Blown expansion tank again

Funny, mine is now 15 years old with no problems.

I sometimes wonder whether a slightly leaking sleeve or head gasket may cause the cooling system to pressurise with a high combustion pressure load, like towing a camper uphill on a hot day.

Have to be combined with a malfunctioning pressure bleed in the cap I suppose. But I wonder if the volume becomes too much for the little hole.
The blow off level of the cap should only be reached on "heat soak" after the car is switched off. If ever.
Regards Philip A

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Originally Posted by PhilipA

Funny, mine is now 15 years old with no problems.

I sometimes wonder whether a slightly leaking sleeve or head gasket may cause the cooling system to pressurise with a high combustion pressure load, like towing a camper uphill on a hot day.

Have to be combined with a malfunctioning pressure bleed in the cap I suppose. But I wonder if the volume becomes too much for the little hole.
The blow off level of the cap should only be reached on "heat soak" after the car is switched off. If ever.
Regards Philip A

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Yep I am worried that it's a head gasket, but there doesn't appear to be any bubbles .
The Thermo fans run after shut down on hot days sometimes on short trips also. I know they are supposed to run for 10 mins if the conditions are right after shutdown to cool things.
The top of the right hand side radiator is quite hot. I know as I have a good scar from when my arm touched it for a split second and my skin peeled off and was stuck to the metal. It was HOT.
It runs on Gas so it would run a little hotter. The temp gauge normally sits on 1/4 though.

A few years ago I was travelling down the Princes Highway in Victoria (driving a disco) when I saw a disco pulled to the side of the road with the bonnet up. Being the sort of person that I am, I stopped and asked what the trouble was, The chap didn't know for he had just borrowed his fathers disco and caravan for the long weekend. His problem was that the engine was violently overheating and spewing hot water out the top of the overflow tank .(lid kept blowing off). I suggested he had a blown head gasket ant that I would organise RACV to assist. Hope they found him ok as he was in the middle of nowhere.

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A few years ago I was travelling down the Princes Highway in Victoria

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Hope they found him ok as he was in the middle of nowhere.

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You'd want to hope so, he's be getting a bit peckish by now, I should think.:D

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The Thermo fans run after shut down on hot days sometimes on short trips also. I know they are supposed to run for 10 mins if the conditions are right after shutdown to cool things.
The top of the right hand side radiator is quite hot. I know as I have a good scar from when my arm touched it for a split second and my skin peeled off and was stuck to the metal. It was HOT.

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How long since you had the radiator rodded, or a new core?
Its just that the fans on my 92 RRC have NEVER kept running after engine off. Even after Low ratio in 48C.
The switch is on the thermostat housing so it indicates that the motor is pretty hot.
It would be unusual for the head gasket to blow adjacent to the two holes in the heads, but not unheard of.
Regards Philip A

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Originally Posted by PhilipA

How long since you had the radiator rodded, or a new core?
Its just that the fans on my 92 RRC have NEVER kept running after engine off. Even after Low ratio in 48C.
The switch is on the thermostat housing so it indicates that the motor is pretty hot.
It would be unusual for the head gasket to blow adjacent to the two holes in the heads, but not unheard of.
Regards Philip A

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Never had the radiator rodded or recored.
Has 250000 on clock now.
I always have run coolant., and changed regulary.
Why would a radiator gunk up?
Even when I recently replaced the thermostat and the water pump everything was clean as a whistle.
Do they just break down with age? 11 year old now.

Rover Radiators have very small tubes, that can block up with tiny bits of rubber,silicone sealant etc etc.
Also have you looked at the fins? Often in old age the fins turn to dust.
If it is in as good condition as you believe, it will take a rodding at AFAIK around $100, not a lot.
If it is bad, you will be up for a $600 core but you may not have to buy any more header tanks.LOL.
Regards Philip A

just been quoted $385 to recore my 89 rr and thats in tassie so you should be able to get that price over there
cheers
blaze

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Originally Posted by PhilipA

Rover Radiators have very small tubes, that can block up with tiny bits of rubber,silicone sealant etc etc.
Also have you looked at the fins? Often in old age the fins turn to dust.
If it is in as good condition as you believe, it will take a rodding at AFAIK around $100, not a lot.
If it is bad, you will be up for a $600 core but you may not have to buy any more header tanks.LOL.
Regards Philip A

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LOL:D
What's got me buggered is the temp guage ( it will show normal operating temp. When I lost water from the split header tank it rose, so let's assume it is working correctly)
Ok, I turn on the aircon, the gauge would sit on normal. The Cooler fans operate as they are operated by the sensor on the Thermostat cover. . When I switch off engine, sometimes, not always the fans keep running for 10 mins to cool the system..
The sensor has been switched and same occurs. So let's rule that out.
The thermostat has been replaced, so I assume it is not sticking.
The heater is hot in no time, drive .5 of a kms and it's hot, so the system must be heating fast.
Waterpump recently replaced.
If a radiator was blocked then wouldn't the temperature gauge also rise to hot?
Open the bonnet and the engine is hot.
If there was an airlock wouldn't the temp gauge also show hot also?

Temp gauges are designed to show"normal" ie just below half for a wide range of temperature so as not to alarm the driver at every hill .
I do not know the exact figures but maybe 80-105c.
I do not think the fans go on until 105C.
While this is all relatively OK, A Rover V8 does not like to be over 100C very much as the sleeves become a looser fit due to the differential expansion of steel and alloy.
AND the radiator is just about the only remaining explanation for your relatively high temps, unless there is a basic but small engine problem.
Regards Philip A