1G Oil Consumption

[91las]

1st off sorry for the long post. Trying to add all the info prior to being asked. Trying to pass IM and figure out where it’s drinking oil.

I am stumped on where my oil consumption is coming from. Gen 1 4g63 NA with roughly 20,000 miles on the top end. Adding 1 1/2 qts, roughly every 500 miles. Slight misfire felt. New plugs and wires, tried a coil with no difference. Tested ign module and is good. Dry and wet comp test shows decent. Dry: #1=181, 2=180, 3=185, 4=190.
Wet: #1=190, 2=205, 3=205, 4=219.
Some slight compromises there, but I have a hard time believing that is the source of consumption. Mostly smokes after a long sit and now getting worse after it sits for 12 hrs or so.
Not seeing evidence of blow by, fresh pcv. Air filter clean.
Leaning towards valve stem seals but with the low mileage on the head and proper maintenance, makes me think more than a few times on that being the faulter. Thought of doing a leak down test and filling valve cavities with oil or soapy water (under the valve cover) and watching for some bubbles. This seems like a far stretch to me.
Thank you in advance! Very much appreciated! Trying to get it through emissions. HC’s are roughly 315 on high and low speed tests. Have a top notch cat and working O2 sens, coolant temp sens, ign timing correct, windings are good in the injectors. I did have the injectors cleaned and flow tested. PCM sent off 2 yrs ago for injector caps. Did recently replace all the small vacuum lines and pretty damn certain the lines are placed correctly.
Thanks again!!!

 

[BLACK'98DSM]

Definitely sounds like a valve stem seal issue. They could have been damaged during installation, or just some new/old parts that are hardened by age. Without installing them yourself, there's no way of knowing. A good check would be pulling intake & exhaust manifolds and inspecting the valve stems. Some should be wet with oil after sitting.

 

[91las]

1st off sorry for the long post. Trying to add all the info prior to being asked. Trying to pass IM and figure out where it’s drinking oil.

I am stumped on where my oil consumption is coming from. Gen 1 4g63 NA with roughly 20,000 miles on the top end. Adding 1 1/2 qts, roughly every 500 miles. Slight misfire felt. New plugs and wires, tried a coil with no difference. Tested ign module and is good. Dry and wet comp test shows decent. Dry: #1=181, 2=180, 3=185, 4=190.
Wet: #1=190, 2=205, 3=205, 4=219.
Some slight compromises there, but I have a hard time believing that is the source of consumption. Mostly smokes after a long sit and now getting worse after it sits for 12 hrs or so.
Not seeing evidence of blow by, fresh pcv. Air filter clean.
Leaning towards valve stem seals but with the low mileage on the head and proper maintenance, makes me think more than a few times on that being the faulter. Thought of doing a leak down test and filling valve cavities with oil or soapy water (under the valve cover) and watching for some bubbles. This seems like a far stretch to me.
Thank you in advance! Very much appreciated! Trying to get it through emissions. HC’s are roughly 315 on high and low speed tests. Have a top notch cat and working O2 sens, coolant temp sens, ign timing correct, windings are good in the injectors. I did have the injectors cleaned and flow tested. PCM sent off 2 yrs ago for injector caps. Did recently replace all the small vacuum lines and pretty damn certain the lines are placed correctly.
Thanks again!!!

Just came to mind i replaced all the lifters 2 yrs ago as well for tick. Used the special tool with camshaft in.

Definitely sounds like a valve stem seal issue. They could have been damaged during installation, or just some new/old parts that are hardened by age. Without installing them yourself, there's no way of knowing. A good check would be pulling intake & exhaust manifolds and inspecting the valve stems. Some should be wet with oil after sitting.

Thoughts of if the leak down test would be somewhat helpful for testing.?

 

[dwb]

Does it smoke on startup and/or after idling for a while? That would be indicative of valve stem seals.
Do you see oil in the intake?
Is your crank case vent routed directly to the intake snorkel or do you have a some sort of filter/catch can inline? I've tried both an inline filter (bad) and a sealed catch can (good).
Any check engine codes?
Have you noticed any reduction in your gas mileage?

I'm not sure how Utah's emissions testing is compared to Colorado, but I've had successful tests on a very tired 4g63t that consumed a lot of oil (blow-by and bad valve stem seals). The key is to make sure the CAT is as hot as possible and everything else is in working order with no major vacuum or exhaust leaks. Try to pick a time when wait times are low and go for a spirited drive before hand. The only time I failed a roller sniffer test in my DSM is when the o2 sensor died.

 

[91las]

Does it smoke on startup and/or after idling for a while? That would be indicative of valve stem seals.
Do you see oil in the intake?
Is your crank case vent routed directly to the intake snorkel or do you have a some sort of filter/catch can inline? I've tried both an inline filter (bad) and a sealed catch can (good).
Any check engine codes?
Have you noticed any reduction in your gas mileage?

I'm not sure how Utah's emissions testing is compared to Colorado, but I've had successful tests on a very tired 4g63t that consumed a lot of oil (blow-by and bad valve stem seals). The key is to make sure the CAT is as hot as possible and everything else is in working order with no major vacuum or exhaust leaks. Try to pick a time when wait times are low and go for a spirited drive before hand. The only time I failed a roller sniffer test in my DSM is when the o2 sensor died.

Smokes on start up and beginning to smoke while driving. No catch can. I can see trace amounts of oil through the intake (after pvc). Ran a manual yesterday and it passes ok when the car is light up. Don’t have an inspector at my shop anymore, so im having to have someone I don’t know run it. Going to take it there now and tell them to pre condition prior to running the test

You must be logged in to view this image or video.

Does it smoke on startup and/or after idling for a while? That would be indicative of valve stem seals.
Do you see oil in the intake?
Is your crank case vent routed directly to the intake snorkel or do you have a some sort of filter/catch can inline? I've tried both an inline filter (bad) and a sealed catch can (good).
Any check engine codes?
Have you noticed any reduction in your gas mileage?

I'm not sure how Utah's emissions testing is compared to Colorado, but I've had successful tests on a very tired 4g63t that consumed a lot of oil (blow-by and bad valve stem seals). The key is to make sure the CAT is as hot as possible and everything else is in working order with no major vacuum or exhaust leaks. Try to pick a time when wait times are low and go for a spirited drive before hand. The only time I failed a roller sniffer test in my DSM is when the o2 sensor died.

No codes, and does have reduction in mpg. O2 functioning as should. Tips of plugs look lean, but all around the electrode looks rich. Put a little seafoam in the fuel to get it by (have 2 or 3 days left with free retests). So not enough time to get the valve stem seals ordered and installed with shipping and what not…if that is the culprit

 

[curt-s]

Smoke on startup is a reasonably reliable indicator of exhaust valve seals (although there are others, like excessive oil on cylinder walls or on the piston itself). I'd pull the exhaust manifold.
To determine if your O2 is functioning as it should, do you have a narrowband and a wideband installed? That way, if your narrowband is getting fouled, your wideband would be showing that as it's highly unlikely they both foul exactly the same way.

 

[91las]

Smoke on startup is a reasonably reliable indicator of exhaust valve seals (although there are others, like excessive oil on cylinder walls or on the piston itself). I'd pull the exhaust manifold.
To determine if your O2 is functioning as it should, do you have a narrowband and a wideband installed? That way, if your narrowband is getting fouled, your wideband would be showing that as it's highly unlikely they both foul exactly the same way.

Engine is stock, so standard o2 sensor-narrowband. The exh manifold is easy to pull. Intake manifold, well that’s a different story

 

[dwb]

A broken valve guide is a possibility too.

 

[91las]

A broken valve guide is a possibility too.

Damn bud. Thx for the input. I have heard some strange noises every once in a while. Very very minute, or it’s my ocd and meticulous brain running. That’s a head removal for sure.

Wouldn’t I have a noticeable difference on my compression tests for a guide issue

 

[dwb]

Wouldn’t I have a noticeable difference on my compression tests for a guide issue

Not necessarily. According to your compression tests, the valves are not greatly compromised and still sealing the combustion chambers.
A valve guide issue is pure speculation and is not a common problem. However, if that head had been rebuilt due to a bent valves, the valve guides would have been compromised and should have been replaced. If not and a guide broke loose from the head casting, it could just be floating with the valve.

 

[91las]

Not necessarily. According to your compression tests, the valves are not greatly compromised and still sealing the combustion chambers.
A valve guide issue is pure speculation and is not a common problem. However, if that head had been rebuilt due to a bent valves, the valve guides would have been compromised and should have been replaced. If not and a guide broke loose from the head casting, it could just be floating with the valve.

The head was rebuilt for the issue of not passing IM, not oil consumption. This was quite some time ago and dent timber what they replaced-maybe valve seats…? Looks like it may be time to yank that manifold and get the euro tool to compress the springs for a closer look

 

[chrysler kid]

pull the exhaust manifold and inspect for oil.

my old that had bad vale stem seals would smoke out of the cylinder when you pulled the spark plug after a long drive. the plugs would also be wet with oil.

you have compression so its not a piston ring, it is most likely the valve stem seals. the blue ones go on the exhaust and brown on the intake if I recall correctly.

 

[dwb]

Pardon my ignorance, but what exactly is "IM" and what specifically is it failing for?

 

[91las]

Pardon my ignorance, but what exactly is "IM" and what specifically is it failing for?

Emissions or smog test if u r from California. Hc’s are high. My limit is 220 and I’m around 315. One of my previous posts has a high speed manual test ran.

 

[91las]

pull the exhaust manifold and inspect for oil.

my old that had bad vale stem seals would smoke out of the cylinder when you pulled the spark plug after a long drive. the plugs would also be wet with oil.

you have compression so its not a piston ring, it is most likely the valve stem seals. the blue ones go on the exhaust and brown on the intake if I recall correctly.

I’ve been looking at stm tuned for the seals and they are all the same color, according to the websight pic. But that seems like that is the direction I’m headed. Hopefully not valve stem guides. Which there is no way of telling if they are cracked without removing the valves.
My hope is to do the valve stem seals with the head still bolted on. STM has a euro tool to collapse the valve spring and pull the keepers

 

[91las]

Emissions or smog test if u r from California. Hc’s are high. My limit is 220 and I’m around 315. One of my previous posts has a high speed manual test ran.

Update….the high speed will pass if preconditioned, but low speed drops off. To the 315 the range.