Top Fill Radiator

Ok another question.

I think i owuld like to go for a top fill radiator would this in turn do away with my expansion bottle ???

What are the Pros and Cons of them ??

Are they very expensive ??

Are they easy to fit and maintain ??

I've got a 1.1 with a top fill radiator and no expansion tank as the expansion tank is part of the radiator?

Only has an inlet and outlet pipe?

Sorry I can't be of more help  :dontknow:

hi ad

you need a big block top fill radiator - i.e. 1.5+ paul_h has just fitted one in his mk1 g60 in the projects section.

fits beautifully with the sprinter intercooler. the top fill radiator lets you do away with the expansion tank, the only downside i found with mine was that you couldn't assess coolant levels with the cap on, like you can with an expansion tank.

i got one for my golf (1.3, so cap at opposite end) from GSF for about 30 quid 2 years ago, i'd imagine you'd be looking at the same price for the big block one - paul could confirm price and where he got his from.

Could also look at BMW rads dude as they have top fill rads too !!

Cheers all Paul got his from Ebay as i have PMed him, I just want to make sure if i do get one i get the correct one.

I read a post recently on the caddy forum where a member took their top fill rad apart and mated the plasic section to a 16v rad core section. Thus creating the 16v top fill rad.

Apparently there only held together with tabs just bent over, I queried the sealing and the reply was " Used some high temp sealer, not had a problem yet"

Food for thought.

dubassasin said

I read a post recently on the caddy forum where a member took their top fill rad apart and mated the plasic section to a 16v rad core section. Thus creating the 16v top fill rad.

Apparently there only held together with tabs just bent over, I queried the sealing and the reply was " Used some high temp sealer, not had a problem yet"

Food for thought.

Have you a link to that thread mate please sounds intresting.

Just read through the posts and theres no mention of if they have worked, But can't see why it wouldn't.



http://www.vwcaddy.com/showthread.php?t=36560&highlight=top+fill+rad
http://www.vwcaddy.com/showthread.php?t=31084&highlight=top+fill+radiator

Cheers will read through that lot today.

The expansion tank is used by VW and pretty much every motor company since the 80's due to it improving the cooling system. It may be less tidy, but if its a daily runner it might be worth leaving in.

Be aware it's much harder to get all the air bled out of a VW system w/o the external expansion tank. A semi-permanent air lock often is present during/after the first fill up, possibly causing localized over-heating and/or poor heater output. You may have to remove one of the heater hoses to get the system properly bled. Even then, keep a watch of the coolant level in the rad end-tank the first few weeks as it may go down some more as other smaller air pockets in the system eventually work themselves out. These are among the reasons VW went to the external, high-mounted tank.


The system is filled though the filler neck on the radiator and should be filled to about ?? to 1? below the bottom of the filler neck. If the system is filled any higher, it will be over full and the excess coolant will be vented from the system. This happens when the heat builds up within the coolant, it expands, increasing the system pressure above the pressure holding capability of the pressure cap (listed on the cap in pounds per square inch or PSI) causing the excess coolant to be vented out through the overflow vent which is exposed when the cap sealing plate is forced upwards. The excess coolant is then vented to either the atmosphere or into an overflow tank, which functions as a catchment basin. The overflow tank is under atmospheric pressure while the cooling system is under atmospheric pressure plus the pressure generated by the heat expansion of the cooling medium


may not be worth considering, but interesting none the less

Cheers Emm


Good read and i think i will try to fit everything in the bay with the expansion.

you can run the topfill with the cap off just the same as one with an expansion tank to bleed the system makes no difference.

I have one fitted to the my car. bought from G&S, however they were running out of them. there is a place selling them on E-bay for about ?70

It's a valeo one for a golf 1.5. 'tis also running a slim line pusher fan instead of that messy junk VW fitted.

Seems to be running fine, bled it out without the cap on.

You'll need a 16mm bung and a bit of pipe to complete the conversion, as you'll be left with a spur on the metal waterpipe (if your running an 8V )

Well I did mine today….for anyone that does want to do this conversion it took about an hour to do, and you will need to drill a 22mm hole in the bottom of the top fill section to allow the thermostat to be installed.

Basically take the thermostat and nut out of the section of the 16v rad (the bit your doing away with)
Drill the 22mm hole in the top fill section and push the nut into the two nibs of plastic that are there from the moulding process. you'll see them.




was going to pressure test but ran out of time…..

just found this on google after searching top fill rads.

dubassasin- any news on how it turned out? is it worth doing?
ive been reading up on top fills and ive seen a few people have done this.
just no follow up after they have been made.. so…  :dontknow:

heres mine





its a brand new mk2 rad, home made to be a top fill ;-)

i messed the fins up a bit, but it works

Hi guys, I've got a 1.1 mk1, the radiator at the minuet is a top fill with no expansion tank but when I bought the car it came with a radiator that the guy before bought but didn't fit it and it's not a top fill… Is there any way of fitting it still?

Cheers will