Thermostat advice needed Z18XE

[Saulty]

Hi All,
My 55 plate facelift Veccy 1.8 thermostat needs changing as the tempature is not stable and drops when the heater is going or when out on the open road. I looked into getting it changed but at first was quoted £61 +vat as it is a complete unit! On searching the net, I have found that you have to buy the complete housing. I also found that you can buy just the stat. I have searched a few Vauxhall forums and found no definate answers.
Can anyone tell me if I have to buy the whole unit or can I change just the stat?
thanks.

[Big Sig]

Its easier to change the whole unit but you can just change the stat iirc someone on here has already done that to theirs.

BTW I believe a 55 plate will be a z18xer as its the vvt engine rather than the earlier z18xe - just not sure if the thermostats are the same.

[Ste]

If the engine is not the VVT, you can buy just the stat and you don't need the full housing.

It is simple to remove. Locate it at the front left hand side (when looking in from the bonnet). It is dentifiable by the large water hose going to it, and the temp sensor wire.

There are 3 bolts holding the housing to the block. Undoing these will release the housing (and coolant water too). There is no need to disconnect the main water hose, but do disconnect the temp sensor wire.

Then look inside the housing and you will see the 'stat. Removal is easy, simply twist the retaining plate that goes straight across the centre of the stat and locates into grooves in the housing. Push down gently and turn this plate to release from the grooves.

Then pull the stat out and replace with the new one. Fit the new seal ring to the housing face and refit to the block. Reconnect the sensor wire and refill the coolant with the correct mix.


If you disconnect the coolant temp sensor wire, the cooling fans will run when the ignition is ON.

That's it, 5 minute job.



NOW, if it's the VVT engine, then I can't help.

[Tony W]

Its easier to change the whole unit but you can just change the stat iirc someone on here has already done that to theirs.

BTW I believe a 55 plate will be a z18xer as its the vvt engine rather than the earlier z18xe - just not sure if the thermostats are the same.

Our Facelift 55 reg Vectra C Club Hatch has the Z18XE pre VVT engine and registered at the end of December 2005....

I was under the impression that the thermostat was an integral part of the housing on the Z18XE engine(Haynes Manual )....but not having had any problems with it yet @ 46+k miles will no doubt find out for sure at some future date....

I believe the Z18XER VVT engines became available from around January/February 2006...(for the 06 plate registrations???)..

Cheers..

[Big Sig]

Our Facelift 55 reg Vectra C Club Hatch has the Z18XE pre VVT engine and registered at the end of December 2005.....

That's why I stated "I believe" I did not state it as a fact.

[Das]

Saulty I have ordered a thermostat(not the housing) this week so all well will be doing this next week. I know it should be a simple job but I may take pictures for a how2.
Whilst were on this might as well flush the system and replace the coolant. Does anyone know how many Lt's of Red Antifreeze are required after a full flush?

[Big Sig]

In the 1.8 the whole system is about five and a half litres. So three would be about right.

[Das]

Thank you.

[Big Sig]

Thats ok

[Ste]

As above in my post #3.

The stat is not integral with the housing, and the instruction to change it are noted.

The stat itself is less than a tenner.

Here is an Ebay auction for one.

http://cgi.ebay.co.uk/VECTRA-C-1-6-1...item45f61e05aa

The pic shows the centre retaining plate that fits into the housing grooves. It's at the bottom in the pic, just above the circular end plate