I hate cars

Wow, so the heater by itself has a high enough heat capacity to cool the engine in those temps?

gatrhumpy

iTrader: (1)

ZOMGVTEK

Above about 40ºF and the car acts fine. Once it starts to go below freezing is when it starts to be a problem. Generally once or twice a year it breaks into negatives and thats absolutely brutal. I'd imagine it starts to fall off quick below that. Ever see a car start in -40 or -50ºF? It's some questionable stuff.

I'd say about 20ºF or so ambient, and cranking the heat, at least on the Accord, resulted in dramatically lowering the water temps. That car started to dump fuel to try and keep the engine warm, which made for absolutely horrible winter FE. When it was REALLY cold outside, the water valve on the Accord would close in an effort to keep the engine warm. Without a grillblock, the heat barely worked and the coolant temps were in the 150-160's. On cars that run much higher water temps, are way less efficient, and don't have a water valve, you typically don't notice the impact as much, but its still there.

I didn't drive the TL through a winter yet, but the temp gauge hides the coolant temp. Once the engine comes up to temp, it never really moves from there unless it starts getting really hot or really cold. The Accord used to actually show coolant temp and I could watch the needle dip when the thermostat opens at a light.

I hate cars

It sucks our temp guages are buffered but these days it would probably result in unneeded trips to the dealer if the typical owner saw the guage move at all lol.

Dumping fuel will generally lower temps both combustion, EGT, and coolant but it will run rich when very cold to avoid hesitation on acceleration.

I had mine up in Flagstaff and also Minden which had roughly 15F mornings and it took a while for the water to warm up, like 10 minutes of idle. After a while I let it idle for a couple minutes and started driving very easy which cut warmup times in half. I also didn't turn the heater on until the guage began to register.

I felt bad for the car starting it in those temps, -40 is hell on a car. I ran a 0w-20 for the 17F weather, I would run a 0w-10 oil if the car were regularly started in -40 degree weather.

One thing I've noticed is the ULEV cars warm up much quicker as that's a part of the ULEV qualification. Was your Accord ULEV? That might be the difference possibly. My TL once it's warm won't lower the coolant temp much at 17F with the heater going. It will start to go from hot to warm when sitting at a light but it's not too bad. It feels like my GN all the time in the winter which runs a 160 degree thermostat. I'm only guessing but I guess the TL never sees below 160 coolant temps in pretty cold areas, extreme climate excepted of course.

One other thing that I need to look into is the fuel cut on decel. I've confirmed the injectors shut off when going downhill with the car in gear. On the grapevine which is miles and miles of downhill, my GN will get down to ambient with it in gear and foot off the throttle. Thermostat is 160 but since it's not actually running it cools off below the thermostat with the engine acting as an air pump and cooler ambient air being pumped through. The TL never loses a lot of heat on this hill. I'm not sure how they do that unless they randomly cycle the injectors but you can usually hear and feel when it comes out of fuel cut.

ZOMGVTEK

I'm fairly sure the Accord was LEV. The biggest thing that appears to impact how the vehicle drove was the intake temps. On very cold days the intake manifold never really warmed up unless I sat at a light for a long while. The block heater made a BIG difference here, since the intake manifold started off at something like 60-80ºF on cold days, which made a big difference in drivability. If the cars in a garage with no wind, most of the engine bay and metal bits connected to the engine sit around 100ºF. That makes a gigantic difference when you start off with a 'warmish' car, since things like P/S fluid typically warms very slowly, resulting in a stiff steering wheel when cold. The worst case was my typical drive from school. Sitting in a parking lot, covered in snow, right to the onramp and going 60 less than a minute later. The transmission never came up to temp until I slowed down. I presume it was the radiator overcooling since the bottom of the rad was always super cold in wintertime. Until the car sat long enough for the thermostat to stay open for a little bit, it never warmed up.

I don't have very long hills here, but the TL does loose substantial heat from fuel cut, especially when cold. I typically avoid fuel cut and let it idle to a stop until the temp gauge reads about in the middle. Even then, it takes 5-10 minutes longer until the engine bay is warmed up enough to have stable coolant temps. On some longer slopes, I did notice the water temp appears to decrease sharply at first and then simmer right around the temp the thermostat opens at. It does not appear to decrease rapidly once the thermostat is closed. I never saw the TL cycle the injectors back on once fuel cut starts, unless the RPM's fall low enough, or you stab the throttle and the RPM's aren't above something like 1K-1200rpm when you let back off. If I go into a hill at say 1200 RPM, off the throttle, fuel cut typically won't kick on at those RPMs. Yet, as the car starts to accelerate you can see the MPG's go up and then the kick over to fuel cut once the car sees you are accelerating off the throttle. The Ultragauge reads fuel cut as 999MPG, so it's really easy to see when it occurs. Sometimes it's hard to be sure just based on the vehicles feedback. Interestingly enough, even after fuel cut stops, the vehicle uses less fuel than if it was out of gear and just at idle speed. The engine speed is higher, but it is spraying less fuel for a small period of time after fuel cut ends. The Accord didn't do this, but it also had an automatic.

The whole J series might be hyper sensitive to intake temps. It might not even matter that much as to what the actual intake temps are, but rather what the ECU thinks the intake temps are.