How many miles must you drive to make a short trip a long trip in order to not sludge up the engine? Can it be done in the city (some stop and go but not bumper to bumper traffic).
For this particular case, the car is a 2000 Corolla.
It depends on the car and the climate. The engine oil needs to get hot enough to drive off condensed water and gasoline. That’ll happen pretty quickly in summer, but not in winter.
I have a Scanguage hooked up to the ODBII. Is it possible to tell by the water temperature? The climate here is around 40-50 degrees here. The water temperature gets to around 190F while driving and in long stop and go…it will hit 206F when the fan will kick in.
Most cars need at least a 10-12 mile one-way trip to thoroughly warm up and drive off any moisture and liquid fuels in the crankcase. In my old Dodge Dart manual it advised me to do just that. This is preferred to more frequent oil changes and also cheaper.
We live in a large city and just going shopping to Costco will put on that many miles. They don’t have to be highway miles, although those are preferred.
@xaml It is the oil temperature that really drive sludge formation. The water will heat up first but the oil will be much slower. Your Corolla is unlikely to have an oil temp sender that your scantool can read. If you have one of those point and shoot IR temp sensors, stop and pull the dipstick. Shoot the tip and it will give you a decent read on oil temp. It cools pretty fast, though so you need an instant temp reading. As others have posted, the oil will heat pretty quickly in the summer but not the winter. Stop and go traffic will heat the oil up pretty darn well, no airflow across the oil pan to cool the oil.
Ok, so 5 minutes of heavy stop-n-go (probably 3-5miles) should be enough.
How about just letting it idle 10mins?
5 min is too little. Even here in Dallas. 15 min might do it. Idling won’t, engine temp rises very slowly when idling.
Don’t overanalyze it
Just follow the severe maintenance schedule and be done with it
I just looked at your maintenance schedule. For you, that means an oil change every 5K or 4 months, whichever comes first.
In your case, it probably means every 4 months
http://www.toyota.com/t3Portal/document/omms/SMG100_MS0001/pdf/2000_Toyota_SMG_PDF.pdf
@db4690, the way I read that maintenance schedule, the 5,000 mi/4 month interval is only for
-driving on dusty roads
-towing
-repeated trips under 5 miles in freezing weather
All other conditions use the 7,500 mi/6 month interval.
I drive my Honda CRV mostly on short local trips and change the oil every 6 months and have never had a problem with sludging.
@jesmed
I understand what you’re saying
Nevertheless, most mechanic’s would consider OP’s driving to be “severe”
I’m sorry if I can’t explain my reasoning better
I would measure the oil pan with an IR thermometer, but I think 15 minutes after the temp gauge comes up to it’s normal level is OK.
@db4690, I agree “better safe than sorry.”
Changing the oil at 4 months vs. 6 months costs only one more oil change per year and is an extra $30 well spent if in doubt.
Yeah, I change every 3 months or 3000 miles regardless of what the manual says.
You are doing a good thing
Yes, if you’re changing every 3 mos you have nothing to worry about. Don’t worry, be happy. 
xaml:
Your 2000 Corolla had the engine that was prone to sludging. Toyota shrunk a cooling passage in the head causing the oil in an adjacent passage to overheat.
The Toyota Owners Manuals for those years originally said to change the oil ever 7.5K/6months for normal driving. But they after the oil sludging problem got exposed, they sent out updates to every owner saying don’t go over 5K/6months
Changing the oil every 3K/3months, is more frequent than I’d recommend, even for frequent short trip driving. It’s one way of solving the question you posted.