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.

bungle4by4

water pump/head gasket/blocked rad/failed thermostat/temp sender all jump out. if you can check these yourself odds on you'll find your fault. if not, you need a spanner man.

Yorky1

bungle4by4 wrote: »

water pump/head gasket/blocked rad/failed thermostat/temp sender all jump out. if you can check these yourself odds on you'll find your fault. if not, you need a spanner man.

Thanks.

Water pump replaced - made no difference.
Head Gasket- how should I check this?
Blocked rad - how should I check this?
Thermostat replaced-no difference.
Is the temperature sender the same as the thermostat? If not, how would this cause overheating? Is there a simple way of checking it?

Rolandtheroadie

Blocked radiator would be drive a while then feel top and bottom of rad. Check and see if it's the same temp at the top as it is at the bottom.
With things being changed, could there be an air lock in the system? The drop to 92degrees and blowing cooler could signify this. See if the water levels down any. If yes, top up.
An old (but different) vauxhall I had once had the wire fall off the sender which gave false high temp readings.

bordercars

emulsified oil in the water, water pipes rock solid when run are pretty good signs of head gasket or cracked head. difficulty starting is another due to low compression. if you know a mech and he will lend u, you can screw in a compression tester

Yorky1

scotsman4th wrote: »

Blocked radiator would be drive a while then feel top and bottom of rad. Check and see if it's the same temp at the top as it is at the bottom.
With things being changed, could there be an air lock in the system? The drop to 92degrees and blowing cooler could signify this. See if the water levels down any. If yes, top up.
An old (but different) vauxhall I had once had the wire fall off the sender which gave false high temp readings.

Thanks. Will check temperature of rad. I think the high temp reading is accurate as there is a lot of pressure in the reservoir when hot. The engine also 'smells' warm also which it didn't do in the past.

goldspanners

Yorky1 wrote: »

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

Any advice would be appreciated.

i think this would be the best place to start.
i don't know where it is on the corsa but there should be a temperature switch somewhere usually on the radiator,this controls the fan speed. sometimes disconnecting or shorting out the wires can bring the cooling fan on full speed,so keep hands clear when testing.(oh and don't wear a tie either)

hartcjhart

goldspanners wrote: »

i think this would be the best place to start.
i don't know where it is on the corsa but there should be a temperature switch somewhere usually on the radiator,this controls the fan speed. sometimes disconnecting or shorting out the wires can bring the cooling fan on full speed,so keep hands clear when testing.(oh and don't wear a tie either)

classic 'goldy' classic:rotfl::rotfl::rotfl:

PsiDOC

Radiator is blocked. It's a common problem on the corsas with the Isuzu diesel.
Run the car up to temperature and then feel the rad fins from top to bottom. I can guarantee the bottom will be cool.

Psi

goldspanners

hartcjhart wrote: »

classic 'goldy' classic:rotfl::rotfl::rotfl:

you'd be surprized.


cover all bases.

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.