2007 220CDI correct coolant & Thermostat swap tips.

[Droverunner]

Going to fit a new thermostat (plus aux belt & tensioner) to the 2007 CLK 220CDI tomorrow.

I wondered about the correct coolant. The handbook refers to info sheet 310.1 which I found online and for our engine gives a MB coolant spec of 325.0 or 326.0. Looking up products listed on those sheets (such as Comma Xtreme G48) I see it is a glycol mix and the makers of the antifreeze only advise a 3yr life... but MB give a 15yr life. Odd??

Also re the stat change. Any tips where a couple of litres can be drawn off to save spillage. Looked on the forum for a procedure and several how-to guides mention a short hose on the bottom of the stat than can fall in the undertray as you pull the stat away. But the new stat has no connection underneath for another coolant hose... and I can't see one on the old stat looking at the engine. Also if it just falls away with no clip holding it on surely it can't be a coolant hose?? Puzzled??

Finally does it self bleed when the job's done? There looks to be an elec coolant pump clipped to the front of the expansion tank... or am I mistaken?

 

[Andyn666]

Can't comment on the rest but there should be a tap on the bottom of the radiator where you can bleed some coolant from, it should be at the bottom right as you look at the radiator from the front of the car.

 

[Yugguy]

Is it a 646? Stat change is easy but stick a rag down the hole next to it that leads straight to the bowels of the engine bay as it's very easy to lose a bolt down there.

 

[Droverunner]

Yep a 646... I've already had the long flexy magnet tool out to recover a nearly lost bolt while servicing. It has a lot of nooks and crannys!

 

[Yugguy]

I took the oil filter off too to improve access.

 

[Droverunner]

I've a huge selection of tools so might get away with leaving the filter but I'll know in an hour after late breakfast is finished.

I'll just raise this question again... Finally does it self bleed when the job's done? There looks to be an elec coolant pump clipped to the front of the expansion tank... or am I mistaken?

 

[Yugguy]

It should self bleed yes, according to the various articles I've read. I didn't do a total drain, just the expansion tank and about 1/2 litre loss from the stat itself.

I filled up the tank, then drove. Once the car was at temperature and the stat opened I got the low coolant warning. Got home, left it for half an hour to cool and topped up. Level has stayed static since, and the temp is correct.

 

[Droverunner]

Oh well not too bad a job if a little fiddly. I did take the oil filter out to give more room. I also pumped about 2l of coolant from the header tank first and these was no spillage. Yes it does self bleed.

Haven't taken it for a run yet but just comparing blowing through the two stats when cold the new one let just the tiniest amount past through the poppet valve as it should... but you could blow through the old one freely. So warm up should be loads better.

When I removed the aux belt I was going to check the water pump for smoothness anyway but it was immediately obvious it was wobbly and sounding harsh (no coolant leak yet though) so I'll change that in a few days.

Also my year of 220CDI doesn't have that short connecting hose I've seen mention between stat and block that you might lose down in the engine.... so one less thing to worry about.

Finally something I've seen mentioned on several posts re differing thermostat makes... on my Gates stat the holes for the engine cover and front bracket bolts were not tapped so I did this on the bench before fitting. Used an old spare bolt of the same thread and made a hacksaw cut up the bolt to act as a cutting tool with WD40 as the cutting wash/lubricant... which works fine in alloy.

 

[Lord_Lucan]

Just seen this post today else I'd have said to jack up the front near side and this means you'll not have to remove more than 500ml or so of coolant.

I also removed the oil filter housing when doing mine too and all in all it wasn't too difficult a job so well worth doing.

Enjoy your car getting up to temp better/faster and you should see a few more mpg in the process too.

 

[Droverunner]

Thanks LL that would help bit with the fluid suction pump I have it was easy to get the header tank empty.

As a matter of interest I mentioned in the first post if there was an aux elec coolant pump and there is... you probably all know that. So just with the ign on it self bleeds. I didn't lose any coolant so when I poured back the coolant I knew it was the right amount to bring it to level... the elec pump did that to within a few mm in about a minute.

 

[Yugguy]

Didn't know that, cheers.

 

[Droverunner]

Just had a 15ml test run. Great improvement. Previously I was seeing 75-80deg and now looking at live data from the iCarsoft it reaches temp far more quickly and stays in the range 93-95deg.

An example of speed of warming is... we live in a village where it's only a couple of mins to the A1(M). Previously from cold the car just reached 50deg by the time we reached the southbound slip. Now it gets to 72deg and climbing by that point. It's also stopped the business of dropping down in temp as the load decreases in very gentle driving... once warm stays in the 90+deg range.