In reply to Patrick :
I found the frost on the inside was typically due to moisture trapped in the carpets or floor mats due to snowy boots or leaks letting water get inside where it shouldn't be.
In reply to Patrick :
I found the frost on the inside was typically due to moisture trapped in the carpets or floor mats due to snowy boots or leaks letting water get inside where it shouldn't be.
buzzboy said:Pete. (l33t FS) said:And then as soon as you start rolling, the moisture laden air condenses on the windshield, and instantly freezes...
I've never had this problem living in cold snowy areas, both Lake Tahoe and Southern Vermont.
Happens to me all the time. Living by the lake, it's always humid, and the temperatures like to hover around freezing. Just warm enough that the air can hold a lot of moisture and just cold enough that a 20mph wind on the windshield will make it condense out and freeze.
Same thing happens when warm person gets out of hot shower and 10-15 minutes later gets into cold car. Insides of the glass near the driver fog over right away.
Mr_Asa said:What is the BMW that doesn't even show the top 2-3k of the tach until it reaches operating temp?
Until the temp gauge stops saying "low" I keep it under 3k
The E39 M5 has a moving redline based on engine temp. Maybe later ones, too, but I think maybe that was the origin.
I've done a version of my own that'll show a "cold" redline and also one that starts getting lower if the temps get too high, to encourage short shifting.
Pete. (l33t FS) said:buzzboy said:Pete. (l33t FS) said:And then as soon as you start rolling, the moisture laden air condenses on the windshield, and instantly freezes...
I've never had this problem living in cold snowy areas, both Lake Tahoe and Southern Vermont.
Happens to me all the time. Living by the lake, it's always humid, and the temperatures like to hover around freezing. Just warm enough that the air can hold a lot of moisture and just cold enough that a 20mph wind on the windshield will make it condense out and freeze.
Same thing happens when warm person gets out of hot shower and 10-15 minutes later gets into cold car. Insides of the glass near the driver fog over right away.
We used to keep a little pillow made out of chamois material in the car for this. Just wipe it off, it's never thick.
I have been starting and driving cars/trucks with less than a minute warm up in central Minnesota for 43 years. We had -27 degrees with wind chills of -40 this last week. In the early 80s I used a block heater for the V8 engines. I have never had an engine failure or excessive oil consumption as a result. 5,000 mile oil changes, 5w30 in winter, 0w20 on new cars. I just returned from 6 weeks in Florida. Frost warnings. I watched a guy start his car and leave in run for 5 minutes before driving on a 35 degree day. Very amusing and a waste of gas.
If the temperature is around or below freezing, I usually wait for the high idle to drop. Assuming the windows arent iced up. Usually takes around 15-30 seconds maybe.
After starting it probably takes 3 seconds to build ample oil pressure in any car. The way I see it, the 30 seconds I wait gives the pistons and cylinder walls time to heat up and expand with the first few thou ignition cycles. If the cat is happy I assume the explosion part of the engine is too.
Remote start to warm it up for me. My M5 is a bit different as it needs to be warm before it is driven. The cars ecu limits rpm and performance until it is warm. My takeaway from this is warming up a car is a good thing especially if the manufacturer makes you do it.
When it's cold out I warm it up until the windows are clear. Regardless of what it does to the car,if I can't see I ain't driving.
When it's summer it's usually just long enough to get the AC to cool the cabin down
The clear windows thing is common sense, which is lacking in many. I don't think warmup is as critical as it was 40 years ago, engines now seem to be able to last 200K miles almost regardless of care. Personally, when it is below 10 I will warm the engine for a few minutes. Below 20 also but less time. Regardless until warm air comes out of the vents I don't push the gas much.
Who remembers the old air cooled VWs? I loved the John Muir book, start it and don't drive until you have rolled a cigarette and had a few good draws. But he also advocated using a chisel and hammer to remove the flywheel bolt!
In reply to porschenut :
The windshield on a Bug was close to the driver, which made it easier to steer with one hand and scrape the windshield with the other. 
An old credit card was a convenient scraping tool.
I'm no fan of idle warmups when not necessary. A lot of engines warm up pretty slowly at idle, so they spend a lot more time running in a sub-optimal cold state when warming up at idle. Plus, some engines will suffer extra cylinder wall or cam lobe wear from an idle warmup, as some engines don't get enough oil to those parts with cold, thick oil until you bring the revs up a little. So it's generally better to get moving once the engine is running happily, just keep the revs down and don't work it hard while it warms up.
In practice, for cars, I'll typically start it, let the RPM stabilize at whatever high idle the car wants to give, then it's time to go. If it's really cold (like sub-zero) I'll typically give it an extra 30 seconds or so. Then very gently for the first few minutes in extreme cold, and always be gentle (I generally say under 50% throttle and under 50% of redline as an absolute upper limit) until it's good and warm (oil temp is warm, or coolant warm plus a few minutes if there's no oil temp or pressure gauge). Keep in mind that while a transmission will slowly warm up a bit from idling, it's not much in most cars and other parts like differentials and wheel bearings won't warm up at all until you're moving.
In particular, I hate letting the E38 warm up. Idling while cold is probably a bit rough on the timing chain guides oiling-wise, and it also takes forever to warm up without a little load on the engine. Plus, that thing drinks fuel when the engine and trans are cold, so letting it run to warm up only magnifies the cold weather gas mileage penalty (which is significant in that car for shorter trips around town).
In reality, sometimes a bit of idling to get a little heat is necessary in a car, as some conditions mean you need a little heat for the defroster before you can safely start driving. In those cases, it doesn't really matter what's best for the car, you don't have a choice.
Mind you, these days I'm not regularly commuting to work, so I don't have a lot of cold starts after being parked outside for more than a couple of hours. The worst we get in the winter is if we're visiting family or something and one of the cars sits outside overnight while we're there. At home, the cars are coming out of the 55-ish degree garage normally, so they're not really all that cold.
On other equipment, it varies a bit based on usage pattern. For the lawnmower and snowblower, they're going to get cranked up to full RPM and then a decent load put on them pretty much right away once I'm ready to move, so I normally let them idle for 2 - 3 minutes to build some heat, then bring them up to full revs, give it a few seconds, then engage the blades or augers. Then a few more seconds with the slight load, then it's time to put it to work. With equipment like that it's not really possible to give it a lightly loaded warmup, it's pretty much no load or significant load.
For the boat, I normally crank up the engines and bring them right to high idle at 1100 - 1200 RPM. Confirm oil pressure and cooling water flow are good, then start un-doing dock lines. When I'm down to the last remaining lines, bring the engines back to idle, confirm stable idle, drop the last lines and go. It's normally 1 - 2 minutes from start before putting them in gear, but the first few minutes after leaving the dock are always at or just above idle anyway, so they get plenty of time to warm up under a light load (and even turning 900 RPM in gear warms them up faster than sitting at high idle with no load).
I see no harm in giving an engine a minute or 2 when its really cold. (25F or lower). Let the lifters pump up and get oil flowing. Block heaters are great if you want to cut down on that. Modern synthetic oils in theroy should help cold starts and need less warm up time vs conventional oils. Older blends of oil (think pre 1970) and hot air chokes are where warm up time really needed to be followed.
In reply to Gearheadotaku (Forum Supporter) :
So you are aware, at 20F, there's a emissions test. Where the car has to start up and drive away at 15 seconds. The oil is thin enough to move effectively at that temp. And the clearances/materials are designed to deal with that, as well.
I don't see a problem with waiting if you want to, but you really don't have to at that temp.
Keith Tanner said:Iirc my Dodge diesel's manual says not to let it idle to warm up. Start and drive. That thing has a big enough cooling system and thermal mass that it's not going to generate heat for a while anyhow, especially not at idle. Bundle up :)
Being able to pre-heat/cool the interior is the best thing about an EV.
As for washing the walls with fuel, that's a concern with poorly tuned aftermarket ECUs - although I don't know if it's based on actual experience or just theory.
Diesels also don't build heat without load as readily as gassers do, so idling them doesn't do as much for warmup and can actually be detrimental. Sitting at low load (little heat) for extended periods of time can result in unburned fuel washing down the bore. With diesel gensets they call this "wet stacking". I don't know if that term is also used in the automotive world or not.
Winters here are usually mild, so a typical cold start is barely below freezing. With the Matrix or the 5, I start it, get the defroster and defogger going, and scrape the windows. That's enough time to start building cabin heat. I have been doing that for 30+ years and have yet to really wear out an engine.
The carbureted, iron-block pickup takes longer to warm up, but even it can be driven gently after a minute or two on the fast idle cam.
The pickup has a 727 transmission, and the pump does not work in the Park position. The owner's manual states that the transmission should be shifted to neutral after starting the engine. If it is cold, dropping it directly into gear from Park will result in a few seconds of inactivity while the fluid gets pushed around the transmission. It's just enough time to wonder whether it's broken or just quaintly outdated.
dean1484 said:Remote start to warm it up for me. My M5 is a bit different as it needs to be warm before it is driven. The cars ecu limits rpm and performance until it is warm. My takeaway from this is warming up a car is a good thing especially if the manufacturer makes you do it.
That's BMW telling you not to romp on it until things are warm, not to let it sit at idle. I don't think anyone here is recommending peeling out of your driveway on the rev limiter 5s after a 0F start. But they'll warm up faster if you're actually driving.
Sayeth Keith: As for washing the walls with fuel, that's a concern with poorly tuned aftermarket ECUs - although I don't know if it's based on actual experience or just theory.
We had a Skyactive (direct injection) Mazda6 that had serious fuel dilution issues when it was cold out and the car was driven only a few miles at a time. I checked the oil at a fillup and it was nearly a quart high. Smelled like gas. Oil analysis confirmed it. This is more related to cold weather and short driving distances than whether you warm it up before driving, but it can be a problem on direct injected motors.
Edit: Mazda issued a bulletin on this - SA-026/18
In reply to jwagner (Forum Supporter) :
Interesting, I don't think we've come across that on our Skyactiv Miatas.
I just want my heated seats and steering wheel warm when I jump in. 5 min usually means they are toasty even in single digits. I can wait on the cabin heat.
I just checked the owners manual for my 2019 VW GTI, page 159:
"Do not let your vehicle warm up while standing; instead, start driving right away after making sure that you have good visibility through all windows. This will help the engine reach operating temperature faster and keep down emissions."
The coldest it gets here is in the teens (F) and it's usually dry so visibility through the windows is rarely an issue. So yeah, it's not sexy to do so but I trust the engineers that designed the drivetrain.
Somewhere in the manual it states to not go wide open throttle until the oil temperature has reached 190 degrees. It was surprising to me how long it takes for the car to reach that temperature. When it's 20-40 degrees(F) outside, it may take as long as six miles of driving to hit 190 oil temp. Warmer temps (like 60 and above) will see the 190 mark in maybe 3-4 miles, the lower numbers coming from higher ambient temps.
This is also the first vehicle I've ever owned that specifies a "0W" viscosity (0W-20). In the ~30 degree low temps we see, that stuff flows so freely that I have no concern about starting and driving the car as directed in the manual.
Gone are the days of my youth in the Great Lakes region where we'd put a piece of cardboard in front of half of the radiator to help everything come up to operating temperatures.
Anyway, just a story, some data, and anecdote. Have a good one.
If the inside is fogging make sure recirculation is off and you are getting outside air mixing in the cabin. Crack the window to let some moisture laden air out until you're getting heat. This is extra important when it's very cold, if you have wet mats, or carpets, or boots or dogs or ice fishing gear, heavy breathers, etc.
If the inside is fogging make sure recirculation is off and you are getting outside air mixing in the cabin. Crack the window to let some moisture laden air out until you're getting heat. This is extra important when it's very cold, if you have wet mats, or carpets, or boots or dogs or ice fishing gear, heavy breathers, etc.
In reply to petemc53555 :
The easy button is to make sure the AC is on when using the defroster. It will remove water from the air being blown out. The only cars I ever had that also had a bad condensation/freezing problem were the ones without a/c.
In reply to alfadriver :
I don't think the compressor will run below 50 deg. ? The compressor automatically runs on defrost if it's over 50 deg.
Keith Tanner said:dean1484 said:Remote start to warm it up for me. My M5 is a bit different as it needs to be warm before it is driven. The cars ecu limits rpm and performance until it is warm. My takeaway from this is warming up a car is a good thing especially if the manufacturer makes you do it.
That's BMW telling you not to romp on it until things are warm, not to let it sit at idle. I don't think anyone here is recommending peeling out of your driveway on the rev limiter 5s after a 0F start. But they'll warm up faster if you're actually driving.
I was highly abusive to my '88 300ZX in high school. I got it at 85k miles, sold it at 170k miles. I would start that thing up in freezing weather and immediately beat it like a rented mule. Still didn't burn oil or anything. I would not do this to a modern car though, although, once it's up to temp I think it's always a good idea to make a pass or two to redline if you can.
In reply to z31maniac :
The fun thing about modern engines is that they tend to have much tighter bearing clearances, afforded by stiffer engine blocks and cranks.
Now, aluminum and steel expand and contract at different rates. The bearing clearances with an aluminum block at subzero temps are going to be quite a bit different than at operating temp.
Iron blocks don't have nearly as much of an issue.
Edit: The difference in expansion between aluminum and iron is roughly .0009" per inch per 100c. (I love mixing systems ) That's .0018" or 1.8 thousandths for a 2" journal. That sounds awful, but we also measure bearing clearances at about 15c, so hot clearances will be higher than what is in the engine build spec.
Not sure how having a steel-backed bearing shell would affect this, as the bearing shell will crush but it will simultaneously be resisting the block's crushing it.
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