- Jun 8, 2024
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- 2007 Toyota Tundra 4X4 Double Cab 5.7L V8, 2015 Chevrolet SS LS3 V8
The cylinder block will contain several types of bearings, namely main cap bearings, and connecting rod bearings.If the new ones at the dealer have the same sound then it’s most likely normal. A universal bearing what is that. The only one I can think of is the rod bearing. A bad Rod bearing isn’t likely to get silent. Someone needs to try to listen to the sound on a Tacoma.
An inline 4 cylinder will have 5 main journals on the crankshaft, and 4 rod journals. The main journals are held in place by either main bearing caps or in this instance a main bearing girdle assembly, each journal will have a dedicated main bearing which is a Babbitt type bearing, one of these will also employ a thrust washer to regulate fore and aft movement of the crankshaft. Additionally each connecting rod will also employ a Babbitt style bearing on the big end of the connecting rod. All of these bearings have oiling holes and groves to allow lube oil to be forced through to create a fluid film between the bearings and the crankshaft.
This particular 4 cylinder also employs a set of balance shafts that is driven off of the crankshaft by a set of polymer gears. This is used to counteract the inherent unbalanced nature of an inline 4 cylinder. The balance shafts will also ride on some type of bearing, but I don’t know if they’re Babbitt or roller bearings.
In any of these cases a loose fitting bearing is not going to get quieter with operating temperatures increasing. They will sound terrible no matter the temperature, making a distinct knocking sound. If you hear this just keep driving to the nearest safe spot or dealership/repair shop because the engine is trashed already; run it till it blows up or gets you home.
I predict the OP is hearing a waste gate on the turbo bleeding off boost at low engine temps due to ECU programming for emissions or longevity. Alternatively it could be associated with the hybrid system.
My guess is the OP isn’t going to be happy with the new Land Cruiser and should consider moving on with something else.
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