qim Posted October 12, 2016 Report Share Posted October 12, 2016 Please, forgive me but I do not know the name of the part of the radiator where the cap fits (the vertical bit) at the end of the horizontal length that comes out of the actual radiator). I had my radiator serviced but it seems that there is not a proper seal between the cap and that vertical part, and the radiator people said that they could only replace it with a different type (shallower or higher). Do you know where I could find that bit so that at the next opportunity I would have it welded in to replace the current one? Thanks qim Quote Link to post Share on other sites
Motorsport Mickey Posted October 12, 2016 Report Share Posted October 12, 2016 I don't know what the radiator cap housing is called either, unless it's called a housing ! (that's where the rad cap screws into). If this is the original radiator and also the original radiator cap you were using you've just found where your overheating was coming from. The rad caps are available in various lengths and you need to ensure that the sealing rubber on the rad caps bottom flange seats onto the housing and bottom flange which is fixed into the radiator neck extension, otherwise the radiator cannot build up pressure (which increases the boiling point of the coolant) and the coolant will boil much earlier. If the above is correct then buying a new rad cap the correct length and poundage will give you the correct seal with no need to replace the radiator housing for it. Mick Richards Quote Link to post Share on other sites
qim Posted October 12, 2016 Author Report Share Posted October 12, 2016 Hi Mick yes, I realize that now. In fact, most of the overheating came from the radiator itself. That's been sorted out. YThe cap is a new one, which I bought from RimmerBros. What I need now is what you call the housing... Is it possible to get one, even second-hand? Quote Link to post Share on other sites
rhino_mac Posted October 12, 2016 Report Share Posted October 12, 2016 This links to a picture of the correct 4lb TR3 radiator cap. https://jsk404.wordpress.com/2014/08/18/ac-delco-radiator-cap/ But if the overflow neck has been changed, you will need to ensure your radiator cap is long enough to seal correctly. Quote Link to post Share on other sites
Motorsport Mickey Posted October 12, 2016 Report Share Posted October 12, 2016 HHhmmm never had to replace or source the housing separate but the TR rads with their long neck extensions or as you call it the horizontal length (so you can fill it when the front panel is fitted) solder onto the top of the rad and so a used one would presumably need removing from a tank and then resoldering onto yours, this would have the rad cap housing already fitted to it. Is the rad cap housing on your long neck extension damaged ? is that what the repairers say ? Mick Richards Quote Link to post Share on other sites
qim Posted October 12, 2016 Author Report Share Posted October 12, 2016 Hi Mick Is the rad cap housing on your long neck extension damaged ? is that what the repairers say ? To be honest I am not sure. It is a possibility that in order to make a good fit on top they increased the height of the thing. I would not mind to have a spare "long neck extension", if that is what might be needed, just in case. Where do I look? Quote Link to post Share on other sites
stuart Posted October 12, 2016 Report Share Posted October 12, 2016 TBH I suspect your problem is you were sold a short rad cap and you need a long one. I doubt your local rad repairers will have seen one as they went out of general use an awful long time ago. The only way you would get a rad extension housing is by buying a knackered rad to cut up. Stuart. Quote Link to post Share on other sites
qim Posted October 12, 2016 Author Report Share Posted October 12, 2016 How can I test it properly? I assume that the cap should make a perfect seal up to the point when the pressure goes above the cap's rating. What if it is not making that seal? I guess the pressure will lift the spring and water will run out by the overflow tube, OR by another imperfect fit at the top of the cap's housing, which is what I am afraid of. Quote Link to post Share on other sites
qim Posted October 12, 2016 Author Report Share Posted October 12, 2016 Hi Stuart No, I have a new, long rad cap Quote Link to post Share on other sites
Fireman049 Posted October 12, 2016 Report Share Posted October 12, 2016 I fitted my 3A with an expansion tank fitted to the bulkhead. The tank is from a Rover SD1 and has a 7psi cap fitted, The radiator has a plain cap fitted. I've never had problems with water loss. Tom. Quote Link to post Share on other sites
Don H. Posted October 12, 2016 Report Share Posted October 12, 2016 ...I've never had problems with water loss... Is your car running now, Tom? Well done! Quote Link to post Share on other sites
Fireman049 Posted October 12, 2016 Report Share Posted October 12, 2016 Hi Don ~ No, my car isn't running at all. I think it's still in the garage but I haven't been near it for ages. I've lost all interest in it. These photo's were taken a long time ago. Best regards ~ Tom. Quote Link to post Share on other sites
Lebro Posted October 12, 2016 Report Share Posted October 12, 2016 Time to start getting it ready for next summer ? Best wishes Bob. Quote Link to post Share on other sites
qim Posted October 12, 2016 Author Report Share Posted October 12, 2016 Hi I found this webpage http://www.fillernecksupply.com/cold-rolled-steel/ it does not say how deep the filler necks are. Am I to understabd that they are all the same size, which for a TR3A should be, I believe, 1 inch? Thanks Quote Link to post Share on other sites
Don H. Posted October 12, 2016 Report Share Posted October 12, 2016 (edited) No, not all filler necks are 1-inch depth. That's a long obsolete standard, in fact, many decades out of common use. Radiators these days are commonly done to an SAE standard of 3/4-inch reach. There were, ISTR, even longer reaches on some radiators in years past -- 1 1/8-inch or more. Using the wrong cap for the radiator neck reach will give problems. If the cap is too short, it won't seal and will give boiling over due to not holding pressure. If it's too long, it will give higher pressure than intended and overheating. Use the right one for the radiator. The original cap for an original sidescreen TR radiator would have been 4 psi, 1-inch reach. Those caps are still easily available. A related subject is to use a cap with a one way valve to allow siphoning back if an overflow bottle is used (like on my and many other's cars here on the forum). There are threads here discussing that topic. Edited October 12, 2016 by Don H. Quote Link to post Share on other sites
qim Posted October 12, 2016 Author Report Share Posted October 12, 2016 (edited) Hi Don Are you saying that none of those in the webpage are 4 psi, 1-inch reach ? Those are still easily available. If so, where can I get the correct filler neck? Thanks Edited October 12, 2016 by qim Quote Link to post Share on other sites
Don H. Posted October 12, 2016 Report Share Posted October 12, 2016 I have no idea about that webpage. Why do you need a new filler neck again? Quote Link to post Share on other sites
qim Posted October 12, 2016 Author Report Share Posted October 12, 2016 To replace the existing one that may be slightly damaged. qim Quote Link to post Share on other sites
Richardtr3a Posted October 13, 2016 Report Share Posted October 13, 2016 Forget replacing the filler neck. If you still have a problem, fit a plain blanking cap to the radiator and a hose on the small overflow pipe to a separate pressure expansion chamber. Fit the 4 lbs cap to the new chamber. This will allow the filler neck to be full at all times. This worked on my car and we never have water loss now. Leave the filler neck or you will make the problem more complicated. Good luck, Richard & H. Quote Link to post Share on other sites
Fireman049 Posted October 13, 2016 Report Share Posted October 13, 2016 Richard ~ See my reply #10. Tom. Quote Link to post Share on other sites
Don H. Posted October 13, 2016 Report Share Posted October 13, 2016 Ongoing discussion of expansion tanks here, qim, which you might want to follow: http://www.tr-register.co.uk/forums/index.php?/topic/59728-rear-lights-and-hydraulic-brake-switch/page-2 Post some photos of your radiator's filler neck. A number of folks here will give you an opinion about damage to the sealing surfaces. Be sure to show both the top seal and the sealing surface 1-inch down into the neck. Quote Link to post Share on other sites
Bob324 Posted October 5, 2021 Report Share Posted October 5, 2021 I have a 1960 TR3a, I am I need for a radiator core or a rebuild radiator. Any idea where I can buy one for cheap? Thank you Quote Link to post Share on other sites
Bob324 Posted October 5, 2021 Report Share Posted October 5, 2021 I have a 1960 tr3, I am in need of a radiator core or a rebuild radiator for cheap. Thank you Quote Link to post Share on other sites
Ralph Whitaker Posted October 7, 2021 Report Share Posted October 7, 2021 I had mine re-cored and it was thick end of £200, plus the cost of a second hand radiator as I didn`t have one, but at least I was able to do away with the starting handle hole which blocks off 10% of the cooling fins. If you already have a rad there are plenty of specialists around that could re build it for you. Ralph. Quote Link to post Share on other sites
John Morrison Posted October 7, 2021 Report Share Posted October 7, 2021 Do well to get it for under £200 these days! John. Quote Link to post Share on other sites
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