Guest Budz86 Posted July 14, 2013 Share Posted July 14, 2013 Am I right that the rad cap should be rated to 1.3 bar? Mine looks to only be 1.1 and I'm boiling through coolant a bit so want to uprate this and see if it cures it. Can I go higher than 1.3? If so, what do you guys recommend? Thanks in advance Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted July 14, 2013 Share Posted July 14, 2013 No the rad cap should be 0.9bar standard. Quote Link to comment Share on other sites More sharing options...
antno Posted July 14, 2013 Share Posted July 14, 2013 You will probs pop the heater matrix is you go too high Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted July 14, 2013 Share Posted July 14, 2013 Oh right, that's that theory blown out the water then! Wonder if it's the cap for the expansion bottle not having a good seal and losing it that way. Doubt it's a split hose or anything otherwise I would have seen it leaking by now. Quote Link to comment Share on other sites More sharing options...
Nic Posted July 14, 2013 Share Posted July 14, 2013 Is the 1.1bar rad cap new? If it's old it could still be leaking, a loss of pressure in the system will cause the coolant to boil at a lower temp. Clean up the area the radiator cap seals against and fit a new OEM Toyota rad cap, if it's still boiling over then there's a problem elsewhere. Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted July 14, 2013 Share Posted July 14, 2013 Yep the cap is new Nic, came with the rad which I replaced in March. Must be the expansion bottle as the cap doesn't fit as well as I think it should. Considering the system is pressurized, that seems the weak point to me if it's not the rad cap Quote Link to comment Share on other sites More sharing options...
Nic Posted July 14, 2013 Share Posted July 14, 2013 Yep the cap is new Nic, came with the rad which I replaced in March. Must be the expansion bottle as the cap doesn't fit as well as I think it should. Considering the system is pressurized, that seems the weak point to me if it's not the rad cap For the small cost I think I'd still replace the cap with a new one, provided there is coolant in the expansion bottle and the hose is into coolant then it should make no difference. Quote Link to comment Share on other sites More sharing options...
Digsy Posted July 14, 2013 Share Posted July 14, 2013 Must be the expansion bottle as the cap doesn't fit as well as I think it should. Considering the system is pressurized, that seems the weak point to me if it's not the rad cap The expansion bottle isn't pressurized. Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted July 14, 2013 Share Posted July 14, 2013 Thanks guys, useful info there. Coolant is escaping somewhere as if I top up the expansion bottle, the level is dropping within about 100 miles. Level in the rad is always good through. Bit of an odd one really as everything is brand new! Tried topping up with both water and coolant and it doesn't make a difference. Might try to temporarily seal the expansion bottle and see if that helps. Quote Link to comment Share on other sites More sharing options...
Digsy Posted July 14, 2013 Share Posted July 14, 2013 I would top up the expansion bottle with the engine cold and then run it up to temperature and observe what happens (might have to take it for a short run as tickover might not get the enging hot enough to start venting through the rad cap). The level in the expansion bottle should increase and then drop back to where is started as the engine is left to cool. Coolant only flows from the expansion bottle back into the system as the engine cools down so if you are seeing the level drop as the temperature increases then it does sound like the bottle itself is leaking. I wouldn't seal the lid as it might stop air escaping and thus prevent the normal flow of coolant into the bottle as the engine warms up. Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted July 14, 2013 Share Posted July 14, 2013 Thanks digsy, this is going to seem like a really stupid question but should the expansion bottle be full when the engine is cold!? From what I understand reading your post it should be partially filled when cold, when the system is hot it then fills up, then drains back into the system when cold again? Quote Link to comment Share on other sites More sharing options...
stevie_b Posted July 15, 2013 Share Posted July 15, 2013 Fill the expansion bottle to the "full" mark, not to the brim of the bottle. The full mark is some way below the brim. Quote Link to comment Share on other sites More sharing options...
Rummy Posted July 15, 2013 Share Posted July 15, 2013 Fill the expansion bottle to the "full" mark, not to the brim of the bottle. The full mark is some way below the brim. I've always topped to just above the LOW when cold so the coolant has room to expand into when hot Quote Link to comment Share on other sites More sharing options...
stevie_b Posted July 15, 2013 Share Posted July 15, 2013 I think the "full" mark isn't at the top of the bottle so that the coolant's got room to expand when hot. Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted July 15, 2013 Share Posted July 15, 2013 Ah right! Thanks guys, makes more sense now. I've got an alloy expansion bottle from SRD so it doesn't have markings on it as far as I remember. Doesn't sound like I've got a problem then Quote Link to comment Share on other sites More sharing options...
stevie_b Posted July 16, 2013 Share Posted July 16, 2013 You have got a problem if you're boiling your coolant off. Have you been filling the expansion bottle to the brim? If so that would probably explain why you've been losing some. Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted July 16, 2013 Share Posted July 16, 2013 Yep I've been brimming it Stevie so that explains why will keep an eye on it over the next few days to see if it drops further. If it does, I've probably got a split pipe somewhere, which will be fun to find! Quote Link to comment Share on other sites More sharing options...
scott87 Posted July 16, 2013 Share Posted July 16, 2013 No the rad cap should be 0.9bar standard. So the TT rad cap is rated lower than the n/a then? Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted July 16, 2013 Share Posted July 16, 2013 What's the NA rated to mate? Quote Link to comment Share on other sites More sharing options...
scott87 Posted July 16, 2013 Share Posted July 16, 2013 What's the NA rated to mate? 1.1bar i believe Quote Link to comment Share on other sites More sharing options...
stevie_b Posted July 16, 2013 Share Posted July 16, 2013 Yep I've been brimming it Stevie so that explains why will keep an eye on it over the next few days to see if it drops further. If it does, I've probably got a split pipe somewhere, which will be fun to find! Ah, you should be fine once you put less in. I don't know if the SRD bottle is the same shape/dimensions as the stock one, but I'd try filling it no more than 1/2 full and see what happens. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted July 16, 2013 Share Posted July 16, 2013 Why wuld an N/A run hotter/higher pressure than a TT? Ask yourself that question. Quote Link to comment Share on other sites More sharing options...
Nic Posted July 16, 2013 Share Posted July 16, 2013 What's the NA rated to mate? The radiator cap is the same on all Supra models 0.9bar. http://img5.imageshack.us/img5/4017/t2hj.jpg Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted July 16, 2013 Share Posted July 16, 2013 Cheers for that Nic. Stevie, the SRD bottles are a slightly different shape so will try half full and go from there. Thanks for your help on this guys Quote Link to comment Share on other sites More sharing options...
Nic Posted July 16, 2013 Share Posted July 16, 2013 Cheers for that Nic. Stevie, the SRD bottles are a slightly different shape so will try half full and go from there. Thanks for your help on this guys Provided the end of the tube that goes into the overflow bottle is always sumberged in the coolant - whether hot or cold - you'll be fine. What you don't want to happen is the coolant drop below the end of the tube as this can allow air to be drawn back into the system. Quote Link to comment Share on other sites More sharing options...
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