: 97 deville blown head gasket question

04-22-09, 12:31 AM
i got a question? when the head bolts pull out of the threads,. are their any threads left? what i mean is i noticed they give you a choice on new head bolts getting them longer, has anyone heard of someone putting in longer bolts and it holding the heads down? just curious

04-22-09, 03:58 AM
No, you do NOT want to torque down new bolts (weather they are long or normal sized) without at least drilling and installing threaded inserts into each head bolt hole. The aluminum has already been weakened and it's a gamble with too much odds against you. The best way to go would be to install studs and have the heads secured with nuts.

04-22-09, 09:53 AM
Why two threads on the same question ??

Longer bolts are not an option, especially at the 4 head corner holes.

04-22-09, 09:54 AM
2 threads, same question.......I believe the longer head bolts are for late 2002+ blocks, when the hole, thread pitch, and depth were changed.

04-22-09, 11:15 AM
well i know it may have sounded like a dumb question but had to ask. anyway sorry for the double thread, in all the months i have been reading on here it was my first thread and did not realize it would end up that way. sorry.

04-22-09, 01:06 PM
Not a dumb question, and you can see that a moderator merged the two together. There were several bolt/thread changes over the course of the FWD Northstar run with the largest and longest bolts in the 2003 - on series.

Jake (97EldoCoupe) seems to have engineered the best fix: head studs. BUT, the engine must be out of the car and there's a bit of intense drilling and tapping to do on a well-protected short block. (Tape and cover EVERY hole except the one being drilled and tapped.)

04-22-09, 02:39 PM
the stud treatment is interesting. why would studs be better then new bolts with timecerts. would studs have a chance at pulling out too? also i have another question, i dont seem to have water flow. after the car heats up the fans do not come on and when i pop the cap in the serge tank the water is cold in their? im going to check for a plugged serge line today but was wondering if the blown headgasket could cause no circulation? also when i do pop the cap their seems to be lots of pressure.

04-22-09, 04:30 PM
was wondering if the blown headgasket could cause no circulation?
If the head gasket is breached, then it is putting exhaust gases into the cooling system. Water pump won't pump air.

also when i do pop the cap their seems to be lots of pressure.
That may well be exhaust gases. It will pressurize the system.

04-22-09, 04:58 PM
thats what i thought because i noticed when i poped the cap their was some (smoke) coming out of the purge tank! i guess its time to decide what i want to do.
either rebuild or part out! i only paid 900 for the car and its really clean., so i am thinking a rebuild might be a good investment as long as i keep it for a few years after.

04-22-09, 08:46 PM
If you are wise young grassChopper there is much to read here to guide your path. Here is one thread but there are many others: http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/152360-my-northstar-hg-project.html

Search for HG threads by Zonie77 and Tateos

04-22-09, 11:38 PM
WOW! nice thread! and my hats off on the rebuild! i have built several of my own motors, small block chevys and dodges! and just built a 2009 chopper from scratch off the internet lol. and wow you know i guess its the fear of the unknown, its so overwelming when ya look under the hood, its not like working on my 66 impala or my 70 chevy el camino, lol. but i guess its one of those projects that ya start and part way into it half of ya says wow what did i get myself into and the other half says well ya got too much invested to stop now lol. i love this forum, its not just a bunch of guys that read then come on and act like they know what they are doing, its guys that have been their done that! this is my kinda place, mabey soon ill post some pics if i decide to tear into my 97 deville.

04-23-09, 02:06 AM
The HG job is not real hard just long and tedious, use the head studs they are the best thing since sliced bread you won't ever have a HG problem again and even if you do you can re-use the studs so you don't have to buy another $500 kit but I truely don't believe you will have another problem....