Losing Coolant

[colimar99]

I have a 1998 Avensis GS. About 3 months ago I noticed that I was losing coolant but there is no obvious leak. With the colder weather over the past 2 months I have the following problems:

a) The car never gets up to running temperature with the temperature gauge never rising above half way from zero to running temperature on long motorway runs. When travelling in built up areas it rises to about 80%. The heater is fine and warms the car up quickly.

b ) There is no trace of water in the oil.

c) The car never gets below 1400 rpm even after a 70 mile run.

d) There is no problem with the performance of the car.

e) Fuel consumption is not affected.

I fear that it is the start of a blown head gasket but there is no sign or symptom of this. I would be grateful for any ideas.

[gazza1286]

That model was prone to coolant loss from the water pump. As the pulley wheel bearing wears coolant leaks from a check hole which is only visible from underneath. It's right next to and in line with the spindle shaft.

It also sounds like the stat is permanently open given the symptoms you've described.

[Konrad C]

I have the same car/engine and had the very same issue. I agree with Gary and had changed the water pump a few years ago, so that was sorted.

Then the car had a another mysterious leak, similar yours last year. The coolant level kept dropping but there was no visible sign of leaks. I changed my coolant and it was getting worse after that.

Eventually I did get a drip and it was a hairline crack in the plastic part of the radiator.

Within a few of hours of discovering the cause of the problem, I had fitted a new radiator and no more leaks.

Like you, I did look at other parts of the cooling system but found nothing.

Since the radiator replacement, the level has been just above the MAX mark with no top up needed.

Konrad

[avensis rob]

changed my rad about a month ago at 93k miles

the header tanks crimps were showing pink crust so thought id change it before I got stuck

I also had to clean up the hose outlets from the engine and the radiator hoses as these were building due to the not so efficient spring clips.

had a time bleeding system to the heater

had to drive round the block using all g force angles

top up repeat

to get the coolant upto the heater matrix

[colimar99]

Thank you all for your help. I think I have found a pinhole leak from the radiator. I have had trouble free motoring for 11 years from it and the cost of repairs is greater than the value of the car.

[Konrad C]

It's very sad because you could get a salvage radiator for £10-£20.

I bought a new radiator as the car is in constant use and I changed the radiator myself.

At least with a pinhole repair should not be too difficult. Good coolant helps keep corrosion at bay.