Bubbling gurgling noise
Discussion
Maybe a simple question - but on turning off the engine after a good drive in my 7 weeks of V8S ownership I often hear a bubbling gurgling noise for about 15 seconds. Sounds like its coming from the passenger side of the engine. Is this air in the cooling system? Is this something to be worried about? Otherwise she's going well (touch wood)
Thanks
Thanks
This would be air in the heater matrix. Not particularly harmful, just means your heater will be even more useless than normal. You ought to be able to clear it by fully opening the heater control valve, clamping the top hose flat, and revving the engine for a couple of seconds (assuming the swirl tank is full).
If that doesn't do the trick then you have probably got the pressure cap and blanking cap the wrong way round :lol:
If that doesn't do the trick then you have probably got the pressure cap and blanking cap the wrong way round :lol:
Some dokey bloke that fitted a new water pump to mine got them the wrong way around and the car overheated on the drive home.
Changed to pressure cap on the tank and blank cap on the swirl (with new hoses too) and it's now OK.
According to the local radiator specialist that fitted my new one also, the swirl tank also needs a particular type of cap. Since he had a look and changed it (god knows to what type) it's worked brilliantly
Changed to pressure cap on the tank and blank cap on the swirl (with new hoses too) and it's now OK.
According to the local radiator specialist that fitted my new one also, the swirl tank also needs a particular type of cap. Since he had a look and changed it (god knows to what type) it's worked brilliantly
jons_s3 said:
Yes, the pressure cap goes on the swirl tank and the blanking camp on the header tank as I understand it.
Mine (formaly Wildfire's) S3 gurgled alot after switching off the engine. I flushed and refilled the cooling system and it seemed to resolve the problem.
I can tell your new
Thanks everyone. I was going to post after a friend of mine who I was proudly showing the engine to and checking the coolant levels commented that the expansion tank wasn't pressurised and the swirl tank was. After reading Steve Heath's book which seems to go into detail about this I have left it. I'll have to get back to the book to find the heater matrix valve - or ask the garage to!
GreenV8S said:
I'll have to get back to the book to find the heater matrix valve - or ask the garage to!
Under the bonnet, at top of the passenger's footwell where the heater pipe pass through the bulkhead. Should be cable operated from the heater controls in the cabin.
But to which vessel should the pressure cap be fitted?
Interestingly enough I've always subscribed to the thought that 15lb pressure cap goes on the swirl tank (large red tube at front) and blanking cap on the overflow tank (not expansion tank as the swirl tank acts as an expansion tank)and have never had a problem save small loses in water over time. I have just noticed recently that the fans have been coming on in traffic queues. I had my radiator recored recently and refitted by my local garage. They had reversed the caps and put the blank cap on the swirl tank. Because of this the engine was running hotter. As a result, presumably, if the engine had overheated the weakest part of the system would have given way - probably a hose because there would be no safety valve of the pressure cap.
The swirl pot is the metal tube about 12 inches high and three inches diameter which sits on the front chassis rail close to the battery.
The expansion tank is the plastic one near the bulkhead / brake servo.
The pressure cap is the cap with the integral sping assembly.
HTH
>> Edited by SotonS2 on Wednesday 6th April 23:46
The expansion tank is the plastic one near the bulkhead / brake servo.
The pressure cap is the cap with the integral sping assembly.
HTH
>> Edited by SotonS2 on Wednesday 6th April 23:46
I posted this a few months ago....
Here we go again....
MY UNDERSTANDING - Version 1
1. Engine gets hot...
2. Water gets hot and pressurises the system...
3. The Swirl pot fills up...
4. The Pressure cap on the swirl pot takes the pressure...
5. If the pressure gets high enough or expansion gets high enough...
6. Pressure cap expels hot water into the expansion tank...
7. Water level in expansion tank rises...
8. If the system is over full...
9. Expansion tank over flows without any resistance as the is no pressure cap...
STOP...Engine cools
10. Water contracts...
11. System De-pressurises...
12. Water level in Expansion tank goes down...
13. When cold level is a few inches down in the Swirl pot...
MY UNDERSTANDING - Version 2
1. Engine gets hot...
2. Water gets hot and pressurises the system...
3. The Swirl pot fills up...
4. The Cap on the swirl pot lets water straight through the tubes to the expansion tank...
5. Water level in expansion tank rises...
6. Pressure cap on the Expansion tank resists expansion...
7. If the system is over full...
8. Pressure cap releases and overflows...
STOP...Engine cools
10. Water contracts...
11. System De-pressurises...
12. Water level in Expansion tank goes down...
13. When cold, level is a few inches down in the Swirl pot...
Come on then....Shoot me down, (if I'm wrong....)
AFAIK
There is no right or wrong way. Both versions have worked for me...
They just pressurise different areas of the system at different times.
Dave
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