Thermostat or something else.

[Dean Fletcher]

This little problem has been around for a while now and obviously not causing the car any harm but I want it sorted. So... Driving to golf this morning roughly 14 mile trip. car gets up to temp in about 11 minutes and sits at 87 degrees and stays there. On the way back however the car get up to around 80 degrees within 6 minutes then drops back down by about 10 degrees then goes up and down. If I give it some beans it goes up to temp and sometimes drops back to 70 or 80 when going down a hill for instance. This problem has been around 18 months. I can remember when it used to get up to temp and stay there and not move regardless.

 

[Wighty]

It’s usually a fairly cheap fix to change the thermostat , they don’t last forever

 

[grahamcol]

It'll be the start as you suspect. I've had exactly the kind of behaviour you mentioned on 2 Mercs in the past and similar behaviour with my newly acquired CLK. In each case a new thermostat has cured the problem, and in the case of the CLK fuel consumption has dropped dramatically.

 

[Dean Fletcher]

It’s usually a fairly cheap fix to change the thermostat , they don’t last forever

Thanks @Wighty and @grahamcol is it a easy job to change it or is it a garage job?

 

[grahamcol]

I'm not sure Dean on your car but usually a stat is quite simple or at least used to be years ago. That said l got my indy to do all three of mine.

 

[Dean Fletcher]

I'm not sure Dean on your car but usually a stat is quite simple or at least used to be years ago. That said l got my indy to do all three of mine.

I'll see if I can find any instructions on the net if not I'll fire it in the garage. Many thanks

 

[grahamcol]

Good luck. It shouldn't cost too much.

 

[Blobcat]

Good luck. It shouldn't cost too much.

Depends if it’s a traditional thermostat or a new all singing and dancing chips with everything one... they are not in any shape or form cheap

 

[grahamcol]

Depends if it’s a traditional thermostat or a new all singing and dancing chips with everything one... they are not in any shape or form cheap

Oh, OK. I bow to your superior knowledge. I was lucky with my cars then!

 

[Dean Fletcher]

Depends if it’s a traditional thermostat or a new all singing and dancing chips with everything one... they are not in any shape or form cheap

Just done a quick search on ECP and CPFL and both come in at around 50 nicka.

 

[malcolm E53 AMG]

As above, usually £100-150ish for the stat mind you I wouldn’t be tempted to buy aftermarket, replaced mine a couple of years ago on the O642 from memory £120ish for the genuine stat, I would replace sooner rather than later before the DPF starts to play up

 

[LostKiwi]

It's nice for once to find a part for the129 that's cheaper than later cars! £15 for the 129....

 

[mioba]

OP, get a genuine one form the dealer and ask for disount.

 

[daibevan]

Or get a Mahrl (I can't spell it) off the bay as its the same one merc use. Its not worth saving a few quid on a non OM thermostat.

 

[LostKiwi]

Or get a Mahrl (I can't spell it) off the bay as its the same one merc use. Its not worth saving a few quid on a non OM thermostat.

Mahle is the brand you're looking for

 

[M80]

Go to a reputable supplier,
I bought a Mahle intentionally from eBay, while it arrived in a chewed Mahle box the stat was unbranded.
The supplier argued but got it back anyway.

 

[Wighty]

Thanks @Wighty and @grahamcol is it a easy job to change it or is it a garage job?

My CLK was easy , 2 bolts and a slight fluid top up . Not sure where yours is on the car ? Buy one from MB would be my top tip

 

[sonic]

My CLK was easy , 2 bolts and a slight fluid top up . Not sure where yours is on the car ? Buy one from MB would be my top tip

Nearly had to do that on my CLK270, it was stuck open & it was winter. But the 212 came along at the right price, so I just part exed it. It had 115K on the clock at the time.