DanB Posted May 31, 2020 Report Share Posted May 31, 2020 Hello. I’m a newbie here having taken delivery of my TR4A on Friday, a picture of which I have attached. This is my first classic car. So firstly I’d like to introduce myself and say hi, but secondly I have a question about the radiator expansion bottle. I went for a lovely 40 mile drive yesterday without any issues, and thoroughly enjoyed myself. I took the car out again today for a shorter drive and when I got home, about 1 minute after I switched off, the car sounded like a rumbling stomach and then deposited a load of water and coolant onto the garage floor, just under the expansion bottle. Is this possibly because the dealer topped up the radiator too high or is this normal? I’ve checked for leaks and there doesn’t appear to be any. The dealer has a good aftercare scheme so they are coming to visit in the week and I will raise with them then, however I just wondered if anyone else had a similar experience and is it anything to be overly concerned about? Thanks! Dan Quote Link to post Share on other sites
Jase Posted May 31, 2020 Report Share Posted May 31, 2020 (edited) Welcome and wow your car looks fantastic. I’ve recently joined and everyone on this forum is helpful and passionate about TRs. The car shouldn’t do this, it could be a number of things, wrong rad cap fitted, your timing or carb balancing could be out but I’d go with the rad cap as my first port of call. Edited May 31, 2020 by Jase Quote Link to post Share on other sites
John Morrison Posted May 31, 2020 Report Share Posted May 31, 2020 Well Dan, welcome, and congratulations on buying what looks a belter. I am a long time TR 4 owner and if I overfill my rad, above half an inch over the tube tops when looking into the rad, then it does what yours did. Check the level when cool, and if it is over the tube tops, I would take the car for a run, watch the temp guage and see what occurs. I would not be surprised if you have not got an issue. More phot's would be great, and a location, lots of folk happy to help. John. Quote Link to post Share on other sites
Andy Moltu Posted May 31, 2020 Report Share Posted May 31, 2020 It doesn't automatically mean something is wrong. I assume the car wasn't overheating when you were driving? When you switch off after a run the cooling largely stops but some of the heat that has built up in the block continues to pass into the coolant and as it expands it vents via the rad cap (7lbs on a 4A) into the expansion bottle. As the car cools it sucks it back up into the rad. If the expansion bottle is overfull it won't have capacity to catch the fluid that is vented from the rad via the rad cap. When cold the expansion tank should be about 1/3 full. If it checks out with no faults such as a blown head gasket then there isn't anything to worry about. If you have an electric fan on it you could fit a timer relay that keeps the fan running for 30 seconds to a minute after the ignition has switched off. Personally never found this necessary on the my ^ or 4A although the controller that operates the electric water pump and fan on the Stag keeps both running until the coolant temp has come down to the below the controlled temperature. Quote Link to post Share on other sites
peejay4A Posted May 31, 2020 Report Share Posted May 31, 2020 While you’re looking into it make sure you have the correct type of radiator cap. It should be bidirectional, having a small valve in the centre which opens to allow coolant back into the radiator when cooling down. As Andy points out it should be a 7 lb cap and the overflow pipe should be immersed int the overflow bottle which should be 1/3 full when all is cold. Make sure that the pipe has a slash cut at the end so it doesn’t get sucked into the base of the bottle. Quote Link to post Share on other sites
DanB Posted May 31, 2020 Author Report Share Posted May 31, 2020 Thanks all for your feedback. It looks like the right cap and is rated 7lb. I opened the cap and the liquid is brimming to the top, which I am guessing is overly full. There should be no other problems as the car has just come from a day of professional mechanical checks, a full service and is also supplied with a new warranty. Cheers all for your feedback. Quote Link to post Share on other sites
RogerH Posted May 31, 2020 Report Share Posted May 31, 2020 Hi Dan, reduce the fluid content to about 1" below the top of the rad (where the cap fits). It needs to cover the tubes. Roger Quote Link to post Share on other sites
trchris Posted June 1, 2020 Report Share Posted June 1, 2020 Hi Dan Welcome to the forum , the level on my 4a is always to the very top of the radiator and the expansion bottle about 1/3 to 1/2 full since engine rebuild and new radiator Chris Quote Link to post Share on other sites
peejay4A Posted June 1, 2020 Report Share Posted June 1, 2020 That’s how mine is and how it should be I believe. Quote Link to post Share on other sites
Z320 Posted June 1, 2020 Report Share Posted June 1, 2020 Hi Dan, a very nice car, I love the surrey top but my wife sadly not. So guess what is on my TR4A....? As others pointed out: do not overfill the rad, you need enough air in the system and the air is no problem at all (as some owners wish and will tell you). My 4A came with a 13 lbs cap and without overflow bottle. That works without loss of coolant if you do not overfill. Enjoy your TR4A, best decision to buy this badge and model. Ciao, Marco Quote Link to post Share on other sites
NigelH Posted June 1, 2020 Report Share Posted June 1, 2020 Hello Dan, Nice car..an colour, reminds me of Valencia Blue from my Herald days.. Rad caps can vary in quality and performance too..from personal experience.. Mine did the same when I first had it. I was over filling and the rad cap wasn't operating correctly. Followed the advice of forum members, and the issue was resolved.. Its a great forum with a lot of experience..I'm a newbie 2nd grade..roughly equivalent to a 'tea stirrers mate'.. Nigel H Quote Link to post Share on other sites
Mark1965TR4aBRG Posted June 1, 2020 Report Share Posted June 1, 2020 Welcome to the forum and congratulations on what looks like a lovely car. Plenty of advice above and welcome to the joys of classic cars and blemished drives/garaged floors.. Quote Link to post Share on other sites
ctc77965o Posted June 1, 2020 Report Share Posted June 1, 2020 If the rad cap looks in any way old or crusty then I suggest replace it.. this controls the pressure in the system...if it is weakened or leaks you'll get the type of problem you saw... It could be over-filling...but that normally corrects itself after one heat cycle...you say this happened on second cycle.....makes me think radcap. Quote Link to post Share on other sites
ChrisR-4A Posted June 1, 2020 Report Share Posted June 1, 2020 Hi Dan, welcome to the forum, most items are covered by the above posts I would just like to add, 1. Make sure the rad cap has a large rubber seal where it seats on the upper rad lip, some being sold by Moss a short while ago had this missing, they promptly replaced one I bought but without the top seal the "draw back" will not happen. 2. Check the expansion pipe is clamped to the rad neck and there are no leaks or holes in it. As above draw back will not work Chris Quote Link to post Share on other sites
peejay4A Posted June 1, 2020 Report Share Posted June 1, 2020 Not wishing to complicate matters but after one heat cycle any air below the radiator cap will have been replaced by coolant drawn from the overflow bottle. This is why it’s correct that when cool the water level will be at the base of the radiator cap. Quote Link to post Share on other sites
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