My recent purchase

[classicgreendog]

[i]

Hi, It's me again.

I thought my problem was resolved but it has re-surfaced, and I have a new query.
On Saturday afternoon I was sitting in a car park waiting to exit when a loud POP was followed by a gush of water and a third core plug had blown.!

I spent all day today re-fitting a new one and checking the thermostat etc.,

The car was running OK - The temperature was sitting nice and steady at 40 degrees, and I had set the Kenlowe to cut in at 45 degrees.

I am mystified.

I let the car tick over until the temp was steady, and made sure the Kenlowe cut in etc., which it did.

I checked the rad cap and it was duly stamped 15 degrees.

However, and this is my query. Having reached operating temperature I was surprised that I was able to remove the rad cap without any pressure or steam blowing out. In fact there was no pressure obvious at all ??

Very different to my Daimler 250 V8 where pressure is very obvious and water is expelled out of the overflow pipe.

Why haven't I got any pressure at the rad cap ? - and is this why the core plug is blowing instead ? The pressure is at the bottom of the engine instead of at the radiator top ?

Any ideas guys ??

Regards,
MIKE

[GREG]

Was the car stood a long time before you bought it? I am wondering if it's corrosion from being stood so long with no antifreeze, but sorry , no real answers for you !

I hope it's sorted now

Greg

[412usa]

Mike,

Have you checked if the thermostat is clogged shut? This could build up
pressure in the block.

Peter

[David Olivant]

If you have sufficient pressure to blow a core plug, but no pressure at
the radiator cap, there are perhaps two reasons
One .- excess pressure from a head gasket/block.
Two:- Blockage to or at the radiator.
Check the thermostat and the bottom of the radiator. If both are blocked the
core plugs take the brunt of the pressure.
Hope this helps and happy digging.
David

[Kevin H]

Originally Posted by classicgreendog

[i]
However, and this is my query. Having reached operating temperature I was surprised that I was able to remove the rad cap without any pressure or steam blowing out. In fact there was no pressure obvious at all ??

Well it sounds like there is pressure in the block, so to my mind the logical conclusion would be a blockage. Maybe one of the waterways in the block?

Was the top of the radiator hot?

This situation would make me very nervous. Imagine if you lost a core plug while you were driving along and didn't notice!

Kevin

[classicgreendog]

Thanks Guys,

I have fitted a new thermostat, and I fear you could be right, but nothing
is obvious. The car has stood for 3 years or more and it has blown before I bought the car. The underside of the bonnet and the top of the engine show signs of heat by way of crackled paint etc.,
The top of the radiator does get hot.

I took the car for a 15 mile run this morning and it behaved perfectly.
The temp gauge held perfectly steady at 80 degrees in and out of traffic.

regards,
Mike

[Rubbond]

If you still have the old thermostat, wife permitting, you can easily check
if it is/was working by putting it in a pan of water and bringing it to
boil.
At least you will know if a faulty thermostat was a contributing factor.
I would at least take off the top and bottom radiator hoses, and flush both
radiator and the engine seperately. See what comes out.
Good luck!
Andrew.