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Old 03-08-2009, 08:54 PM   #1 (permalink)
Master EcoModder
Join Date: Apr 2008
Location: Michigan
Posts: 259

Bio Deezler (sold) - '03 Volkswagen Jetta GLS TDI
90 day: 50.78 mpg (US)

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TDI Cooling System Upgrades

Hey all.

Spent several hours this weekend addressing a couple specific cooling system upgrades that I've had planned for my VW Jetta TDI.

First up, a Zero-Start coolant heater. I found a 750W unit on ebay for 30 bucks that I couldn't pass up. (kind of wish I had more watts, but oh well). Don't ask me why I've had this heater since Christmas but not installed in until now.
Followed an excellent installation write up found here:

Plumbed it inline from the coolant-oil heat exchanger outlet:

Fairly tight fit in the engine bay. For context:

Unfortunately, the plug I had for the heater wouldnt fit through my grill blocks, so for now I have to plug the heater in this way. I plan to grab one of those Marinco outlets eventually. Yes, I know my garage is messy.

Next up, the thermostat. My scan gauge always showed a 179-181 deg. F opening temp for my O.E. thermostat. Too low for my liking, so I picked up a 195f Stant replacement. Upon removing the OE unit I was surprised to see the following:

87 C = ~ 188 F. So either it was leaking a bit / prematurely opening, or my coolant temp sensor is reading a bit low. In either case, the new 195F Tstat gets my coolant temp up over 190F (per scan gauge). Should help bump up the oil temps also, since they attempt to equalize through the heat exchanger.

I'll report some FE data once my next tank is through. Fortunately I filled up right before starting this work.

After ~2 hours in my 44 degree garage, the coolant temp is up to 92. Meh, not bad I geuss. But I was hoping for a little more impact. Any EE's here? I bought a 240V unit and simply wired it for 120V. Its rated at 3.1 amps draw at 240 V, so I figured it would just draw over a little double that at 120, and produce the same amount of heat, right? Could there be any way that I'm only getting half my watts?

The timer is set for 5am tomorrow, so we'll see how hot she gets before the drive into work.

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