lexus-is2

My 2006 IS250 RWD is just over 180k miles (miles not kilometres) i do oil changes approximately every 5k miles because of the high mileage. Been noticing oil residue along certain areas of the engine block and even at the block where the intake pipe connects even though that hose gas no leaks whatsoever. There's also residue around certain areas of the sump but there is no oil dripping or anything. I don't get any drips of oil. Just wondering if anyone could shed some light on this?

Gville350

iTrader: (10)

Well, what I'd recommend for locating the source of an oil leak is to first clean the block surface with brake clean. Then monitor the problematic area thereafter for the source of the leak. Once the area is cleaned, you should more easily find out where the oil is dripping/running from.

Another test is adding an oil-safe UV dye into the engine and taking a black light to the leaking area to see where it is coming from.

lexus-is2

Thanks for your reply. I suspect that it may be the cam covers both sides of the engine block. When I did my spark plugs change 3 years ago I noticed oil residue around the parameter of the block where the cam cover is. There is also little recess pockets where leaking oil ends up just sitting. I cleaned it all up back then but looking at it now again it seems dirty again and i' thinking maybe oil seeping out of the came covers is making it's way down to other areas. Also when I removed my old spark plugs i was getting little amounts of oil on the back of the plug as i'm lifting it out. So I suspect maybe the seals inside the cam cover that seal the spark plug tube also are not sealing properly. Are there any risks to leaving a leaky cam cover? Considering it's been like this for a good few years and I don't really lose that much oil between oil changes and i'm not having oil drip down to under the car or anything. I think maybe at some point I may attempt to do it myself as taking it to a garage will cost a fortune because the cost of the repair is mainly the amount of hours of labour. Material's isn't really much just the gaskets right? Do I need to change the top intake manifold gasket everytime I open it? I changed it when I did my spark plug change.

Is the timing chain cover different to the two cam covers?

2013FSport

iTrader: (2)

No real risk. Timing chain cover is a whole different beast. Like, some would sooner pull the engine.

Check PCV system at both valve covers and make sure neither are plugged. If the crankcase is building pressure (unable to vent it), it can make seams seep.

PLUGS: if the plugs were not tight, combustion gasses go past the threads and make a black oily mess that looks just like coil. Actual oil leaks will fill the plug wells.

Tighten plugs until they stop turning under light to moderate pressure; prevents this oil like build up...

lexus-is2

So the cam covers are the metal covers on top of each side of the V block? This isn't the timing chain cover? The reason I asked is because from some videos I watched when the cam covers are removed you can see some sort of chain on each side of the V under the cam cover. Where exactly is the chain cover?

When you say check PCV system on both sides. What exactly am I looking for? On the right side there is a PCV valve which I replaced about 3 years ago and on the left side is it the hose that goes from the engine block to the air intake tube?

Does leaks like this not effect oil pressure etc? Is engine oil dye safe to leave in the engine oil? Or should it only be used before I plan to do an oil change?

Moisture

Sounds like some seals/gaskets leaked a bit of oil and then sealed themselves up from the heat. Not a big concern until you get oil dripping onto your belts. Now that would be problematic.

lexus-is2

By belts you mean the serpentine belt? Oil doesn't seem to be making it's way that way as far as I can see. I had the car up on the ramp so inspected from underneath. The right side Bank 1 of the V hardly has any oil residue. The Bank 2 left side part of the V when I look from underneath through the gap I can see oil stains and residue just above where the Air Fuel Ratio sensor and manifold is. So whatever leaks out probably gets dried by the heat of the manifold etc. That is the main area I could see oil stains but not enough oil to make a drip or puddle anywhere. It doesn't leak down on to the ground or anything.

Moisture

Hmm. Have you pulled out your spark plugs recently? Are they looking burnt? Is your coolant reservoir full? Not noticing any overheating? Any check engine light? Have you replaced any faulty ignition coils?

2013FSport

iTrader: (2)

WITF are you ^^ doing!!!!!? STOP!!!!
OP ignore this foolishness. It has zero relevance to your cause. Someone likes stirring the pot for the sake of controversy and/or getting threads locked during said controversy.

XXXXX
As for the seepage, the V-block has heads. Those start just under the exhaust manifolds. Above the exhaust manifolds are the valve covers which also home the camshafts. When the valve covers are removed, it does expose the camshaft drive chains at the top of the engine. That said, a bulk of the chain is covered by the front cover which also covers the front end of the crankshaft.

FWIW: as the rubber o-ring harden on the valve cover, they weep. This in not uncommon over time. It has nothing to do with "resealing from heat". It is the opposite. Heat cycles harden and reduce elasticity of rubber and polymer sealants. So I'm not sure what mr rain is implying.

Gville350

iTrader: (10)

It sounds like you have both leaky valve cover gaskets and spark plug tube seals. But check your PVC first. If its clearly makes a rattle-type noise, it's GOOD. Reinstall. Then time to address the actual issue, the leaky gaskets/seals.

Do it all at once!

2013FSport

iTrader: (2)

^^ yes, as long as PCV is working... if its just a film with no drips and no oil loss...... Clean and drive!

firelikeiy

That's where my car developed a leak while under warranty. No leaks under the car but there was a sheen of oil all around the front bottom half of the motor. The dealership had the car for 5 days to repair it. The service rep even made it sound like it was a pita to repair. At least they gave me a new water pump as well and a RX as a loaner.