Nice pics AJ - your photography is improving ;-)
Nice pics AJ - your photography is improving ;-)
interestin story..very technical but extremely upsettin...basically what im sayin is like i always say....cadillac engineers should b taken to da shed!! seems they know the problems but peddle the machine anyway, kinda like throwin ......against the wall and see how much sticks...knowin a few will cum back under wanrranty, hopin most wont...all vehicles have inherent probs. but this is a very good reason gm is losing mkt share...huge huge prices low low quality...seems u all seem to say they is prob with the block before it even in a manufacture state! i know in my biz if i treated my clients like this they would horsewhip me...and if i knew of problems in production and design but provided them with the product anyway knowin it was gonna stand a very very big chance of failure..well, then i deserve to b horsewhipped AND put out of biz...hate to tell u guys but u dudes r pushin me back to audi and mercedes yeah they got thier problems but aint NOTHING like the stuff i read here...
Has anyone had a HG fail after inserting and replacement. I don't mean have the inserts failed... I know they sometimes fail in the '96-99 blocks with powdery aluminum. I am asking if the factory (or Fel-Pro like I used) head gaskets fail, like after say 25-50K miles. I think they might, since I am pretty convinced that the gasket fails and that causes the threads to be contaminated and fail, but I was wondering if anyone has had that happen after repairs?
This is a little information on coolant. I am still testing the coolant when I service it, but I have not found any that has been acidic.
TSB #00-06-02-006D: Engine Coolant Recycling and Warranty Information
Portion of the bulletin that talks about Sealing Tabs and Dex-Cool
Cooling System Sealing Tablets (Seal Tabs) should not be used as a regular maintenance item after servicing an engine cooling system. Discoloration of coolant can occur if too many seal tabs have been inserted into the cooling system. This can occur if seal tabs are repeatedly used over the service life of a vehicle. Where appropriate, seal tabs may be used if diagnostics fail to repair a small leak in the cooling system. When a condition appears in which seal tabs may be recommended, a specific bulletin will be released describing their proper usage.
The integrity of the coolant is dependent upon the quality of DEX-COOLŪ and water. DEX-COOLŪ is a product that has enhanced protection capability as well as an extended service interval. These enhanced properties may be jeopardized by combining DEX-COOLŪ with poor quality water. If you suspect the water in your area of being poor quality, it is recommended you use distilled or de-ionized water with DEX-COOLŪ.
DEX-COOLŪ is orange in color to distinguish it from other coolants. Due to inconsistencies in the mixing of the dyes used with DEX-COOLŪ, some batches may appear pink after time. The color shift from orange to pink does not affect the integrity of the coolant, and still maintains the 5 yr/150,000 mile (240,000 km) service interval.
Only use DEX-COOLŪ if the vehicle was originally equipped with DEX-COOLŪ.
Mixing conventional green coolant with DEX-COOLŪ will degrade the service interval from 5 yrs./150,000 miles (240,000 km) to 2 yrs./30,000 miles (50,000 km) if left in the contaminated condition. If contamination occurs, the cooling system must be flushed twice immediately and re-filled with a 50/50 mixture of DEX-COOLŪ and clean water in order to preserve the enhanced properties and extended service interval of DEX-COOLŪ.
After 5 years/150,000 miles (240,000 km)
After 5 yrs/150,000 miles (240,000 km), the coolant should be changed, preferably using a coolant exchanger. If the vehicle was originally equipped with DEX-COOLŪ and has not had problems with contamination from non-DEX-COOLŪ coolants, then the service interval remains the same, and the coolant does not need to be changed for another 5 yrs/150,000 miles (240,000 km).
Think about the head gaskets
TSB #05-06-02-001: Information on Aluminum Heater Core and/or Radiator Replacement
The following information should be utilized when servicing aluminum heater core and/or radiators on repeat visits. A replacement may be necessary because erosion, corrosion, or insufficient inhibitor levels may cause damage to the heater core, radiator or water pump. A coolant check should be preformed whenever a heater core, radiator, or water pump is replaced. The following procedures/ inspections should be done to verify proper coolant effectiveness.
- Verify coolant concentration. A 50% coolant/water solution ensures proper freeze and corrosion protection. Inhibitor levels cannot be easily measured in the field, but can be indirectly done by the measurement of coolant concentration. This must be done by using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale), or equivalent, coolant tester. The Refractometer uses a minimal amount of coolant that can be taken from the coolant recovery reservoir, radiator or the engine block. Inexpensive gravity float testers (floating balls) will not completely analyze the coolant concentration fully and should not be used. The concentration levels should be between 50% and 65% coolant concentrate. This mixture will have a freeze point protection of -34 degrees Fahrenheit (-37 degrees Celsius). If the concentration is below 50%, the cooling system must be flushed.
- Inspect the coolant flow restrictor if the vehicle is equipped with one. Refer to Service Information (SI) and/or the appropriate Service Manual for component location and condition for operation.
- Verify that no electrolysis is present in the cooling system. This electrolysis test can be performed before or after the system has been repaired. Use a digital voltmeter set to 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator coolant, making sure the lead does not touch the filler neck or core. Any voltage reading over 0.3 volts indicates that stray current is finding its way into the coolant. Electrolysis is often an intermittent condition that occurs when a device or accessory that is mounted to the radiator is energized. This type of current could be caused from a poorly grounded cooling fan or some other accessory and can be verified by watching the volt meter and turning on and off various accessories or engage the starter motor. Before using one of the following flush procedures, the coolant recovery reservoir must be removed, drained, cleaned and reinstalled before refilling the system.
Flushing Procedures using DEX-COOLŪ
Important: The following procedure recommends refilling the system with DEX-COOLŪ, P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. This coolant is orange in color and has a service interval of 5 years or 240,000 km (150,000 mi). However, when used on vehicles built prior to the introduction of DEX-COOLŪ, maintenance intervals will remain the same as specified in the Owner's Manual.
- If available, use the approved cooling system flush and fill machine (available through the GM Dealer Equipment Program) following the manufacturer's operating instructions.
- If approved cooling system flush and fill machine is not available, drain the coolant and dispose of properly following the draining procedures in the appropriate Service Manual. Refill the system using clear, drinkable water and run the vehicle until the thermostat opens. Repeat and run the vehicle three (3) times to totally remove the old coolant or until the drained coolant is almost clear. Once the system is completely flushed, refill the cooling system to a 50%-60% concentration with DEX-COOLŪ, P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M, following the refill procedures in the appropriate Service Manual.
- If a Service Manual is not available, fill half the capacity of the system with 100% DEX-COOLŪ, P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. Then slowly add clear, drinkable water (preferably distilled) to the system until the level of the coolant mixture has reached the base of the radiator neck. Wait two (2) minutes and reverify the coolant level. If necessary, add clean water to restore the coolant to the appropriate level.
Once the system is refilled, reverify the coolant concentration using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale) coolant tester, or equivalent. The concentration levels should be between 50% and 65%.
Ok, my son has a 99 STS and the head gaskets went. On the rear head all head bolts snapped loose upon removal. (Front not yet pulled, figured rear would be the worse due to heat. Gasket bunching evident.) So far looks like no coolant made it to the head bolt threads so I suspect we may not have the gray dust of death when we drill and tap for inserts. None were mushy. We have, the following kits M11-1.5 time-sert, M11-1.5Big-sert and M11-2.0 time-sert.
So the coarse thread gets a better bite into the aluminum and GM does not warranty the Big-serts. So I am leaning toward the M11-2.0 inserts. The engine came out the top due to lack of facilities, so we want to do this once and do not want to go back. The gasket kit that will be used is Felpro.
To be able to utilize the M11-2.0 inserts, what bolts do I purchase? I believe the later engines used two different lengths of head bolts. Are the LSx bolts the same length as the 97-99 Northstar? If so I would just purchase 3 sets of LSx bolts and be set.
1994 to 1999 Head bolt Part number ------- 1647217
Thread size ------------------------------- M11 x 1.5 x 30mm
Bolt Length (under washer) --------------- 139.9 mm
Bolt Thread length ------------------------ 44.5 mm
Hole depth ------------------------------- 75 mm
Cylinder head boss height ----------------- 76.0 mm
Counter bore depth ----------------------- 35 mm
2000 to 2003 Head Bolt Part Number ------ 12557775
Thread size ------------------------------ M11 x 1.5 x 30 mm
Bolt Length (under washer) -------------- 157.2 mm
Bolt Thread length ----------------------- 45.3 mm
Outboard hole depth --------------------- 96.5 mm
Counter bore depth ---------------------- 51.5 mm
Inboard hole depth ---------------------- 80 mm
Counter bore depth ---------------------- 35 mm
Cylinder head boss height - outboard ----- 76.0 mm
Cylinder head boss height - inboard ------- 92.5 mm
2004 to 2008 Head bolt Part Number -----11589058
Thread size ---------------------------- M11 x 2.0 x 30 mm
Bolt Length (under washer) ------------- 157.2 mm
Bolt Thread length ---------------------- 64.8 mm
Outboard hole depth -------------------- 89.5 mm
Counter bore depth --------------------- 45.5 mm
Inboard hole depth ---------------------- 73 mm
Counter bore depth --------------------- 29 mm
Cylinder head boss height - outboard ---- 76.0 mm
Cylinder head boss height - inboard ------ 92.5 mm
If you but a set of 2004+ bolts and cut 17.3 mm off the bottom you will have 47.5 mm of threads left on the bolt. The 94 to 99 have only 44.5 mm on them. So the 2004 bolts will have 3 mm more.
A.J. Math looks good. I'll check later with pencil and paper.. So what do I do for lube/sealant after I cut the precoated portion of the bolt off ?
On VW water boxers head nuts, I have used a pipe joint compound with Teflon. On the VW the coolant comes up the stud and rusts the cap nut to the stud. Years later attempted removal, breaks the stud.
Is there any equivalent coating for the original coating on the head bolts ?
On the used bolts it looks like installing them smears the coating up the bolt.
From what I understand the coating has micro spheres of thread lock and must be torqued within something like 30 minutes after being run into a hole.
Also does GM use coatings on the head bolts that go into iron blocks ? The cut-down bolts will be going into a steel threaded hole with the inserts. I wonder if the coating is there originally to prevent galvanic corrosion between the steel bolt and aluminum block.
STS Tom Sr.
The thread pitch is 2.0
So I counted the thread and you will sill have some of the blue stuff. T would think putting blue loctite on the bolt would work. Not really sure I have never done this. THESE BOLTS ARE VERY STRECHY! When torquing you turn them 60° and the turn back about 5° It was a little tricky
1993-1999 Head Bolt Torque
- First Pass ----- 30 lb ft
- Second Pass -- +70°
- Third Pass ---- +60°
- Fourth Pass -- +60° (190 Degrees total)
2000-2003 Head Bolt Torque:
- First Pass ------ 30 lb ft
- Second Pass -- +70°
- Third Pass ---- +60°
- Fourth Pass -- +45° (175 Degrees total)
2004-2008 Head Bolt Torque:
- First Pass ------ 22 lb ft
- Second Pass -- +60°
- Third Pass ---- +60°
- Final Pass ---- +60° (180 degrees Total)