Diagnosis Confirmation Please?

[MBDublin]

Car W211 E Class 220 CDI 2002 Mileage 83,000

The following are the symptoms:

Recent drop in fuel economy together with erratic readings such as morning run into town 8-10 miles 31 MPG, afternoon reading for the same run 37-39 MPG

Yesterday, pretty cold day, engine slow to respond and prone to chugging for first 5 minutes of the journey

Erratic cabin temperature

unable to get a temp reading of more than 60° after a 25-30 minute run today + I had it running at 2,000 RPM for 4-5 minutes in the driveway when I got home. Arrival home temp - 50° got it up to 60° running at high revs in the driveway.

My conclusion - thermostat is gone.

Would be grateful for some 2nd opinions and or other possibilities.

Many thanks

MBD

 

[davidjpowell]

Thermostat would be my guess too. MB makes them out of chocolate.

 

[daveenty]

For the cost of a thermostat I'd certainly go that way first.

Your temperatures are definitely too low.

 

[jazzyglobe]

+1 for thermostat

 

[MBDublin]

Thanks for the confirmations guys.

I tried Euro car parts - they don't seem to stock the part. We have a Mister Auto here in Dublin

Thermostat, coolant for your MERCEDES-BENZ E-CLASS (W211) E 220 CDI (150Hp)

They are showing 3 available parts:

The 1st doesn't have what I assume is a temp sender or O ring priced at almost €40.00.

The second seems to have all I need priced at €46

The 3rd seems rather expensive for what looks like the exact same part coming in at over €113.

Based on the "MB makes them out of chocolate" comment - my initial thought would be to go with the 2nd part listed branded "Vernet".

Views / thoughts?

Thanks again

 

[jazzyglobe]

I would replace with a genuine merc part. i replaced mine 2 years ago with no issues

 

[grober]

Vernet are French as you might expect as are VALEO - Vernet claim all their stuff is made in France if that's any comfort.

 

[MBDublin]

I sent an email to my local stealership to check on price and availability of a genuine replacement.

Although only 83,000 genuine easy miles on the clock, the car is 12 years old, I'm the 2nd owner so using quality non MB parts doesn't cause me any sleepless nights.

As I said my initial thoughts are to go with the Vernet, but we'll see what price the genuine article is. I also have to consider how quickly I can get the part - I have some time off this week to replace the unit.

 

[MBDublin]

Thermostat Update

As can often happen "life" got in the way of my thermostat repairs until today.

A couple of things for anyone reading this now or in the future.

1. Genuine Vs Spurious - I had a Vernet Calorstat sent in from the UK at a total cost of €48. Prior to fitting the new unit I was able to compare the MB genuine thermostat & the Vernet side by side. The genuine part was, in this case, manufactured by a company call Behr in Germany. Have a look on line available from €29 to €45. Wahler is another German manufacturer I came across does a lot of the BMW as well as Mercedes thermostats.

2. Removal & refitting - Technical difficulty 1 (simple) Awkward Difficulty 5 (medium), a couple of brackets, front & to the side, to remove (E10 Torx).
Remove the two hoses from the thermostat housing - one from the rad and the other from the expansion bottle. I had a 1 litre jar on stand-by and used it to collect the coolant that escaped from the rad hose. I bought a 10mm and a 40mm jubilee clip just in case either of these broke, seized or whatever during the removal process - as it turned out neither were required.
The back bottom bolt & the Top bolt are a bit fiddly & awkward to get to. If you have a 3/8 or 1/4 drive with a knuckle joint it will make life considerably easier. I actually removed and replaced the front Torx bolt using a ring spanner as it was far handier. The temp sender cable clips into a small female plug on the thermostat. I disconnected after I had all the bolts out and could move the unit a little to make getting to the plug a little easier.
With all the bolts removed and the cable disconnected and hoses removed and pushed out of the way a gentle tap of a hammer against a piece of timber sitting at the side of the thermostat housing will break the seal.
There are two braided hoses that run very close to the unit i I found pulling these forward allowed me to get the thermostat past the hoses & oil filter.

3. I'm a great believer in removing / disturbing as little as possible so took nothing other than the above off.

4 . I gave the face of the block where the thermostat sits a quick clean with a stanley blade and some 400 sandpaper then cleaned it all up.

The seal on the new unit sits in a groove in the housing. Its a snug fit so shouldn't move but to be sure I pulled out the seal ran a small bead of vaseline into the groove and then bedded the seal back into the groove. You really don't want to discover the seal has popped out having struggled to get it back into place.

Replacement, as they say, is a reversal of the removal process. The two mounting bracket holes on the new stat probably won't be tapped. Don't worry - simply treat them as if they were, the bolts will cut their own new thread.

So top up the coolant, replace engine cover and start it up. ran it for 5 - 10 mins just to check for leaks and to check coolant level. Then took it for a run.

On turn on and having run it for 5 mins the gauge showed zero movement. Nothing, Nada. I rechecked the sender cable and connection to the stat all seemed fine.

Took it for a run and within a couple of miles gauge was showing about 50° then 60 and all the way up to between 80 and 90.

I've only put 10 or 15 miles on the car with the new stat in place but already I notice that the hesitation on kick-down is gone, cabin temp is much steadier and the exhaust appears to be running cleaner.

So if your temp is only getting to 40 or 50° like mine - change the stat. €40- €50 very well spent.

 

[Dee James]

Thanks for the detailed update, a few tips in there for me when i do my ML

 

[MBDublin]

Thanks for the detailed update, a few tips in there for me when i do my ML

I know I've benefited hugely from the info, tips and guides contained within the forum.

Happy that I can perhaps give something back. It's a bit like paying it forward.