Not a Lexus but I'm working on an 04 Cadillac CTS with a 3.6L V6. The engine was noisy and I narrowed it down to the timing chains. After opening up the timing covers, I'm seeing all kinds of oil sludge built up and caked on the inside of the timing cover. The valve covers also had a thick coating of sludge on them that I'm having a hard time getting off. The car has 117k and I got it from an old lady. She has some receipts for oil changes from Valvoline but there was a 20k mile gap between visits. I asked her what happened and she insisted that she had the oil changed but just at a different shop.

The oil filter is an internal cartridge type and it's all shriveled up like it was clogged and just collapsed. I tried checking the part number on the filter and I can't even find what this filter is.

I've seen varnish before and a bit of sludge, but not like this. The varnish on the inside of this engine is dark brown and there are chunks under the valve covers. What the heck went wrong here? Just bad oil? I can post pictures if needed. I'm just worried that if the timing chains had this much trouble, how are the engine internals?

 

Here's pictures of the problem

 

Just wow! As I was reading what you were saying I was expecting massive goo 3 inches thick. That is so totally clean, all that darkness is normal stuff and nothing to worry about. That is not even called sludge, it is staining, and unless the chain guides were bad you just did a lot of work for nothing. That looks like a low mile grocery store car.

 

Thanks for the perspective. It's got 117k. I sent in an oil sample to be analyzed by WIX and we'll see what they say. The timing cover actually cracked when I tried to put it back on because I had the sprockets backwards so I have to wait another week for a used timing cover off of ebay.

Yeah the chain guides didn't have much wear on them at all, light grooves but not eaten all the way through like some I've seen. The chains were slightly stretched though and the main sprocket was actually worn. The teeth were all slanted toward the direction of rotation. I guess we'll see if the engine is quieter once I get it all bolted back together. I just didn't want to risk the timing chains breaking because if they do, it takes the whole motor with it.

 

Here's the Wix oil analysis report if you're interested.

 

And that read out is in ppm. That means parts per million. And the green check mark means good shape. So see what I said was right on, wasted time and $ on that project. Especially the low miles.

 

Yeah that sure was a waste of money man! No kidding on that.

 

Don't worry about it. Your condition is not considered as sludge buildup IMO, everything looks quite normal to me. The discoloration on the timing chain cover is very common, I wouldn't worry about it. As the oil analysis says, everything is fine.

Do a quick google search and see what a real sludge engine looks like, here are some pics: https://www.google.ca/search?q=sludg...HYwPCeUQsAQIGw

 

that's varnish and is normal

 

I'm beginning to suspect that the noise is actually the power steering pump.

 

What kind of noise is it making, it could be normal for that car, and engine noises can be many things like chains, exhaust, etc. That does not look like sludge build up or anything to worry about like everyone has said but simply normal staining and varnish. I would not even both trying to remove it though you could do a engine flush with a engine flush product before the oil change to knock some of that down if you are worried there may be some minor sludge/deposits but I doubt sludge would cause a engine to be very noisy, it mostly affects power and fuel economy and sometimes causes stalling.

 

It was a whining type sound so I thought it was pulleys. I did all the pulleys, idlers and belts and the sound was still there. I put in new timing chains and there is less noise, but there's still kind of a whining sound almost like an electric motor. Its definitely not an exhaust or induction noise because its quiet besides that, actually a lot quieter than a Infinit G35x I recently test drove. Its just that the quality of the noise is very annoying. When I turn hard, I hear some power steering noise so thats what makes me think its the pump. When I stick my head under the hood, I do hear more noise from the power steering side of the V6 engine too but I can't tell what or where its coming from.