Overheat

[stefan442]

On the way home from tesco the other night i heard a few hissing sounds and then the temp gauge shot up, to about 3/4 the way up, I was literally just pulling up to park at home. When i turned off the engine after parking i could hear the expansion tank bubbling away!

Today i got some new coolant, flushed the system into a bucket using a hose to keep the expansion tank full gave the top and bottom rad hose's a squeeze. Did this 4 times, first couple of times the water was brown which i am assuming is rust. Worth changing rad?

I filled system back up, by flushing the coolant through with engine running and when the coolant started coming out the other end i put the bung back on. Used about 6-7 litres of coolant. Found the method on one of the FAQ forum links to previous coolant problems.

however... i was running the van for about 30 mins after finishing, and took it for a quick blast. Temp guage was fine, didnt rise. But the bottom pipe didnt seem to get warm... which i thought meant the stat isnt working? But i was reading some more and people seem to have different ideas on how long it takes for the bottom hose to become warm?

[francophile1947]

The bottom hose on mine hardly ever got much above warm - it needed either a high speed run or a lot of revving the engine whilst stationary, to get the thermostat to open

[NathM]

If stat was stuck closed it would boil up quite quickly, as francophile said, getting to open whilst stationary takes lots of holding at high revs, and even a blast up the road doesnt always get it to open and if it does open its not always fully, so that you'd feel it 'hot hot' to the touch, can also indicate poor flow in the rad?


Nath

[stefan442]

When I filled it all up it seemed to flow ok... I should really take the rad out and give it a try. Could clear the big pipes a bit better as well.

Say I did have a cracked head.... would white sludge show just by checking the dip stick and oil fill point? Or would I have to take something apart? Or even do an oil change?

[mikeonb4c]

When I filled it all up it seemed to flow ok... I should really take the rad out and give it a try. Could clear the big pipes a bit better as well.

Say I did have a cracked head.... would white sludge show just by checking the dip stick and oil fill point? Or would I have to take something apart? Or even do an oil change?

I would imagine that for white sludge to happen at all, water would be having to get into the oil. I'm not sure that every scenario of a cracked head (or busted head gasket) would necessarily involve water getting into the oil at all, but perhaps a BF techie could comment on this.

The presence of rust in the water suggests (to me) that corrosion and clogging could have taken place in the cooling system. I recall Adrian at JapanDirectshowing me a Bongo he was doing repairs on. I think it had needed a new head, but the underlying problem was a stuffed cooling system, caused by lack of corrosion inhibitor (anti-freeze) and leading to both main rad and heater rad being totally blocked and needing replacing. The way you might be able to tell he said, was if you squeezed the top hose (I think) hard and it felt hard and then yielded with a crunching sensation, then there were corrosion salt deposits in the system, and these would reduce flow in the narrow channels in the system.

[stefan442]

Top hose seemed lovely and squiggy to me, was quite easy to squeeze it and see the coolant rise and fall in the expansion tank. Ill have to just keep a good eye on it untill I can afford to buy a new lot of coolant and have the time to drain the rad and find any underlying problems.

Seems to be running fine since... done about 50 miles. Time will tell... thanks for the feedback people!!