Petrol Smart 450 & Roadster - Bad Thermostat Warning

[tolsen]

Just received an aftermarket thermostat bought on ebay. Price just below £20 with free delivery.

Its internal check valve is fitted wrong way around meaning engine will constantly leak warm coolant to radiator and therefore take forever to get up to operating temperature.



Water runs out as quickly as it runs in. No good for a warm and cosy cabin on cold wintry mornings.

This thermostat has no number or name. Can be distinguished from the original Wahler by the clip that hold temperature sensor in position. Clip on this one looks far eastern in origin, is made from thin 0.7 mm diameter round zinc plated wire and does not clip on securely. Clip on the Wahler is made from heavy duty square zinc plated wire.

Another thermostat to avoid is the Gates TH40390G1 for the diesel 450/451. The gates is just as bad as this one.

[10:45PM]

Clip on this one looks far eastern in origin

[lalli_d1]

buy cheap, buy twice!

[tolsen]

buy cheap, buy twice!

Not necessarily so. I recently bought two original Wahler thermostats for my 450 Cdi for £13 each including delivery.

[lalli_d1]

is that the FULL assembly (housing and all) or just the thermostat as all i can find is the full assembly and that comes in at about £21

and how much is a new one from mercedes as you get a 2 year unlimited mileage warranty with it.

[mac999]

I always tend to buy them from Mercedes as already mentioned all Genuine parts come with a 2 year warranty

[tolsen]

is that the FULL assembly (housing and all) or just the thermostat as all i can find is the full assembly and that comes in at about £21

Kindly advise where your source these for £21.

[lalli_d1]

http://m.bestpartstore.co.uk/1718889

Here you go

[tolsen]

http://m.bestpartstore.co.uk/1718889

Here you go

Add £8 for delivery plus VAT and the total becomes £32.43. Not what I call cheap.

[tolsen]

The problem is more widespread than I had ever thought.

I just received a replacement thermostat. Ordered from Carparts4less this time. Exactly the same poor thermostat as shown in post one was what I got. It is sold by both Eurocarparts and Carparts4less as Circoli 209910030. Photo on their web sites shows a Wahler but regrettably that is not what you get.

Summary of the problems with this thermostat:

1. Check valve fitted in sealing element (the disc) is wrong way around. Purpose of the check valve is to ease bleeding air out of cooling system. Bleeding will become difficult with check valve wrong way around. The main problem with check valve wrong way around is that there will be a constant flow of coolant and heat through check valve to radiator resulting in engine taking a very long time to get up to operating temperature.
2. Clip for holding temperature sensor to thermostat housing is poorly made and does not provide a positive lock like the original Wahler. Could result in sensor popping out and engine overheating with no warning.

Links to this thermostat on Eurocarparts and Carparts4less web sites:

http://www.eurocarparts.com/ecp/c/Sm...06f1b6d&000325

http://www.carparts4less.co.uk/cp4l/...4c8fd30&000325

[lalli_d1]

and we go back to my question of how much is it from mercedes?

[tolsen]

and we go back to my question of how much is it from mercedes?

About £30 with smart discount.

[lalli_d1]

So thats £30 for a thermostat with 2 year warranty... How long is the warranty on your wahler thermostat?

And how often do you change your thermostat? Iv only ever changed 1 on the 3 cars that iv owned

[tolsen]

It is for BETY, a 2002 Smart 450 owned by an OAP.

[10:45PM]

It is for BETY, a 2002 Smart 450 owned by an OAP.

Wait !...You've got two smart's !?!