Corsa 1.5 Diesel overheating

[Yorky1]

Hello all,

I've got a 1995 Corsa 1.5 diesel (Isuzu engine) which has done 163,000 miles.The water pump and thermostat have been changed but it's still overheating. I drove about 18 miles in it today and the water temperature gauge almost reached 100 degrees so I pulled over and waited for it to cool down.

I then drove with the cabin heater fan on full which kept the water temperature around 95 degress - still a lot higher than the 90 degrees that it used to run at.

On the way home it almost reached 100 degrees again despite having the heater on full. I pulled over again and allowed it to cool. I started off again and it rose again after a few miles. Then I noticed the cabin heater fan was not quite as hot and the water temperature also dropped - for no apparent reason- to about 92 degrees.

I called my mechanic who said it may be the head gasket and to check the radiator hoses for resistance but they are quite soft and pliable.

The radiator cooling fan does not come on at all but when it was checked by shorting it worked.

Any advice would be appreciated.

 

[jonnyfishing]

I would first check that you don't have an air lock in the system. When you are sure you have no air locks in it and if the temp still continues to rise, have the head gasket checked by a local garage.

 

[jctilingservices]

Hello all,

I've got a 1995 Corsa 1.5 diesel (Isuzu engine) which has done 163,000 miles.The water pump and thermostat have been changed but it's still overheating. I drove about 18 miles in it today and the water temperature gauge almost reached 100 degrees so I pulled over and waited for it to cool down.

I then drove with the cabin heater fan on full which kept the water temperature around 95 degress - still a lot higher than the 90 degrees that it used to run at.

On the way home it almost reached 100 degrees again despite having the heater on full. I pulled over again and allowed it to cool. I started off again and it rose again after a few miles. Then I noticed the cabin heater fan was not quite as hot and the water temperature also dropped - for no apparent reason- to about 92 degrees.

I called my mechanic who said it may be the head gasket and to check the radiator hoses for resistance but they are quite soft and pliable.





The radiator cooling fan does not come on at all but when it was checked by shorting it worked.

Any advice would be appreciated.

If the fan does not come on at all then the engine will overheat, could be the thermal switch at fault

 

[Burnerman]

If the heater and temperature gauge suddenly start to fail, its often a sign of low coolant, so do keep an eye on this.
Your car is quite elderly now, so maybe the main radiator core is getting blocked. However, a head gasket leakage test is a good move even if only to rule it out.
John

 

[Yorky1]

Thanks for all of the replies.

Update: The water level has not dropped overnight so it's not losing any water. Drove the car to the same spot where it overheated yesterday - about 15 miles travelling at 50-60mph approx- and the water temp. barely rose above 90 degrees and the cabin heater air was only luke warm also.

On the way back the water temp. (and cabin heat) rose quite quickly to 95 degrees so I pulled over to feel the radiator. It was mainly cold and only slightly luke warm in places!

When I got home the temp was just above 90 degrees ( urban driving towards the end of journey). I felt the radiator hose and it was firm and the pressure was released when the header tank cap was removed.

It seems to overheat when travelling at speed and not in slow moving traffic.

Do these problems sound like a clogged radiator or the head gasket about to go?

Thanks again.

 

[Burnerman]

The main radiator - assuming the thermostat is open - should be uniformly warm all over, and hot at the top if circulation is as it should be.
I think a rad flush is called for, if only to rule it out!
John

 

[Yorky1]

Thanks for your reply.

I decided to flush the radiator today and followed the Haynes manual instructions: drain the system via the bottom radiator hose and remove the thermostat. ( By the way, the capacity of the car is 6 litres but only 4.5 -5 litres drained out as I didn't know where the cylinder block drain plus was so it wasn't fully drained.)

When drained, I connected the garden hosepipe to the lower radiator hose, as directed, and turned the tap on. The water just backflowed with no water coming out of bottom radiator outlet. I then tried connecting the hosepipe to the top radiator pipe and blocked the expansion tank vent hose and the water ran out of the bottom radiator outlet. The water running out was clear with no sign of rust or deposits.

So the water is not making it through the engine from the lower hose but will flow through the radiator from the top hose. Why might this be?

I saved the coolant and reused it - it took the same amount to refill it so there must have been no deposits removed. It has a self-venting cooling system according to the manual so it didn't need manually bleeding.

I left the car idling for about 20 minutes and the temperature crept up to above 90 degrees. The top rad. hose felt quite hard and then released when the expansion tank cap was removed. Coolant did not overflow but then it wasn't that hot as I hadn't driven it.

Is this a sign that the head gasket may be going?

I know the car is old but it's a Japanese diesel and has only done 163k miles.

Could you offer any more advice?

Thanks again

 

[Peter.N.]

Sounds like thermostat failure, its closed until the engine reaches normal working temperature which is why you can't get the water to flow through the engine, sounds as though yours is not opening at all, or only at very high temperature. They are not expensive or normally difficult to fit.

Peter

 

[Branflake]

Hello, 95 is normal running temperature for a 1.5 TD. It should sit in the middle of the gauge.

Mine will fluctuate between 95 and 97.5 (the next line on the gauge) and has done so since i got. I guess this small change is due to the fact that the gauge only really shows a very small range.

It also says in the Haynes that 95c is normal running temp.

Also check the sender, because they can fail. Its in the thermostat housing on this model.


Hope this helps,

Thanks,
Mat

 

[willisg]

Hi there, i have recently experienced the same thing - a cold rad but temp rising to 100 when on the motorway. The thermostatic valve had seized. this opens when the temp reaches normal running temperaqture, allowing the water to circulate around the engine to keep it cool. When seized, the radiator is in effect not cooling the engine so it will overheat.
It is a quick and pretty cheap repair to effect.
I am now suffering with the thermo switch to the electric fan not working and will check / change that this weekend.
Good luck!