94 ZR 5FSE Overheating

[XR8320]

Hi my sons 94 Zr has developed overheating problems and thus coolant usage from overheating I think.

We have done a flush and appears to be now oily sludge etc. After some fault finding for the Haynes manual we elected to change thermostat as indications were it maybe faulty.

Car will sit running for 30 minutes with temp gauge normal, top radiator hose gets hot but bottom hose stays cool?

He has taken car for drive and after about 15 mins car is overheating?

He pulled over and felt bottom radiator hose and still cool?

Any ideas?

I am now thinking water pump?

[95celica]

these engines can be a bit tricky to bleed. when you replace the thermostat make sure you remove the dangly thing and put the hole facing the top. Also get your radiator checked, could be blocked. Make sure you get it sorted quick as you will blow the headgasket otherwise.

[JDM-GTFour]

How many km on the clock? Has it ever had the timing belt replaced? If it hasnt.. replace the timing belt and water pump.. it does seem like there is a blockage or the pump is not circulating the water. If there is oil in the water.. you may have bigger problems.. gasket blown already maybe, check the oil for water. If it's milky you have a big problem. It might be the thermostat, but oil in water is not a good sign.

[XR8320]

Just realized typo in my post no water in oil and no oil in water.

Thank you for all replies aftermarket thermo did not have bleed jiggly thing.

Is there a simple test for water pump or blocked radiator?