Avensis Overheating & Losing Coolant - Help !?

[brizy83]

My 1999 Avensis 1.8 after 2years of behaving impeccably suddenly overheated and has started to lose about a pint of water per journey ( doesn't seem to matter how far) from expansion tank and gurgles loudly from expansion tank area when started - no obvious leaks around water pump and thermostat working fine. Pressure test inconclusive. Could it be the head gasket or is there another likely culprit ? Oil shows no sign of water contamination on visual inspection of dipstick.

Any thoughts welcomed.

[Chris Dance]

You say the pressure test is inconclusive?? In what way? Did the test show any pressure loss at all? Can you see any steam "mist" coming from the top of the radiator? Have you tried a new RAD Cap. Could be a small hole in the radiator at the top. If you run the engine at night under street lamps any steam coolant loss is more visible than in daytime.

You may have done this already.

I had a similar fault on another make of car. The garage changed the head gasket but it did not fix the fault. In the end I removed the RAD myself and took it to a RAD specialist his test showed up the small hole in the top of the RAD.

Hope this may help.

[brizy83]

You say the pressure test is inconclusive?? In what way? Did the test show any pressure loss at all? Can you see any steam "mist" coming from the top of the radiator? Have you tried a new RAD Cap. Could be a small hole in the radiator at the top. If you run the engine at night under street lamps any steam coolant loss is more visible than in daytime.

You may have done this already.

I had a similar fault on another make of car. The garage changed the head gasket but it did not fix the fault. In the end I removed the RAD myself and took it to a RAD specialist his test showed up the small hole in the top of the RAD.

Hope this may help.

Thanks - will try steam test but haven't noticed anything. Local garage did pressure test and said VERY small fluctuation but nothing major

[gazza1286]

Is the temp needle indicating overheating? Losing water through the expansion tank? Do you mean that the coolant in the system is expanding such that the amount in the expansion tank leaks out through the overflow?

Had a similar problem. After the journey, feel the lower hose (bottom radiator to engine block) If it feels 'flatish' suggesting a vacuum in the system then all you need is a new radiator pressure cap.

[brizy83]

Is the temp needle indicating overheating? Losing water through the expansion tank? Do you mean that the coolant in the system is expanding such that the amount in the expansion tank leaks out through the overflow?

Had a similar problem. After the journey, feel the lower hose (bottom radiator to engine block) If it feels 'flatish' suggesting a vacuum in the system then all you need is a new radiator pressure cap.

It did overheat a few days ago. Rose almost to red zone then dropped quickly. Top hose feels hot when idled up to temperature but bottom hose cold and warm air from heater. Getting gurrging noises on start up and revving. Also idle speed seems to have risen a bit.

[welshandy]

Is the temp needle indicating overheating? Losing water through the expansion tank? Do you mean that the coolant in the system is expanding such that the amount in the expansion tank leaks out through the overflow?

Had a similar problem. After the journey, feel the lower hose (bottom radiator to engine block) If it feels 'flatish' suggesting a vacuum in the system then all you need is a new radiator pressure cap.

It did overheat a few days ago. Rose almost to red zone then dropped quickly. Top hose feels hot when idled up to temperature but bottom hose cold and warm air from heater. Getting gurrging noises on start up and revving. Also idle speed seems to have risen a bit.

Hi,

My 94 3L v6 Camry does the same normally after about 45-50 miles(did it last saturday taking family to seven valley railway santa special,ok till got stuck behind flogas lorry going up clee hill suprising as outside temp was just above freezing!) heater blows cold and temp sender goes into red,coolant overflowing from resivoir tank.I think mine maybe rad cap(this along with radiator was replaced by previous owner as it was happening to him) I have had new water pump,resivoir tank(small hole in that) and cooling fan ecu(hydrualic cooling fan not running). have mine running with cooling fan bypassed to run all the time which seems to work until new cap comes in post. will let you know if this cures it.

[Beagh1958]

To brizy83, A pint of water per journey is a lot. I'd have another pressure test carried out making sure large piece of cardboard placed underneath engine, to show signs of any posssible drips,rad, w/pump,pipes etc. Another thing is, what happens if you start vehicle from cold do not allow it to warm up & remove rad cap straight away, are you getting a blast of pressure from exsp tank - possible head gasket problem which can be caused by faulty thermostat. Also hot/cold pipes denotes lack of circulation- Thermostat sticking in closed position. To carry out check for H/Gasket problem you really need to have a combustion leakage test carried out, any good garage will be able to do this, tube placed onto exsp tank & special fluid poured in if colour ghanges very high chance of combustion leakage into cooling system showing possible head gasket problem. Another easy thing to do before getting to complicated is remove thermostat, make sure you bleed system of all air & see if you still have same symptoms. Good Luck.

[welshandy]

Fitted new rad cap(genuine Toyota) totally different to one fitted by previous owner. Coolant now rises and falls in resivoir tank as engine temp alters and doesn't go above Max line. Before resivoir tank level would stay at min until pressure built up and then forced into tank and out of overflow under pressure. cured i think :D

[M Rogers]

My avensis is using a gallon of water a day 

it is not leaking, but overheating from expansion tank! 

[Heidfirst]

Hi Malcolm, welcome to TOC 

A few details would help people to help you e.g. what engine, what mileage, when last serviced ...

Possible head gasket problem?