I am looking for some insight here. So my car is 67 326 w/ 70K original miles. It ran awesome, purred with the exception of an exhaust leak. The car had sat for awhile while I was having the paint/body work done but I drove a few hundred miles afterwords and it was fine except for a oil pan gasket leak.

After a shop did the pan gasket leak, they call me, tell me the pan gasket is done and say they "discovered" a rod knock. WHAT? How could that be? I asked. The explanation was "well there was lots of sludge and build up in the pan and the oil pump, so maybe that was keeping it quite."

This make no sense to me, but maybe I am missing something? Of course they offered to do the rebuild for $6K which made me even more suspicous. The knock appears to be coming from the lower passenger side of the motor. Any ideas? I havent had the chance, but I am going to check they flywheel bolts maybe it's not a rod knock at all? Problem is it only seems to be present when the car is warmed up? Opinions?

So I am a little confused.

1. Did you have them replace the oil gasket?
2. Did you ever hear this noise before the oil gasket was replaced?
3. Do you trust this shop?

There are three scenarios I can come up with that would explain a noise suddenly appearing after an oil pan gasket.

1. Something fouled the oil pump suction and you lost pressure long enough to do some damage.
2. The noise was there all along, its just now you've noticed it because of additional scrutiny.
3. They intensionally loosened the rod studs on a piston(s) for additional work.

They say you can tell if it's a rod by pulling one plug wire at a time and if the knock stops after one of them is off then that one may be the offending rod. Just some backyard mechanic diagnostic.

Thanks for the reply.

To Answer you question. I dont trust the shop at all. Story starts out that I contact them because they are supposed to be a high end resto shop that also does standard mechanic work. I ask them for a quote to do the pan gasket and the pinion seal. They tell me about a $1000 (the motor had to be lifted). I bite the bullet because I dont have the room or a picker to lift the motor. I've done one before and would have done it myself. Then they call and want to replace some dry rotted front end parts. I agree... they say we are about $1500... weeks go by and he tells me everything done, but they hear a rod knock. I say okay, well thats strange it was fine before... he says well there was a lot of sludge in the pan, it may have been keeping it quite. He then says well it may just work it self out if its a lubrication problem. I say, well okay I'll take my chances because I cant get into the expense of ripping the motor down. He says well you may want to hear it before you drive it. I say okay, well where are we at cost wise for what have done... HE SAYS $6K!!!. I flip out and say there is noway I am paying that, Im picking up the car. Ill give you $2K,he agrees but asks for cash!

So long long story short, I think the guy is a crook. I know there was no knock before... but what am I supposed to do but get my car out of this guys shop before he threatens to keep it unless I pay him his crazy invoice.

If the knock was there, wouldn't it have mad sense to inspect the bottom end when the pan was off? Could cleaning sludge out of the pan/pump really uncover an issue like this or am I being jerked around?

Sounds like a crook to me, I mean come on! a $1000 to replace the oil pan gasket and pinion seal? wow And who's to say they didn't go out and run the living dog sh!t out of it and cause the rod knock.

It sounds like maybe the crank is hitting the oil pan someware.
It can sound like a rod knock !

10 to 1 the pan gasket is going to leak on your way home from the shop.
Pay him the $2k, get your car back and sue him for $1500. They probably won't give you all your money back because he did work on it but if you show exorbident pricing and shotty workmanship, plus extra damage that wasn't there before that you are going to have to pay somebody else to fix now, chances are you'll win. More than likely you won't be the first person to sue this guy.

Sounds suspicious to me. I don't trust anyone is my motto. Sounds expensive also.

Don't know if they have an equivalent of the California BAR there in Illinois, but if they do get them involved, they can at least tell you how many complaints they have against them. May be under the Illinois dept of consumer affairs.

I had an issue with a "knock" only after the engine warmed up and it was a rod bolt nut hitting the pan. I had just changed rod bolts and the pan gasket and the ARP bolt had a longer nut than the stock. When I rolled the engine over by hand before installing, there was no interference, but once it warmed up and things expanded, it hit (from now on I will bolt the oil pan w/o gasket and check for interference). Maybe he used a thinner gasket? The sound hollowed out through the pan so it was difficult to figure where it was coming from. As Bob mentioned you can ground out each cylinder by pulling the plug wire. If there is no combustion in that chamber, there won't be a knock. This hopefully will help you understand what is wrong with the car.

And who is this shop? If you don't what to post their name
could you please PM me with it. Being in IL myself I'd like
to steer clear of them.

Show up with a tow truck, pay the cash, get a receipt and have a witness present with you when picking it up. Then have it towed to another, reputable shop, and have them inspect it. Have them remove the pan and inspecting the bottom end. If you find that things have been messed up, have the new/reputable shop document everything for a possible lawsuit. Then go back to the crooked shop and tell them what the other shop found out, and ask the owner if they want to return your money, or if they want to go to court. Have your new/reputable shop fix the bottom end noise..if there is one.

Not a pretty scenario at all. Good luck!

So here is where I am... I paid the cash, brought the car home and it's stange. It sounds like the early sounds of bearing ware, sometimes. Thats whats strange is that it seems to come and go. At times it sounds like a tick and sometimes it sounds like a low deep knock. A lot of the time it's not even there. It almost sounds to be coming from dead center of the motor. I removed plug wires one at a time and no change. Something is going on, but it's not so loud that I am afraid to drive it. What really threw me was when the car is hot and I shut it off, I can hear a slow tapping in/under one of the valve covers??? I have never heard anything like. Nothing it moving at that point, WTF coould be tapping? I had a local engine builder out who builds race cars and he had a lot of theries, but even he was puzzled. I guess Im just going to baby the car and see what happens. I dont beat on the car anyway, just cruise.

Does the engine have compatable oil in it? Most of the new oils for modern engines have little zinc in it. Change the oil with a good oil with a higher zinc content & see how it runs. There are zinc additives if you can't find an oil that wil work in your engine.

Steve

I was told the shop put 10-40 Pennzoil in it. When I first got it home and checked it, it was low and reading on the dipstick at the add line, so I topped it off with castrol gtx 10-40. I ran it for a few minutes, but that was really it. I am sure the engine is starting to get gunked up due to age and long periods of sitting. I have heard about chemical motor flushes... anyone have any expeirence with those products. Are they a gimmick that will do more harm that good?

From your discription, sounds like a lifter sticking.
Sometimes you can pin point it by holding a screwdriver to the valve cover and your ear.

First thing to do is install an oil pressure gauge if you don't already have one. Verify that your oil pressure is within range when hot, then you can start looking for the noise.

Valve train is the most likely suspect if the bearings are okay.

id change the oil to a factory recomended 30tw. not to sound bad, it might be a broken pistion they can break without signs of smoke and sound like a lifter/rod. listen to the side of the block. if its broke you'll hear it clear as a bell.

I've used Seafoam before, on my motors and other motors with noisy lifters and it does do a good job of cleaning things up. If you go that route with yours, warm up the motor, open the oil cap and pour in slowly while at idle, you may have to throttle it up a bit to keep it from stalling out, that's normal the oil is being thinned out and the lifters at idle aren't pumping up enough to actuate the valves. Once you get it all in and get the idle to stabilize, take if for a 20 minute run, bring it home and change the oil(optional, but I like to do it) Let us know what happpens.

Heard Seafoam's good. Can it be used in the crank case?
I've always had good luck with Rislone crank case clnr.

Sounds like valvetrain. Bottom end noise only stops when it breaks. Try the seafoam like jeff said. I would change the oil afterwards. Make sure you have some kind of zinc additive in it. May have a lifter giving up. I had it happen on an original motor that had never been appart. I know some don't like to do it but I only changed the lifters and fixed problem. Keep us informed..... JOE

Yup.

Just skimmed...early posts.

Oil pan and pinion seal about 2-3 hours of labor and $30-40 in parts.

Thats $250-300 in my book.

Secondly, to rebuild a 326 does not cost ANYWHERE near $6k.

If I provided a complete engine core, installed new top of line parts with labor, maybe $3k tops, more in line of $2500.

Now if you needed install and whatever, maybe $500 tops.

BTW, rod knocks dont magically appear...even after sludge is cleaned. I believe, in theory, if there was sludge, and the oil pump was stuffed up, you would hear it prior to whatever that shop did.

Oh...and plus one on the Seafoam.

Put 12 ounces in the crankcase and a full can in gas tank and drive for 100-125 miles.

When you're about to change oil, take for a ride, get her hot. Take vacuum line off booster and take another can of Seafoam and allow the vacuum to suck up the whole can aiming for complete stall from Seafoam. If not, have friend shut car down.

Change oil, start up car and take for a ride.