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how to tell if head bolts have been fixed


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I bought a 1999 deville with 200,000 miles. I bought it knowing it had recently had run but did not as of then. I buy cars with problems, fix them and sell them. I knew of the issues northstar has with head gasket problems. My plan for this car because of how clean inside and out it was, is to rebuild the motor, and give it to my daughter who just turned 16 last week. I was told it had a blown head gasket from the seller. It did run but had zero power in drive. So I knew it was more then HG issue. I got it home and pulled the valve covers off and found a stuck exhaust valve. I pulled the motor (out top) and have it down to bare block. Yes I do have the service manual with all updated torque specs. I work in a machine shop so I have access to tools, and have found that everything is in spec to service manual requirements. My plan is to drill the headbolt holes before installing anything on the bottom end. I made my own guide plate at work which has two threaded holes to hold in place, one threaded for tapping, one for drilling with a 2 inch drill guide welded to the plate. Now with block bare I have found that many bolt holes have serts installed already which were counter sinked in block. when I pulled the heads off I was expecting to find one or more head bolts loose from pulling out causing HG failure. That was NOT the case. All head bolts were extremely tight and made a loud pop when loosened. There was no aluminum thread in any bolt I inspected. upon removal. I inserted a long punch down the bolt wall in block and came to a ridge that is my guess 1/8 wide. Now my question for you experts. Did the factory sert any bolt holes(aside from head bolts as I know they did not) to explain how they got done already? And how or is there a way to check if the head bolts have been serted already. The HG had only one spot that had cut thru the gasket, which was at the location of the stuck/bent valve I found. The gasket seemed very weak and flimsy like it had been there for awhile. the gasket also does not look to be as quality as the new one I have in the rebuild kit. So before I start drilling I really need to find out if its been fixed in the past, because I assume I should not attempt to drill thru a sert. My thinking is the metal sert shavings might cause issues in the aluminum wall in drilling. I have done much reading into studs and serts. I am very comfortable with serts due to the fact that the factory says the bolt will expand under heat and load, and with a stud to me anyway would not be able to do this. therefore over time something(weakest point will give) like the gasket could fail from crush. This is my opinion and this is why I went sert method. To each his own I guess. So any info would be great on the serts that have been done already and possible head bolts having been done or how to know.

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If all the head bolts all pulled out clean, it's probably been TimeSerted. The head gasket that you see is probably a cheap one that either was installed improperly or failed. The sticking valve may have happened because the car was left too long with a blown head gasket.

The TimeSert has a shoulder that screws down against the block material. That may be the shoulder that you are seeing. Someone that has done a TimeSert job can tell you what tool will engage the TimeSert at the bottom of the head bolt well and tell you for sure that it is there. Check all 20 holes to make sure that one wasn't skipped so you don't end up putting it together with an aluminum head bolt thread.

Check the bore for cross-hatching. The cross-hatching is necessary to hold oil to keep the rings lubricated and the car will burn oil or even lose compression once the bores go slick. If a car is run too long with a bad head gasket, coolant in the bad cylinder can cause it to wear the bores slick. If so, the cylinder must be re-honed to spec.

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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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If the timeserts are intact, I would use them. Did any pull out or are they all in place? If a timesert pulled out you will need a "big sert". I would just timesert all the remaining holes not timeserted. Are you saying that EVERY bolt seemed tight and no bolt pulled?

No Northstars were timeserted at the factory. If a dealer timeserted the block they may have the details in their computer if you provide them with a vin number

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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Yes cylinders look very good. I wasn't going to do anything with them. There was heavy build up on pistons and ring slots but they are completely clean now. And yes all bolts were equally Tight and pulled out clean. I'm waiting now for new head bolts and connecting rod bolts. Thing is I have a 17/32 drill bit which does not fit it the block where head bolts go which makes me second guess the thought of it being serted already. If I drill thru a sert will it hurt the aluminum in any way?

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DO NOT DRILL ANYTHING until you determine whether the TimeSerts are there already. I just checked the TimeSert web page on the Northstar kit for the 1993-1999 model years and the 1997 model year factory shop manual, page 6-26 for the thread repair instructions.

The TimeSert is 12L14 carbon steel, plated with zinc phosphate and are black. If you clean the hole with a long Q-tip type cleaning instrument, you should be able to see it clearly.

The drill bit for a first repair is 29/64, which is 5/64 smaller than your 17/32 drill bit.

If you drill into a TimeSert, you will ruin it and will need to replace it with a BigSert, which GM calls "second repair." If you drill too far, you may damage the block. The TimeSert installation kit comes with bits, taps, and TimSert installation tools that all have a line that is flush with the top of a plate that comes with the kit and you bolt onto the deck surface to align and guide the drilling, tapping, and installation process. You can get these kits used from people that needed them once. They are offered occasionally here and on eBay and such.

Look at the threads of the old head bolts very carefully. If they have no trace of aluminum on any of them, the block has already been TimeSerted.

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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An inspection mirror usually has a small magnet at the handle end. You could use that to see if there was a Timesert in the hole as the magnet would stick to the steel Timesert.

If all the bolts made the "cracking" noise when loosened, the existing inserts are fine. Just Timesert the ones that are not Timeserted and it will be fine.

Actually, some holes were Timeserted from the factory. It was a rare occurrence but it did happen if a tap or drill broke on the assembly line. Rather than scrap the block, the hole was repaired with a Timesert. I doubt it was the case with this engine though.

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

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Interesting info on the factory timeserting Kevin, I vaguely recall the guru saying that now.

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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Great info guys. I would have to assume that the inserts were done by a dealer due to the fact it was not just one size hole fixed it was all bottom end block bolts were serted and I would say 50% of bolts on the exterior were done which would require a pretty expensive kit which i have seen selling for about $700 and up. Funny thing is I tried the magnet in the head bolt hole and got no pull on it. So how in the world did this block make it 200,000 mile without pulling a headbolt? Now I couldn't say that this engine is what came with the car but why fix all the other bolts and not the head bolts? I rechecked the head bolts and only thing on the threads is a semi hard brown gunk. I was thinking it was the lock tight from the factory. Most of it was at the top of the threads. I figured when the bolt was being tightened it moved up the thread. But I can say for sure that every head bolt was so tight I thought I would break it before it was going to loosen. I had to turn the engine stand to the wall to hold it in place while loosening, and as I said before every bolt made a loud crack when it freed up. I had been reading other peoples posts for a few weeks so I knew to check every bolt when I removed it but there was nothing. Well one bolt had a tiny spec of shinny material, about the size of a grain of sand but that was it. Im in no hurry to move forward since this is not a car that is needed for a daily drive. So I will look into it and have the dealer check the vin and order the kit. Its a funny thing with this engine because you can take all the knowledge you have learned over your lifetime about engines and throw it out the door, because this engine is unlike anything I have dealt with. I have a Mercedes and have done all the work on it its whole life. but never had to crack the engine open yet. If this Cadillac is anything like what I would run into with it I may think twice about it. These cars have come a long way since my first one 1970 mustang with a 302. That being said this caddy will purr again real soon with a new lease on life! Thanks for all the help guys I will follow up with my findings...

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If a car is well-maintained, particularly keeping the coolant fresh, it won't necessarily pull a head bolt, ever.

Anyone who pulls the heads and knows what thy are doing will TimeSert all 20 head bolts, not just a dealer.

The steel used in the TimeSerts is very high carbon and you may have to actually get the magnet to touch it to feel the pull. I would try to clean it out down there and look with an LED penlight. You say there is a shoulder that you can feel, and that tells me that there is a TimeSert down there.

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 like to say that is true.

My 96 Deville has generous coolant changes and is well maintained. even with 200000 miles on it, it runs strong.

My 97 Seville had 4 pulled headbolts. overheating started at 97000 miles, dealers threw tons of parts at it, never fixed real problem. Thats when I bought it and fixed it.

I like your posts are very detailed and cant wait to see the end result.

If you want to throw all your knowledge out the window, work on a Ford Diesel engine. It is nuts

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Well, if someone comes here with a problem with a Ford Diesel, I'm sure someone would try to help.

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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