, I found the expansion tank cap had come off. I filled up with 5 litres of coolant and have tried see-saw method to bleed the system. I am not sure whether any burps of air have come out, the water in the system heats up when the engine is running, hot air comes out of the heaters, temperature gauge reads at 11 o'clock. Question: the pipes going into the top of the radiator are hot, the one at the bottom does not get hot: can anyone advise on what the problem may be and how to solve it?

If anyone is prepared to let me call them to discuss, please pm me with a contact number.

[francophile1947]

The bottom hose rarely gets even warm on mine, especially when it's cold outside.
If you've got heat from your heaters, it sounds as if you may have been lucky. Just keep an eye on it for a while.

[daveblueozzie]

Same as John's my bottom hose does not get very hot . but 5 litre's coolant is a lot to put in.
check it first thing in the morning to see if any air bubbles have lowered the coolant.
fingers crossed you will be OK. was you motoring at the time when the coolant alarm went off,?

[Matt&JoyBongling]

Thanks, that's very reassuring!

Matthew

[Matt&JoyBongling]

DOB: thanks for the advice, and yes, I was motoring when the alarm went off.

M

[daveblueozzie]

DOB: thanks for the advice, and yes, I was motoring when the alarm went off.

M

I hope you stopped straight away.
the reason i asked, if it was first time starting and the alarm went off it would mean a leaking pipe.

[Matt&JoyBongling]

I had driven 10 miles when the alarm started a slight whine which stopped when I braked. I continued for a little longer and the alarm started again. When I braked, it stopped. Soon after I pulled off the dual carriageway to check it and the alarm screamed. I stopped - steam came from the bonnet and water was gushing out of the tank - the cap was where the leisure battery tray would be. I can only assume that I had not put it on firmly enough when topping up yesterday. The temp gauge did not move beyond normal. I added the water I was carrying by coincidence and continued for 2 miles. I tried sew-sawing to check for air locks but now believe that I did not do it for long enough. I took a test drive - the temp gauge did not go beyond normal, no air came out when I tried sew-sawing on 3 different occassions during the drive and the coolant level did not change once it had settled down following the sew-sawing. The low coolant pipe did not change temparature - staying at ambient temp.

I looked for but did not see any bubbles in the expansion tank - hoping that there is no exhaust gas getting into the water .

I will try the sew-saw method again in the morning, this time using a rotation of idle & 2500 revs for 5 mins and checking the expansion tank & drain pipe until the low coolant pipe warms up. I will also check the pipes to look for signs of damage.

I will also

[The Great Pretender]

Matt, have sent you a pm.

[Matt&JoyBongling]

Update;
I bled the system again today and got heat into the lower pipe, having alternated between 2,500 revs & idle and took Mr Bongo for a test drive - fully laden & with a trailer. The temp gauge stopped at the 11:55 position. I stopped for an hour and topped up with a small quantity of coolant. I had a second laden drive - the gauge and coolant level were fine. No bubbles were seen in the expansion tank.

Fingers' crossed, no damage was caused and all air has vented. I'll have a probe test done to check whether any exhaust gasses are entering the coolant.

Many thanks for the advice - with special mention to Haydn, his alarm that warned me that coolant loss had taken place and his advice as well as the advice from The Great Pretender.

[haydn callow]

Well !! for a change it sounds like we could have a HAPPY ENDING !!
Nice one.

[missfixit70]

Fingers crossed, guys, but unless you've got a Mason alarm fitted to resensitise it(highly recommended)- please don't rely on the temp gauge to tell you anything useful, as discussed endlessly, its useless.