2005 LM7 and Sea Foam

[Alberta Tahoe]

My 05 Tahoe, with a previously poorly maintained 200 000 mile LM7 is a oil burner. And a leaker too. Before I pull the valve covers and address what is probably a valve guide seal issue I'd like to try the Sea Foam vacuum trick.
Looking through ALL of the online tutorials it seems that the procedures are many and varied.
Anyone here have a refined and proven approach for adding an additive to a running engine via a vacuum line?
I'm guessing that the PCV system is pretty much plugged and am thinking that an injection or two might provide some relief.

 

[strutaeng]

I have never hear of adding Seafoam through the vacuum hose, but I'm no expert either...

Why not add it to the fuel tank, since you suspect the injector(s) may be plugged? The method of doing a few WOT accelerations (on an engine at full operating temperature), aka., The Italian Tune is also reportedly a good way to burn off carbon deposits.

Since you know the truck had poor maintenance, I would strongly recommend you do a compression and leakdown test. That will provide cranking compression on the cylinders and tell you where you have compression losses, which is likely where your oil consumption problem lies.

 

[Alberta Tahoe]

Sea Foam, or similar additives, through a vacuum line seems to be a popular method to address the crankcase and valve cover sludge issues. That in turn is supposed to help with the PCV problems as they're all interconnected.

I've no doubt the injectors are in poor shape and I've done several fuel tank additions of a number of "cures". More directly I've used Sea Foam's aerosol spray (maybe 4 times) into the throttle body with the engine running. I can't say for certain if there was much improvement.
I've also added several bottles of Liqui Moly Motor Oil Saver in an attempt to help with the potentially poor (and most likely ) valve guide seal condition. The results of that too are debatable. The HUGE cloud of blue smoke on start time is a tell tale sign of that.
Doing the hard acceleration with another car following (when it's dark and the headlights are on) doesn't show any smoke out the tailpipe visible in the lights behind. The rings may still be in good shape. Undoubtedly suffering from the oil consumption though.

At one time, the engine threw a misfire code on cylinder 4. It was plain to see that number 4 spark plug was completely fouled with deposits but it wasn't oil. Kind of a yellow/green crust that I figured was the result of the stuff I'd been dumping into the engine's crankcase and fuel tank. New plugs, although clearing the trouble code didn't do much to improve the overall condition.

I can practically guarantee that when I pull off a valve cover it'll be full of slime and gunk. It's not an uncommon problem. I'm postponing that until the nicer weather is finally here (no garage to work in and it's -20°C ! ). In the meantime if I can manage this vacuum line treatment, maybe that'll provide some relief.
If the crankcase ventilation is compromised then the excessive pressure will contribute to oil consumption and leaks. That's where I think I'm at. That and other things actually.

As for a compression test and leak down test, that's always a good diagnostic practice but to tell the truth, I couldn't be bothered. At least not now. It might be in the books if I park this rig for the summer and do a full round of maintenance and repairs. That said, given my work load, both in my day job and around the fort, that'll be a process done over several weeks.

 

[Scottydoggs]

ive used sea foam in another car. its not going to fix any leaks. it cleans the valves and the pistons, maybe some intake oil. if you pull the pcv valve out of the valve cover and shake it and hear a ball rattle inside the pcv valve is fine. no rattle its all clogged up. buy a new one.

the way id go about using it in a tahoe 5.3. likely has hydro boost brakes, so no va cline to a booster to use, i would be to pull the hose off the pcv engine running and pinch the hose to stop the vac leak, then pour the sea foam into the end as you open the end up and let it suck it in, bottle says 1/3 of a bottle into the intake, then give it a healthy amount of sea foam and let the hose open, engine should stall out. if it dont shut it off asap. let it sit for 20 minutes. then re fire and rev the snot out of it. should smoke a lot out the tail pipes.

 

[afpj]

I've always wondered how that does not shorten Cat life?

 

[Fless]

Your '05 likely has no removable PCV valve; it's integrated into the driver's side rocker arm cover. You might be able to clean the passages while you have it off. If it's really plugged, consider just replacing it with the newer style cover.

Does it have vacuum boosted brakes, or hydroboost?

To clean injectors, run a tank of E85 if it's a Flex Fuel engine, or use Techron in the tank.

 

[Alberta Tahoe]

There's no PCV valve, per se, on an LM7. It has a fixed orifice type of PCV control and that orifice is at the rear of the driver's side valve cover. THIS is the part that gets plugged. With a plugged orifice, the result is increased crankcase pressure. That's where the leaks come from. And since the crankcase can't breath, the combustion gases that get pushed past the rings build up as sludge and make things worse.
For the record, lifted from the www:

Key Details for 2005 LM7 PCV System:

Location: The orifice is located at the rear of the driver's side valve cover.

Design: It has no moving parts and consists of a small, calibrated hole that can become clogged with sludge.

Maintenance/Fix: Because it is built-in, you cannot simply swap a $5 valve. If it is clogged, you must either remove the valve cover and clean the baffle, or replace the entire driver's side valve cover.

Symptoms of Failure: Excessive oil consumption, smoke on startup, or oil in the intake manifold.

I believe you are correct on the hydroboost. So the vacuum booster isn't an option. I'll have to further investigate other vacuum line routing. Maybe right where the hose is attached to the valve cover is a reasonable option.
Or maybe I'll just bite the bullet and pull the valve covers. When I do, I'll post pictures of what I find. But that's months away.

 

[Alberta Tahoe]

I've always wondered how that does not shorten Cat life?

That's also a concern of mine. That oil burning isn't doing the cat any favours that's for sure. It's only a matter of time before another DTC gets thrown for just that.

 

[Fless]

You might consider running a catch can.

 

[Alberta Tahoe]

You know, it's interesting that the further this conversation goes, the more I think it is a PCV problem and not the valve guide seals.
When the warmer weather arrives, the valve covers are coming off for sure.

 

[Alberta Tahoe]

You might consider running a catch can.

Very common practice on the LS engine swap platforms. I run one on my hot rod Camaro although that's with a Gen 1 SBC. Very helpful with a tired engine.

 

[Alberta Tahoe]

Your '05 likely has no removable PCV valve; it's integrated into the driver's side rocker arm cover. You might be able to clean the passages while you have it off. If it's really plugged, consider just replacing it with the newer style cover.

Does it have vacuum boosted brakes, or hydroboost?

To clean injectors, run a tank of E85 if it's a Flex Fuel engine, or use Techron in the tank.

Seems the valve cover cleaning and or replacement might be the cure. Which is far easier than valve guide seals.
As for flex fuel, not in this case. And Techron, that's difficult to find but not impossible here in Canada.
I did manage to Amazon order Berryman's B12 and added a few of those to the tank. But as reported above, results were difficult to quantify.

 

[Marky Dissod]

... if you pull the pcv valve out of the valve cover and shake it and hear a ball rattle inside the pcv valve is fine. no rattle its all clogged up. buy a new one.

Replaced my PCV valve that used to rattle, with a 12572717 (that part number may be old by now?) PCV valve that's more like a whistle with no moving parts.
Cut down my oil consumption considerably, using Valvoline Restore & Protect 5w30 has also helped.
Turns out the valve covers were also in need of updating, specifically to address oil consumption issues as per a TSB (whose reference no. escapes me).
Maybe you have the older valvecovers and need the redesigned ones?

... Techron, that's difficult to find but not impossible here in Canada.
I did manage to Amazon order Berryman's B12 ...

Check to be sure whatever fuel system cleaner you use has 'Poly Ether Amines' (PEA) in it.
Techron has some in it (maybe less than it used to), don't know about Berryman's, there's one called 'BG44K' that is also known to have PEA in it.

 

[Fless]

Replaced my PCV valve that used to rattle, with a 12572717 (that part number may be old by now?) PCV valve that's more like a whistle with no moving parts.
Cut down my oil consumption considerably, using Valvoline Restore & Protect 5w30 has also helped.
Turns out the valve covers were also in need of updating, specifically to address oil consumption issues as per a TSB (whose reference no. escapes me).
Maybe you have the older valvecovers and need the redesigned ones?

Check to be sure whatever fuel system cleaner you use has 'Poly Ether Amines' (PEA) in it.
Techron has some in it (maybe less than it used to), don't know about Berryman's, there's one called 'BG44K' that is also known to have PEA in it.

The SEARCH function is your friend...

See the post by @donjetman and the link to the TSB and the work he did for his.

2007 Yukon Denali low oil pressure

So I know there are a lot of threads regarding this but I wanted to ask a few questions and maybe some can help me. I have a 07 Yukon Denali 6.2 6l80 163k miles I have an oil consumption issue and a low oil pressure issue. for the oil pressure it is about 45-50 cold start. Hot idle 15-20 Hot...

www.tahoeyukonforum.com

Engine stalling, rough idle, rpm fluctuation.

I'm far from perfectionist due to lack of skill, but that sounds like something I would do. I do wonder how mine stacks up? How many miles on your truck? There are 156K on mine. I don't have a vacuum gauge...yet! I had wondered about the PCV valve since NBS LS had them but NNBS don't. Any...

www.tahoeyukonforum.com

THAT particular TSB isn't specified for the '05 engines, but if you look on Rock Auto you can see that the GM and Dorman valve covers are the newer style.

 

[Alberta Tahoe]

Replaced my PCV valve that used to rattle, with a 12572717 (that part number may be old by now?) PCV valve that's more like a whistle with no moving parts.
Cut down my oil consumption considerably, using Valvoline Restore & Protect 5w30 has also helped.
Turns out the valve covers were also in need of updating, specifically to address oil consumption issues as per a TSB (whose reference no. escapes me).
Maybe you have the older valvecovers and need the redesigned ones?

Check to be sure whatever fuel system cleaner you use has 'Poly Ether Amines' (PEA) in it.
Techron has some in it (maybe less than it used to), don't know about Berryman's, there's one called 'BG44K' that is also known to have PEA in it.

No valve in this case. Just a fixed orifice so no rattle.
As for the valve covers, that subject has come more than once and certainly something I'll investigate. They're original equipment that's for sure.
Despite this black Tahoe being as "shiny as a new penny" on the topside, the underside leaves something to be desired. As well as the engine internals. My guess is that as a city truck and operating in very cold climates half of the year, short commutes never let the engine get to operating temperature and as a result it just got clogged with gunk from the condensation that never burned off.

 

[Alberta Tahoe]

The SEARCH function is your friend...

See the post by @donjetman and the link to the TSB and the work he did for his.

2007 Yukon Denali low oil pressure

So I know there are a lot of threads regarding this but I wanted to ask a few questions and maybe some can help me. I have a 07 Yukon Denali 6.2 6l80 163k miles I have an oil consumption issue and a low oil pressure issue. for the oil pressure it is about 45-50 cold start. Hot idle 15-20 Hot...

www.tahoeyukonforum.com

Engine stalling, rough idle, rpm fluctuation.

I'm far from perfectionist due to lack of skill, but that sounds like something I would do. I do wonder how mine stacks up? How many miles on your truck? There are 156K on mine. I don't have a vacuum gauge...yet! I had wondered about the PCV valve since NBS LS had them but NNBS don't. Any...

www.tahoeyukonforum.com

THAT particular TSB isn't specified for the '05 engines, but if you look on Rock Auto you can see that the GM and Dorman valve covers are the newer style.

I've searched. Trust me. And am still searching.
Now I'm going down the updated valve cover rabbit hole...
Thanks for the link. On my way.

 

[Alberta Tahoe]

So, the TSB doesn't address a 2005 or an LM7.

https://static.nhtsa.gov/odi/tsbs/2014/MC-10114272-9999.pdf

And the updates apparently are in their 3rd revision.
So, if anyone here has the latest information, I'm all eyes.
The search continues...
And another thread started too.

 

[Fless]

Here's a link to the other thread if y'all feel like going in circles.

2005 LM7 Valve Cover Upgrade: What's the Latest?

I started a thread about adding Sea Foam via a vacuum line to address a undoubtedly plugged PCV system. Among other issues. https://www.tahoeyukonforum.com/threads/2005-lm7-and-sea-foam.157832/#post-2034167 Now I'm pursuing what appears to be a popular fix for a common problem on several...

www.tahoeyukonforum.com

 

[Alberta Tahoe]

Sometimes a circle gets to where you want go!

 

[rockola1971]

You want to remove carbon off your piston crowns in a hurry? Just pop the intake air inlet off and spray mist cold water into intake with engine running around 1000-1200 RPM. Use about a 1/2 quart of water. Clear all codes when done.

DO NOT POUR LIQUID WATER INTO INTAKE STREAM.