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Cold weather starting and performance problems.

1964 Views 0 Replies 1 Participant Last post by  jfoj
Just something for everyone to keep in mind over this cold Winter season, be careful of fuel related issues, having batteries compromised and even your engine oil will be like molasses.

With temperatures dropping below freezing and below 0F/-18C in many parts over the past few days and into the next few weeks keep in mind trying to get your car started may be more of a challenge than usual. Even for the folks in the warmer climates, just dropping down by 20F or more than your typical cold temps may cause problems.

First there is the battery, a chemical device that the capacity is directly related to temperature. The lower the temperature, the lower the battery capacity. At some point even a battery can freeze and then there is very little capacity and the battery can even be permanently damaged. If you think you are in for some ultra cold temps, get a battery warmer, trickle charger or remove your battery and bring it into the house to stay warm over night. Keeping a battery on charge can keep it warm and help it stay a bit warmer but warming the battery somehow is probably the best approach.

Engine oil, well it is too late to do anything about this, but keep in mind that all oils get very thick as the temps drop. So again, trying to keep the engine/car warm overnight is not a bad idea. Also try to not let your car sit in cold storage over many days even if you are snowed in. It may be a good idea to start the car daily and warm it up for at last 10 minutes to circulate the oil, get the battery active and warmed up as well as keep the oil from hopefully turning to jelly. The thick oil may also slow the engines ability to crank along with the reduced battery capacity so these can combine to cause no/hard starting issues.

Fuel, well again, this is a problem. May not be a problem immediately, you may even run into this as a problem after the weather breaks and warms up a bit. Most of the fuel in the US and Canada has Ethanol in it. The Ethanol behaves a bit differently when the temps really drop. Ethanol can also absorb a lot of water and keep it in suspension. One of the problems we all have to deal with is when fuel is stored and transported above ground. When the temps drop dramatically it can cause the Ethanol and any water absorbed in the Ethanol to separate. The water can then also freeze much easier once separated. Search the term Ethanol Phase Separation. We have already had a number of forum members hit with bad fuel this season and I expect this to be more of an issue as these super cold temps blanket North America and other areas over the next few days/weeks.

So stay alert, do not forget to think about fuel issues as you run into no start and/or performance problems. You may have problems in your tank with your current fuel or you may be unlucky enough to fill up with bad fuel from a local gasoline station. Not much you can really do to combat this issue, just be aware and do not forget to think about fuel issues if you have no start/performance issues. You should probably keep records of where and when you are buying your fuel in case you have a problem. You may be able to get reimbursed from the gas station/fuel supplier if there is enough proof and others had problems as well.

Rough running, misfiring and SES/CEL/MIL coming on at start up. This is somewhat normal on older cars during very cold weather, usually due to aging parts and lack of maintenance. Do not be overly alarmed. As the temps drop dramatically the cold start fuel enrichment is even more important for a smooth running engine. Any vacuum leaks or other fuel/ignition related problems become more apparent as the temperature drop and the car has not been driven for days.

If you start the car and it is running very rough with a SES/CEL/MIL light on, if after about 20-30 seconds the problem does not clear with a slight throttle application, turn the engine off and restart it. Many times this will clear the misfires. This does not always correct or solve the root cause of the problem, but many times will clear the misfire and allow the engine to run normally and be driven without issues. If you have these issues, put this on your Spring to do list if you can make it through the Winter while managing the issue.

Also one thing you want to avoid in the cold weather is starting the engine and only letting it run for a very short period of less than 3 minutes. Many people need to start and move their cars just in the driveway or to the street, but anytime you start your engine in the cold weather, let the engine run at least 3-4 minutes before you shut it down. This will hopefully avoid engine flooding and cylinder wall wash down situations.

Keep in mind if you do think your engine became flooded and is not starting, push the throttle to the floor and hold while cranking the engine. This puts the engine in "clear flood" mode, shutting down the fuel injectors and will hopefully clear out the fuel in the cylinders while trying to start the engine. Do not crank the engine for more than 30 seconds at a times and allow 1-2 minutes between starting attempts for the starter to cool down. Usually if you cannot get the engine started by the 3rd attempt during a "clear flood" mode, the engine is not flooded and will not likely start.

Weak/soft thermostats, extremely cold temperatures and condensation build up in the crankcase can be disastrous for VW's. Everyone needs to pay careful attention to the engine coolant temperature as well as condensation build up in the crankcase over the Winter. Best thing to do is at least once a week, when the engine is cold, remove the oil fill cap and look for yellow goo/mayo build up. If you are seeing any form of yellow goo/mayo build up, check your engine operating temperature (do not use/rely on the dash temperature gauge as it is not accurate), make sure you drive the car for between 30-45 minutes at least once a week, preferably at highway speeds to fully heat the oil up to cook out any accumulated moisture. Keep in mind it takes a long time for the engine oil to heat up, usually 2-3 times longer than the engine coolant temp. For engine coolant temp and thermostat info, check the link below in my signature.

These are just a few things to watch out for during the very cold weather that we are currently seeing across the North America and maybe other areas around the world.

So everyone stay safe and warm over the next few days/weeks.
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