Vantage not getting up to temp after thermostat replaced

[Wozza]

Hi all,

I recently bought a 2009 Vantage Roadster.

After getting hold of it and a road trip to Wales to bed myself in, I had a small list of jobs for the supplying dealer HWM to take a look at under warranty.

The thermostat and part of the radio were replaced and all seemed good.

However I took the car out for a chilly roof down blat last night and the car still seems to be struggling to get up to temperature and stay there again.

The outside temperature was about 2 - 3 degrees and when I first took the car out and had a gentle initial run the temperature got up to temperature very slowly and then stayed below half way until the car was stationary for a while. When I got going a bit faster the temperature gauge would again drop slightly from the half way point and the heating system was frankly pretty pathetic - a tiny dribble of warm air coming out despite being on max.

This was pretty much the same symptoms I had before the car went in for the thermostat to be replaced.

Anyone have any ideas what it might be and what I can ask them to take a look at next?

Thanks


Marc

[MollyGTi]

Wozza said:

This was pretty much the same symptoms I had before the car went in for the thermostat to be replaced.

Anyone have any ideas what it might be and what I can ask them to take a look at next?

Thanks


Marc

You could try asking the dealer if he can prove his workshop bothered to replace the thermostat. IMHO you need to put the ball firmly back in their court.

BTW - good to know you are using it properly and out there having fun despite the weather

[Quinny]

The thermostat seal is actually a rubber o ring... When it fails the o ring goes a bit soft and gets trapped between the thermostat plate and the spring, thus stopping the stat from fully closing....... If its going to fail this is the best sort of failure as the engine can't overheat....

It's possible that on fitting the new stat and o ring, that the o ring has become unseated, and is trapped again between the spring...
Or
The new thermostat itself is faulty, at the end of the day its just a wax capsual, a bit of metal and a spring, hardly high tech, and something that's remained unchanged for donkys years...

The o ring thing happened on my car, and I was lead to believe that once an updated part had been fitted, it cured the problem.... It didn't happen again on mine...

[Wozza]

Ok thanks for that both - very helpful.

I'll get back in touch with the dealer again and get them to take another look.

[mikey k]

Quinny said:

The thermostat seal is actually a rubber o ring... When it fails the o ring goes a bit soft and gets trapped between the thermostat plate and the spring, thus stopping the stat from fully closing....... If its going to fail this is the best sort of failure as the engine can't overheat....

It's possible that on fitting the new stat and o ring, that the o ring has become unseated, and is trapped again between the spring...
Or
The new thermostat itself is faulty, at the end of the day its just a wax capsual, a bit of metal and a spring, hardly high tech, and something that's remained unchanged for donkys years...

The o ring thing happened on my car, and I was lead to believe that once an updated part had been fitted, it cured the problem.... It didn't happen again on mine...

classic over cooling

[MaverickV12]

MollyGTi said:

You could try asking the dealer if he can prove his workshop bothered to replace the thermostat

I wish my car ran cold (er)

The cooling system is a pretty simple system and as mentioned above has not changed design in donkeys years, aside from the Thermostat there is no where really to look, if it was over heating, then you can look all over the place, but over cooling .....

.... Thermostat ....

[divetheworld]

The thermostat is well explained in the FAQ at the top of the forum if you need it.

[Wozza]

Thanks again.

Reading the FAQ, my temp gauge isn't dropping as far as a quarter though - more like 5 degrees under halfway?

My understanding was that once up to temperature, the gauge should stay rock solid at midway? In 'normal' weather my car does this. When its only a couple of degrees outside, the gauge drops as described above and only stays at midway when stationary for a bit.

This is exactly the trait I noticed in the first place when I asked the dealer to replace the thermostat.

Marc

[Impasse]

Either they've cocked up fitting the new part or it's failed prematurely. Explain your symptoms to them and suggest another thermostat is fitted.
It's not an expensive part even if it's you who end up paying.(unlikely)