Lamont Clemons

2008 gl 320 heat at vents but not hot just warm turn it up it’s cold replace thermostat aux water pumps ran water thru heater core

dhurley

Are you sure the engine has heated up enough to provide heat? The diesel take about 10-15 minutes to heat up. The GL has two heater sources. An electric unit that provides heat when the diesel engine is cold and the regular heater core. The electric core is barely adequate in cold weather.

Lamont Clemons

I ran over a hour with cap off, getting the air out,, I Replaced one Aux water pump, do green antifreeze make a difference

dhurley

First you need to confirm that the Aux water pump is working after replacement. Also need to let the engine run with the cap on so it can build pressure and work out the bubbles. Just keep an eye on the temp.

If its anything like a W209, the engine must reach operating temperature for the thermostat to open and the heater core pump to circulate fluid.
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Green antifreeze should not be ran in the OM642 because of the various types of dissimilar metals within the engine (Aluminum block/heads, brass/bronze sensors, steel water pump impeller, etc..). When exposed to electrolysis, not having the right amount corrosion inhibiters can cause the surfaces of those metals to pit and corrode over time.

The spec antifreeze for it is MB 325.0 aka Blue G48 or Yellow G-05. Both are relatively plentiful at a local NAPA and cheap.

DennisG01

FYI, using green AF wouldn't affect the heat output, though.

What does the engine temp get up to? You can check this in the dash display.