In the late 90s and into the early 2000s Toyota and Lexus introduced a revised version of the 3.0 1MZ-FE V6 that was more prone to burning oil than the same engine from an earlier vintage. There were many conflicting reasons given as to why the engine burned oil (some blamed poor oil maintenance, others the PCV system), but the problem was apparent – something about the design of the engine, regardless if it was in an Avalon, Camry, Highlander, ES300 or RX300, caused the engine to slowly burn through oil. In some cases the engine would run entirely out of oil, resulting in catastrophic failure.
At CARspec, here at some symptoms we look for when diagnosing the cause of a 1MZ 3.0 V6’s oil consumption:
- Blue-grey smoke at start up out the tail pipe after a cold soak
- A fouled #2 spark plug
- Bank #2 camshaft cap galling, especially the first cap right behind the camshaft seal, behind the timing belt sprocket
- Sludge inside the #2 bank valve cover
- Low dry compression on cylinder #2 brought into specification when oil is added to the cylinder (wet compression)
Blue-grey smoke comes from the oil inside the cylinders pooling as the car sits, burning upon start up. Sometimes the smoke can be very slight but worsens over time, especially if the vehicle is only driven a short distance and allowed to cool again.
A fouled spark plug specifically on the #2 cylinder is the most common symptoms of a 1MZ-FE burning oil. We’re not entirely sure why #2 is the worst, only that it is a nail in the coffin for the engine. This also goes along with a galled aluminum underneath the #2 bank’s camshaft caps and journals – the damage to the aluminum indicates low oil pressure on these journals and caps.
1MZ Sludge
Sludge is another common symptom of the 1MZ-FE, and is extremely easy to spot once you take off the front valve cover. The level of sludge from the above requires immediate attention.
Compression Tester
While not common, low compression indicates piston and ring wear that require engine replacement to fix. Early in the period of Toyota fixing these 1MZ-FEs under warranty they were replacing just the piston rings with little success – engines would frequently return with the same level of oil consumption. Toyota later switched to replacing the entire short bock assembly as the approved repair.
For any of the above symptoms CARspec recommends a guest begin an oil consumption test to monitor the exact amount of oil being burned by the engine. By changing the oil, marking the exact level, and having the owner return at a predetermined mileage CARspec can advise the owner on the best course of action.
As Eden Prairie and Chanhassen’s Toyota and Lexus repair specialist we hope this helps an owner understand a bit more about the condition the 1MZ-FE suffers from. We are happy to diagnose the issue for an owner and discuss options for repair, so call today!
