Anyone know how to thermostat on 2.1L?

Gabe Athouse

New member
Need to swap it out, and I’d like to have an overview before diving in. I can’t find any info on it. Strange, seems like a standard part to be replaced. It’s right on front but under a bunch of delicate wiring and it has like 8 hoses connecTed to it so it’s a bit crazy
 

sailquik

Well-known member
Gabe
Why do you need to change it?
With the variable vane impeller (vacuum controlled I believe) there’s a lot more to the USA spec OM-651 than
a simple change of the thermostat.
I suspect some of the hoses going to/from the thermostat are actually vacuum controls for the water pump.
Roger
 

Gabe Athouse

New member
It was sticking in various positions. Nope, all 5 ports are wet, and there’s a sensor too. Whoever designed it should be shot. It’s a very stupid design in that you have to force it in two directions at a right angle, unless there’s more more removal of parts that I don’t see. In any case its pretty tough to swap out despite being on the front top of engine. I was able to do it but it took a lot of swearing and some blind fastening and high dexterity moves.
Variable vane pump? Is that really true? Wow. I hadn’t considered that. Why would they design that in?

I wonder if a coolant filter would be a worthwhile install.
 

Gabe Athouse

New member
Test run now coolant PID reads 175°-199° And heater is stabilized. Hopefully my engine didn’t overheat. I haven’t been able to source a lot of tech info on this engine. And any I find is usually from other vehicles they used them in.

I will say it’s quite a little power package and paired with that trans it makes for a very versatile drivetrain I can see a lot of smaller cars benefitting from.
 

mikeme

2015 LTV IB: 2015 3500 V6
...Why would they design that in?

....
You have a very well-engineered fuel-stingy powerplant pushing a pretty large and heavy vehicle.

there is a lot of engineering optimization involved, and management of heat flow directly impacts the operating condition of the engine.

The design is complicated because the design goals are challenging.
 

Bobnoxious

GONE FISHING
It was sticking in various positions. Nope, all 5 ports are wet, and there’s a sensor too. Whoever designed it should be shot. It’s a very stupid design in that you have to force it in two directions at a right angle, unless there’s more more removal of parts that I don’t see. In any case its pretty tough to swap out despite being on the front top of engine. I was able to do it but it took a lot of swearing and some blind fastening and high dexterity moves.
Variable vane pump? Is that really true? Wow. I hadn’t considered that. Why would they design that in?

I wonder if a coolant filter would be a worthwhile install.
Water pump made from plastic too.
 

Attachments

Gabe Athouse

New member
Is there a special procedure to burp system after flush?
 

Bobnoxious

GONE FISHING
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Kajtek1

2015 long/tall limo RV 2.1l
I'd love to have a car with this powertrain. A buddy gets over 50 MPG in his E-class with the OM651.
I have black one for sale.
Takes grandma driving to get 50 mpg, but even with me averaging >80 mph between CA left lane huggers, I am still getting 40.
Sorry for sidetracking the main thread, but this is very exiting powertrain and comparing to OM642 engine in sedan, I am getting 30% better mpg on the same trips.

 
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