C350 thermostat replacement.

[KingMaz]

Tried replacing the thermostat on my W204 C350 CDI today. Got as far as the last bolt but couldn't figure how to get it out. I managed to get it loosened but can't remove it due to the pipework. Seems to be a load of videos online of people replacing thermostats but none for this model. Any ideas?

Thanks

 

[allybassman]

Looking at that, I'd be inclined to remove the fuel filter or disconnect the fuel send and recieve pipes to it to give you better access.

I am no mechanic, i'm just giving an opinion!

 

[LostKiwi]

Will the pipework not flex out the way a little?

 

[KingMaz]

@allybassman I was thinking about doing that but wasn't sure if this was the right way/ the only way to do it...

@LostKiwi I've tried, no matter which way you try flex the pipes and there always something in the way.

Thanks for the suggestions though

 

[Oldspanners]

Here's how they do it in Germany.

 

[KingMaz]

This is the video I watched to help me but "conviently" skips out the part to show how he got it out. I also think he's working on a slightly different model, pre 09?, as some of the compents are in slightly different places.

 

[Oldspanners]

This is the video I watched to help me but "conviently" skips out the part to show how he got it out. I also think he's working on a slightly different model, pre 09?, as some of the compents are in slightly different places.

Here is the WIS document https://mbwis.net/en/doc/7027798 if I have the correct engine 642.830
In para 9 it states,
The fuel line (8) must be pushed slightly to the side to pass the bolt (9) by at the fuel line (8).
The fuel line (8) must not be bent. It will be damaged otherwise.
It also shows a second bolt 5 to be removed on the other end of the fuel pipe perhaps that will allow enough flex?
If that's of any help.

 

[KingMaz]

@Oldspanners thanks for your help.

It does look like the right engine and I and did try what it suggests, just seemed like I had to force it far too much too get it out potentially damaging some of the pipework. It's a puzzler!

 

[Oldspanners]

@Oldspanners thanks for your help.

It does look like the right engine and I and did try what it suggests, just seemed like I had to force it far too much too get it out potentially damaging some of the pipework. It's a puzzler!

Did you manage to take the second bolt (5) off the fuel line on the lhs of the engine (rhs as you look at it) as that may allow more movement.

 

[onefortheroad]

A flexi 3/8 th socket rod would do nicely here i think.

https://m.ebay.co.uk/itm/1-4-3-8-1-...0f7bffdcf426&_mwBanner=1&_rdt=1&ul_noapp=true

 

[Oldspanners]

A flexi 3/8 th socket rod would do nicely here i think.

https://m.ebay.co.uk/itm/1-4-3-8-1-2-Drive-FLEXIBLE-SOCKET-EXTENSION-BAR-TOOLS-Length-Flexi-/382416381669?ul_ref=https://rover.ebay.com/rover/1/710-53481-19255-0/1?ff3=4&pub=5574631662&toolid=10001&campid=5338243305&customid=e5c014c95fea6e7fe623ebae4be5b595&mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fitm%2F1-4-3-8-1-2-Drive-FLEXIBLE-SOCKET-EXTENSION-BAR-TOOLS-Length-Flexi-%2F382416381669%3Fvar%3D&srcrot=710-53481-19255-0&rvr_id=2019375149959&rvr_ts=8afd4fdb16b0ad78a3700f7bffdcf426&_mwBanner=1&_rdt=1&ul_noapp=true

I don't think loosening it is the problem it's to get clearance to get it out as its about 8cm long.
See video at 10:40.

 

[DaveE320CDI]

Did you manage to take the second bolt (5) off the fuel line on the lhs of the engine (rhs as you look at it) as that may allow more movement.

As above that should work!

 

[Dean Fletcher]

Tried replacing the thermostat on my W204 C350 CDI today. Got as far as the last bolt but couldn't figure how to get it out. I managed to get it loosened but can't remove it due to the pipework. Seems to be a load of videos online of people replacing thermostats but none for this model. Any ideas?

Thanks View attachment 50949
View attachment 50948

Can I ask why your replacing the thermostat. There's a possibility mines on the blink also

 

[LostKiwi]

I don't think loosening it is the problem it's to get clearance to get it out as its about 8cm long.
See video at 10:40.

You can often leave the bolt in the housing and remove with the housing once the bolt is clear of the threads if space is tight.

 

[KingMaz]

@Dean Fletcher thermostat needs replacing as it is stuck open, car will not hear above 60 degrees should be 92 degrees.

@onefortheroad as @Oldspanners says, I can loosen then bolt just fine. It's the length of the bolt is the issue.

@Oldspanners yes I tried that aswell, one of the photos I've attached shows the bolt removed. I could probably try force it abit further but I was already putting quite abit of bend on it to try get it out. Had a feeling anymore would cause some damage. It's just a pain because the other two bolts are like 3cm!

 

[m17ull]

Hello

I’m new to this forum and I stumbled across this post last week as I was changing my thermostat.

I managed the change it wasn’t actually that difficult. The problem is the 3rd bolt hidden beneath its very long and won’t just come out.

What you need to do is remove the silver intercooler pipe on the right hand side, once that is off you can slightly move the fuel line and get the bolt fully out.

If you get stuck let me know

 

[allybassman]

Old thread revival! I am currently changing mine out, and I am stuck on the long bolt and getting it out without damaging anything..... All hints and tips appreciated. I was able to loosen off two bolts that hold the metal fuel line in place, but still it will not give me enough clearance to get the bolt out. Maybe I am not being forceful enough? I'm considering taking the fuel line off to give me more space to slip the bolt out.

 

[onefortheroad]

Old thread revival! I am currently changing mine out, and I am stuck on the long bolt and getting it out without damaging anything..... All hints and tips appreciated. I was able to loosen off two bolts that hold the metal fuel line in place, but still it will not give me enough clearance to get the bolt out. Maybe I am not being forceful enough? I'm considering taking the fuel line off to give me more space to slip the bolt out.

Looking at the photo . It seems the only obvious thing to do.

 

[allybassman]

Just to loop back - I can confirm that the easiest thing to do to get that ridiculously long bolt out is to:

- Loosen the two bracket bolts holding the metal fuel lines in place to give you wiggle room

- Disconnect the larger of the two fuel lines connected to the filter (the one on the right if you're looking down at the engine from the front of the car. I found it easier to disconnect it from the filter side as the clic clamp connected to the metal fuel line is tricky to get to.

This gave me enough wiggle room to get the bolt out.

If you get this far, getting the bolt in and tightened is MUCH easier after replacing the stat.

Took the opportunity to replace the fuel filter and clic clamps, Orange turbo seal, black and green intercooler seals and air filters while it was all apart.... phew.

 

[Malcolm Johnson]

Last year attempted to replace my the thermostat on the S, basically same engine i think !!. struggled with the same bolt. Bendy extension pinged off the ratchet and broke the return fuel coupling. buggered...My local indie got me another return pipe which has the six return couplings. I fitted it. The original return fuel pipe sits under the big Alloy tube. Didn't do that on that side of the V6, just got everything working again.

Fortunately my mobile mechanic was coming down to change brake fluid and coolant on both cars.
I added on thermostat replacement on the S. I explained my tail of woe. To get around access he removed the aluminium bar/tubing completely, rerouted the return fuel pipes on that side that side as they should be under the alloy bar. One thing i would add was that did not buy the housing just the thermostat.