Weeping rad

[dlgis]

Me again! I’ve got a weep from what looks like a seam half way up the RH side of my rad. Nothing major but i will need to sort it soonish. It looks like I have a 4.2 rad rather than the original Marston? There’s a sticker on the top from a radiator repair company that suggests its been previously repaired. Just thinking through the options:

1. Chuck in some Barr’s leaks. I’ve no idea how many times (if any) this may have been tried before, so might this clog up the waterways?
2. Get it brazed/welded - not sure what material it is - aluminium?
3. Bite the bullet (in view of the previous repair) and get a new one from someone like Fosseway?

[Gfhug]

Darryl, why not try Barrs while you continue to get to know the car and find any other things to sort out?

Geoff

[dlgis]

That would be my preferred option Geoff, being as though it’s the cheapest, just wanted to check I’m not likely to block up any arteries

[Heuer]

Jaguar added two jars of Barr's to every car on the production line.

[Philk]

As you've already surmised, this is not the radiator that Jaguar would have fitted to your car on the production line (i.e. the Marston fluted side radiator) but it's worth highlighting that many 3.8 cars would have had their Marston rads replaced with the 4.2 version by Jaguar Service Centres when owners came in with cooling/radiator issues after the 4.2 cutover. When you eventually do come to replace the radiator, it's then a matter of choice as to whether you want to replace it with a correct period-look radiator such as those supplied by Fosseway (which is the route I took with my '64 OTS) or go with a 4.2 version (which would do the job but is not as attractive from a period perspective).

In the meantime, I fear the days of your radiator are numbered. Even if the pin-hole can be temporarily fixed by Barrs, it remains an area of weakness. A further interim option to look into is the pressure rating on the filler cap. These were uprated in March 1963 (Service Bulletin D.8 / Spares Bulletin N.3) to a 9lb pressure rating to allow the water temperature to increase further (without boiling) prior to escaping from the header tank through the pressure relief hose. If yours has a 9lb cap, you could reduce it to 7lb thereby reducing stress in the tank when the water is very hot.

[dlgis]

Thanks Phil I’ll check the current cap rating and try a 7lb one if the current one is 9lbs. I'm inclined to agree that the bars leaks is only likely to delay the inevitable, which will then leave me in a quandary over whether to fit a more expensive replica Marston or 4.2 style.

[Series1 Stu]

Hi Darryl

You don't say that you have an overheating problem so changing the pressure cap isn't really going to make any difference. A 50% coolant mix will boil at around 108C at atmospheric pressure while pressurising to 7 psi will raise this to around 118C and 9 psi to around 121C. Unless your coolant is at the upper end of this range then it will not make any tangible difference to the situation.

Your leak will mean a (very very small) drop in coolant pressure anyway with the resultant drop in boiling point. This will obviously get worse as the leak gets worse.

As the car is new to you I would change the coolant for a good quality ethylene glycol mix anyway and then add the Barrs Leak and see what happens. Don't be surprised if your leak/weep gets worse because fresh anti-freeze has a happy knack of finding weaknesses in the system. Discouraging maybe, but you would really want to know if failure is imminent.

I would plan and save up for a new radiator if I was you. Which type is a matter of personal preference. I have an all-aluminium one with integral fan and shroud. It looks fantastic and is very efficient but is a long way from the original appearance, which doesn't bother me in the least.

Good luck with the repair.

Regards

[Philk]

... My previous recommendation re the pressure rating of the cap was only in the context of when coolant was v. hot (not knowing the status of the rest of the cooling system and its circulation efficiency). Fully agree that it would not come into play until the pressure in the system was reaching the "blow off" point. If it was to go that high though, this would save the radiator more stress.

[Geoff Allam]

Darryl, before you throw in Barrs Leaks or do something drastic like buying a new radiator you may want to try a simple solution that I used on my header tank(pressurized just like the radiator). Drain the radiator completely and let it drain for a day or two. Then scrub the area with soap and water followed by a degreaser. Then lightly sand the whole area with fine sandpaper down to bare brass (or whatever). Once it is bright metal clean the area with acetone and then apply one or two coats of a quality 2 part epoxy. West system is my favorite for this type of thing. Let it cure for a couple of days before refilling and using. My header tank had a few pinholes on the bottom that I repaired this way over 25 years ago. It has not started leaking again yet. From the picture it looks like you have excellent access to the area.

[Jeremy]

I bought a Fosseway rad during the restoration of my car and it started leaking about 6 months ago. The leak was buried behind the fins, a joint between one of the horizontal elements and the side tank.

I previously had a leaking SS header tank from Terry's Jag ( who ignored my emails) so I was getting fed up to the back teeth with puddles of coolant on the floor. Simon at Fosseway suggested an epoxy repair - which I was very uncomfortable about. It seemed impossible to pinpoint the hole, never mind clean the area, never mind get the epoxy in to where it would seal it. And how long would it last anyway?

He also offered a small discount on a new rad but of course I had lost confidence in the product.

I asked Angus if he would set off on a continental tour with a blob of araldite patching up his cooling system. His response was crisp and to the point.... He recommended a new rad from Radtec, which I bought and fitted. A costly and disappointing experience but it's nice not having to keep mopping glycol up.

[Norton]

Hi. If your rad isn’t an aluminum and you know were the leak is, solder it! Don’t use «electronic» solder have to much lead for this application. Use something with more than 90% tin. A bit more difficult to work with but done properly it will last. Theese rads were soldered up when produced. I soldered a split header tank long ago - no problem. Heated it with a heat gun to get the temperature up and used a100w solder iron. It had been previosly repared with what I suspect to be with «electronic» solder. Save the Barrs leak for another time when you might be out on a trip. It adds up and probably will first show as a clogged heater.
Harald

[Geoff Allam]

Just to clarify. I was not suggesting a blob of araldite to patch up a cooling system. I was presenting the option of a properly prepared, well executed repair, using a quality 2 part epoxy that is suitable for multiple marine uses among other things.

[dlgis]

Thanks all, lots of great advice. The car’s going into my mate’s garage (shop in US/Can?) in a few weeks and we’ll go over all the mechanicals and fix as required (well mostly him, with me making tea!) He has a 4 post lift to make life easier. In the meantime I’m unlikely to do many miles so will just top up the rad as necessary.

[mgcjag]

Your in Kent...and cars in US?......Steve

[dlgis]

Doh..no Steve, its just that some advice came from Canada and i believe over there a garage that fixes cars is called a shop.

[mgcjag]

got it