Engine Sludge?
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Pit Crew
Joined: Jul 2010
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From: Hawaii
Engine Sludge?
I had posted a previous thread trying to determine where my oil is going. Several ideas were suggested with engine sludge being one of them. Yesterday I opened the front valve cover and took two pictures. My first impression would be that there was no significant engine sludge but I wanted to get the opinions of you fine men and women first. So, how do I look?
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Pit Crew
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From: Hawaii
Yes, the compression results were really good. They hovered around 180psi with one in the 170's and one around 190. It's been something of an interesting dilema because according to the previous owners (parents) they were having to put about a quart every 600 miles or so. The thing is the exhaust isn't emmiting white or blue smoke, the engine seems to be free of sludge, and the compression is good.
Lexus Champion
Joined: Feb 2008
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From: Ca.
Shark- certainly no sludge there, just the normal "cooked on deposits" from a crankcase that obviously runs very hot (not the radiator). I am curious about the dryness though. That seems awfully dry unless it has set for QUITE some time before you removed the VC. Normally wouldn't drain that dry for maybe even several days. What brand of filter is used on it?
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Pit Crew
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From: Hawaii
Good call Code58. It's actually been sitting for several months. My parents transmission went out and they offered me the car for free. I have been away on business and will be taking the car in soon to have the transmission replaced. I just wanted to address a few things related to the oil loss before I took it in.
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Intermediate
Joined: Nov 2003
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From: Oswego, IL
shark13:
There is a great deal of varnish build up here, but it's certainly not sludge. The cam lobe on the last cylinder on the intake side looks like it's a little scarred, but that wouldn't cause an oil consumption issue and it's pretty minor. If you are burning that much oil, you either have a valve seal cracked (or several?), or piston ring misaligned/broken. These wouldn't show up in a compression test. I have a Ford Windstar with 115K and a broken ring. Tests fine, but burns about a quart of oil every 500-1000, depending on driving conditions. Removing the spark plugs will tell the tale. One or more will appear fouled - coated in thick black soot, or with black deposits. It probably won't look this way now because it's been sitting, but after running the engine a fouled plug can look wet with oil.
There is a great deal of varnish build up here, but it's certainly not sludge. The cam lobe on the last cylinder on the intake side looks like it's a little scarred, but that wouldn't cause an oil consumption issue and it's pretty minor. If you are burning that much oil, you either have a valve seal cracked (or several?), or piston ring misaligned/broken. These wouldn't show up in a compression test. I have a Ford Windstar with 115K and a broken ring. Tests fine, but burns about a quart of oil every 500-1000, depending on driving conditions. Removing the spark plugs will tell the tale. One or more will appear fouled - coated in thick black soot, or with black deposits. It probably won't look this way now because it's been sitting, but after running the engine a fouled plug can look wet with oil.
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Thread Starter
Pit Crew
Joined: Jul 2010
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From: Hawaii
Tinman, thanks a bunch for the info. You are exactly right. If I remember correctly the front left spark plug was about 10psi lower than the rest and had black oil on it. The rest where all gray with what looked like carbon deposits. Are there any clues by looking at the valve seals closer that would indicate if that's the case? Should I try a leakdown test?
Intermediate
Joined: Nov 2003
Posts: 266
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From: Oswego, IL
I'm assuming that you have checked the ground where the car is parked to make sure it's not leaking oil, while sitting and/or idling. I'm also assuming that you have checked the other fluids in the car to see if there is not a ton of oil in them? like coolant? If you have eliminated those, then the oil must be going out the tail pipe.
A leak down test will tell you if it's rings. IMO, that is the next reasonable test to conduct. Unfortunetly, if the test reveals a problem, you won't be able to fix it without disassembling the engine into its discrete components. Bummer. You could try a little thicker oil i guess?
For valve stem seals... err... um... I think that's mostly diagnosed with symptoms, not inspection? High vacuum in the intake will cause oil to slip past the seal, most of the time this oil just sits on the back of the valve and doesn't get burned until you give it some gas, then blue smoke comes out the tail pipe. If letting the car for a while idle then punching the gas = blue smoke that fades quickly, then it's probably a seal. I don't think you can see the seals in the 3.0L 1MZ-FE engine in the RX300. But if it's seals, you still won't able to fix it without disassembling the engine into its discrete components. Pretty sure you have to take off the head to replace them. Double bummer.
A leak down test will tell you if it's rings. IMO, that is the next reasonable test to conduct. Unfortunetly, if the test reveals a problem, you won't be able to fix it without disassembling the engine into its discrete components. Bummer. You could try a little thicker oil i guess?
For valve stem seals... err... um... I think that's mostly diagnosed with symptoms, not inspection? High vacuum in the intake will cause oil to slip past the seal, most of the time this oil just sits on the back of the valve and doesn't get burned until you give it some gas, then blue smoke comes out the tail pipe. If letting the car for a while idle then punching the gas = blue smoke that fades quickly, then it's probably a seal. I don't think you can see the seals in the 3.0L 1MZ-FE engine in the RX300. But if it's seals, you still won't able to fix it without disassembling the engine into its discrete components. Pretty sure you have to take off the head to replace them. Double bummer.
Lexus Champion
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From: Ca.
Tinman- some good information indeed. I have had the front VC off of my DIL's RX but don't remember much about whether you can see the seals though. I have a repair manual CD but no time now to look it up. On some cars at least, you are able to change the valve seals with the heads on by pressurizing the cylinder (I have the equipment) which allows you to compress the springs and replace the seals without removing the head. That may not be possible on an RX engine though. Often leaking valve seals will manifest themselves by a cloud of smoke on start because of the oil that has drained down the stem into the cylinder. I think I would try and locate a borescope and take a peak down into that cylinder since it's easy to get to. If a ring has been broken for very long it will begin to show signs of it on the wall. Sounds like something is going on if that plug showed black oily deposit and that cyl. was lower than the rest, if only by 10 lbs. A compression ring can show good compression if it's not worn and the oil ring still lets the oil by if it's broken.
By the way, exhaust does not ALWAYS show evidence of smoke with oil consumption because the Cat conv. runs so hot it burns most of the oil off.
By the way, exhaust does not ALWAYS show evidence of smoke with oil consumption because the Cat conv. runs so hot it burns most of the oil off.
Last edited by code58; Sep 8, 2010 at 12:36 AM.
Thread Starter
Pit Crew
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From: Hawaii
Thanks for the notes guys. Yes, the engine does emit some whitish blue smoke if I punch it. Because both the rings and valve seals would most likely require significant engine work it sounds like I either drive it the way it is or have if fixed properly.
Lexus Champion
Joined: Feb 2008
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From: Ca.
Shark- I WOULD consider 1 or 2 treatments with Auto RX. Those would be a full oil change (say 3K mi. each). I say that because if it is caused by stuck rings (percentage wise not a large chance, but still possible) The A-RX would likely free them and if it is valve seals, a fairly good chance it would rejuvinate them and stop the oil burning. It has been successful for quite a few who have had a bad rear main seal leak because of a rock hard rear main seal leak. It softens and restores pliability to rubber while it disolves the varnish and sludge. I changed the RMS in my DIL's RX and believe me, it was like a rock! It had worn a groove in the CS which is quite common. For what it costs, I would certainly try it if it were my car. It is a product (unlike many) that really works! I have no financial interest in the company whatsoever.
Lexus Test Driver
Joined: Aug 2009
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From: NJ
Shark- I WOULD consider 1 or 2 treatments with Auto RX. Those would be a full oil change (say 3K mi. each). I say that because if it is caused by stuck rings (percentage wise not a large chance, but still possible) The A-RX would likely free them and if it is valve seals, a fairly good chance it would rejuvinate them and stop the oil burning. It has been successful for quite a few who have had a bad rear main seal leak because of a rock hard rear main seal leak. It softens and restores pliability to rubber while it disolves the varnish and sludge. I changed the RMS in my DIL's RX and believe me, it was like a rock! It had worn a groove in the CS which is quite common. For what it costs, I would certainly try it if it were my car. It is a product (unlike many) that really works! I have no financial interest in the company whatsoever.
If you don't want to spend the money on buying it, go onto BITOG (Bob is the Oil Guy) and make a new thread, explaining your situation and you want to try auto-rx, and i can almost bet you that atleast one person will volunteer to send it to you for free...there are really great people on that forum, and they want to do research on auto-rx and see if it really works. The most that they will ask in return is going to be a picture of the valve cover before Auto-RX and after. And, you already a picture of the valve cover currently.
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