I got the P0128 error last night. I noticed over the past several weeks my car has been running a little cooler than normal. My new thermostat (Wahler 483 4100D) will be delivered tomorrow. I found a few DIY videos etc, I just cannot find the required torque settings for the two torx bolts. Anyone know? I'll be installing it this weekend on my 2007 E350, any pointers? Thanks!

 

25Nm

 

^thanks!

 

My new T-state showed up yesterday, but it is too darn cold here to do the work, and my garage is not heated.

I might give in and take it to a local, but I hate having to do that.

 

Got it changed.


2 1/2 hours in a cold garage.


About 1/2 hour was because it was the 1st time under the hood of this car.
About 1/2 hour was finding the right tool with my garage a mess.
About 1/2 hour was waiting for it to warm up to double check everything at 33 deg.


Next time on a warm day on the drive way will be a 1 to 1 1/2 hour job.

 

^Doing my T-stat tomorrow morning. Here in Southern California, not too cold. I think with wind-chill factor it may dip into the 70’s. You have any tips for me now that you’re a pro?

 

Watch this Video
You do not have to take the air pump off, but you do have to take out all four screws so you can move it about 1/4 inch.
You will have to remove one end of the short rubber hose on top and bother ends of the rubber hose that comes out the front and goes to the back. Both are easy, but be carful because the air pump housing is plastic and cracks easily. (Don't push against the little fins to get the hose off because they will crack )


If you don't care about loosing fluid you can skip a few things I did.


I pumped out the overflow tank. Then I pulled the top radiator hose and let it drain into a 1 Qt container.
After pulling off the hose I pumped out what collected in the t-state outlet (several times).
This saved about 1/2 gallon of coolant.
When I pulled the T-Stat I lost about 1 Qt of coolant.
So I would have been up to about using the full gallon, if I just let it spill.


I later realized the coolant I had was concentrated so I was over-worried about not having enough for no reason.
Still why dump perfectly good coolant (as long as you use CLEAN containers to capture it)


The sensor wire was hard to get off.
I lifted the lock tab and it would not come off, so I gave the lock tab another nudge and it shot across the garage never to be seen again.
I then nudged the connector off, and it come but not without a small piece of the sensor body (the nib that lock tab grabs, I think) breaking off.
No worry, as the sensor is thrown away with the old T-stat.


When I put the connector on to the new T-Stat sensor, it fit plenty tight, so I am not worried even though I no longer can lock it in place.
If it works loose, I will replace the connector then.


Topped the coolant with the filtered old coolant and about a Qt of the new coolant (properly diluted), and started it up to warm up.


After it got to about 90 deg the T-state opened, the top hose got hot, I closed the overflow tank cap and shut it down.


All looks good.

 

Thanks for the great info! I plan on reusing 100% of the coolant. That is the goal anyway. I’ll drain roughly 2 gallons (via the radiator drain plug) into a very clean drip pan. My goal is to spill much less than the guy in that video. Great tip on the air pump too. I know all too well about those gray lock tabs. When I installed new spark plugs I had to deal with the same style locking tab. The secret is to pull the gray tab out, then push down on it to “de-latch” the tab. At that point the connector comes off fairly easy. I pulled my hair out trying to figure that out.

 

Now you tell me!

 

T-stat install. Fun DIY. My radiator drain plug was black, not red as I thought. A little hard to find. I did lose like two cups worth of coolant. I just added distilled water to get the level where it needs to be. I'll check level one more time tomorrow. With the belly plate off I also took advantage and installed my new fog lamp bulbs.