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WOT Procedure


rockfangd

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Barsleaks sole purpose was to seal possible porous aluminum castings and will do nothing to prevent or cure a head gasket leak.

Of course never cure, but prevent.... I have my own opinion. If it's purpose is to seal porous aluminum, who's to say that porous aluminum is not in contact with my head gaskets? What I am saying is that I'd like to keep my bolts & gaskets free of coolant. In addition, if the bars although unintentional of the engineers keeps seepage of coolant away around the internals of the gasket - namely the bolts, - then all the better.

I am thinking that if one section of the gasket, and not all gets wet with coolant, it will expand & contract differently from the rest causing uneven stress on the gasket, and eventually failure.

The head gasket IS the barrier between the coolant passages and the cylinders. Based on that, my assumption would be that the gasket is already in contact with the coolant, in which case porous castings wouldn't really be an issue unless it was porous enough to allow coolant AROUND the gasket and into the cylinder. By all means use the Bar's leak (I do). After all it is recommended. But I can almost guarantee you that it won't prevent a gasket from failing.

If I am wrong, I will stand corrected. smile.gif

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Barsleaks sole purpose was to seal possible porous aluminum castings and will do nothing to prevent or cure a head gasket leak.

Of course never cure, but prevent.... I have my own opinion. If it's purpose is to seal porous aluminum, who's to say that porous aluminum is not in contact with my head gaskets? What I am saying is that I'd like to keep my bolts & gaskets free of coolant. In addition, if the bars although unintentional of the engineers keeps seepage of coolant away around the internals of the gasket - namely the bolts, - then all the better.

I am thinking that if one section of the gasket, and not all gets wet with coolant, it will expand & contract differently from the rest causing uneven stress on the gasket, and eventually failure.

The head gasket IS the barrier between the coolant passages and the cylinders. Based on that, my assumption would be that the gasket is already in contact with the coolant, in which case porous castings wouldn't really be an issue unless it was porous enough to allow coolant AROUND the gasket and into the cylinder. By all means use the Bar's leak (I do). After all it is recommended. But I can almost guarantee you that it won't prevent a gasket from failing.

If I am wrong, I will stand corrected. smile.gif

We are all saying the same thing & We all understand the original Purpose/intent of Bars. I am just trying to keep my headbolts dry. Of course I cannot say with 100% certainity that it will do anything, and I am definately not saying I have cured the dreaded NS headgasket failure. But I am just sticking to what I have been doing & letting the community know what & why.

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If you all get Ultimate Factories from the National Geographic cable channel, there is a show on now about how a Ferrari is made, it is not quite as good as how the Corvette is made BUT, when they build the V12, it is STUDDED..... Each engine is hand built, which you would expect, as is the V series engines. It is interesting to note that the Ferrari usings magnetic ride control struts made in the US baby!

If you can check it out, I watched it yesterday, Mike

http://shop.nationalgeographic.com/ngs/browse/productDetail.jsp;jsessionid=0DC0AB606FAD02910B8FED580B03FC5E?productId=1095136

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Carla, the porous casting could be any aluminum component, head, block, crossover manifold, water pump cover. It has nothing to do with head gaskets. I believe it has more to do with the aluminum casting process which in RARE cases could produce a bad casting. I guess GM thought it serious enough to use the sealant tabs. Not sure if the process (or the aluminum make up) has changed, but they no longer use them.

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Carla, the porous casting could be any aluminum component, head, block, crossover manifold, water pump cover. It has nothing to do with head gaskets. I believe it has more to do with the aluminum casting process which in RARE cases could produce a bad casting. I guess GM thought it serious enough to use the sealant tabs. Not sure if the process (or the aluminum make up) has changed, but they no longer use them.

I do realize that. What I was saying is that I don't think porous casting could cause a head gasket failure unless it was bad enough to allow coolant to pass around the gasket...in which case it wouldn't really be porous, but more of a relatively gaping hole...and that I don't think coolant contacting the gasket would cause failure either.

I read somewhere that the porous castings were caused by the sand that was used in the casting process. Perhaps that has since changed and done away with that concern? Just a thought...

big4870885.jpg

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Carla, the porous casting could be any aluminum component, head, block, crossover manifold, water pump cover. It has nothing to do with head gaskets. I believe it has more to do with the aluminum casting process which in RARE cases could produce a bad casting. I guess GM thought it serious enough to use the sealant tabs. Not sure if the process (or the aluminum make up) has changed, but they no longer use them.

I do realize that. What I was saying is that I don't think porous casting could cause a head gasket failure unless it was bad enough to allow coolant to pass around the gasket...in which case it wouldn't really be porous, but more of a relatively gaping hole...and that I don't think coolant contacting the gasket would cause failure either.

I read somewhere that the porous castings were caused by the sand that was used in the casting process. Perhaps that has since changed and done away with that concern? Just a thought...

Correct on both counts.

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  • 4 years later...

First timer on the Cadillac Forum. I've read so many informative and enlightening posts I couldn't help myself, I had to sign-up.

I recently purchased a well cared for, 13 year old, 80k mile Cadillac DTS. Given the age, condition and number of miles, this hot rod was lucky to see 6k miles of highway a year on average. Given the toll the Southwest desert sun takes on paint, she was likely kept nicely tucked away in a garage when parked. I would place it in the category of "luxury grocery getter with an occasional day trip to somewhere".

Since I've not been in the habit of finding the floorboard with the back of a gas pedal for a while, it surprised me the first time I chose to do so in the DTS. Wow! talk about the cloud of grey smoke! It didn't start out that way, but at about the time it hit 6-grand, she was blowin' and goin'. Back in the day, when you saw that large amount of grey smoke, it typically meant you were due a ring or valve job and things were likely to only get worse. Needless to say it kinda freaked me out. Motors with this kind of mileage don't typically blow this much smoke, unless they've been trashed.

I need say no more regarding my reasons for joining the Cadillac Info Forum. Jan's post was the final read I needed to put my concerns to rest.

So, my checklist for this evenings journey home is a bottle of Techron, a fresh tank of gas and a clear stretch of highway. I can't wait.

Many thanks.

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Keep hammering it until there is no more grey/black smoke. That is the carbon being blown off the tops of the pistons. Put the gear selector in 2nd gear and punch it at 45 MPH - run it up to around 70 but before the PCM shifts it to 3rd, then let off the gas and let the engine brake it down to 45 and repeat. The engine braking generates a lot of vacuum and will exercise the piston rings so they do not stick in the grooves.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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KHE,

Thanks for the input on the process. Prior to start I filled the tank with Chevron and a bottle of Techron. Since leaving the post, I've noticed a significant decrease in the amount of grey smoke at WOT (a small amount just as it nears red-line). Another by-product is that it seems to run a little smoother, no more "ticking" and it has a bit more "go" off-idle. It's pretty amazing how the Northstar transforms and "comes to life" at around 4,500+, it just goes. I will guess that this is the first time this motor's been run through the WOT. Is there a general rule of thumb on how frequent this procedure should be performed afterwards?

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KHE,

Thanks for the input on the process. Prior to start I filled the tank with Chevron and a bottle of Techron. Since leaving the post, I've noticed a significant decrease in the amount of grey smoke at WOT (a small amount just as it nears red-line). Another by-product is that it seems to run a little smoother, no more "ticking" and it has a bit more "go" off-idle. It's pretty amazing how the Northstar transforms and "comes to life" at around 4,500+, it just goes. I will guess that this is the first time this motor's been run through the WOT. Is there a general rule of thumb on how frequent this procedure should be performed afterwards?

Everytime road conditions (and gas prices) allow lol

Bruce

2016 Cadillac ATS-V gray/black

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KHE,

Thanks for the input on the process. Prior to start I filled the tank with Chevron and a bottle of Techron. Since leaving the post, I've noticed a significant decrease in the amount of grey smoke at WOT (a small amount just as it nears red-line). Another by-product is that it seems to run a little smoother, no more "ticking" and it has a bit more "go" off-idle. It's pretty amazing how the Northstar transforms and "comes to life" at around 4,500+, it just goes. I will guess that this is the first time this motor's been run through the WOT. Is there a general rule of thumb on how frequent this procedure should be performed afterwards?

The coming to life around 4500 is due to the overhead cam design of the Northstar. Thre was a 5.0 L Northstar V8 in development but that got screpped during the 2008-2009 time period. I would bet it would have had cam phasers that would give the low end torque typical of a pushrod engine along with the high end power that an overhead cam engine makes - the best of both worlds.

There's no rule of thumb - I do it every so often - if there is no crud coming out of the tail pipe, I don't tend to repeat it very soon.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I don't do the full WOT procedure, but I will "STAND ON IT" on an entrance ramp when I am going slow enough for it to drop all the back to 1st gear.
Then I let it run thru the gears up to about 100 a few times a month...

It keeps the soot blown out of it, plus I just like hearing the sound of the Northstar at high RPM...LOL :)

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I don't do the full WOT procedure, but I will "STAND ON IT" on an entrance ramp when I am going slow enough for it to drop all the back to 1st gear.

Then I let it run thru the gears up to about 100 a few times a month...

It keeps the soot blown out of it, plus I just like hearing the sound of the Northstar at high RPM...LOL :)

Jim, over the years, i have been amused at your road trip stories.

If it weren't for new members constantly joining, i'd vote to rename WOT the "Texas Jim"

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