Z20NET Overheating / Head Gasket?

[ropa83]

I put a post on a while back asking if anyone could help with my Vectra Z20NET overheating.

Basically the car started to overheat when driving quickly, i had the water pump replaced as it sounded like it had gone.

Vauxhall replaced the pump and i thought that this may sort it.

But nope, still overheats very quickly.

Water pump is working as the fluid comes back into the tank via the small hoses. The heater does not work at all.

I've no mayo, smoke or water in the oil. Although it does seem to pressurise the system.
I've replaced the Thermostat, coolant, tried to bleed any air out of the sys. Tried 'Steel Seal' into the coolant mixture.

Anyone ideas of anything else i can try

My options now are:

1) Replace the Z20NET (any ideas how easy?)
2) Have head gasket replaced / skimmed, although not 100% that it's this.
3) Sell car as spares or repair. 04 plate, 74'000 miles, MOT til May next yr and new tyres all round so i'll prob loose a fair bit on it.

At the mo i'm in Volvo V40 so no rush, but any ideas / help would be greatly appreciated!

Im gutted as the car run's quiet and smooth apart from this!!

Thank you

[Das]

Do the radiator fans kick in when it heats up? Have you had a sniff test done on the header tank to check for hydrocarbons and confirming a head gasket failure? You've had the thermostat changed but did you get the sender unit on the stat housing changed?

[Critch]

Defiantly not an air lock in system?
Is the fan kicking in? Sounds daft but is car actually overheating and not just gauge saying it? Ie the thermo sensor could have failed?

Heater matrix is not blocked?

Just some other ideas instead of such drastic thing as selling car

[ropa83]

Just thought i'd add what the problem was so people know if it happens to them...

Turns out it was a broken water pump chain tensioner. Due to this the water pump chain was so slack it kept jumping off the water pump.

Turns out best place for your Vauxhall is not the main dealer as they never spotted this and so NEVER EVER use the Reg Vardy Vauxhall dealers in Horsforth, Leeds. Useless!

I sold the car before it was fixed and this was the fault that the guy who bought it found.

So no longer a Vectra C owner but hopefully this may help a Z20NET owner in the future.

[m8internet]

[QUOTE=ropa83;1691767]Turns out best place for your Vauxhall is not the main dealer as they never spotted this and so NEVER EVER use the Reg Vardy Vauxhall dealers in Horsforth, Leeds/QUOTE]
Did you specifically ask them to swap the water pump or to diagnose and fault find the reason for the overheating?
If you asked them to swap the water pump then that is what they have completed as you requested
However, they should really have noticed and reported during the work
They could then have refitted the working component and effected the correct repair

When I book my cars in I just give them symptoms, no other details (even if I know what the fault is)
If their diagnosis does not match the work I want done I take the car elsewhere

[Caveman_nige]

Good info thanks for letting us know its much appreciated.