Overheating R3Tub

[CritCare]

Hi,

The problem with my R3Tub is when the car is on boost usually in 5th at speed on and above 100 the temp gauge begins to climb...at roughly the rate of a notch every 3 seconds. When I get off the pedal it will begine to fall back to just below half way.

The has happened since i bought the car and has left me feeling uncomfortable with it. Ive had a leakdown test down to find all the cylinders running under 20% and det cams to determine the engine is firing fine.

The car runs great and has no problems other wise, just this overheating problem which i want fixed..

A previous owner has removed the aircon system but left the aircon rad, so i removed it thinking it was blocking the main rad. STILL HAPPENS The coolant has been changed twice and bled a number of times STILL HAPPENS

The main rad works fine and im outta ideas..

Can a clogged cat hold back gas and create overheating?
Could a cylinder have a crack that only opens under extreme heat and add to the coolant pressure?
Could the thermostat be stuck?

[Slarty]

In answer to your three questions, they're all possible with the cat being least likely, then the cracked bore and the thermostat being most likely.

Change the 'stat or just remove it temporarily until you can get hold of one and see what it's like afterwards.

Also worth considering the radiator/expansion cap. If it's weak or letting by slightly the coolant system will not pressurise and the coolant will boil at a lower temperature. Although, you'd expect to lose coolant if that was the case, are you?

[nailmonkey]

Hi,

I had a similar problem a while ago, at sustained motorway speeds, the temp gauge hit half-way rather than the slightly under half-way that it always used to register. I'd had the car for over 3 years at that point so even that very small change was enough for me to know something was wrong. Rogue Motorsport correctly diagnosed the problem as an inefficient radiator, so I had a new coolant rad and new aircon rad fitted and it was fine after that.

Nik

[CritCare]

thanks for the replies. i would maybe have to add around a half can of coke sized amount of coolant every week.

As far as removing the thermostat, would this just cancel out a bad thermostat?

Is there a way to keep the rad fans on all the time to see if it i the rad?

When the temp rises it recovers quite quickly, but the fact that its there will drive me mad.

[Razor04]

Check both rad pipes in the frunk are hot after you've driven the car for a bit (1 port & 1 stbd in the frunk) fat silver pipes. this will tell you if your rads doin its job

[CritCare]

they are both hot to the point you cant hold them for more than a few secs...

[Razor04]

thats a good sign mate, means the coolants getting round ok and the thermostat is doin its job. Get another rad cap from toyota they're approx £9 worth it to rule it out.

[Razor04]

Also somethin you can do today:
take off the small diameter pipework that runs from the rad cap to the expantion bottle lid and the pipe thats on the underside of the lid.

clean them out in the sink, make sure they're not blocked up with rust flakes / gunk

mine were blocked up pretty bad which means that the coolant cant get in and out of the expansion tank when the engines hot.

and make sure you have coolant in the expansion tank, use the pipe as a dipstick gauge, should be wet up to about half way.

[CritCare]

cheers man, already got a new rad cap. When i bought the car it had a trd on it but ive since got a brand new stock one. ill do the pipe cleaning now. thanks