3800 Crank Sensor and Harmonic Balancer Replacement

[digitaloutsider]

Overview:  This guide covers removal and reinstallation of both the Harmonic Balancer and Crankshaft Position Sensor on a Series II/Series III 3800.

 

Tools Required:  24mm socket for the crank bolt, 19mm socket for the lug nuts, 18mm socket for the subframe bolts, 15mm/belt tool for the belts, 13mm socket for the crank position sensor bolts, 10mm socket for the flexplate inspection cover, harmonic balancer puller, OEM 27296 GM 3800 bolt kit, screwdriver, various extensions, torque wrench, breaker bar/impact/both, vice grips, ratchet.

 

Instructions:

 

1. Remove the drive belt(s) from the engine.

 

2. Lift the passenger side of the car and remove the right front wheel. Always use jackstands, NEVER trust jacks, especially not scissor jacks. Only place jackstands on a solid surface like concrete or asphalt.

 

3. Remove the flexplate inspection cover:

 

 

4. Put vice grips on the flexplate to prevent it from rotating. There is probably a J-tool for this, but this how I've always done it:
 

 

5. Remove the undercarriage passenger side splash shield.

 

6. Lower the subframe/engine cradle on the passenger side by approximately one inch.  You should not be totally removing the bolts and insulators. 

 

7. Remove the harmonic balancer bolt.

 

8. Insert the adapter pin from the OEM kit into the hole in the balancer where the bolt came out of.

 

9. Attach the balancer remover.  You should be using washers on the heads of the bolts, unlike my picture:

 

 

10. Tighten the center bolt on the puller until the balancer comes loose.  Remove the puller and remove the balancer.  If you're only replacing the balancer, you are done with removal. Proceed to step 16.

 

11. With the balancer removed, unplug the connector from the CKPS. Looks like I have a small front main seal leak.  I'll worry about it later:

 

 

12. Remove the black plastic debris shield.

 

13. Remove the two 13mm bolt/studs that hold the CKPS. Remove the CKPS.

 

14. Install new CKPS. Bolt torque is 22 lb ft.

 

15. Reinstall debris shield and plug sensor in.

 

16. Reinstall harmonic balancer and bolt. Torque is 111 lb ft, plus 76°.

 

17. Reinstall splash shield.

 

18. Remove vice grips and reinstall dust cover.

 

19. Reattach wheel and torque lug nuts to 100 lb ft. 

 

20. Reinstall drive belts.

[Imp558]

It takes (3) 1/4"- 28 X 3" bolts for the balancer.

[digitaloutsider]

I recommend just getting the OEM kit I listed since it already has the right bolts at the right lengths AND it has the proper tip for the puller.

 

Then again I'm lazy and I'd rather just spend $8 on the bolt kit than fuck around at the hardware store.

[Imp558]

It's just me but I keep them in a sandwich bag and put a marker mark on every time I use them. When I use them a third time I throw them in my scrap metal pile and buy 3 new ones.

Just so one never breaks off in there but the balancer will come off with a 2-Jaw puller if need be. I had to do one that way because of a defect with the balancer.

[55trucker]

The aftermarket ARP balancer retaining bolt is reusable, it is not a torque-to-yield item. (230 lbs.ft). If this is something that you might find yourself doing more than once that could be an economical alternative.

[scottydoggs]

It takes (3) 1/4"- 28 X 3" bolts for the balancer.

its really a metric bolt you should use, the standard fit if your stuck.  off the top of my head i cant real its size tho. 

[Imp558]

its really a metric bolt you should use, the standard fit if your stuck. off the top of my head i cant real its size tho.

I thought so too. when I find it I will edit that post I think it's M 6 by 100

[rich_e777]

This entire procedure could be used for the 3100/3400 almost exactly as well, although the sizes and torque values could be slightly different.

[scottydoggs]

 found it, your right ,  three bolts M6 x 1.00 and 70-75mm in length.  get washers so the heads dont pull through the puller. 

[Imp558]

I think it's one of those things where the size and thread is so close it really doesn't matter. Kind of like backing up a 14mm bolt with a 9/16" wrench. For all I know it could be the SAE, there are other fasteners on that engine that are SAE anyway.

[Dan]

I am having an issue that hopefully someone here can help with. I just changed my timing  cover gasket due to a coolant leak. Now I have a crank no start condition. I have fuel to the rail and spark at the plugs, but it sounds like I am way out of time. What is the proper procedure for putting the balancer in the correct position?

[Dan]

Never mind guys, took it back apart and i missed the key the first time

 

[CobraR306t]

Yeah u better look a little further because when I was a young buck working in the Chevy dealership while in the Gm A.s.e.p. program I didn't have the balancer on the crank key perfectly and when I tightened the balance bolt I didn't feel anything weird but come to find out that the balancer pushed the crank key inward and busted the hell out of the timing chain gear on the crank. Not cool man my shop foreman/mentor while I was 17-18 years old made me a necklace out of the destroyed crank gear to wear in the shop. Let's just say I never did that shit ever again.