Gen 2 Cooling system Question: DCCV and heater

[rgorke]

2004 LS V8 with 231,000 miles, all plastic cooling system parts have been replaced.

My question is that sitting in traffic, my temp will rise to the low 220s, monitoring through my OBD2 reader. For an experiment, I turned the heater/defrost on to 90 and blowing high. I watched the temperature drop from 223 down to 205 while still sitting in traffic. The temp needle on the gauge never moves (not that I would expect it to).

Is this pointing to a problem somewhere (DCCV?) or is this (heater on) just a function of helping the system expel heat?

Just trying to make sure my car has all its little problems fixed.

Thanks

 

[joegr]

The heater is just a small added radiator as for as the engine is concerned, one that bypasses the thermostat.
It (the lowering of the engine temp) is expected behavior.
Maybe your thermostat is a bit on the high side?

 

[rgorke]

The heater is just a small added radiator as for as the engine is concerned, one that bypasses the thermostat.
It (the lowering of the engine temp) is expected behavior.
Maybe your thermostat is a bit on the high side?

Possibly. It is a Motorcraft. I'll look into replacing it. could there be just a difference in tolerances between thermostats?

thanks,

 

[GreyWisent]

I can tell you from experience that turning the heater on was one of tricks I used to get a one time "cool shot" on my overheating car while transporting it to my garage. I got about a 10F decrease out of it, the first time I use it. This was in 80F ambient, so maybe more now that the weather is cooler.

I would say that the heater core is a 1/4 to 1/3 the size of the radiator (I've held it in my hands) and the cross-sectional area of the inlet and outlet pipes vs radiator is of a similar proportion. It and the pipes leading up to it can also hold quite a bit of standing water when not on, much cooler than what's in the engine. All in all, it should have a cooling effect on the engine. The whole system pressurises together, so I don't think opening up the heater would allow an opportunity for pressure release.

That being said, all I can see is that I too have experienced what you described, but I don't know if my DCCV has problems or not - none that I've experienced yet, anyway.

 

[TooManyToys]

I've been experiencing a weird issue lately with my coolant temps. Both the T/S and DCCV are a few months old as I flipped them for the same issue.

Within a few miles of starting out in the mornings my temp can rise up to 240, and I can tell if I don't have Forscan up on the phone by the cooling fan engagement. No matter the outside temp, if I kick the interior temp all the way up so the HVAC goes into heating mode, the coolant temp will drop, sometimes all the way to 180 as the motor isn't heated up fully. Once that's done, everything is normal and I can reset the interior temp to 72.

No trapped air, two different thermostats. Just weird.

To the OP, during the warmer weather months it's not that abnormal for my vehicle to be in the 220 range, but now in the 205 range. All stock but with an aftermarket radiator which may be a little undersized to OE.