How to Replace Connecting Rod Bolts

What You'll Need
Gaskets for the oil pan.
Rod Bolt stretch gauge
Socket ratchet wrench and sockets
Small square made of Styrofoam or cardboard, to keep track of small bolts
Torque wrench
New Rod bolts
Oil to refill oil pan
Oil pan sealant

Replacing connecting rod bolts is a time consuming job that requires advanced engine repair knowledge, and expensive special tools. It is not an easy task; be patient, you may need to take a break from time to time to avoid cramps or mental fatigue.

Step 1 – Preparation 

Remove undercarriage parts as needed to allow for the removal off the oil pan. Remove the oil pan being certain to not deform or scratch the gasket surfaces of the oil pan. As you remove the oil pan bolts, keep track of which order they were in when first installed; number them with tape, or affix them to a Styrofoam mold or a heavy cardboard piece as you remove them. Some of the bolts may be different lengths. Clean the gasket mating faces of oil pan and engine block to remove old gasket debris.

Step 2 – Replacing the Connecting Rod Bolts

Rotate engine via cam gear or crank to Top Dead Center. Locate a piston at BDC (Bottom Dead Center. is the exact position of the crankshaft when a piston reaches its extreme limit of bottom end travel within the compression cylinder.) Using the rod bolt stretch gauge measure stock rod bolt length with gauge for reference. Using torque wrench measure break-away torque of one nut on one bolt of this rod; remove nut. (measure the torque on three bolts and create an average for reference.)  Remove the old rod bolt just measured. Lubricate and then install a new rod bolt into rod and run nut down finger tight. Install rod stretch gauge. Record rod length with no torque applied to nut. Tighten nut down until stretch gauge reads +0.0069 inches over initial length.

Loosen the nut completely and measure rod bolt length. If rod bolt length is greater than 0.001 inches from its initial length, then discard this new bolt.  For a second time, to secure the nut in permanent tighten the nut down until stretch gauge reads +0.0069 inches over initial bolt length. Check torque reading against average recorded earlier for reasonableness. Repeat this procedure for the bolt on the other side of this rod. After you have completed replacing both bolts on the first rod, repeat the procedure for each bottom dead center rod until all the rod bolts have been replaced.  

Step 3 –  Reinstall the Oil Pan

Apply an adhesive bead of sealant to the cleaned oil pan After the sealing has begun to cure, reinstall the oil pan, being certain to reinstall the bolts in the same locations they were taken from. Some of the bolts may be different lengths. Finger-tighten a few bolts and wait at least 1 hour for sealant to fully cure. Torque oil pan bolts to specifications. Reinstall the other undercarriage parts that exposed the oil pan. Reinstall the oil return lines with new gaskets.