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New here and was looking for some info as searching the model or engine has turned up nothing. My lexus is right around 300K miles and I'm noticing some light rod knock under more than average (best way to describe i guess) acceleration. Want to tackle that before it gets serious and have already ordered a new set of rod bearings. I crawled under it today to see how much of a PITA the pan was going to be to drop. It's AWD. Looking like I've gotta pull the front axles to get that upper pan free, other than that everything looks to be accessible. Anyone here done this before? is it a straight forward, pull the axles and drop the pan like normal or is there anything I should be looking out for? Thank you in advance
These engines, are pretty good at not loosing crank bearings. Maybe what you are hearing is engine knock, from an engine that is choked up. Let me explain, the 2006 GS300 is the only GS that has carbon issues. The intake ports/valves eventually build up carbon soot, from the poor design of the fuel system. The intake ports do not get washed by fuel. Lexus used to rebuild these engines for free, and would basically clean the heads, and piston rings.
When the crud gets so bad, the engine misfires and gets choked and makes weird noises. I would unbolt the top plastic air intake first, from there you should be able to see the intake valves, just shine a light at down the ports and look at the condition of the valves and the port walls. If its gunked up then you can manually clean it with chemicals, stiff brushes and light scrapers.
These engines, are pretty good at not loosing crank bearings. Maybe what you are hearing is engine knock, from an engine that is choked up. Let me explain, the 2006 GS300 is the only GS that has carbon issues. The intake ports/valves eventually build up carbon soot, from the poor design of the fuel system. The intake ports do not get washed by fuel. Lexus used to rebuild these engines for free, and would basically clean the heads, and piston rings.
When the crud gets so bad, the engine misfires and gets choked and makes weird noises. I would unbolt the top plastic air intake first, from there you should be able to see the intake valves, just shine a light at down the ports and look at the condition of the valves and the port walls. If its gunked up then you can manually clean it with chemicals, stiff brushes and light scrapers.
I know the sound you're referring to. She makes that sound everytime it starts and has for a long long time. It is most definitely not that. The unmistakable tatatata of a bearing is clear. Also the better half has been using it as her daily driver for quite a while now. She mentioned the noise to me the other day, had I her start it up it made the noise referenced, then idled smooth, I then had her give it hard gas and that death noise was unmistakable. Had her turn it off and i checked the oil, below min. dot, barely any on the stick. I have most definitely been neglecting it, I've known its been seeping oil from the pan gaskets for a loooong time. Life happens and out of sight out of mind busy with other stuff and just plain forgot to check the oil situation in it for a while with my rarely driving it lately.
Last edited by Callahanjo; 05-05-23 at 04:38 AM.
Reason: Clarity/detail
interesting! Have you tried topping off the oil to see if the noise would go away? Did she not see the low oil light come, because usually that gets tripped when the system is down 1 or 2 quarts of oil.
Try draining the oil, and catch it in a clean pan and examine the old oil, if its got a lot of shiny metals then proceed with removing the oil pan and seeing if any connecting rods are loose. If there isnt any metals in the oil, I would just change the oil.
interesting! Have you tried topping off the oil to see if the noise would go away? Did she not see the low oil light come, because usually that gets tripped when the system is down 1 or 2 quarts of oil.
Try draining the oil, and catch it in a clean pan and examine the old oil, if its got a lot of shiny metals then proceed with removing the oil pan and seeing if any connecting rods are loose. If there isnt any metals in the oil, I would just change the oil.
I did top it off, used 10w-40, it took almost 4 quarts. It quieted it down but it's still there. With the low level sensor/warning on the dash, it has also been coming and going randomly for a couple of years. It trips, I would check the oil and level is good, would go away next start, chalked it up to a bad sensor and just keep an eye on it, that being said, as previously mentioned, ive been neglecting it as of late. After she said something, she mentioned the pressure warning would ding for a brief second in hard/sharp turns the last couple of days. So yeah, that info combined with hearing it made me pull out my phone and order a bearing set on the spot. Maybe it will be ok with a little TLC, maybe damage is done but I won't feel comfortable until I get in there and get eyes on
Edit- I will be draining the oil after work today and checking for shavings
Last edited by Callahanjo; 05-05-23 at 06:18 AM.
Reason: Add info
So, lower pan out, most of the upper bolts out. Looking like the steering rack needs to at least have the 2 frame bolts removed so it can be pushed out of the way. One upper pan bolt is clearly visible, but the front transfer case is blocking attempts at getting it free so it will have to be unbolted.
The float on the oil level sensor was broken and sticking against its frame, explains its intermittent operation.
Nice fat chunks of bearing on the bottom of the pan
So, lower pan out, most of the upper bolts out. Looking like the steering rack needs to at least have the 2 frame bolts removed so it can be pushed out of the way. One upper pan bolt is clearly visible, but the front transfer case is blocking attempts at getting it free so it will have to be unbolted.
The float on the oil level sensor was broken and sticking against its frame, explains its intermittent operation.
Nice fat chunks of bearing on the bottom of the pan
Ouch bummer that sucks, atleast you know whats going on. Then ya I would do those connecting rod bearings. Ive done the same thing to a relatives cadillac just swapped out the connecting rod bearings. Because they neglected and kept driving the car with it knocking, when I opened the oil pan the crank journals were badly damaged. What I did was sanded them down, made long strips of sand paper and the grooved stuff I would use 180 grit, then work my way down to 2000 grit. From 1000-2000 grit I used water with the paper. Replaced all connecting rod bearings, and torqued all to the correct spec, except for the ones that were damaged I added a bit more torque. Then you gotta remove all the shavings in the engine, with the oil pan off I just sprayed all the inside of the engine with carb cleaner, and when I had the oil caps open I sprayed carb cleaner inside of the crank ports. Then after completing I changed the oil twice.
When I was finished the car ran great, with good oil pressure. This lasted a year and half, until they the careless relatives didnt change the oil again and the same thing happened.
What a PITA. The passenger CV....no amount of beating and torching would break it free, bearing completely seized. 14 hours over 2 days trying everything imaginable. Nothing. While laying under there I realized I could reach most of the bolts to the plate covering the crank.
If you find yourself having to get in there and your passenger CV is stuck, don't waste your time fighting it like I did, this works.
I took the front drive case loose and all the upper pan bolts out, loostened the engine mounts on the passenger and driver side could jack the engine a good 4 inches. This gave me clearance to pry the shaft loose on the drive case side and the upper pan to drop far enough to get the upper portion of the oil pump loose and the bolts out of the plate covering the crank and push it to the passenger side, then just work through the upper pan to change out the bearings
#3 and #6 were by far the worst
Also, rod cap bolts have angular torque spec of 90 degrees. You're supposed to mark the bolt heads then turn them 90 past your mark. I did not look this up before removing them. 60 foot lbs was the breaking torque so I went with that for tightening
Passenger CV pulled away from drive case Not the clearest, but with the cover plate pushed to the passenger side(left side in photo) you can access the rod cap bolts through the upper pan, hand fits through center section to actually reach in and pull/set bearings
Ya the passenger cv axles are a nightmare in these cars, people custom build weird pulling spreaders just to get them to come loose. As for the 90 degree torque, you could have just torqued the bolt, and with a marker marked its position and turned it 90 degree. Were you able to replace all of the connecting rod bearings, how were there condition? How was the crank?
I was able to reach and replace all of them. 1, 2, 4 and 5 were undamaged, 3 had some light scratching, 6 was beat all to hell, I imagine because it's last to get oil and there was none to get. The crank looked in great shape on the bottom side, couldn't see the top half but felt to be in pretty good shape by hand/finger. The rod caps bolted snug, no play and the engine runs smooth and no noise. Caught it early enough that I shouldn't have to worry about it again, just keep an eye on the oil. I haven't replaced the low level sensor yet, it's ordered and easy enough to change once I have it. Stuck a rare earth magnet on the lower pan and going to change the oil again this weekend and next to make sure I've got all the shavings out. Should be in good shape moving forward
Did you try to spraying any kind of cleaner inside, or shove something inside of the ports of the crank to make sure theres no oil blockage in the oil gallery? Maybe adding an oil cleaner before the next oil change, btw I would do an oil change atleast 50-100 miles just to make sure none of the shavings from the bearing go through and tear stuff up internal.
im glad you got it taken care of, and didnt cost much, good job!
I wiped what I could reach with a shop towel, oil ports looked clear so I didn't poke at them.
She drives it about 50-75 miles a week, hence the plan to do weekend changes. I'll change it Saturday, then next weekend drop the lower pan and clean it and any metal the magnet picks up. Probably a 3rd oil change a week or 2 after just to be on the safe side
I would pour in some kind of engine cleaner like marvel mystery oil before you change the oil. Because having a crank heat up at the end like that tells me theres an oil issue, maybe because of oil starvation, maybe the crank oil ports are clogged, maybe the oil pickup was clogged, or maybe oil pump is bad and not giving good oil pressure. Even if the engine had 2 qt's oil it shouldnt cook bearings.
As for oil change you should be fine with 1 oil change, just examine the filter for metals, if you find metals then yes I would change the oil.
05-04-23, 02:58 PM
06 GS300 oil pan removal
