strange oil leak at the heads

[kikkegek]

about 2000 miles ago I have had the heads replaced. refurbished heads with copper guides and teflon seals. Heads were flattened to make sure they seals nicely.

oil consumption went down from 1 quart every 600 miles to 1 quart every 1200 miles. so thats good improvement. And the coolant stays clean. car ran superweet for some weeks....dirty nr3 sparkplug stayed clean....so I was happy.

recently the engine started to run a little rough at idle and starting became a little harder.

any ideas? I have no clue where this oil is coming from and how external oil can clog the plug so much?

nr 1 cilinder

nr5 cilinder

the glossy black makes it a pain in the ass to see where it is leaking. The shop decided on that color...never again glossy black on my engine parts...

all other cilinders had a light-brown-yellowish-whititsh color and some had very little light white composite on the tips. so those are fine.

looked at the engine again yesterday and pulled the plugs after a night of letting it sit.

nr1 cilinder
bottom

topview

driverside front corner near nr1 cilinder

nr5 cilinder
bottom

topview

how can it leak oil at the gasket, when there isnt any oil near?

 

[mathd]

It may sound stupid but, it look like its coming from the valve cover

 

[kikkegek]

It may sound stupid but, it look like its coming from the valve cover

already checked that and the valve covers and gaskets are dry...

 

[grumpyvette]

http://forum.grumpysperformance.com/viewtopic.php?f=54&t=1800

READ THRU THIS LINK
http://www.chevyhiperformance.com/tech/ ... index.html

http://www.chevyhiperformance.com/tech/ ... index.html
there is an oil passage that was supposedly plugged under the heads that if its leaking could be a source of an oil leak, but its supposed to be plugged.
these threads may help, BTW an improperly sealed intake gasket could easily be the source of the oil fouling the plugs and oil leaking onto the engine as could a bad oil pressure sensor,bad valve seals, worn valve guides, or leaking intake manifold front or rear seals, and you won,t be the first guy with a PVC valve or valve cover breather or dipstick that leaks oil

viewtopic.php?f=44&t=1430&p=3168#p3168

viewtopic.php?f=44&t=308&p=373&hilit=valve+cover+gasket#p373

viewtopic.php?f=55&t=4891&p=13459&hilit=dimple#p13459

viewtopic.php?f=50&t=1859&p=17369&hilit=studs+sealant#p17369

viewtopic.php?f=52&t=2005&p=5328&hilit=positive+crankcase#p5328

 

[kikkegek]

hi thanks for the reply.

I checked my PCV and its working fine.

I'll do some reading, thanks for the info.

is there an easy or quick way to check intake gasket? remove the carb to see or some thing else?

 

[grumpyvette]

theres not really,any way to easily inspect and check the gaskets seal, without removing and inspecting the intakes , simply because theres a huge range of how badly the intake gaskets leak, theres at least a dozen different gaskets that could have been used with different size ports, and other potential problems ,especially if the heads were angle milled and the intake was not milled to match exactly, you can in some cases use an optical inspection tool that allows you to look thru the spark plug holes and down the intake runner when the engines not running and that can be useful but removing the intakes usually the best route
(do a google search on (SLIPV618)

viewtopic.php?f=50&t=2988&p=9055&hilit=angle+milled#p9055

viewtopic.php?f=52&t=5537&p=16750&hilit=1205+1206#p16750

 

[kikkegek]

something else I checked yesterday. I stood behind the car while my wife started it (yes I know! very dangerous!) to see if there is any smoke during the cranking or afterwards. well....there isnt..no smoke during cranking or after it starts. The exhaust fumes are clear and frankly invisible.

thats strange, because the fouling of the plugs would suggest some interal oil leak and that should produce some smoke after sitting a night?

 

[kikkegek]

we checked today and the whole engine seems to be dry above the spark plugs. We cant find a leak.

the oil on the spark plugs is from inside the engine cilinder, because its only on the sparkplug up to the tapered part and not beyond. so its from inside.

the oil on the outside of the engine is probably coming fro a remote leak somewhere and flowing along the edges. need to look into that.

we have now tried one degree hotter plug in the nr5 cilinder, where the fouling is the worst, to see if this fixes the fouling and burn the oil.

I'll check the plug in a couple of days.

the lines from my engine oil cooler sweat a some oil, maybe it gets on the engine from there?

 

[grumpyvette]

something else I checked yesterday. I stood behind the car while my wife started it (yes I know! very dangerous!) to see if there is any smoke during the cranking or afterwards. well....there isnt..no smoke during cranking or after it starts. The exhaust fumes are clear and frankly invisible.

thats strange, because the fouling of the plugs would suggest some internal oil leak and that should produce some smoke after sitting a night?

a leaking intake gasket or leaky head gasket will fairly frequently suck oil mist from the lifter gallery., or allow coolant to seep into the combustion chamber only after the engine heats up and parts expand, and oil thins, and/ or coolant pressure increases and if the intake sucking oil mist will usually burn to ash during combustion, leaving that residue , now obviously if the amount of oil mist or coolant entering the cylinder is minimal the smoke or lack of smoke due to complete or almost complete combustion will be minimal

 

[kikkegek]

the thing is, when I clean the plugs, the engine runs very smooth, is responsive and has good power.

I have tested for 25 miles now with a one degree hotter plug R44TS in stead of CR43TS I had in the nr5 cilinder with the heavy fouling. I bought the car with CR43TS and never give it a thought. untill I checked with ACDELCO and my VIN code M type engine is a 350 V8 Heavy Duty 4 bolt main. and ACDELCO says that L type (350 V8 2 bolt) should use R43TS and M type (350 V8 HD) should use R44TS...dont know why...but now the plug seems to stay dry.

So maybe I'll try one class hotter plugs and hope that solves it for now.

 

[Ken]

Had an issue with the rear of the intake sealing by the oil sending unit, top large flat on block to intake, also I had hear the steel tube and or elbow for oil sending unit will crack.

 

[Grumpy]

also check BOTH sensors that may be near the distributor

both these sensors, located near the base of the distributor on the block, are known to fail & leak,oil at times, especially the smaller one with two blade connectors

 

[Ken]

One of my bud's said that sometimes when people put the engine in they hit the fire wall and crack this unit that Grumpy posted above...