Paul372 Posted July 18, 2016 Share Posted July 18, 2016 I have a jap spec auto tt, the car runs and drives fine and the temperature gauge is at the normal half way point but after a hard drive the I can hear the coolant boiling up. What could this be and why is it doing it. The oil is fine and the coolant is fine and the car still has loads of power no lost at all so I'm pretty sure it's not head gasket and there's no smoke Quote Link to comment Share on other sites More sharing options...
evinX Posted July 18, 2016 Share Posted July 18, 2016 Is the Coolant level fine? Bubbling means build up of pressure, and what condition is the radiator in? Quote Link to comment Share on other sites More sharing options...
Paul372 Posted July 19, 2016 Author Share Posted July 19, 2016 Yeah coolant level is fine but it does look like it could do with a change as it turns a bit brown looking and the rad I replaced a few years ago now for a new oem which cost me a bit of money so the rad is still in good condition. Could a air lock in the system cause it Quote Link to comment Share on other sites More sharing options...
Big Mark Posted July 19, 2016 Share Posted July 19, 2016 How's the rad cap? Might need changing? Quote Link to comment Share on other sites More sharing options...
Dnk Posted July 19, 2016 Share Posted July 19, 2016 (edited) First thing i'd look at is the rad cap then the thermostat Edited July 19, 2016 by Dnk (see edit history) Quote Link to comment Share on other sites More sharing options...
Paul372 Posted July 19, 2016 Author Share Posted July 19, 2016 I Think it's still the original rad cap that I had on the old rad, does anyone have a part number to hand for the rad cap, I think I will also do a coolant change as I think it's been about 3 years since I changed the coolant Quote Link to comment Share on other sites More sharing options...
Dnk Posted July 19, 2016 Share Posted July 19, 2016 (edited) I'd change the cap first and see if it cures your problem, if it does then change the coolant, i'd pop a new stat in there too and personally use OE parts from Toyota for both. Use an Ethylene Glycol based coolant, it doesn't have to be Toyotas branded stuff. The stat I think is rated at 82c but double check that. No idea on part numbers though, sorry Edited July 19, 2016 by Dnk (see edit history) Quote Link to comment Share on other sites More sharing options...
Big Mark Posted July 19, 2016 Share Posted July 19, 2016 I had an issue last year and a new rad cap fixed it. I got mine from Eurocarparts as was down the road. Quote Link to comment Share on other sites More sharing options...
evinX Posted July 19, 2016 Share Posted July 19, 2016 Oem rad caps are 1.1 bar, its self bleeding, you can pop the cap of, turn the car on and see if any bubbles come to the top, jacking the front up helps Quote Link to comment Share on other sites More sharing options...
Paul372 Posted July 19, 2016 Author Share Posted July 19, 2016 Thanks guys for your help. I shall get a new rad cap and while I'm at it I might as well change the thermostat Quote Link to comment Share on other sites More sharing options...
rider Posted July 20, 2016 Share Posted July 20, 2016 Thanks guys for your help. I shall get a new rad cap and while I'm at it I might as well change the thermostat If your radiator is getting warm then there is no point changing the thermostat in a getting too hot scenario. The engine normal temperature is usually in the 85C to 95C range and the cap (if working at normally around 13lb pressure) will raise the boiling point to around 113C. Which is why boiling sound in the engine area is either air trapped in your heater matrix or more usually just a faulty rad cap. Quote Link to comment Share on other sites More sharing options...
Paul372 Posted July 20, 2016 Author Share Posted July 20, 2016 What's the benefits of a trd rad cap, is it worth buying trd over an oem Quote Link to comment Share on other sites More sharing options...
evinX Posted July 20, 2016 Share Posted July 20, 2016 What's the benefits of a trd rad cap, is it worth buying trd over an oem TRD are 1.3 so will raise the pressure. Quote Link to comment Share on other sites More sharing options...
Paul372 Posted July 20, 2016 Author Share Posted July 20, 2016 So by raising the pressure what are positive and negative of doing that Quote Link to comment Share on other sites More sharing options...
Dnk Posted July 21, 2016 Share Posted July 21, 2016 If your radiator is getting warm then there is no point changing the thermostat in a getting too hot scenario. The engine normal temperature is usually in the 85C to 95C range and the cap (if working at normally around 13lb pressure) will raise the boiling point to around 113C. Which is why boiling sound in the engine area is either air trapped in your heater matrix or more usually just a faulty rad cap. My point about changing the stat was if your doing a coolant change you might as well fit a new one and replace the potentially 20 + yr old one, preventative maintenance Quote Link to comment Share on other sites More sharing options...
Dnk Posted July 21, 2016 Share Posted July 21, 2016 So by raising the pressure what are positive and negative of doing that http://www.tuneruniversity.com/blog/2011/06/beating-the-heat-advantage-of-a-high-pressure-radiator-cap/ Quote Link to comment Share on other sites More sharing options...
Paul372 Posted July 21, 2016 Author Share Posted July 21, 2016 Cheers, that's a good read and I will be changing the thermostat as like Dunk said it is 23 years old and putting a new one in wont do any harm Quote Link to comment Share on other sites More sharing options...
Paul372 Posted August 30, 2016 Author Share Posted August 30, 2016 Replaced the rad cap with a nice new oem one from Toyota and the problem is fixed thanks guys, I've also got a new thermostat and seal so will be changing that and a coolant change Quote Link to comment Share on other sites More sharing options...
Dnk Posted August 31, 2016 Share Posted August 31, 2016 Nice simple fix Quote Link to comment Share on other sites More sharing options...
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