Herald 1360 Radiator caps

[pageste]

Is there a definitive answer to which radiator cap I should have on my 13/60 conv ? I have an issue with it blowing water out the overflow after a run, I suspect an air lock as I had a bit of work done for the MOT and they changed all the hoses while they were at it. I went to the excellent Duxford meet and it did it there so I bought a rad cap from the mobile club shop which was the same as the one on my car 7lbs. However when I checked a few online sellers some quote 13lbs for the 13/60. Its not a full width rad. I decided to take the thermostat out and check it. Using a slow warm up on the hob and my homebrew thermometer it seemed good starting to move at about 82' .  Work has stopped me investigating further but the plan is to reinstall the thermostat and jack the front up a bit and slowly fill her up with the engine running and the heater valve wide open. I should add the gauge never showed the car running hot. I dont beleive its head gasket as takes ages to warm up and no overdue pressure in the hoses and no bubbles in the rad. Does having the wrong cap make that much difference ?

[Darren Groves]

I've always used a 13lb cap on my 13/60, I fitted a 7lb one briefly and had similar issues with it pushing water out the overflow, with no signs the car was running hot. I always use an 88deg thermostat as I find the engine runs too cool otherwise. If I was you, I'd use the 13lb cap and you'll probably find it will be fine, don't look for problems that aren't there.

 

I tend to fill the system with the front as high as possible to get the filler as high as possible.

[pageste]

Thanks Darren , that makes sense. Ive only just got it back on the road and just idling it on the drive it doesnt get hot enough to cause a problem, only if I take it for a "ahem" spirited drive does it seem to do it. Just to confuse me even more I have two spare rads and one has a 7lb and one has a 13lb. I will try the latter on the car and take it for a good run this weekend. Appreciate the help

[Darren Groves]

All the traders seem to list both for the Herald, not sure why, probably for different markets to suit the climate of the country....I'm guessing. The 13lb one will allow the car to get hotter before allowing water past, if the rest of the cooling system is in good order, I'd just go with that.

 

Good luck.

[Guest]

Hello.

 

Out of interest what does the Standard Triumph Drivers Handbook for the 13/60 state as the required rad cap - I doubt it gives a choice. Have you got the correct length rad cap, which I presume is standard rather than long reach.

 

Secondly, is it possible that your rad is a bit clogged ?? Okay whilst idling on the drive but incapable of dealing with coolant temperature when cruising at a spirited pace.

 

Along with the 13lb rad cap, it may be worth flushing the system through again and back flushing.

 

If you have the chance to borrow a digital thermo lance it may help to indicate any hot-spots.

 

I agree with your view on the h/gasket as it would bubble up through the rad once the thermostat opened - that's a positive to begin with !!

 

Regards.

 

Richard.

[Pete Lewis]

The higher pressure just raises the boiling point by good few degrees

in reality with a filler above the highestbpoint youmshould run fine with the cap off

 

Do check the seat in the filler is flat and soind and as Richard suggests check the filler seat and cap are comparible depths

 

 

Just browsed the 1200 1360 wsm and went from 7psi to13psi after com numbers

1200 GA240782E and 1360 GE 22521E

 

looking further this could be introduced when they changed the rad header

to a raised rather than a sunken top tank.

Pete

[Pete Lewis]

Cant edit very well on a silly tablet but if a rad tube is capped then its stays full of air , like finger over a straw when you dip it, with extra heating on a good run the volume of hot coolant heats the air in the tube and it expands

the change in volume gets expelled out the cap as pressure rises, but can idle for hours ok.

often confused with thoughts about head gaskets

 

pete

[juppy]

The other way to check what you should have fitted is the lug size on the cap, 7 lb caps have 7/16" wide lugs and 13lb caps have 11/16" wide lugs, so if the radiator was designed for a 7lb cap you can't fit a 13lb cap, however you can put a 7 lb cap on a radiator designed for a 13lb cap.

If you look at the filler neck you can work out what should be fitted.

[Casper]

A long time ago, in another place, JK explained that the change came when the quality/reinforcing of the hoses improved.  Not too sure which was chicken, which was egg.

 

C.

[Pete Lewis]

also later ideas of using 88c to weaken emmissions may have induced a higher pressure , but unsure if triumph went this route 

 

Garth,  Ive just been to the bathroom and cant measure the lugs in varfocals so no idea what i run at   but it can be high pressure at times     Ha !