View Full Version : What cold weather does to your engine and transmission

01-02-06, 11:48 PM
This is a recent post of mine from the Chevyhiperformance.com message boards. I thought I would share it with you because it's very interesting. My name over there is 85Caprice.

From: 85Caprice (http://forums.chevyhiperformance.primediaautomotive.com/dir-app/bbcard/profile.asp?webtag=chevyhi&uid=754802789) Dec-12 10:19 am To: ALL (1 of 4) 1435.1 (http://forums.chevyhiperformance.primediaautomotive.com/chevyhi/messages?msg=1435.1)
When it's 6 degrees out in the middle of winter, what parts of the engine are affected the most? I heard that there's 8 times as much wear on an engine when the coolant is 100 degrees compared to when it's 200. What about blowby? Does very cold weather strain anything else? It just makes me wonder, since here at campus, I see women and men alike getting into their vehicles when it's below zero and within a second of starting the vehicle, it's already in reverse and they're giving it half-throttle. A good friend of mine drives a BMW X5. He tells me BMW says never to wait, just get in and drive, the engine will handle it fine. So what's the deal? Are people taking the life out of their engines or am I just paranoid? I always try to wait 30 seconds in the cold of winter before putting it in gear.


From: oldBogie (http://forums.chevyhiperformance.primediaautomotive.com/dir-app/bbcard/profile.asp?webtag=chevyhi&uid=401583453) Dec-12 11:57 am To: 85Caprice (http://forums.chevyhiperformance.primediaautomotive.com/dir-app/bbcard/profile.asp?webtag=chevyhi&uid=754802789) (2 of 4) 1435.2 (http://forums.chevyhiperformance.primediaautomotive.com/chevyhi/messages?msg=1435.2) in reply to 1435.1 (http://forums.chevyhiperformance.primediaautomotive.com/n/mb/message.asp?webtag=chevyhi&msg=1435.1&ctx=0#a1)
Winter is brutal on engines, transmissions and rear axles, those people that jump-in, fire up, gun the engine a few times then take off are just killing the machine. The car doesn't want to take off cold anymore than you do.
The oil is stiff at 6 degrees, even 5W something, so the engine is starved for oil, there's probably, if not undoubtedly, amounts of frozen water in the oil, water being the major bi-product of combustion it can't help but get into the oil with the blow by gases.
All the internal components have shrunk from thermal contraction, therefore, clearances are very wide. Combine this with poor oil circulation and you get pounding in the bearings and scuffing of the pistons. The rings have a hard time scraping the cold oil off the cylinder walls so you get more oil into the top end where it forms and deposits carbon coke on the valves, combustion chamber, and spark plug. This grit breaks off and eventually works it's way around the piston where it sand papers the bore, piston and rings.
As the engine heats up you have a very hot piston crown in a cold bore. You quckly get a very hot exhaust valve trying to seat in an icy cold head. The oil is still not circulating to where the valve stems are receiving the small amounts of lubrication they need.
New engines that route the oil into a heat exchanger with engine coolant are a lot more tolerant than older designs that don't heat/cool engine oil.
The transmission is in something of the same fate for oil circulation but at least doesn't have combustion bi-products and alternating loads being put on it. I've seen automatics that won't take a gear till they warm a while. Sticks with 80-100 weight oil essentially have no lube till they warm up.
The rear axle is 100 percent dependent upon the splash lubrication of bearings and gear teeth from 80-100 weight oil at freezing temps. This stuff is so thick as to nearly be a solid at 6 degrees.
Tires, here you have what's essentially a plastic composite structure (polyester cord and kevlar belts are what?) imbedded in rubber that undergoes a lot a flex and relax movement as the tire rotates into loaded (bottom) and unloaded (everywhere else) moments.
The amazing thing is that things work as well as they do, but that's no reason to temp fate.
I warm everything up, every time, I don't move the thing till I see 120 125 on the temp gauge. Then I put it in gear and taxi it to the freeway. Since I have to go a mile on surface streets with traffic lights, I can usually get the engine up to 140-150 by the ramp. I get on and keep the rpms not over 1500-1700 till I see 180 on the temp gauge. I do this summer or winter. Winter if it's really cold, I hold the road speed down to 55 for a few miles after the engine gauge reads 180 to make sure the rear axle, u joints and tires have an opportunity to warm.


From: 85Caprice (http://forums.chevyhiperformance.primediaautomotive.com/dir-app/bbcard/profile.asp?webtag=chevyhi&uid=754802789) Dec-12 2:19 pm To: oldBogie (http://forums.chevyhiperformance.primediaautomotive.com/dir-app/bbcard/profile.asp?webtag=chevyhi&uid=401583453) (3 of 4) 1435.3 (http://forums.chevyhiperformance.primediaautomotive.com/chevyhi/messages?msg=1435.3) in reply to 1435.2 (http://forums.chevyhiperformance.primediaautomotive.com/n/mb/message.asp?webtag=chevyhi&msg=1435.1&ctx=0#a2)
So I'm not crazy then! Thank you for confirming what I suspected. What about newer high-performance engines, like the BMW or the Northstar? Are they any different at all or do they need to warm up just the same? I suspect that BMW would like to tell it's loyal customers to just get in and drive because it'll put more wear and tear on the engine leading to repairs and more frequent $90 oil changes.


From: oldBogie (http://forums.chevyhiperformance.primediaautomotive.com/dir-app/bbcard/profile.asp?webtag=chevyhi&uid=401583453) Dec-13 9:09 am To: 85Caprice (http://forums.chevyhiperformance.primediaautomotive.com/dir-app/bbcard/profile.asp?webtag=chevyhi&uid=754802789) unread (4 of 4) 1435.4 (http://forums.chevyhiperformance.primediaautomotive.com/chevyhi/messages?msg=1435.4) in reply to 1435.3 (http://forums.chevyhiperformance.primediaautomotive.com/n/mb/message.asp?webtag=chevyhi&msg=1435.1&ctx=0#a3)
Brian, new engines don't take as long to warm up because the oil is circulated through a heat exchanger in the radiator much the same way factory automatic transmission "coolers" work. This greatly speeds the warm up time, it was done as an emissions measure but has significant benefits in stabilizing overall engine temps. Now for example, you don't have 200 degree coolant and 250 degree oil. The oil temp is held down to coolant temp, which when the engine is hot and working hard, is a good thing.
The other major and expensive components like a manual transmission and the rear axle are still on their own for getting up to operating temp, which happens as a result of friction within the bearings and compression of the oil between gear teeth. So one can see that at winter temps, it can take these items a rather long while to reach temps where the oil is flowing freely. Oil flow with these heavy gear oils is somewhat of a double whammy; the cold thick oil doesn't flow into the bearings very well and when trapped between closing gear teeth it takes a considerable amount of force to squeeze the oil out which puts a lot of load on the gears, their under lubricated bearings, and the cold and stiff structures that hold it all together. Of course many new manual transmissions use a lube more similar to ATF which reduces these problems. But differentials whether conventional rear drive or front wheel still use thick Extreme Pressure lubricants that are mighty stiff at below freezing temps.
As for BMWs and Mercedes and these kinds exotic/expensive Euro cars, if your Chevy spent as much shop time and maintenence dollars as these things, you'd shoot it. I always found it funny that the same people who expect an American car to run forever with no maintenance, will happily buy these Euro-cars and take them to the shop for all their required/recommended maintenance, which is frequent and expensive. If you had a typical American car and gave it the kind of maintenance these expensive foreign cars require, it would be impossible to wear your Detroit iron out.


01-03-06, 12:03 AM
all that for 6 above ????

LOL .....
little overkill there .....

Start it and go ....No warm up , just take it easy ....itll build heat faster if your driving it ....go Synth in the rear end , and in the tranny if a manaual ....

at 6 above it should be plugged into a head bolt outlet anyway with a oil pan heater and engine coolant heater , battery blanket optional ....

he also should have a 5w in that engine if he is THAT worried ....

Where i lived for four years i saw gasoline freeze into a soild chunk of ice , anyone who knows gasoline can tell you how COLD that is .....and my fleet carried a 99.9% in commision rate average 2 of the 4 years (ok i had 2 bad years at 92%).....

Caddy Man
01-03-06, 12:17 AM
i always start and then wait about 30-40 seconds. If you notice when you start your car with a cold engine, the RPMs will always be a bit higher than normal idling, then they will drop slowly. So I always wait until my RPMs drop to a bit below 1000, then I shift and lighty accelerate, never going above 3000 RPM until engine is fully warm. I dont have time to sit there for 10 minutes everytime I go somwhere for the engine to warm up. Plus I hate that the 2003 CTS has no temp gauge.

01-03-06, 01:45 AM
I was told by my vehicle services teachers to let it sit and idle on the coldest mornings (10* and below)

I do let my car sit and idle for like 5 minutes in the morning when I first start it when its that cold out.
Is that bad?

01-03-06, 06:36 AM
I give it about 5 seconds. Then again, it's almost always above freezing anyway.

01-03-06, 07:41 AM
On extremely cold days, it is a good idea to wait a few seconds to allow the 'juices' to flow and allow everything to be properly lubricated. You do not, however, need to sit and idle for an extended period of time. Just take it easy until things are at operating temperature. Thats for Northstars, the 3.6, 3.2, and the like. Not sure how this would apply to older engines like the 4.9 and such.