Thread: radiator expansion tank 300tdi

Hi Kelvin,

Off to MR's for you and get a white one, all the black one's do it eventually, they split along the joint, lucky it was on a short run and the motor didnt run dry as that could have been expensive

As for coolant the green stuff is ok just get the ratio correct so its not watered down.

Do people ever flush the cooling system with anything other than water when doing a coolant change?

Something like this?
http://www.penrite.com.au/files/RGFP38394F/RAP7-PIS.pdf

Can flushes damage anything internally there? Does the flush really clean it up?

Pete

they can be welded---

Last time I was at MR they said that even the white tanks have split. possibly it is a problem with the caps not releasing pressure when required. I have to get a level indicator one of these days (said for the last 4 years.

possibly it is a problem with the caps not releasing pressure when required. I have to get a level indicator one of these days (said for the last 4 years

It will probably all go norks up now, but I routinely depress the valves in the cap & give it a squirt of silicone spray & I posted my thoughts on this here some time back but received no feedback from anyone.
Seems like a common sense thing to do, to me, as if the pressure can't escape then something has to give, & that may be a weak-ish plastic weld.
Regardless, I will keep on doing this.

Diff. You shouldn't need a level indicator, as there is one built in & if you routinely check your cap as per above, then you can see it.

Originally Posted by 4bee

but I routinely depress the valves in the cap & give it a squirt of silicone spray

Seems like a common sense thing to do, to me, as if the pressure can't escape then something has to give, & that may be a weak-ish plastic weld.

good idea, i haven't even checked my cap, will do from now on

Do people ever flush the cooling system with anything other than water when doing a coolant change?

Something like this?
http://www.penrite.com.au/files/RGFP38394F/RAP7-PIS.pdf

Can flushes damage anything internally there? Does the flush really clean it up?

a flush can't hurt, and if you're using a silicate based fluid it can help move any that's dropped out of suspension. (one of the biggest hassles with a silicate based fluid)
Talking to the techs at Tectalloy, one of the biggest coolant suppliers in Oz, they suggest an alkali based flush for silicate based fluids (generally green coloured ones), something like their 'Mukowt', and an acid based flush if you are converting to an OAT type coolant.

Weeds, my Tdi appears to have come from the factory with OAT coolant (and the green power steering fluid) as it was made right at the changeover from Tdi to Td5.

be warned
my mate (LR mechanic) absolutely swears that 95% of expansion tank leaks/failures are cuased by overheating (less than the guage will show)
he doubts that there is much wrond with the balck bottles
maybe a little weakness but that they are a good indicator something else is up
whenever he sees a split bottle he pulls the radiator and sends it to the radiator shop for a remove tanks and "rod out" type clean
most of them are over 50% bolcked
also tells me nearly every head gasket he does on a tdi it has had a split bottle (normally just repaced by owner or someone else and radiatotor not done) within last 12 mths
he can't remember ever doing a haed where there hasn't been a warning sign first
maybe this is your sign
Jase