Overheating - top up tank water hot....

[mikeymancs]

Hi,

Took the van out for a good run lastnight, at one point on a slight gradiant in 5th gear at about 55mph the engine temp guage went to about 2/3rds, the warning light didn't come on though, but there was a lack of power, so i dropped a gear and put the heater on. The temp needle dropped gradually and power returned.

Upon stopping I checked the coolant levels, both tank levels were fine, but i did notice the water in the to-up tank (behind number plate flap0 was hot. Shouldn't this remain cold, as it is only required to compensate for any drop of level in the expansion tank???

What could be causing this problem?

I am still in the early stages of T25 ownership - please be gentle and not over technical... my brain is already in overload!!

[skint-van-man]

ive had lots of overheating problems and not being a wiz myself...

Top tips i got were bleeding the Radiator (properly), check fan is coming on and i replaced all my sensors. Then you should know and understand it all (i wish i did)

[kevtherev]

The top up tank or expansion tank is what it is.
Coolant will expand as it heats up so the hot coolant will expand into the tank... otherwise the Header tank would explode.

the lack of power was probably due to the gradient, the engine is working hard to get up a hill and all that heat due to the extra work will be transferred into the coolant.
Make sure the header tank is topped up to the brim and there is no air in the system

[mikeymancs]

Hi Kev, thanks for the reply matey, I have a clearer understanding now!

Have bought some manuals so will spend time absorbing them! A lot to learn me thinks..

Thanks again
Mike

[Plasticman]

Yep, and you will get to know each section and page (some more than others)over the years
mike