Ok well went out to Dalby the other day and noticed when we stopped for gas at Toowoomba on the way home the coolant started to boil while the car was stationary. It seemed to have started after I changed the radiator cap as the old one literally fell apart in my hands.

I thought I have fixed it as I flushed the radiator and replaced the thermostat and gasket the other day and now it seems to be doing it again, just wondering if anyone have any ideas as to what might be wrong?

Maybe the water pump or something...Another thing to note is that the Temp gauge never moves any hotter or anything like that.

Cheers

Are you sure its actually boiling?

When you turn a car off you get heat soak, that is, the heat left in the block soaks into the water thats in the block.

As its no longer circulating it heats up substantially.

It may just be that your cap aint sealing properly, this is sometimes caused by the opening on the top of the rad being slightly warped.

Get a pressure test done at a rad place, it should cost sod all and will ensure your system is ok.

Thanks for that mate, it may not be boiling but it does make a hell of a lot of noise, I will got get a test done sometime this week and see what that turns up

Are you sure its actually boiling?

When you turn a car off you get heat soak, that is, the heat left in the block soaks into the water thats in the block.

As its no longer circulating it heats up substantially.

It may just be that your cap aint sealing properly, this is sometimes caused by the opening on the top of the rad being slightly warped.

Get a pressure test done at a rad place, it should cost sod all and will ensure your system is ok.

Think I May have found the culprit mate, what do you think... Also something to add the top radiator hose seems to suck itself flat also when the car is stationary but I guess this is related to the system not sealing properly

http://i733.photobucket.com/albums/ww332/sam_ang/Photo0113.jpg
http://i733.photobucket.com/albums/ww332/sam_ang/Photo0114.jpg

Thats definately a worry in the rad.

The water pump draws water from the bottom hose and returns it to the rad via the top hose.

If the top hose goes flat it normally indicates a problem in the thermostat area or the hose has gone soft. (usually means the rad cap is sealing ok too, ?????) .

Did you put the right thermo in?

Did it have a little hole in it next to the valve?

If it doesnt, try drilling a hole thru the flat disk obout 1/8 inch as a bypass.

This stops the hose flatening and saves the engine if the thermo jams shut.

Yes there is definitely a hole in the thermostat its has a little toggle looking thing sitting loosely in it, the hose was flattening even before I changed the thermostat and I am 100% sure its the right thermostat, perhaps the hose has just gone soft, will try replacing the radiator and the hose and hopefully that might fix it

With the top radiator hose sucking flat make sure the small hose to the overflow bottle is not crimped or blocked

Ok thanks mate I will check that out tomorrow, cheers

When a top hose goes flat it means that the rad cap is stuffed, there is a return valve, when the pressure builds up to a certain point it allows the coolant to flow to the bottle. When the engine cools the coolant contracts and is drawn back into the radiator. If this valve in the cap (little round bit) is not allowing coolant to flow back the hose will tend to suck itself in as there will be neg pressure in your cooling system

When a top hose goes flat it means that the rad cap is stuffed, there is a return valve, when the pressure builds up to a certain point it allows the coolant to flow to the bottle. When the engine cools the coolant contracts and is drawn back into the radiator. If this valve in the cap (little round bit) is not allowing coolant to flow back the hose will tend to suck itself in as there will be neg pressure in your cooling system

Awesome, you have just solved a problem I wasnt aware I had.

My hose goes flat and I hadnt thought about it until now, but tomorrowI will grab a new cap.

Thanks.

ive had the same problem sort off with my old magna mine would bubble into the reserve radiator and the radiator hose went flat found out it was my head gasket on its way it blew about 3 months later
have a look and make sure the water is not turning a milkish color

When a top hose goes flat it means that the rad cap is stuffed, there is a return valve, when the pressure builds up to a certain point it allows the coolant to flow to the bottle. When the engine cools the coolant contracts and is drawn back into the radiator. If this valve in the cap (little round bit) is not allowing coolant to flow back the hose will tend to suck itself in as there will be neg pressure in your cooling system

My radiator cap is brand new well 2 weeks or s old but yeah, so maybe that chip in the top of the radiator could have the same effect as the valve in the cap not working properly?

My radiator cap is brand new well 2 weeks or s old but yeah, so maybe that chip in the top of the radiator could have the same effect as the valve in the cap not working properly?

take to a radiator place get checked out if its ok then it will be your head on its way you can get this silver stuff cant remember the name you put in radiator and can stop it from bubbling may work for a while might only work for two days

Hmm ok then I will do, hope its not the head, thats the last thing i need lol

When a top hose goes flat it means that the rad cap is stuffed, there is a return valve, when the pressure builds up to a certain point it allows the coolant to flow to the bottle. When the engine cools the coolant contracts and is drawn back into the radiator. If this valve in the cap (little round bit) is not allowing coolant to flow back the hose will tend to suck itself in as there will be neg pressure in your cooling system

This actually happened to me, it also caused my thermostat to jam. It's quite bad, easy to diagnose. Just pull out your rad cap and push on it, it should push down and come back up (there is a spring in it).

When a top hose goes flat it means that the rad cap is stuffed, there is a return valve, when the pressure builds up to a certain point it allows the coolant to flow to the bottle. When the engine cools the coolant contracts and is drawn back into the radiator. If this valve in the cap (little round bit) is not allowing coolant to flow back the hose will tend to suck itself in as there will be neg pressure in your cooling system


Awesome, you have just solved a problem I wasnt aware I had.

My hose goes flat and I hadnt thought about it until now, but tomorrowI will grab a new cap.

Thanks.

Mal, whilst you may be a grumpy bastard you were spot on the money. Thanks Champ.

This actually happened to me, it also caused my thermostat to jam. It's quite bad, easy to diagnose. Just pull out your rad cap and push on it, it should push down and come back up (there is a spring in it).

Thanks didn't realize thats how they work:gtfo:

My radiator cap is brand new well 2 weeks or s old but yeah, so maybe that chip in the top of the radiator could have the same effect as the valve in the cap not working properly?

Could also be one of the crap CPC caps with the big rubber seal that will tend to block off the overflow hole

The chip will actually cause the coolant to flow more freely, not restrict it more.

Get the whole lot pressure tested

Could also be one of the crap CPC caps with the big rubber seal that will tend to block off the overflow hole

I went and grabbed a new radiator cap recently from Mitsu... the CPC ones are now the only ones they sell.

When a top hose goes flat it means that the rad cap is stuffed, there is a return valve, when the pressure builds up to a certain point it allows the coolant to flow to the bottle. When the engine cools the coolant contracts and is drawn back into the radiator. If this valve in the cap (little round bit) is not allowing coolant to flow back the hose will tend to suck itself in as there will be neg pressure in your cooling system

In reference to the above Post. I've been having a over-heating problem over the past week. I replaced the radiator cap and over-heating is still occuring. On cooling, the Top Hose goes flat. The Radiator was replaced (new) 19 months ago, so surely it wouldn't be that. could it be the water pump? Any takers? TH Magna 3.0 Lt, done 354,000 Km.

new caps can still cause problems if they r not sealing right....
have u checked ure thermostat???

With the top radiator hose sucking flat make sure the small hose to the overflow bottle is not crimped or blocked

Check this! pull hose off near cap and blow through it, should bubble in overflow tank

The Cap is new, (although the cap screws down very loose, fitting, not tight!) I'd thought it was the thermostat, so I removed it to see what would happen. Same problem. I'll get another cap, and thermostat, see what happens now.

The Tank Hose is also clear!

In reference to past issue with overheating: After replacing the thermostat and radiator cap (cap twice)the boiling problem is still occuring. However, This ONLY occurs after TOWING, a 1.3 tonne van, NOT during normal driving use. Also the boiling does not happen after idiling in traffic. This has got me really confused, what the problem could be
! I thought it could be a head gasget. Oil is Okay.:roflwtf:

sound like a head gasket or cracked head to me