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Astra 1.7 td Isuzu engine overheating problem

Hi I've just replaced the radiator on my girlfriend's new motor- a

1997 Astra 1.7 td. I replaced it because I thought it was running hot. Normal operating temperature seems to be 91 to 94 and it quickly went to 99 if stuck in traffic. After putting a new radiator on there seems to be little change.....

So, does anyone know what the normal temperature is for this car? I've got a Corsa with the straight diesel 1.7 version of this engine and after putting a new rad on that it sticks to 90 degrees and only moves to 91 when driven very hard. The Astra seems to have a greater range (91 to 94) and also takes a trip up towards 100 more readily than the Corsa. Am I correct in saying that even in traffic the temp should be stable unless, it shouldn't need the fan if it's just had a new radiator unless it's a steaming hot day??

The fan is supposed to cut in at 100- this seems very high!!! I haven't let it get that far yet but would like to test it. I've taken out the plug to the thermostatic switch and this has 3 points. I can remember taking a paper clip to a car and just linking 2 points then putting ignition on.... - is this correct procedure with a 3 point one?

I have thought the next thing to look at is the thermostat but in over

20 years of running bangers |'ve never had an overheating problem from a stat it usually not warm enough if it's the stat.

Someone has suggested the pump- possibly one of the impellers has corroded off. Surely one would hear this rattling around??!!!

Thanks for any help and thanks for previous help with the Stag!

Jon

Reply to
jayseeblue
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Thanks, It isn't stuck shut as the rad gets very hot!

Jon

Reply to
jayseeblue

jayseeblue ( snipped-for-privacy@sky.com) gurgled happily, sounding much like they were saying :

Don't automatically believe the numbers on the gauge - the sender and gauge aren't calibrated.

What was the old coolant like when you took the old rad off? Have you considered flushing it out? Is the header tank pressurising OK?

Reply to
Adrian

That sounds about right.

No, if it's stationary it will need the fan unless it's the depths of winter

All of the above assumes the guage is even vaguely accurate, it probably isn't. Buy a thermometer, see if it cuts in.

It's a two speed switch. So you'll need to connect the right two together

Reply to
Duncan Wood

if it isn't boiling over then it is fine. Leave it idling till the fan kicks in, if it boils before the fan comes on then there is a fault.

Reply to
Mrcheerful

Sounds normal to me. Unless you can actually make it boil without the fan coming on, then its fine. 100deg C is actually fairly low for the fan cut in temp- on the latest BMW's they run at 100-104 and the fan comes on only at

110deg C!

Tim..

Reply to
Tim..

From memory, check to see if it has a two speed fan switch. If it does, chances are the resistor for first speed has failed, meaning the fan doesn't cut in until quite a high temp. The resistor is mounted somewhere behind the bumper IIRC.

We used to get endless problems with the GM diesels blowing head gaskets, which eventually got traced to that problem.

Reply to
moray

Thanks for the replies. The old coolant was very murky. I didn't flush it out, but it took 6 litres to fill so must of the old coolant must've come out.The header tank is pressurising. I've had a look in a haynes service manual and it says the fan thermoswitch cuts in at 100 and off at 95 although the book is for the same engine it only goes to

1996 which is a year before the car concerned. I'll have a look in the library about the two speed issue but this maybe difficult to find out. I just can't believe they'd allow the car to get to 100 before cooling as the constant heating and cooling is what's supposed to blow head gaskets isn't it?

Thanks again

Jon

Reply to
jayseeblue

No:-)

Reply to
Duncan Wood

Can confirm it must be a 2 speed as i've just used the paper clip on my corsa and that had two speeds so if it got to 99 without the fan cutting in then the resistor idea sounds like a good one. Thanks a lot for the help!

Jon

Reply to
jayseeblue

Thanks very much guys. It was the resister and the front bumper has to come off. I now have slow speed fan cut in at 96 and full speed at

100.

Jon

Reply to
jayseeblue

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