Does anyone know for sure what is the cause of the Toyota engine sludging? I have a 4-cyl sludger (got the letter from Toyota) and I'm confused about the possible cause. I've read that it's caused by hot spots in the cyliner head but I've also read that it's caused by cold spots (an Exxon/Mobil engineer stated this). If it's hot spots I plan to use synthetic in the warm weather months only (Mobil 1 5W-30 EP) to save money and run dino in the winter. If it's cold spots I don't know what the h*ll to do as paying $6 a quart when I can pay almost the same for 4 quarts of dino AND the filter is tough to swallow year 'round!
SLUDGE ENGINE CAUSE
- Thread starter MADMIKE
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Hotter designed operating temps coupled with Toyota's recomendation of 7500 mile oil drains with 5w-30 dino?
You can get by with dino in a sludger! 10w-30 summer, 5w-30 winter and conservativly match the drain interval to the operating conditions. 3,000 miles max if you do all short trips, and 5,000 max if you do ALL highway driving. Use Lube Control if you want added sludge fighting powers.
I'm thinking maybe a semi-syn with 5k OCI's? (Motorcraft or Mobil 7500) The cost of full syn sticks in my craw and 3K OCI's is a pain in the ****!
JHZR2
Staff member
didnt realize the 4 cylynder toyotas were sludge prone... even the 4cyl in my GF's early last-gen 4runner, which sees duty in the USVI (read: very tough service) is clean in the engine. Her mother's camry v6 on the other hand...
Thats a shame. does the camry/scion 2.4L 4cyl sludge up? Thats a decent engine, I liked it in a rental solara I once had.
JMH
Thats a shame. does the camry/scion 2.4L 4cyl sludge up? Thats a decent engine, I liked it in a rental solara I once had.
JMH
JHZR2
Staff member
The innards of an engine are the same temperature year round for the most part. I have to doubt that a hot spot will be cooler just because its the wintertime. The oil bulk may be a few degees cooler, but the guilty area of the engine will likely have little care if the oil passing through is a few degrees warmer or cooler.
Hope that you figure a good solution. Id likely use a syn year round, with LC and auto-rx maintenance doses, use standard drain intervals and see how it goes.
JMH
My 98 Corolla 1.8liter 4cyl had 260k miles when I sold it. Never leaked, but ran bad if I let it go past 6k miles between oil changes. I didn't sweat it. Never used any special oil in it. My wife's 98 Camry 6cyl had tight valve seals and gave us major problems if we let it go past 3k miles.
In a top end re-design to meet emissions, oil galleys were routed *very* close to fire zones and the engine oil is getting cooked as it sees this elevated temperature. Most prone are mineral based oils, obviously, do to their higher oxidation rates (cook ratio).. Full synthetic oils are much more resistant to this issue but still must be changed at reduced ODI's to compensate.. Some Chrysler engines had exactly the same issue due to the exact same design change...
I happen to have 3 Toyotas on the sludge pot list. None of my cars have the slightest amount of sludge, all run on dino 10W-30 with 3000 OCIs.
If I run full synthetic what would be a safe (but not overkill) OCI? I'm thinking 5 or 6K with full synthetic (Mobil 1 EP)--I have been doing 3K with dino but the frequency is killing me--I change oil about every 6-8 weeks. (not a problem now but in the winter it's a major P.I.T.A.)
It was a combination of increased operateing temps to decrease emissions, oil pooling in the head, poor PVC design and over extended oil changes with cheap API dino 5W30!Add all of the above together and it was a recipe for sludge. In the end it effected about 1% of the total engines in that data set. It was the 3VZE and 5SFE I belive! So far people doing 3000 mile OCI and those useing synthetics and 5000-7000 mile OCI seem to be uneffected!
Consumer Reports says to either use the severe service OCI of 5,000 miles with dino or the standard OCI of 7,500 miles with synthetic. I think 5K with dino in a sludger is too long. I would also be afraid to go more than 6K with synthetic. I'm thinking of 4K with semi-syn (Motorcraft or Mobil 7500)or 5-6K with full syn.
I posted on this the other day.
See the last few posts I made (with links).
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=011483
See the last few posts I made (with links).
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=011483
"Hot" spots will cook oil, the cooler areas are where the crud will condense out and deposit to. Oxidation tendency is indirectly related to a base oil's inherent viscosity index - the higher the VI, the less tendency that oil will oxidize. The best Group IIIs come in at a 150-160 VI these days and are very close to PAOs in resisting sludging.
Not the 3VZE or 3VZFE, I think. That V6 was in 88-95 vehicles like my '93 pickup. It was the redesigned version that arrived in 1996 (5VZE) that started the major sludge problems in V6s.
The 3VZE had its issues too though, especially popping headgaskets. Toyota issued an HG replacement recall in 1997. Even the replacement HG have caused problems for some. Still, mine is pushing 200K miles with only 1 HG replacment and looks to have another 100K more to go...
Welcome to owning a vehicle.
I also have a Toyota-sludge-monster engine (2.2-liter) in my '97 Celica GT. No sign of sludge in my engine...bought it with 42K miles and now has 149K on it. Engine has had dino 10W30 till about 117K miles...I switched over to Mobil Synthetic Blend and never looked back...engine is real smooth. I still stick with 3-4K oil change intervals though...its too hot here in Florida.
Not changing the oil enough.
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