This is a common problem for the Previa. I had this problem and its very embarrassing especially when you park in your friend’s driveway. To fix this is very easy and cheap. The goal of this procedure is to take out the oil pan and put in new silicone. The first thing you need to do is to drain the oil. This is also a great opportunity to change your engine oil too. Please read this tutorial before proceeding. How change Previa engine Oil
10 mm Socket
Once you got the oil drained, now it’s time to loosen the head oil return hose. This hose is about1 1/2″ that attached to the oil pan from the head. You need to use a wide opening pliers to squeeze the clamp. Once the oil return hose is disconnected, it’s time to unplug the oil level sensor. Its located opposite side of the oil pan. It’s a simple clip on plug. The next step to remove the 10-12 10 mm nuts and screws. It’s best to use a 8″ to 10″ socket extension to loosen those screws. Once the screws and nuts are loosen, the oil pan will not fall right off. The old silicone still very tight. The easiest way is to use a mallet and bang on the oil pan slightly from different directions. After few bangs, the oil pan should be loosen and take out the oil pan.
Once the pan is out, you need to clean out the old silicone on the pan and the block. The best way is to use a wired brush to clean both contact surfaces. Once the old silicone is all gone. Its best to spray some carburetor cleaner or brake clean to degrease the surfaces and wait until its dry. The next step would be to apply a thin layer of high temperature silicone to the oil pan surface. Once you have done that, its time to put everything back. Here are some pictures of this process.
Picture below is the oil return hose and the oil level sensor. Its located opposite side of the oil pan nut.
Here is a picture of the screws and nuts holding the oil pan Loosen the 10 mm screws with an extended shock
Here is a picture of the engine block when the pan is removed Using wired brush to clean out the old silicone
Spreading a new coat of new high temperature silicone
Final product…. NO LEAK!
This essential maintenance is necessary and its very basic and it can done with basic tools.
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