2004 GXP Headgasket Job

[mk04GXP]

I've had this car for a few years- I parked it about 8 months ago when it started overheating and diagnosed it as a headgasket. Just recently I've been working on it at school doing the whole time-sert head bolt repair bs.

So far I dropped the cradle and motor and removed the heads




Yes, that is coolant on top of the pistons.

The heads went to be crack tested and came back good


Now I'll need to clean up the block surface and find a way to get the guide dowels out - I can't even turn them they are hella seized.
Luckily I was able to borrow the repair kit (guide plate, drill bits, tap, etc.) from a local dealer so I don't have to buy that.
Hopefully I'll post more pics as I go along

[CMNTMXR57]

Having coolant on the pistons isn't an issue when you're dissassembling it. It's normal left over from what may be in the water jackets.

Sounds like fun... Good luck

[redfury]

Certainly keep us updated...it's a job nobody wants to do for a variety of reasons...might as well help take the mystery out of it for those that are looking at picking a GXP up...

[maxi426]

The upside of all that is you'll be very proud when it's all done, and it runs great. That's an ambitious project. Been there.

[mk04GXP]

Alright so I started the drilling/tapping/and putting the timeserts in process yesterday. I got the left side of the block all finished. It's not that hard of a process, it's just time consuming.


Oh and here is what the guide dowels look like after about an hour and a half of chipping piece by piece out with a punch and hammer.

[skregal]

Wow, that looks overwhelming.
When I disassemble something anywhere close to that, I have
to put it back together pronto or I start forgetting parts of the
process. I wrote a book when I did the LIM on my 95 so I
could reference it for reinstall.

My GXP has 155K on it. I hope I don't need to do this anytime
soon, as I would have to pay someone, and that would probably
total the car, (for the second time, BTW).

[redfury]

Are you going to replace the starter as long as you are in there?

[300sflyer]

Good on you for tackling this job yourself! Lots of work!

Had you considered using a stud kit instead of time-serts? Its my understanding that they hold in the block much better. I had mine done with studs 2 years ago, and it still runs great.

http://www.northstarperformance.com/

[harofreak00]

I remember those dang dowels, slowed the process down quite a bit!

[wilsonracing]

Hello, very new to this group, just bought a 2005 GXP yesterday with the same over heating problem, and same head gasket diagnoses, is this the easiest way to do this repair? Or can it be done without dropping the cradle and engine? Also, any other tips and tricks to make the job easier would be awesome. 2005 GXP 132k.
Thanks.

[CMNTMXR57]

I think it is. You're not having to work within the confines of the engine compartment, surrounded by other parts and wiring harnesses (especially the big one on the back side to the engine on N*'s). Or the front, confined by the radiator and/or core support. When you restud, there is an alignment tool (northstar performance calls it a "fixture plate", and GM has their own), to make sure that you're maintaining a proper 90* angle to the deck plane of the block (i.E. getting the studs in straight).

However, many here don't have lifts or the means to lift a car off the front sub-assembly, so you're left to other means.

[wilsonracing]

Thanks for the fast reply, Ive got a lift in my personal shop at home so I'm not worried about that part, just worried about the time frame part of it. The wife needs it on the road asap. Ya know how women are...lol.
Also is it easier to restud the block or just use new blots? Ive read about people doing it both ways.

[CMNTMXR57]

Studding is the only way to go. Using new GM bolts, which are a fine thread and only about half of the thread on the bolts are used, will just come out again.

Re-studding is a permanent fix.

I'm copying this picture from N* Performance to illustrate what I mean;

[wilsonracing]

Cool, sounds like I will be studding them. Do you have a part number for the ARP studs?

[00Beast]

Cool, sounds like I will be studding them. Do you have a part number for the ARP studs?

They're not made by ARP. Northstar Performance sells the kit, and it includes everything you need. You need to redrill and tap the block, as you can see the new studs are much larger and coarse thread. They include a jig so that you can drill the holes properly, and the studs and other pieces.

http://www.northstarperformance.com/sgstuds.php

[wilsonracing]

Holy crap, $600 bucks for the head studs. That's over half of what I have in the car already.
Pretty sure I'm gonna go with the factory replacement bolts again.

[CMNTMXR57]

And you'll be replacing them again. You're not fixing the problem, just re-band-aiding it.

If you're flipping the car, I get it. But if you plan to keep it, spend the money once and do it right.

[wilsonracing]

So, starting the tear down process tonight, what is the best way to deal with the break lines? Off at the wheels, remove the master cylinder from the booster, ??? And how about the AC lines, stay on the motor or on the car?

[CMNTMXR57]

I would do it at the wheels personally.

[wilsonracing]

So how do you drop the motor with the cradle and keep it from falling when the motor mount is connected to the body and not the cradle?