Plastic radiator

[Luegonigel]

Anyone with experience of the plastic top and bottom radiator?

 

Symptom, coolant sprayed over top of engine, dripping from somewhere onto steering rack. Couldn't find a specific leak.

 

Radiator changed out for new plastic one as all aluminium one out of stock and was supposed to going to Picos in it so needed it in a hurry. Picked it up after change the day before going to Picos, less leak and spray but still a problem. Went in Audi instead ☹️

 

Got back, dried and cleaned everything, nipped up all the jubillee clips everywhere, five mile run an still the same.

 

It seems to be from the top hose connection area at the passenger side of the radiator.

 

Can't see a leak from the joint between the plastic bit and the aluminium bit, although it may dry super quick due to the heat?

 

Could I have got two duff radiators?

 

Any ideas or suggestions?

 

Have others had similar symptoms or has it been more obvious what the problem was?

 

Weather in Scotland now fab which makes it worse!

[OliW]

Lots of people have had issues. Do a quick search.

 

 

[Martin J]

Did use a screwdriver or a socket & ratchet to tighten the clips?

Don't over tighten but you can get the jubilee clips much tighter with a socket.

 

changed the antifreeze on mine recently & had a leak from the bottom hose on the rad until I really nipped it.

 

[Luegonigel]

Screwdriver used for fear of crushing all the plastic tee pieces, connections etc. I could get a bit more on a few of them but not that much.

 

Problem is I can't seem to see whereabouts it is coming from apart from the top the radiator somewhere. The connection there is easy to get at with a screwdriver to get it tight.

[fauxae]

I've had two plastic radiators, both leaked when cold. When the engine was warm it sealed and stopped. Aluminium radiator replacement is the answer. No leaks now. Alan

50th Anniversary Sigma SV.

[TheManAlive]

I am on my second plastic top one. When changing the coolant the other day I noticed that there was some evidence of it leaking again. I havent been out for a run yet but if it is still doing it then I will probably opt for one of the aluminium ones as well.

[Garth]

Also had a leaking plastic topped radiator - fully welded ali one the way to go - while you are about it replace any plastic T's with brass ones - these tend to go to!

[myothercarsa2cv]

Nip up the crimps between the core and plastic tanks with a pair of grips. Problem solved. 😶‍🌫️

[John Hughes]

Hi Nigel

 

Peter (Domus) and I have both had a go at removing the plastic tanks from the Ali core, ditching the rubber gasket and using a bead of Polyurethane sealant / Adhesive such as Sikaflex or Tiger seal and then re crimping with Mole grips. Seems to have been successful so far.

 

Worth a try and a lot cheaper than a new radiator..

 

John

[pmobbs]

Had exactly the same experience. Seems many have had similar problems. The design seems like an accident waiting to happen. Replaced mine with all aluminium design. Not cheap though CCs contributed price of 3 part radiator because it failed under warrantee.

[Luegonigel]

Thanks chaps, checked it out some more tonight and on the engine side next to the top hose connection the crimping is not that good and dampness can be seen for 75mm from the connection out over. 25mm at the other end same side does not look that good.

Not sure what tool does the crimping and how it is supposed to get a good grip near the hose connection but it certainly hasn't in this case.

Hopefully coming to some arrangement with Caterham on an all alloy replacement. They have been good on it so far.

[diggerman]

Ive had two of these and both leaked from the jont after a few thousand miles. The differential expansion between aluminium and plastic seems to be the problem. I now have the Caterham all ali rad with bigger fan. This is the answer. No leaks and much more efficient.

 

I have driven to far west Wales from Aylesbury in todays heat, no problems. AND WHAT A DRIVE,

 

Peter

 

 

[myothercarsa2cv]

Quoting Luegonigel: 

Not sure what tool does the crimping and how it is supposed to get a good grip near the hose connection but it certainly hasn't in this case.

Get a pair of needlenose pliers in there

[Steve Cornford]

Hi Nigel

Hope you enjoyed your Spanish trip

 

I have gone through 3 CC plastic radiators, and then one CC all aluminium triple pass , and when that failed I replaced it with a Radtec and have not had a problem since!

 

 

[Luegonigel]

Picos mountains in Spain absolutely fabulous thanks, I'll do a bit for Low Flying on it, even if it is just to give directions on a route.

 

New alu radiator received from CC today.

 

I notice it doesn't have the extra small pipe on it which connects to the tee piece to the connection on the back of the block and the expansion bottle.

 

It seems from the manual that the Sigma engine has the connection back to the top of the radiator and the Duratec doesn't? On the Duratec it goes straight from the expansion bottle to the back of the block.

[Garth]

The connection from the expansion tank to the original radiator was to facilitate 'bleeding' I believe - just leave it out and connect the pipe straight to the expansion tank and work the air out another way!? - this is how my Sigma was done.

[John Hughes]

When I had my car upgraded by CCM to 140 spec they fit the all ali radiator without the small air bleed pipe / connector. The way they altered the piping was to cut it just past the T piece and then screw a M10 caphead into the open end and apply a pipe clip.

 

I have had no problem with air locks but when filling but have left the plug out of the top of the radiator until is full, replaced it and continued to fill.

 

I must admit that as an "engineering" solution I liked the idea of all the high spots in the head, the radiator and the expansion bottle being connected as a nice neat solution to avoid all those nasty problem that the K series boys get.

[Luegonigel]

That's the alu radiator fitted, 300 miles done in boilin ot conditions

 

Seems fine, no spray all over the engine bay this time, hopefully it lasts.

 

☹️ pulled up after a blat with new rad.............oil pressure gauge gone to full scale showing 8 million bar! Looks a bugger to get at the sender with spanner or socket. It is a three wire transducer so presume it has gone open circuit for the gauge to read full scale.