Engine coolant not warming. Needle not reaching middle

[CIarkie]

Before i carried out work on my ibiza (before christmas) the coolant would reach the middle which i guess is 90° pretty sharpish nearly before my oil would show a mfa reading (50°). These days however i can drive 20 miles without the needle reaching the middle, the oil will happily show 78° on a normal day the coolant just past the first mark between 0 and half.

Is there reason to be concerned? after all it seems to run fine and temp low is alot better than temp high, just doesnt seem right. The work carried out involved air inlet removed, full service, new vacuum hoses, new coolant sender (large one one coolant hose), and new exhaust sections.

I have searched with nothing special so any views would be great.

 

[crezz]

thermostat

 

[CIarkie]

So that would be the temperature sender i didnt replace then. I think i replaced the sender for the ac, the four wire one.

 

[robreidmotors]

I think you would know about it if the cooling system wasnt operating properly, so probably sendor as above, think there are different ones (yellow/black, and blue/black?) so get the right one.

However, old fashioned test is to check the hoses from the bottom of the engine to radiator etc, make sure they are warm/hot when the engine is running, just to be sure.

 

[chrisgeary]

As Crezz said, this is highly likely to be the thermostat. I've had the same symptoms on a Passat 1.8T and also my Leon 1.8T - replacing the thermostat (which in both cases was opening too early) cured the problem.

 

[CIarkie]

Can anyone just confirm where this is? i havent long replaced a temperature sender in the coolant system, but know there is more than one.

Also thanks for admin for the title correction. coolant not waming indeed!

 

[CIarkie]

Genius. Have changed the thermostat with help from my mechanical friend arge. Has sorted the coolant temperature and its warms as it should. I am seeing much hotter temperatures in the oil which im hoping is a good thing. My usual temp was around 80 but now im seeing 96-98 on 20 mile runs