garybee Posted July 18, 2020 Share Posted July 18, 2020 Sounds like the thread has stripped out of the radiator. Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 18, 2020 Share Posted July 18, 2020 I've used fibre tap washers on mine - it is an allan bung rather than needing a spanner.Can you post a pic?Ian Link to comment Share on other sites More sharing options...
7_Malc Posted July 18, 2020 Author Share Posted July 18, 2020 Thread seems to work fine, but then stops prematurely. If I add a washer the nut will tighten ok. What issues would a washer cause? What material would work best? Link to comment Share on other sites More sharing options...
7_Malc Posted July 18, 2020 Author Share Posted July 18, 2020 Here is my rad screw: Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 18, 2020 Share Posted July 18, 2020 The bung on mine is brass so I wonder if that's original? Link to comment Share on other sites More sharing options...
SM25T Posted July 18, 2020 Share Posted July 18, 2020 Mine is a hex steel bolt with a plumbing brown fibre washer underneath. As long as it hits the washer before the bolt stops turning, you'll be ok Link to comment Share on other sites More sharing options...
7 wonders of the world Posted July 18, 2020 Share Posted July 18, 2020 mines a short cap head with a copper washer. Link to comment Share on other sites More sharing options...
cobaltcodd Posted July 18, 2020 Share Posted July 18, 2020 You probably need a "bolt" where the thread goes right up to the head, not with a gap like yours - so what's technically called a set-screw. That's probably why it would turn - there were no threads left to engage the thread in the radiator Link to comment Share on other sites More sharing options...
Toby S Posted July 18, 2020 Share Posted July 18, 2020 Mines the same as Wrightpaynes's - brass and so is the thread its screwing into - would make sense to be the same material so it has the same expansion properties when it gets hot - I wonder whether that;'s why yours was such a sod to get out.I've also got a a fibre washer as well like SMT25Mine looks like the link below, although I'm pretty sure last time I had it off, my thread went to the tophttps://caterhamparts.co.uk/radiators/1800-bleed-screw-brass-radiator.html?search_query=radiator+bleed&results=72Washer I would guess its this (no image to check againsthttps://caterhamparts.co.uk/fittings/3359-fibre-washer-for-radiator-bleed-plug.htmlWhen filling and bleeding I've always got the front of the car as high as possible (my drives on a slope so arse down the drive, chock the back wheels and then front as high as I can get it) and final fill at the radiatorExpansion tank reservoir up to top, and then bleed first at heater elbow (I've no heater fitted), then at radiator and then on occasions, refill at radiator again and repeated the same process, effectively getting coolant level in expansion tank down to the required level through the bleeding process - problem I've found doing it any other way you can end up with an air lock at top of the radiator and then risk the fan switch being in the air lock and not kicking the fan in at the right point. No doubt others have other methods which equally work for them, but this is what I do.P.S. mine is a 92 1400 K series supersport, so don't know if its different on other models.I know when I was short of time once, just before the Taffia fish and chip run a few years ago, due to work pressure I had to let a local garage fit new hoses and bleed the system, and they used the standard vacuum pump professional system used on modern cars, and that made a right horlicks of it - fan kick in switch was in an airlock and the engine was running well hot circa 5 degrees above normal in all conditions - fortunately found a welsh farm track on a 1 in 2 or 3 slope and stuck the nose up there and did a roadside bleed good enough to finish the run and get home Link to comment Share on other sites More sharing options...
7_Malc Posted July 23, 2020 Author Share Posted July 23, 2020 Caterham brass radiator plug / screw does not fit.Any ideas on what make of radiator this, and what screw will fit? I would rather get the real thing than bodge it… Link to comment Share on other sites More sharing options...
garybee Posted July 23, 2020 Share Posted July 23, 2020 The bolt is not the problem, the threads have been stripped out on your radiator. There is just a small section of thread remaining as the bolt has a plain, waisted portion near the head. Therefore when the bolt was overtightened, and the threads were stripped, a small section of thread remained. You don't need to replace the bleed screw/bolt with a different type of plug. You need to repair the damaged threads in the radiator so that the bolt can tighten the lower face of its head against the sealing washer/radiator. That's what provides the seal. Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 23, 2020 Share Posted July 23, 2020 Mine is the caterham supplied COVRAD radiator with brass tanks. Link to comment Share on other sites More sharing options...
SM25T Posted July 23, 2020 Share Posted July 23, 2020 Can you put a helicoil type insert in there ? Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 23, 2020 Share Posted July 23, 2020 Timeserts are better! Link to comment Share on other sites More sharing options...
7_Malc Posted July 28, 2020 Author Share Posted July 28, 2020 Update - good news!So after a day of faffing and failing to get a bolt of any size to fit snugly, I rang Rob at Ratrace for a chat (he serviced the car in April). We both agreed that driving the car with a loose / absent radiator screw was a bad idea… so he suggested removing the radiator and bringing it over. Smart man. It had not occurred to me that (obviously) the radiator was easy to remove… so I began draining the fluid – and at Rob's suggestion – collected it in a clean container to be filtered and reused at a later date. With the radiator bagged up, I headed to Ratrace for assessment. Rob was able to tap out the radiator thread to 7/16ths and fit a new bolt along with a bonded seal washer (Dowty washer) – so more education for me.Back home, I was able to reattach the radiator, and then refill / bleed with fresh coolant. I ran the car up to temperature in the garage, let the fan cycle three times and shut it off. Using a large cardboard box (flat) as a tell-tale drip tray I left the car over night. No leaks this morning, so a 30 minute test drive was undertaken. Car ran great and I'll head out for a proper drive tomorrow. Malc Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 28, 2020 Share Posted July 28, 2020 Great result!! Well done! Link to comment Share on other sites More sharing options...
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