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Can someone tell me when the new Head Bolt design was first introduced eliminating some of the problems. Some say 2000 and others say 2004.

Thanks

Both... :)

There was a redesign in 2000 to lengthen the bolts and in 2004 the thread pitch was changed to a courser pitch

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Can someone tell me when the new Head Bolt design was first introduced eliminating some of the problems. Some say 2000 and others say 2004.

Thanks

"Eliminating" might be too strong a statement. :)

The saddest thing in life is wasted talent

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You just BURST my buble!

I would guess good cooling service is the best way to avoid problems? Even on a new DTS!

Well... I have not heard of ANY headbolt problems on a 2004 or newer.

Don't mean it hasn't happened... but "I" haven't heard of any on any of the forums I am on.

I did have the coolant and transmission fluid changed on my 2006 the other day.

It is at 95,000 miles.

I figured better to be safe than sorry.. :) :)

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you don't hear about 05 and newer motors being fixed because they are repaired under warranty. if i don't have to pay than i probably won't complain too loudly.

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You just BURST my buble!

I would guess good cooling service is the best way to avoid problems? Even on a new DTS!

Well... I have not heard of ANY headbolt problems on a 2004 or newer.

Don't mean it hasn't happened... but "I" haven't heard of any on any of the forums I am on.

I did have the coolant and transmission fluid changed on my 2006 the other day.

It is at 95,000 miles.

I figured better to be safe than sorry.. :) :)

I have not heard of any headbolt problems on a 2004 or newer either. Hopefully, it is not just a matter of time. Not maintaining the cooling system might contribute in headgasket failures, but nobody will probably say that properly maintained cooling system would eliminate headgasket failures completely. The bottom line- change the coolant per GM recommendations and hope for the best.

The saddest thing in life is wasted talent

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You just BURST my buble!

I would guess good cooling service is the best way to avoid problems? Even on a new DTS!

Well... I have not heard of ANY headbolt problems on a 2004 or newer.

Don't mean it hasn't happened... but "I" haven't heard of any on any of the forums I am on.

I did have the coolant and transmission fluid changed on my 2006 the other day.

It is at 95,000 miles.

I figured better to be safe than sorry.. :) :)

I have not heard of any headbolt problems on a 2004 or newer either. Hopefully, it is not just a matter of time. Not maintaining the cooling system might contribute in headgasket failures, but nobody will probably say that properly maintained cooling system would eliminate headgasket failures completely. The bottom line- change the coolant per GM recommendations and hope for the best.

EXACTLY... that's why I had mine changed the other day. :) :)

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On a somewhat related subject. I decided to buy a 1995 Fleetwood because they come with small block Chevy LT1 engines. They are not known to blow headgaskets as Northstars do. But... the exhaust manifold bolts on an LT1 loosen up and some even break off so that the broken bolt is flush with the heads. One of my exhaust bolts has been replaced by a dealer before I bought the car. Several bolts are loose. I have got exhaust leaks but am scared to even touch them. Folks on impalass forum (great forum, by the way, for those who have 1994-1996 Cadillac Fleetwoods) usually replace all the original GRADE 5 bolts with GRADE 8 ones. They say GRADE 8 works just fine. Now... I do not even ask why GM would not use GRADE 8 bolts which probably cost just a few cents more than grade 5 ones.

The saddest thing in life is wasted talent

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You just BURST my buble!

I would guess good cooling service is the best way to avoid problems? Even on a new DTS!

The 2004 N* HG bolt & thread pitch are in line with what's been used on the LS1 (Corvette) engine. Although no individual car is immune from HG failures, I too have noticed a decline in N* HG complaints on 2004+ models. Remember many of these cars are purchaced 2nd hand, and there's no telling what these people did to the car. Neglect of the coolant system - either by failing to change coolant, or more importantly, running the system low (allowing air into the system) is the worst.

I believe the gasket is MLS (Multi Layered Steel). a little moisture, and air, and we start rust pits on the gaskets. Thus begins the cycle to failure.

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My observation is that gasket problems (head, intake manifold, etc.) begin to appear in a car at about 7 years of age, with another peak at 9-10 years. This is consistent with the coolant going over 5 years and the coolant going acidic, either without ever being changed or after being changed perhaps once.

I would suggest that you addilac get a new set of no. 8 manifold bolts and change them. It's not a big job and, with new gaskets, it's going to eliminate exhaust leaks and give peace of mind. Letting exhaust leaks go for a really long time can result in the leak cutting channels in the head that are difficult to repair with the head on the engine.

I think we need a good, cheap source of coolant test kits. This is true of any engine with major aluminum components, which is to say all of them.

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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I would suggest that you addilac get a new set of no. 8 manifold bolts and change them. It's not a big job and, with new gaskets, it's going to eliminate exhaust leaks and give peace of mind. Letting exhaust leaks go for a really long time can result in the leak cutting channels in the head that are difficult to repair with the head on the engine.

Replacing them is not indeed a big deal if they do not break. I am very uncomfortable with repairs which I cannot do myself.

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I would suggest that you addilac get a new set of no. 8 manifold bolts and change them. It's not a big job and, with new gaskets, it's going to eliminate exhaust leaks and give peace of mind. Letting exhaust leaks go for a really long time can result in the leak cutting channels in the head that are difficult to repair with the head on the engine.

Replacing them is not indeed a big deal if they do not break. I am very uncomfortable with repairs which I cannot do myself.

I often wonder if some kind of zinc rod in the rad will help with any corrosion/acidic issues. Boaters know that part of the trim tab contains a zinc fin who's sole purpose is to corrode to protect the aluminum gear case & minimize reactions.

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I would suggest that you addilac get a new set of no. 8 manifold bolts and change them. It's not a big job and, with new gaskets, it's going to eliminate exhaust leaks and give peace of mind. Letting exhaust leaks go for a really long time can result in the leak cutting channels in the head that are difficult to repair with the head on the engine.

Replacing them is not indeed a big deal if they do not break. I am very uncomfortable with repairs which I cannot do myself.

I often wonder if some kind of zinc rod in the rad will help with any corrosion/acidic issues. Boaters know that part of the trim tab contains a zinc fin who's sole purpose is to corrode to protect the aluminum gear case & minimize reactions.

Winterset, these are exhaust manifold bolts on an LT1 engine. You are obviously talking about headbolts. Sorry, I have kind of hijacked the thread.

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adillac - You might also check and see if there is a lock washer available specifically for exhaust manifolds that will allow heat expansion and do so forever at exhaust manifold bolt temperatures. If so, that will address the root problem, and with the no. 8 bolts you will have a belt-and-suspenders solution. I did *not* turn up an LT1 exhaust manifold bolt set (with washers) on a quick web search. Thse Stage 8 Locking Fasteners from Summit may work for you; they are listed as for the LT5 Corvette engine:

I would call Summitt and make sure that they worked on an LT1 or identify a set that does before I ordered.

winterset - I've seen aftermarket zinc anodes for aluminum radiators. A web search turned up this one from Flex-A-Lite:

How you get it on your car is up to you; it either replaces the radiator drain or is put into another 1/4" NPT bushing somewhere else in the cooling system. If you do put it somewhere not electrically connected to the radiator, you should run a wire that connects the plug holding the zinc anode to the radiator. Don't assume that the radiator is grounded because most are mounted in rubber or neoprene these days, or have plastic tanks that don't provide an electrical connection from the drain plug to the aluminum radiator core. My feeling is that this may be good for iron blocks but the real solution for aluminum blocks/heads/manifolds/water pumps is to keep the coolant non-acidic and corrosion-resistant.

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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adillac - You might also check and see if there is a lock washer available specifically for exhaust manifolds that will allow heat expansion and do so forever at exhaust manifold bolt temperatures. If so, that will address the root problem, and with the no. 8 bolts you will have a belt-and-suspenders solution. I did *not* turn up an LT1 exhaust manifold bolt set (with washers) on a quick web search. Thse Stage 8 Locking Fasteners from Summit may work for you; they are listed as for the LT5 Corvette engine:

I would call Summitt and make sure that they worked on an LT1 or identify a set that does before I ordered.

Thanks, Jim, They also offer a kit which is designed fro LT1. I'll ask around.

The saddest thing in life is wasted talent

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adillac - the kit at your link looks like just the ticket. It looks like the give is in the gasket, which is probably the best place to have it. A good FelPro manifold gasket is also likely to have a graphite impregnated base that allows the inevitable movement you will have with the temperature gradients you have on exhaust manifolds. That's the ting-ting-ting you hear when the engine starts to cool off.

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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