Possible overheating problem!!!

Came back from a long drive yest in the car and when parked up a could hear a bubbling sounds from the engine bay. The expansion bottle at the front of the car was nearly full and boiling bad with water. Never overheated on the dial whilst out and ran fine. Didn't push her that hard whilst a was out either. Do a have a problem and if so what could be causing it?

I presume you mean coolant not water? The ambient temp has been hotter of late. Any leaks? Has the coolant in the expansion returned to the rad when cool? Coolant level when cool? How long since the last coolant change? Electric fans working?

More info please

I'd question the coolant level if it's boiling and not overheating tbh.

By coolant level I also mean the ratio of coolant/water.

As said check coolant levels in the system and in the header bottle when cold. The coolant will initially get hotter once parked up with the engine off, I occasionally got bubbling on mine after parking up on a hot day in HK if the level in the header bottle had dropped a bit low.

Sorry to hear you're having problems Craig

For info, the coolant was checked annually including top up with antifreeze. Its never had overheating problems, i was fanatical about engine temps after a bad experience with another supra i almost bought. In my time i replaced the rad cap twice too, but only because they're known to fail. One thing i intended to do at some point was replace the rad itself, purely because its still the original one and i drove the car daily for 8 years. Only other thing i can think of to mention is that the aircon fans were removed a couple of years ago, this was to make a new fan cowling fit. Hope it's ok bud!

Check the radiator cap, the rubber tends to perish over time and you get a hissing noise, high engine temps etc.

Nicholas is right, the same thing happened to mine when my radiator cap failed.

I would guess the one way valve in the rad cap has failed, or is failing, fit a new rad cap and with luck all should be well. Check the level in the overflow bottle, set it to the correct height, and monitor it with the new cap in situ.

You should have a receipt for the last rad cap Craig, I'm interested to see when it was bought as it'll give me an idea of how long they last on a daily driver.

Sorry for late reply, doesn't seem to be any leaks and main fan running correctly. Topped up the coolant bottle at the front of the radiator with water the other day and ran ok but today is was roasting. Drove 10 miles to my work and seems to have boiled out the bottle again . When a checked it before heading home there the bottle was empty and the rad was filled to the top. On getting home the collant bottle had coolant/water just over the (min). Top and bottom hose were warm and had no leaks as was the rad. The rad cap seems to be fine but not sure ill check when last replaced and let u know jim. Am thinking of emptying it altogether and go with all new red coolant from toyota. Again the dash temp gauge does not rise above just over half way and stays there after 3/4 mins of driving. don't know why it's boiling out the white coolant bottle and not showing over heating

I'd buy a new (stock from Toyota) rad cap either way Craig, they're cheap enough and it'll likely solve the problem bud.

Check the radiator cap, the rubber tends to perish over time and you get a hissing noise, high engine temps etc.

I had the same symtoms, this cured it.

Halfords sell the right cap at the right pressure ( 1.1bar )

Halfords stopped doing them about a year ago apparently. Well irvine store did. Got one from local car parts store. Changed over now topped up the bottle to half way and the rad is full to the top. I'll run it to work and see what happens but am a right in saying it shouldn't boil in the white coolant bottle of my n/a?

Import car parts stock the caps cheap I just got one for mine

Well after another 10 miles to work and with a new rad cap, its still boiling out the expansion bottle any other thoughts

Halfords stopped doing them about a year ago apparently. Well irvine store did. Got one from local car parts store. Changed over now topped up the bottle to half way and the rad is full to the top. I'll run it to work and see what happens but am a right in saying it shouldn't boil in the white coolant bottle of my n/a?

It shouldn't boil in the expansion tank. Don't fill half way as when the coolant expands in the rad and goes into the expansion tank, it will probably be over filling and giving you the overspill.

The boiling id put down to poor anti freeze/water ratio. I'd suggest draining the rad and filling with fresh ready mixed coolant such as Toyota red.

You shouldn't have to but another option is changing to a 1.3 cap or get a hi flow rad

As above.... is it actually boiling? Or do you simply mean "overflowing"?

Yes as above if there is no room for the water in expansion tank then it will over flow

Echo what was said before it will chuck itself out of that little pipe attached to the expansion tank if its to full.

The temp gauge reading fine still?

Flush the lot through with a hose pipe on low power, check thermostat,check all associated pipework for loose clips etc,change radiator cap,check engine oil, and refill and use with water for a day that's how i would progress

And don't forget when bleeding it to have the heater on full until it blows hot

Now, we need to define terms here. "Boiling out the expansion bottle". Boiling as in gurgling, scalding water and a great deal of steam? Or as Scott asks, is the bottle just losing water and you are *assuming* it's been boiled away? If you remove the expansion bottle, and clean it, you will see a "Full" level mark. This is where the water level in the expansion bottle should be when the engine is at full normal operating temperature. As it cools the contracting volume in the cooling system will syphon much of this water back into the radiator. When it heats up again it will purge the excess out into the expansion bottle again. if you look at old cars thy had relatively large end or top tanks on their radiators. Given the lower bonnet lines and desire for small air apertures to feed radiators, makers went to thin end / top tanks and remote overflow bottles. I am guessing, but I feel you are either over filling the overflow bottle, or misunderstanding how it should function. If you are really worried get a garage to sniff the coolant at the rad cap aperture, with either a dedicated combustion gasses in the coolant tester, or using an MOT gas analyser, looking at the HC level.

A think a may have over filled the expansion tank. When it's a cold start should the bottle then be empty? Temp gauge is fine and never went above where it should be. When a stopped the other day and turned the engine off. In the expansion tank the water/coolant (but prob more water now) was actually boiling inside like a kettle. And was coming out of the black lid. The water/coolant is really really warm but not steaming or that. All pipes going into the rad are hot so water is traveling round. All clips are secure and isn't loosing fluid from anywhere apart from the top of the expansion tank. A think a may flush it out and put new red coolant into it see how that goes. I'll speak to a garage as well but people on here would know just the same or had similar problem

A think a may have over filled the expansion tank. When it's a cold start should the bottle then be empty? Temp gauge is fine and never went above where it should be. When a stopped the other day and turned the engine off. In the expansion tank the water/coolant (but prob more water now) was actually boiling inside like a kettle. And was coming out of the black lid. The water/coolant is really really warm but not steaming or that. All pipes going into the rad are hot so water is traveling round. All clips are secure and isn't loosing fluid from anywhere apart from the top of the expansion tank. A think a may flush it out and put new red coolant into it see how that goes. I'll speak to a garage as well but people on here would know just the same or had similar problem

Mine is virtually empty from cold. Definitely change coolant as it sounds like you've got too much water in the mix, hence the boiling/bubbling.

Yeah am hoping that's it mate, thanks