i have a 96 camaro with a 98 firebird series 2 3.8 with like 200000 miles on it now and have heard alot about the conecting rod berrings going out also the oil pressure starts out at 65 on the gage but after a like 30 min of driving on the hwy then getting into traffic the oil pressure drops to 40 should i swich to synthetic? im 1500 miles from home and have access of the tools to pull and inspect the mains b4 i go home? also im leaking oil i belive out of the rear main?

 

At 200k miles, it's "recommended" not go with 100% synthetic, and instead go with a synthetic/conventional oil blend which are just high mileage motor oils.

Quick rule of thumb, oil pressure should be 10psi for every 1000 rpms. But that is not absolute, just an easy guide to keep tabs on how the oil pressure is.

At 200k miles, it's possible the rod bearings could go, it all depends on how the engine was maintained. Was it taken care of with regular oil changes? Or did it lack that and had been beaten like a race car? Note though, that the 3800 engines were some of GM's best built V6's.

 

Your oil pressure sound very good for 200K. You can switch to the "High Miles" oils but there is very little differents. Normally with 200K motors I advise people to jump up a little in oil weight but with your pressure I would not change anything.

The reason these cars have bearing issue is mostly from rapid deceleration. Guys let their foot all the way off the gas at 5000 RPMs the the vacuum tries hold the piston inplace and at the speed the rod bolts strech just a little, do it a couple of times and your done. GM has cheap rod bolts.

Oil pressure issues you heard about is from Pre series II motors. It used to be a real weak spot in the older generation 3800.

Your oil leak will not hurt anything as long as your motor does not run low on oil. Keep your RPMs below 3500 when you are that far from home and make sure she has oil and she will most likely hold up just fine.

 

yes it has been maintained oil plugs belt pullys its seems alot better after i put the new tensioner and new pullys that had new bearings and yes im very hard on the car and as far as week bolts could i just retork the old ones with new berings? also my rpm gage is not working good at idle its fine but when i drive the needs goes bouncing

 

Well retorking them will not make them stronger. It is a weak spot all engine builder are aware of. Anytime I rebuild a GM motor I resize the rods and install new rod bolts. I would not rebuild a 200K motor. The cost will be to high to get it right. Your crank main and rod jornals are out of round and would need ground and your cylinders are out of round. New rings can are designed to handle about .005" out of round. A 200K motor could easly have .015" out of round.

Low mile Series II and III motors are cheap and abundant. Just find a low miles motor and rebuild that. It will save you a lot of money.

 

So the engine has 200k miles, or the car? Just wondering since you said a '96 with a '98 Series II.

Also Gorn, when you say it's bad letting off the gas at 5000 RPM, do you mean when it's still in the same gear, or on an auto when it shifts after you let off, or both?

 

Completely closing the throttle body on motor going 5000 RPM is hard on the motor. Think about the mechanic of what is going on. The Vacuum in the intake can shoot up to 28 inchs. That would mean there is about 14 lbs/ Sq In. of force trying to keep the piston from going back down the cylinder. Mean while you could have the force of the car moving forward trying to turn the crank. This is the opposite of the force the motor is designed to take and it puts all the force on the bolts. It will test your rod bolt, and it is a test GM bolts routinly fail.