1.9tdi thermostat replacement

[Adman]

Since I've had my car the temp gauge has never got above 70 deg. I changed the CTS hoping that was the problem but to no avail. Pretty sure its the thermostat after reading this...

Thermostat, water pump or sender unit (http://www.vwaudiforum.co.uk/forum/showthread.php?110404-Thermostat-water-pump-or-sender-unit)

I'm gonna have a go myself, just wanted to confirm location of thermostat on a 1.9tdi 130? I presume its take the radiator hose off to drain? Also how much coolant should i expect to replace and at what ratio.. 50%?

I normally use genuine parts no matter what but would a cheapy ebay one do the trick? trying to save money as skint at the mo.

Thanks in advance

Ad

[Doctle Odd]

Thermostat isn't expensive mate. There's a drainage tap at the bottom of the radiator you can drain a lot of the coolant there and most of the remainder at the oil cooler. There's 2 hex bolts holds the thermostat cover in place take them out, you can leave the hose on if you wish and move the cover away from the engine. Take out the old thermostat (note which way it goes) and put in the new one and the new seal, don't over tighten the bolts. Make sure all pipes are on properly and the drainage tap is closed then add coolant (G12) don't dilute it. Coolant should be changed every few years anyway. Take you less than an hour

[Col]

Just to add, the thermostat is locked into the plastic flange section.

To remove it twist then gently pull. It is easy to break the plastic retaining tabs in the flange housing.

The flange is tucked up behind the alternator and the two bolts are either 5mm allen (hex) or 10mm normal bolts heads so either should fit. You do not need to remove the alternator.

[Adman]

Thanks guys, much appreciated. Does genuine or not make much difference?

[pdlh]

Sorry to high jack the thread, I'm also experiencing the temperature gauge not going above 70 degrees on a 1.9tdi, I've had the car 8 years and I'm sure it used to go to 90 degrees on most good runs, but now I only see 70 degrees, I'd put it down to the cold outside temperature and having the heating on 26 degrees, but seeing this post, it's now got me thinking, could the engine not running at it's normal 90 degrees, also reduce fuel economy? I'm struggling to return the MPG I used to get?

Paul

[Doctle Odd]

Yes if the ecu thinks the car is at a lower temperature it will use a different map with different settings and parameters so it will effect fuel economy

[Adman]

Sorry to high jack the thread, I'm also experiencing the temperature gauge not going above 70 degrees on a 1.9tdi, I've had the car 8 years and I'm sure it used to go to 90 degrees on most good runs, but now I only see 70 degrees, I'd put it down to the cold outside temperature and having the heating on 26 degrees, but seeing this post, it's now got me thinking, could the engine not running at it's normal 90 degrees, also reduce fuel economy? I'm struggling to return the MPG I used to get?

Paul
Fuel economy will be downs the car is constantly over fuelling to get up to temperature. it should get up to 90 and sit there in all but extreme cold temperatures

[Col]

It is good practice, whilst the system is drained down to replace BOTH the temp sender and the thermostat, as they BOTH fail.

Saves you buying antifreeze twice.

[Alfonzo]

Guys, is there a 'diagnostic procedure' for determining whether its the temp sender or thermostat (or both) that's failed? E.g. Using VCDS?

[Doctle Odd]

VCDS scan will tell you if the CTS has a fault

[Alfonzo]

I'm assuming it can tell if the CTS is dead, but does it know if it's giving out inaccurate readings?

[arman123]

If cts is failing you would get an erratic temp gauge going up and down. If it does not go to 90 and stays at 70 or around then its your stat is stuck open over cooling car poor mpg both parts are not that expensive i would change both when changing the stat. On the plastic housing that the stat locks into make sure the two tabs are not broken if they are change the housing fairly cheap part to replace always buy genuine parts.

[Alfonzo]

Cheers. My car has a gauge which seems to flucuate between 70 & 90, bur rarely sits at 90 for any length of time. Is there a 'how to' guide on replacing the stat & CTS? I'm thinking I'll replace the CTS firstly and see what occurs, but maybe I should just do them both and be done with it..

[Col]

Cheers. My car has a gauge which seems to flucuate between 70 & 90, bur rarely sits at 90 for any length of time. Is there a 'how to' guide on replacing the stat & CTS? I'm thinking I'll replace the CTS firstly and see what occurs, but maybe I should just do them both and be done with it..

Do them both at the same time otherwise you will be buying antifreeze twice

[Adman]

Ok, failed at the first hurdle!! I couldn't drain the flippin coolant. I turned the drain plug through 90 deg with the cap off the expansion tank and nothing coming out. Tried it a few times, even tried compressing one of the hoses with the cap on and still nothing?!
Am i missing something here, i've never done it before but it can't be that difficult can it? I was thinking of just removing the thermostat and letting drain out that way but id like to replace as much coolant as possible. Any help appreciated.

[Doctle Odd]

Turn it a bit more whilst gently pulling it out from it's housing