My recent purchase

[GREG]

The radiator on a 408 has an in built expansion tank. When you look through the filler hole you will see a second hole about 5 " below and you only fill with coolant to about 1/2"below the second hole. Sounds like you have been over filling the system.

The manuals are available from Bristol cars and the Bristol owners club.

I have only heard of three of these engines blowing a core plug even at 45 years old. Heard of more core plug problems with 411 's. I wouldn't question the rad cap apart from if it's working ! Try a new one.

Greg

[Rubbond]

My ignorance no doubt but I've never heard of a core plug? The name suggests
it may be to release the sand after the block has been cast. Or maybe a
design feature to prevent the block from cracking if the coolant were to
freeze? Or to assist with flushing the engine?
But in any case, the radiator cap cannot really fail. It's just a
spring-loaded seal that would leak, rather than get stuck. And surely the
radiator core would be the next thing to burst, or the coolant hoses if
cracked.
I have on many occasions had problems with engines overheating (come to
think of it most recently with a vintage outboard engine). It was always the
thermostat, or in the case of the outboard, blocked water channels, but the
steam always came out of the radiator cap. If these cores "pop out" at less
than 15 psi, then might they not just drop out going over a speed bump?
Andrew.

[caspian pugh]

Originally Posted by Rubbond

My ignorance no doubt but I've never heard of a core plug? .

Even my Willie has heard of a core plug - you have a problem.

I have spoken to Butch our mechanic, he tells me that core plugs often rust but electrolytic corrosion between the edge and the block can cause them to loosen and pop with cooling system content pressurisation.

As Greg confirms, Mini core plugs in steel will fit most Chrysler V8 but the best replacements are brass core plugs from the States fitted with a little RTV sealant (non acetic acid cure) around the edge.

Hope this helps,

Cass.

[Sam410]

I'm not sure about the 408, but the 410's expansion tank is under the bonnet slam panel, between the grille and the radiator. Easy to assume there isn't one!

[pasini s]

Hello,


here's where the expansion tank of my 409 is:

http://www.stefanopasini.it/Bristol_...nsion_Tank.htm

Of course I don't know if this applies to a 408 as well....

Cheers

Stefano

[classicgreendog]

(Please type your reply above this line!!)

You may increase the space between the above lines as needed.

______________________
CURRENT MESSAGE FROM: pasini s

Hello,


here's where the expansion tank of my 409 is:

http://www.stefanopasini.it/Bristol_...nsion_Tank.htm

Of course I don't know if this applies to a 408 as well....

Cheers

Stefano



______________________
PREVIOUS MESSAGE FROM: classicgreendog

(Please type your reply above this line!!)

You may increase the space between the above lines as needed.

______________________
CURRENT MESSAGE FROM: Sam410

I'm not sure about the 408, but the 410's expansion tank is under the bonnet slam panel, between the grille and the radiator.. Easy to assume there isn't one!



______________________
PREVIOUS MESSAGE FROM: caspian pugh


---Quote (Originally by Rubbond)---
My ignorance no doubt but I've never heard of a core plug? .
---End Quote---
Even my Willie has heard of a core plug - you have a problem.

I have spoken to Butch our mechanic, he tells me that core plugs often rust but electrolytic corrosion between the edge and the block can cause them to loosen and pop with cooling system content pressurisation.

As Greg confirms, Mini core plugs in steel will fit most Chrysler V8 but the best replacements are brass core plugs from the States fitted with a little RTV sealant (non acetic acid cure) around the edge.

Hope this helps,

Cass.

______________________
This thread is located at:
http://www.bristolcars.info/forums/8...-purchase.html

To unsubscribe from this forum, please visit this page:
http://www.bristolcars.info/forums/s...bscription&f=3

You may reply to this email to post a reply to the forum.
You can also begin a new thread by sending an email to

(Please type your reply below this line!!)

______________________
This thread is located at:
http://www.bristolcars.info/forums/8...-purchase.html

To unsubscribe from this forum, please visit this page:
http://www.bristolcars.info/forums/s...bscription&f=3

You may reply to this email to post a reply to the forum.
You can also begin a new thread by sending an email to

(Please type your reply below this line!!)

[Kevin H]

Originally Posted by GREG

Heard of more core plug problems with 411 's.

Where did you hear that Greg?

In 10 years of running a Bristol Enthusiasts mail list then web based forum and before that as a member of BOC and BOCA, I can't remember hearing of one 411 losing a core plug!

[Kevin H]

I have started another thread here http://www.bristolcars.info/forums/r...-pressure.html to discuss the topic of radiator caps and why we pressurise the cooling system.

Another thing just occurred to me however given Greg's revelation that the 408 has an integral expansion tank. A modern radiator cap has TWO valves - one pressure activated valve to let coolant out (usually into an expansion tank) once the pressure exceeds the cap's rating. It also has a vacuum operated valve which allows coolant back in from the expansion tank as the system cools. The coolant usually flows out and back in through a pipe in the filler neck where the radiator cap sits. But how does it work on a radiator that has an "integral" expansion tank?