2.5TD Overheating or overpressurising?

[TheBoy]

Is the fan on the Intercooler working?
Mine had seized (and blown the 20A fuse in the aux Fuse-box)
As a result when under strain, the engine had to work harder (more hot air needed than cooler) resulting in the temperature rising
As soon as the engine was allowed to work less hard the temp dropped back
Replacement Fan is £100 ish from VX, & rarely seen (if ever) in scrap yards because the Intercooler is hidden behind o/s wheel arch & goes with the remains of th ecar into the crusher
They seize because they are exposed to the elements at the end of the duct on the bumper
This could be your problem also
IW

I think they seize because they are exposed to heavy water (spray etc) through the cooler duct, and the fact that the fan is rarely on.  The way it is set up is that the intercooler fan only comes on with the slow speed rad fans.

I unseized mine and replaced the fuse about 3 weeks ago...

[Omegatoy]

apparently the engine is safe up to 110 degrees!!!!! which is why the full fan power isnt switched on till 105 degrees!!! the new Omega estate goes up to top of the temp gauge and just as i get  really worried and am looking for steam coming outr of the bonnet the fans cut in on full power including the intercooler fan, and it cools down very quickly!! dont like to see it get that high but apparently its designed that way, BUT it doesent chuck water out!! even when the gauge is nudging the red!! maybe it is just the coolant bottle and cap on yours>>
Omegatoy

[TheBoy]

apparently the engine is safe up to 110 degrees!!!!! which is why the full fan power isnt switched on till 105 degrees!!! the new Omega estate goes up to top of the temp gauge and just as i get  really worried and am looking for steam coming outr of the bonnet the fans cut in on full power including the intercooler fan, and it cools down very quickly!! dont like to see it get that high but apparently its designed that way, BUT it doesent chuck water out!! even when the gauge is nudging the red!! maybe it is just the coolant bottle and cap on yours>>
Omegatoy

Tried yet another coolant cap from scrappy, off an astra petrol. This one holds the pressure much, much better.  However, still seeping a bit from cap when hot (96 ish on the gauge). Unless gauge is wrong of course, but won't know until the CTS is fixed.

[Kevin Wood]

I don't suppose the cap is not sealing properly on the top of the expansion tank, is it? Maybe the top of the thread is a bit rough and allowing it to weep. Loss of pressure then causes it to boil?

Kevin

[TheBoy]

I don't suppose the cap is not sealing properly on the top of the expansion tank, is it? Maybe the top of the thread is a bit rough and allowing it to weep. Loss of pressure then causes it to boil?

Kevin

This cap really does seal - If I remove cap in morning to top up, I get a hiss as I undo, despite it being used since evening before...

[Pitchfork]

Is the fan on the Intercooler working?
Mine had seized (and blown the 20A fuse in the aux Fuse-box)
As a result when under strain, the engine had to work harder (more hot air needed than cooler) resulting in the temperature rising
As soon as the engine was allowed to work less hard the temp dropped back
Replacement Fan is £100 ish from VX, & rarely seen (if ever) in scrap yards because the Intercooler is hidden behind o/s wheel arch & goes with the remains of th ecar into the crusher
They seize because they are exposed to the elements at the end of the duct on the bumper
This could be your problem also
IW

I think they seize because they are exposed to heavy water (spray etc) through the cooler duct, and the fact that the fan is rarely on.  The way it is set up is that the intercooler fan only comes on with the slow speed rad fans.

I unseized mine and replaced the fuse about 3 weeks ago...

That's interesting because both of my electic fans (the ones in front of the radiator) were working despite the intercooler being seized & the fuse blown!
Are you sure that they are on the same circuit?
IW

[TheBoy]

Is the fan on the Intercooler working?
Mine had seized (and blown the 20A fuse in the aux Fuse-box)
As a result when under strain, the engine had to work harder (more hot air needed than cooler) resulting in the temperature rising
As soon as the engine was allowed to work less hard the temp dropped back
Replacement Fan is £100 ish from VX, & rarely seen (if ever) in scrap yards because the Intercooler is hidden behind o/s wheel arch & goes with the remains of th ecar into the crusher
They seize because they are exposed to the elements at the end of the duct on the bumper
This could be your problem also
IW

I think they seize because they are exposed to heavy water (spray etc) through the cooler duct, and the fact that the fan is rarely on.  The way it is set up is that the intercooler fan only comes on with the slow speed rad fans.

I unseized mine and replaced the fuse about 3 weeks ago...

That's interesting because both of my electic fans (the ones in front of the radiator) were working despite the intercooler being seized & the fuse blown!
Are you sure that they are on the same circuit?
IW

Not on same circuit, but powered by the same DPST relay.  The intercooler fan is seperately fused.  Try turning intercooler fan by hand to free up, then connect it to a 12v battery for an hour to really free it up...

[Pitchfork]

It was so seized that it took a hammer & copious amounts of WD40 to get it turning once it was off the car
Even now once the WD40 has evaporated, it's extremely stiff & would probably blow the fuse again, hence it was replaced with a new one At just over £100!
I fear that in reality there is little choice in the matter
IW

[wombatcurry]

My "new" 2000 2.5TD cap is marked as 90 467 964.
It's interesting that the new car runs at an indicated 80C climbing occasionally to 85C if I give it some welly. The old car (97 2.5TD) ALWAYS runs between 92 and 95.
I'll check the cap on the old car when I get home on Tuesday.