View Full Version : Dax aluminium radiator problems

26-11-04, 09:34 AM
Greetings from Spain! I am having probs with the Dax supplied aluminium radiator in my Tojeiro (Chevy 350). After approx 1500km the first rad started leaking, and was replaced under warranty (thanks Dave). With the replacement fitted, the car went perfectly until 3500km, when the new rad also started leaking. I've checked the hoses and unions (all good). There is no visible damage (i.e from the fan or its fixings). The problem both times has been where the galleries join to the side tanks. Question: am I being incredibly unlucky, or is this a 'known problem' with aluminium rads? Is it possible that chassis flex is causing the rad to distort and break at the joins mentioned? Has anyone come up against this and how did it get solved? Thanks in advance for any help. Hasta la vista!

26-11-04, 11:56 AM
Hi Tobias,

Note mine is an older platform chassis.

Although I do not have an Ali Rad when building my car I was not impressed with mounting the upper rad brackets on the inner wings. So I adjusted the brackets supplied so they would bolt onto the top crossmember of the chassis instead. Thats the crossmember that joins the top of the suspension mountings.

Although it is unlike the chassis would flex to much there may be some flex between the inner wings and the chassis itself.

Also this meant I could lean the radiator back a little and raise the bottom support bracket so the rad is less visible around the oil cooler intake.


26-11-04, 04:39 PM
Just a thought, but is your cooling fan mounted directly to your rad as if it is out of balance :( at all the vibration could well be doing the damage to your radiator. Personally i would never mount the fans directly to the radiator.


27-11-04, 08:30 AM
Chris, Martin. Thanks for your replies. The rad mountings are as specified by Dax with the top straps running from the inner wings to bolts on the top of the rad. The fan was originally mounted to the 1st rad using those ghastly plastic ties. When that rad started leaking and I fitted the replacement, I took the time to make a bracket from aluminium so that the fan was not in contact with the rad. I was a little apprehensive as to whether this was going to affect the performance of the fan (it gets to about 40C here in the summer). However, it worked fine and I've had no overheating problems. However, as dicsussed, the 2nd rad has now gone also. Any more ideas anyone?

27-11-04, 11:06 AM
I was heard about electricity running through an aluminium radiator (electrolyse?) starts to dissolve the aluminium... you can check whether there is a currency running from the cooling liquid to the chassis through the radiator... or some copper nearby ???
This starts the electrolyse proces (making currency).

Another item is perhaps it's attached too stiff to the chassis (not strenght, but stifness)...In that case, the radiator start carrying loads... on the otherhand, aluminium is less stiff as steel so I doubt it...

Small vibrations will not affect aluminium when the loads are low. But perhaps the way the fan is mounted on the radiator, is a weight (F = mass x acc.) .. in that case, bumps in the road causes loads on the radiator through those small areas (plastic ribbons). That can cause high stresses...

I don't know the place where it leaks .... can rule out some causes which i mentioned...

27-11-04, 06:08 PM
Hereby an interesting link...

Purple AK
27-11-04, 06:25 PM
I friend of mine ;) with a Dax De Dion suffered a cracked Ali rad at approx 2000 miles. Top lefthand corner by the hose connection. Dax replaced it ok :thumb: but it does seem that it maybe a frequent problem

18-02-05, 11:10 AM
3rd rad now fitted and working fine (for the last 500km) - although I am very suspicious of the whole radiator thing now, so I check for leaks every time I take the beast out. Fingers crossed I won't need ANOTHER one... Thanks for all the posts and suggestions on this thread.