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2007 cadillac dts 4.6 y


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I have fixed at least a thousand northstar engines from 93-08 so far and I have NEVER seen a secondary chain break. I have had the secondary chain tensioners collapse and bend all the valves on that bank. I have never replaced a chain on a northstar in my 23 years of this motor, just tensioners. Now I do know that the 3.6 chains are junk and stretch and cause problems.

Edited by barczy01
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Under is 3 photos, one hole isn't smashed, so I think that one bolt was broken as a new or when previous owner changing timming chain. Aparted bolt I found seamlessly keyed. Head of that bolt havent any scratch, rest bolts have.

Thousands km and whidout one, rest making loose, til fell out totaly. I heard noises but it sound like valve lifters (in fact few shuld be changed), so I ride confident that I still have taime to change lifters.

IMG_1.jpg

IMG_2.jpg

Edited by Kris Poland
forget to write one sentence
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Great pics.

I wonder if those are the bolts that belonged in that usage - are they the OEM bolts?  The threads in all 3 appear to have been effected, although once the one broke the other two may have come under undue stress.   I agree the one must have loosened, then allowing some movement of the base, which allowed the wear of the hole as shown, and cut/broke  the loosened bolt.

Bruce

2023 Cadillac CT4-V Blackwing

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Kris, look at the two bolts that didnt have their head sheared off, I see the tops are very shiny.  Can you show me 1) a photo of the top of the sheared off bolt and 2) the inside of the sprocket where the bolts must of rubbed.  

It certainly does look like the bolts loosened up.

How are the threads those three bolts in the block?, are they damaged?

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/

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All three bolts show thread damage.  I looked in the 2006 FSM for Timesert data and found nothing specific to the intermediate camshaft drive shaft bolt holes.  The thread repair addresses the head bolts and case half (crankshaft main) bolts in detail, and these have templates from GM/Timesert, but other bolt holes are covered by a series of generic procedures for flush holes, recessed holes, etc.  The intermediate camshaft drive bolt holes are flush holes.  These are in M6, M8 and M10 sizes and must have a counterbore to allow the insert flange to install flush with the surface.  Be sure that you have everything you need (taps, tap guides, counterbore tool, tap lubricant, spray can cleaner, threadlock, etc.) before you begin.  Timesert or GM can supply the tools (Amazon or equivalent is good, too!) and inserts and you can get the fluids and spray can cleaner locally.

There is a camshaft intermediate shaft plug under the intermediate camshaft drive shaft - you can see it in the photo in this post that shows the damaged bolt holes.  This tap-in sheet metal plug separates the crankcase from the timing chain area.  It's very touchy and there is a lot of bold color text about it in the FSM.  Install it too deep and the crankshaft counterbalance weight will hit it.  Too shallow and it can interfere with the oil passages to the cylinder heads.  If it's OK, be sure not to damage it so you don't have to mess with it.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Kris, since you are actually seeing the failure in person I am looking for input from you. Photos by themselves don't tell the story.  All three bolts DO NOT show thread damage.  The thread  damage on the 2 bolts that still have their heads occurred from those bolts BEING LOOSE and the fixture itself banging up against the threads, but, the bolt threads that were screwed into the block do not appear damaged.  

The 3rd bolt with its head sheared off has damage where it engaged the threads in the block, but it looks like that bolt came out the furthest and had its head sheared off.  Its possible that the chain sheared the bolt's head off when it came off and went behind the sprocket.

It looks like the chain ripped off the sprocket teeth when it fell off the sprocket due to misalignment due to those three bolts being loose.  

I don't understand how those three bolts could loosen up, was engine work done to this engine?  It appears this went on for awhile given the bolt indentations into the fixture at the bolt hole locations.  

If that bolt that lost its head snapped early on, the other 2 a Bruce said, took undue stress, rocking the base, eventually creating those indentations and further loosening/rocking and subsequent chain misalignment leading to the chain running off the sprocket.  

This engine will need a total teardown due to the debris 

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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To me....the bolts have the appearance of being GM oem bolts. Kind of a hard look to get aftermarket. They certainly do not appear to be of Home Depot or NAPA type level quality. 

It looks as if all 3 were getting loose....witness marks show some rubbing on the head of the bolts...maybe the one failed bolt finally was snagged by the backside of the gear.

I see no evidence of any thread locker on the bolts at all.

The original threads certainly must have some damage. Yeah...maybe...maybe Time-Serts will work. Likely the Kent Moore J-42385-200 kit has the tooling to do it.

Surely the valves are bent. Both heads will have to come off to fix this one.

If you were in the US...I would suggest a used engine might be a more reliable solution to fixing this one.

 

Update.....Time-Sert is great stuff for a stripped thread....not so great for what is likely some oblong wobbled holes. I did attach a pic of some of the Time-Sert rental stuff I have here. These M10 tools are from the Kent Moore J-42385-200 kit. Drill...counter-bore...tap...driver. And a M10 Time-Sert on the driver tool.

 

 

 

 

 

200kit.jpg

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 Hello!

I apologize for my long silence, but I Got very havy week of wór.  Im not a mecanik,  so my car is ony hobby. 

My plan is to do like Logan says, but not M10 fix, Iwan to make M8 hole with new bolts.

BodybyFisher, after my Holiday I make photos you want. Third Bolt head looks like new opposit to rest two.

Logan, unfortunately, I am stil in Poland , and its very difficult to buy a used same motor...
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We can continue to work with you on the teardown and diagnosis.  You can use the old idler sprocket mounting bracket as a template to make sure that the holes are configured so that the new bolts are centered in the holes and hold the new idler sprocket mounting bracket firmly.  This engine has VVT controlled by the ECM so a tiny bit of variation in the position of the holes won't make a measurable difference.  Other problems in the heads, etc. will take time but since you are doing the work yourself the cost isn't too high.  You have a fine car, so I would keep working on the engine.

While the teardown is in progress, you can look online for a recycling yard in Poland, Germany, and other nearby areas that will ship to you.  We have some people in Sweden that are active here and they may have some advice on recycling yards and the SRX.  Anyone know the year range for full compatibility with the 2006 LH2 Northstar?

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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5 hours ago, Kris Poland said:

 Hello!


I apologize for my long silence, but I Got very havy week of wór.  Im not a mecanik,  so my car is ony hobby. 

My plan is to do like Logan says, but not M10 fix, Iwan to make M8 hole with new bolts.

BodybyFisher, after my Holiday I make photos you want. Third Bolt head looks like new opposit to rest two.


Logan, unfortunately, I am stil in Poland , and its very difficult to buy a used same motor...

Kris, if you need anything let us know, we can maybe find and send it if you have difficulty getting something.  

Aren't the existing bolts M8?

Enjoy your holiday!, be safe

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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I know...your not in the US. A engine will be very difficult to find.

I don't think M8 is beefy enough for the job...but that is certainly only my opinion. Pretty major spinning engine component.

The heads will certainly have to come off. Fixing what might be 32 valves if all are bent will take a while.

There may be some useful info about the different Northstar compatibility here:

https://en.wikipedia.org/wiki/Northstar_engine_series

The holes look wobbled damaged to me.

 

 

northstarm10.JPG

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  • 2 weeks later...

Thinking about it.....

A Helicoil won't work.....a standard Time-Sert likely will fail....a M8 is likely not beefy enough...

There are Big-Serts available. They are used as a second attempt repair. Much beefier than a standard Time-Sert.

These are used to replace a failed Helicoil or failed Timesert.

I attached a Big-Sert size chart and a picture of a standard M11 Time-Sert next to a M11 Big-Sert.

 

 

bigsertchart600.jpg

 

 

timesertvsbigsertsnip.JPG

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  • 1 month later...

Hi!

It take a while, but at least engine work (hope that for long years :) )

After disassembly heads it turned out that only 4 exhaust valves and 2 intake was bent.

So, I did like I said before, drill new hols in place of old one, make new thread M8.

// I think, if I was first, that means, that orginal M6 is strongly enough. That why M8.//

Head was totally repaired, valves, gaskets, lifters, etc...

Mount new timming set and idler sprocket.

And engine WORKS!!! Already about 5 hours. IM PROUD FROM MY,  becouse I did It by my self.

 

 

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:bluesbrothers:

Congratulations.  This story went from a mountain to a molehill and ended with a cruise.  Report back after a week or two.  Remember break-in precautions!

Do we have an award for people who achieve things of this magnitude?

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Great job!  Good for you!

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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Thank you all for your help and support.
Now is the time to play with by rear lamp and navigation.

Can any of you feel strong enough to help me by electric components??

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Sure.  Reset the codes, drive it for a day or two, then dump the codes and post them here.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Its not a problem with "check engine", that problem was solved already.  There is no new codes, engine work proper :D

Now I got other problem with radio/navi does't work totally. I dont know why, becouse I bought car with that fault.

I check fuses and its ok. When I put power on (acu agin) cd changer positioning and thats all... Display is black.

Another problem that turn signal blik rapidly, but bulb on front wok properly (bliks :) )

 

Is it right topic for it? maybe I should make new for SRX?

 

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If the timing chain problem is fully solved and we are off to other things, then, yes, we should have another topic.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Congratulations!

That was a really nice work and I'm sure that it will work fine from now on. I really hope that you used Time-Serts for the heads?

I understand the concerns about thread integrity lifted previously in this post but I think they are non-existent in this case. Time-Serts is what is recommended to repair failing threads on certain highly dynamically loaded points. For instance in head thread repairs, where the screws see a high dynamical load variation, mostly stemming from the warming and cooling of the engine. A Heli-coil would "creep" out with time and cause head gasket leaks. But a thread repair kit makes it possible to use the OEM screw size. In this case it really doesn't matter what size of thread you use. If you "oversize" the original thread to a M8 instead of M6 all the old material from the original M6 thread will be removed (as long as the holes are not deformed too much). On this particular spot I would say that the load variation that the screw "sees" is about zero because this particular joint works as a friction joint. The small amount of load variations the intermediate sprocket shaft sees does not transfer to the screws. They only see the clamping force that prevents the entire assembly to move away. Then there is the fact that you always try to make a screw joint as long and as small as possible to get as high clamping safety factor as possible. But I don't think it is a problem here either.

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Thanks Jan!

I disappoint you, because I used only new bolts for head. I even don't known that it's important to use Time Serts for it. If You say so, then I got hope that it will be enough and new head gaskets will not leak in future.

Any way, thread on head screw looks different than usual thread. As I understand there exist kit for it?

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There is a lot of information about Time-Serts in the archives but in short they are needed when you have to replace the head gaskets. The reason is that the threads most likely will be ruined to some extent when you loosen the head bolts which are tightened very hard (and that was done to get as much clamping force as possible from that particular bolt). Other parts of the engine requires a lot less force to keep the parts together but this is a very tough spot whith a lot of thermocycling (when the engine heatens up and gets cold again after use) and the need to ensure that the gaskets seal at all times. No need to have them installed in factory but when you do a head gasket job you'll likely get problems again because the threads are weakened. Heli-coils are designed for repairing steel threads and won't work in aluminium threads exposed to high dynamical loads. Time-Serts are a threaded bushing that will replace the original thread. The reason they are used in some engines and not in others could be debated for years. But a combination of expected temperatures, safety factor against failing, material choises, clamping lengts, gasket thickness, gasket materials number of bolts and method to cast the block all contributes to the design and need to use Time-Serts.

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Kris, see this site for more information

Http://Www.timesert.com

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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