Temperature keeps rising and dropping

**clueless** · 22nd March 2019, 00:08

Hi,

Have an issue with my Vectra C 1.8vvt petrol

Both of the temperature gauges (the dash and the hidden one) drop and then rise at the same time when I am driving on the motorway

It gets up to temperature and starts off at around 90 then drops to 85 then rises back up I am getting hot air from the vents the stat seems to open at the correct temperature (have tested this by feeling the hose to the top of the rad as the car gets up to temperature)

No fault codes and no other issues

Any ideas what it could be ?

Thanks in advance

**nikroc** · 22nd March 2019, 08:10

Personaly I would change the stat and flush the system out a few times...

**fatfred** · 22nd March 2019, 08:11

**clueless** · 22nd March 2019, 08:46

Thanks for the replies

does anyone know what make is the Original manufacturers

i don’t want to end up in the same mess again

thanks

**beavor-bob** · 22nd March 2019, 09:14

Get a genuine Vaux stat, is my advice, avoid what Euro car parts sell, like the plague. Note, the housing cracks very easily, so probably a good idea the replace the housing as well.
Here is one example:
https://www.ebay.co.uk/itm/Vauxhall-...EAAOSw9idaAYOB

**northpole** · 22nd March 2019, 10:03

as above get genuine housing and stat... my 2.0 DTI did the same but the problem was the waterpump was on it's way out... i did replace both with genuine items of ebay although ECP had good prices a little search let me to get genuine parts, all sorted but i noticed if i do short trips the gauge plays about but engine temps are steady when checked with the OBD2 connection ps i have no airlocks or anything like that.

**clueless** · 22nd March 2019, 11:13

I can only hope that the pump is ok as it was changed last year .. :-(

**beavor-bob** · 22nd March 2019, 11:28

Originally Posted by clueless

I can only hope that the pump is ok as it was changed last year .. :-(

With a good quality pump, or a "Cheapo" ? There are a lot of Rubbish pattern parts about for Vaux. I had a duff coil pack, that was an "ebay special" for about £35, lasted a year! A secondhand one, but Genuine - still going strong after 2 years!

**AS86** · 22nd March 2019, 17:15

Could just be an issue with the temperature sender as well. And thats the cheapest option to swap.

If you do change just the stat watch the housing doesn't crack when you bolt it back together, they are v.weak when old.

**clueless** · 22nd March 2019, 18:42

I was thinking the temp sender, but would both the one on the dash and the hidden menu one dip at the same time are they from the same device or do they interact in some way ?