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Oil leak after engine rebuild--where's it from?

10K views 68 replies 13 participants last post by  shudahadaV8 
#1 ·
Just had the LT1 in my '94 Caprice wagon rebuilt. It's got an oil leak coming from the front of the motor. I can see oil on the bottom of the Optispark, and it's going around the crank and all over the bottom of the timing chain cover. How upset should I be?


 
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#2 ·
On a potentially related note, the build sheet indicates a "high volume standard pressure" oil pump. My oil pressure gauge sits at 70ish psi when cold idling and drops to 50ish when the motor is warm, which is a lot higher than it used to. Is it possible that excess oil pressure caused the leak?
 
#3 ·
Did the builder install the front cover and seals? I'd be leaning toward the water pump seal....pretty easy to mess that one up without the tool/knowledge how to install. If you want, you could just try and pull the WP and check the area and replace that seal.

If you want to pinpoint the area, use some dye in the oil and run the engine for a bit. Then see if this helps to find the specific area of the leak.
 
#4 ·
Do you have any idea how the seal surface of the hub looked? Could you catch a fingernail on a groove?
If so, you would want to install a speedy-sleeve, which will be a fresh new surface for the seal to ride against.

I did this to a few balancers back in the day when I worked as an automotive machinist.

To try and track down the root cause I'd clean the timing cover with some simple green/your favorite degreaser, put the car on jack stands, and start the engine.

Have a good flashlight and a mirror (If possible, I know space is limited) to look for the source. You should be able to tell whether the leak is coming from above the hub or not.

4DoorSS always has good advice. It could very well be the water pump drive coupler seal, or the distributor seal as well.
 
#5 ·
If the highest oil residue is the bottom of OPTI then the opti oil seal or perhaps the cam shaft seal. since it is leaking down the middle front of block.

when ever the opti is replaced you should replace that opti oil seal .. also the seal must not have any oil on it must be dry when installing .

I have seen also poorly machined after market opti .. this is the part that rides on that oil seal it could have gotten dinged up.
 
#7 ·
If you had it built by someone I would be taking it back to them... Not a big deal and not an expensive part but can be a pain to install without the right tools.

Water pump seal is the easiest one since you can pull the shaft out. The crank shaft seal is similar but would be harder to deal with since the balancer has to be removed.

Think when I priced those seals they were less than $20 apiece. Biggest issue is when replacing them to apply force across the full surface at the same time. Which again is hard for the crank seal with the crank shaft being in the way. The seals themselves just pull out. You MAY want to put a little oil around the outer edge when inserting the new seals if you do them yourself.

Probably getting to the seals can take the most time since you have to remove pieces to get to them.

The water pump seal would definitely be the easiest to change.
 
#9 · (Edited)
You can get the felpro Front cover kit that will have all the seals for about $10-$15. The Crank seal is a PITA since you need to remove the Hub for the Balancer. the balancer just unbolts from the Hub but the Hub needs to be pulled and pressed back on with a special tool or Hardened threaded rod and assorted HW. In your case, the crank seal is not bad since the leak is above the crank seal and they don't typically cause an issue. There are write-ups and Video's on this process as well as the other seals.

https://www.summitracing.com/parts/...e1-_-fel-pro&gclid=CKrbkbW729ICFYeFswodcMcJmw


The Opti seal is Teflon and should be installed Dry. The WP seal....needs a special tool although I did use a Sharpie case (was a writeup on this years ago) or the tool you can buy. There is also a video up on youtube where you can use a deep 3/8" socket - IIRC. The tool is your best bet but other options are available if the tool can't be found. But this is the 1 seal I'd be leaning toward due to the many issues it can cause. Unfortunately, it's difficult to get to these seals, let alone see a damn thing without removing parts.


So back to my original question....did you or the builder (assuming you worked with them) install the seals. If the builder and you paid them money for this.....then I would take it back to them and have them find/fix the leak. You may even want to do this yourself anyway since it could be more of a hassle to take it there and have them do it.....plus - they did it wrong the first time. :crying:


On a side note, if you do pull the WP and do this yourself, consider adding a drain hose to your WP weep Hole. This could help protect your Opti in the event the WP lets go.
 
#11 ·
#12 ·
Just had the LT1 in my '94 Caprice wagon rebuilt. It's got an oil leak coming from the front of the motor. I can see oil on the bottom of the Optispark, and it's going around the crank and all over the bottom of the timing chain cover. How upset should I be?
OP

As mentioned the most likely source of this leak is the WP drive seal. Installed without the "tool" incorrectly it will leak immediately. Oil migrates down to the lowest point so it can "look" like one of the other timing cover seals below it is the leak source. Your leak looks quite big for a wp drive seal unless you have been driving the car for a few thousand miles. The TC looks "covered" in oil vs what is a small "trail" of oil that comes down from that seal

I assume there is some form of warranty with this rebuild. If the builder installed the timing cover he should be responsible 100% for the repair. The seal itself is only a few $

What typically happens as collateral damage is oil gets into the Opti so that should be opened up to se if oil got inside it. Generally this can be "carefully" cleaned but the shop would need to be "familiar" with the internals of the Opti. Often they are "just bolt parts on" type vs "fixing" the part.

The HV oil pump would not cause this. Builders often use HV pumps when they set the crank & rod bearings up slightly wider than stock. The shop should have provided a "build sheet" noting what clearances they did on the motor
 
#17 · (Edited)
No where as good as "Tru-Coat"....don cha know.


 
#18 ·
The engine builder did the whole job turnkey, start to finish, so he would be responsible for fixing it, but I am hesitant to bring the car back to him. He had the car for literally 7 months, and when I arrived to pick it up, the bill was $2000 more than his initial "worst case scenario" estimate. I expected maybe a $500 overage, not $2k. I settled up for the initially agreed amount with the agreement that I would give him some more (but nowhere near the full $2k) after driving the car a bit and confirming it was in good shape.

The car runs and drives great, and I stopped by a few times while he was working and witnessed him doing detail-oriented stuff like plastigauging the bottom end bearings, gapping the rings, and measuring the pushrod heights, so I am confident he did a good job with the motor. I am just a little sour about the huge unexpected overage and now the oil leak. I am thinking about taking the car to a different shop to fix the leak and deducting the repair cost from what I was going to pay additional.
 
#23 ·
Quote The Whole Thing

The engine builder did the whole job turnkey, start to finish, so he would be responsible for fixing it, but I am hesitant to bring the car back to him. He had the car for literally 7 months, and when I arrived to pick it up, the bill was $2000 more than his initial "worst case scenario" estimate. I expected maybe a $500 overage, not $2k. I settled up for the initially agreed amount with the agreement that I would give him some more (but nowhere near the full $2k) after driving the car a bit and confirming it was in good shape.

The car runs and drives great, and I stopped by a few times while he was working and witnessed him doing detail-oriented stuff like plastigauging the bottom end bearings, gapping the rings, and measuring the pushrod heights, so I am confident he did a good job with the motor. I am just a little sour about the huge unexpected overage and now the oil leak.
I was merely lurking with no better insights than others, but still rather confused why asking the forum before notifying the re-builder first. But this post jumped out at me. No amount of plastigauging, gapping or measuring is gonna tip the scales away from such an egregiously insulting unprofessional cost overage, - which it sounds like you yourself consider unsupportable. If you've gone any amount of time without already notifying the rebuilder of the leak, then I sure would not now. Simply determine whether the WP or Opti is leaking (both quite simple to fix - as mentioned) and do it yourself. I know this ain't Misk, but you're gonna keep getting razzed until you do lol.

The bigger head scratcher is WTF prompted a $2k overage, and that timetable is quite inconsiderate and disrespectful of the client unless such a delay was mutually agreed up front. A professional and experienced mech would never let a client keep throwing so many bad bucks at a job without recommending wiser value alternates.

I am thinking about taking the car to a different shop to fix the leak and deducting the repair cost from what I was going to pay additional.
Ok. Really confused. You have a balance due? This extra $2k is negotiable? As offered, you can't unilaterally backcharge a supplier without first providing them opportunity to perform on their warranty.
 
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#19 ·
Legally you have to allow him to do the repair. You should approach him to do the repair in a timely manner. If you don't have him do it he could use someone else working on it as a reason to throw out any warranty...

Maybe not valid but would certainly try. The oil seal should be a simple job for him.

Rodney
 
#20 ·
the vehicle should be brought back but call first explain the issue and have him setup a time that he will look at it while your there. not drop it off and he stalls for a week or more before he looks at it.

$2K more on his estimate and he did not inform you that is excessive .
7 months to do the work I understand your pain.

I myself did mess up on that cam oil seal at the water pump drive . I did though replace it since I noticed I messed up before putting it all back. it is a bit tricky .

the opti seal does require replacing when you disturb the opti . if he had some lube on that opti oil seal that would also cause leak.
 
#21 ·
You will spend more time in the car driving it to the shop, and without a car - waiting for the work to be done, then you would doing the repair yourself. And you've got to turn it over to the dolt that jacked it up in the first place. Its a stupidly simple job. The seal-kit is like $15 and the job itself will take you no more than 30 minutes. my 12 year old daughter could do the work in 45 minutes and she's never swung a wrench. .
 
#22 ·
12 year old or a professional auto repair tech not gonna happen to do this repair in 45 min. . draining of the coolant alone takes a good 30 min.. then another 30 min to remove the water pump esp if the air pump is still mounted .so it's now ready for the seal replacing . then the install of water pump gaskets/cleaning prep etc...

labor to do this job is more than one hour LOL.... I have done this 4 times ...I sure wish it was a water pump replacement like on a 1980 GM sedan . I could do that in 30 min. reason is NO opti under the pump...
 
#24 ·
He could have built a hundred SBC engines as part of his resume but........if he just pushed the front cover of the LT1, with the seals installed, onto the block then the water pump seal will leak. It seems like a totally logical step but if the water pump coupler was already on there when he did this then there's a leak.
 
#25 · (Edited)
If the mechanic does not have the "tool" be it the Kent Moore OEM one used to manufacture the engine or one made some of us bought for $20 or even a Sharpie pen cap than the seal will likely leak again. Telling the mechanic that seal has a inner lip which folds over on install if some form of "tool" is not used.

When these motors were built new the seals were installed in the TC and then the TC placed on motor...BUT the Kent Moore tool was placed over the WP drive spline allowing the TC to be put on this way. I have the Kent Moore tool which works this way or using over the spline to install the seal on TC if already on motor.

Op has a unresolved $ balance for a job that took to long and cost to much and now has a leak due specifically to poor workmanship. That $ balance needs to be resolved mutually between the two parties or 1. The shop will sue to put a lien on the car or 2. the OP will sue in small claims court. Both of those legal situations suck.

Op needs to confront the mechanic about the leak and repairing it and resolve what $ balance there is.

I agree fixing it himself would likely be a quicker path to ending the oil leak.....if he has the skill set and tools to do so. With that much oil leaking I bet 95% chance oil has already gotten inside the Opti and is only a matter of time before that dies. The cap & rotor need to be removed and Opti cleaned inside already as a result of this leak. This is the collateral damage (pic) this type of leak causes. And yes further complicates the settlement with the mechanic who built the motor.
 

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#26 ·
Some backstory:

This mechanic runs a small shop. Over the years, he's sometimes had an employee or two, but as of late, he's been a one-man show. He's been working on my cars for a dozen years or more. He used to be johnny-on-the-spot. Jobs got done promptly, properly, and the repair bill was fair and reasonable.

In the last few years, things have gone downhill. He had my Caprice a couple of years ago because it was running roughly. The job took.. man, I want to say about 10 months to get completed. He threw all kinds of parts at it (at my expense), including an opti, plugs, wires, etc. Eventually he discovered that it had a broken valve spring and a bent valve in #8. He missed it initially because, he told me, he compression tested 7 of the cylinders but #8 was hard to get to so he didn't do it. Then, after just about giving up, he re-did the compression test on all cylinders and realized that #8 was low.

I drove the car for a little while and then it started leaking oil. I had another shop troubleshoot it and found out that the #1 cylinder was badly scored. Turns out the piston was cracked. (I assume it happened the same time as the broken valve spring--while accelerating aggressively, I thought I was in D and pushed the shifter forward into OD and floored it, only to find that I had been in OD and I had just overreved it in neutral.) I had that shop quote me replacing the bottom end with a used, good one, but when they quoted me a standard SBC bottom end instead of an LT1, I got nervous that they weren't really familiar enough with this engine to trust them with the job.

So I went back to my previous mechanic, since he knows LT1s really well. (He's owned, worked on, and modified multiple ones.) He said it was difficult to give me a written estimate up front because of so many potential variables, so I asked for a "worst case scenario" price for a bottom end rebuild, which he quoted at $3500. That was in August, at which point I dropped off my car. I told him that I wanted the it back by the end of September or, at the latest, early October.

I kept on him over the months and got various excuses--he got hurt at work and only had one good arm; he was fighting with his wife and going to get a divorce, etc. During that time, I made two payments of $1500. I stopped by a few times and he showed me, with pride, the progress he was making. He told me that the pushrods were too long and that the valve locks were leaking (I think that's what he said) so it needed new ones. He didn't offer a dollar amount, but I said "if you say it needs that stuff, do it". I figured that stuff was above and beyond the $3500 worst case scenario and mentally prepared myself for an extra $500 or so.

My wife and one of my buddies had both been on my ass the whole time about using this mechanic again since he took so long with the broken valve spring, and my wife especially was pissed about how much I've spent on this car, which is a lot, relatively speaking. Per their insistence, when I went to pick up the car, I brought a check for $500, with the intent of paying whatever overage the mechanic had after I drove the car for a week or so to make sure everything was in good shape.

I arrived and took the car for a test drive. It seemed fine but the AC didn't work. Back at his shop, he started charging up the AC and gave me the bill to look over, while he shot the **** with my buddy. My draw dropped when I saw that the total outstanding balance was $2475, not $500 or even $1000 as I had expected.

I explained calmly that there was no way I could or would pay that kind of an overage. The discussion eventually got heated and turned into a yelling match. The $2475 overage changed to $1250, which I was sort of okay with, but I knew that my wife would hard line on $1000, no matter what, and I'm not having that battle if I don't have to. I told him that I'd pay him $500 on the spot and more after a week or so--at least $500 but I couldn't promise $750. He wasn't okay with that and I was about to leave without the car, and he said "you've got me over a barrel--I have $42 in my checking account and I need that $500 payment." So I gave him the $500 check and left with my car.

After I got home, I wiped down the underside of the engine, crossmember, trans, etc. A few days later, I checked it and found the leak mentioned in this thread.

My mechanic was supposed to take pics along the way (which I figured would help confirm an engine rebuild if I ever do try to sell the car), which I have never received. I didn't get a build sheet either, which I required as part of the job. There were 4 pages of hand-written notes, which I took pictures of.

The way I see it at this point, the engine probably doesn't have a warranty. Since I have refused to pay his $2K overage, I'm sure he feels like I've screwed him over and if anything breaks, he'll tell me to go screw myself. I did text him about the leak including pics and he told me to "drop it off", but I kind of feel like the only reason he might work on it is because of the $500 (or so) that's still out there.

I'm not at all interested in addressing this legally. He won't sue me because no judge is going to find in his favor for the overage when it wasn't provided up front in writing. And I won't sue him because I've found out the hard way that winning in small claims court costs a bunch of time and money, and all you get is a piece of paper that says you won, but has no actually teeth to be able to collect anything from the losing party. (I've won $20K in judgments against deadbeat clients and have been able to collect $0.)

So, do you guys still think I should take the car back to him to have the seal fixed, or would I be wiser to cut my losses at this point and have it fixed elsewhere?
 
#31 ·
Some backstory:
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So, do you guys still think I should take the car back to him to have the seal fixed, or would I be wiser to cut my losses at this point and have it fixed elsewhere?
Thanks for the detail. Eerbody here can commiserate in identical past situations with cars. It's definitely why I and scads others got to doing our own wrenching. I've already weighed in on the way forward. Your blood pressure will thank you. And letting your wife know she was right all along might return you some side benefits.
 
#27 · (Edited)
Here's the receipt.

Apparently he put in new valves and had them cut, which was never agreed to as part of the project--I was under the expectation that the valves and heads were all in good shape, and all that was being done was a bottom-end rebuild.

Under the "additional parts" page are things that don't seem like they should be "additional".. they should have been planned as part of the base job. For example, head gaskets, valve cover gaskets, header gaskets, assembly lube, oil pump..

He did use ARP bolts, but that was mentioned before I even brought the car to him so the implication was that those were under the $3500 worst case scenario.

Twice when I stopped by, he tried to talk me into spending a bit of extra money on the build to prepare the engine for running nitrous. I declined both times--I specifically told him that I was on a tight budget and my primary concern was getting the engine back together to run reliably for another 100K miles or so and make the same power as before it got hurt.

 
#29 ·
your intent to repair the car and the mechanics attempt to repair it are what they are. You had a history with this mechanic and you felt it would work out....but it didn't. Just like being ape shiat in love and marrying the girl and years later you can't stand each other....shiat happens

you are a "point & pay" guy so you are at the mercy of any shop to do a job right and charge a fair price based on a hourly shop labor rate and parts (they make $ on parts also).

The $3500 to build a bottom end is no bargain and high for just a bottom end but close to what you would pay a "qualified" source with all new parts. Karl at ERE charges $1500 to build a motor + parts but that does not include R&R motor. Generally another $1500- $2k in labor for a shop to R&R the motor so $5500 in total is not far from what shops would charge...but the shop should do a "professional" job and be responsible for any issues resulting from the parts they installed not working (fuking up a wp seal for example)

This guy not checking compression on 1 cyl that turned out bad is just sloppy.

The hand written paper work is sloppy but is a "record" explaining what he did. The 7 degree lock thing and charging more to install valve stem seals on heads he was doing valves on...valve seals are like $25-$30, you need to remove them anyway to do a valve job so they should have been included in original quote

Just bail on this guy, fix the leak yourself or have a shop do it if you don't have the skill set to do so. Maintaining 20+ year old cars, especially ones that are modified, is a expensive situation if you don't do the work yourself and most "repair shops" only have training to repair factory set ups.

Installing 1.800" springs on heads set for 1.750" springs height is just stupid BS. The spring pockets need to be machined down to do it right to get 1.800. Your springs are now set up a little shorter so their open & seat pressure is higher. No big deal really if the cam is small but just BS to do that vs choosing a spring, and there are several to chose from, that installs at a stock installed height. IDK if the decision was his or yours on that but just using that note was not the best decision

Ideally the motor will last 100k mi and you will be fine long term. Right now you need to fix the leak more to prevent opti failure.
 
#30 · (Edited)
The problem many have with these vehicles is when the owner has to hire a tech to work the vehicle , you have to find some old auto tech 50 plus , that has the knowledge on the proper procedures to do the repairs.

on the compression testing that does reveal he is sloppy.
also changing parts at your expense I do hate that .. he did the guessing at your expense.

do not bring back ..
 
#32 ·
Personally sounds like you need to get it checked out by someone else and talk to a lawyer... no way it should have cost that much. Unless I am way off base there are rebuild shops that will turn your motor around in less than a week, give 100,000 mile warranty and cost less than $2000. At least when I looked into it 10 years ago they would have charged me $1000 for my LT1...

And another less than $1000 to swap the motor... I don't get it...



You are going to want to well document what he did to your car and discuss with a lawyer.
 
#33 ·
#34 · (Edited)
There used to be a user active here named: Buffman. He had a run of Aluminum parts made for the installation of this seal.

I just did this over the weekend with my Skip White distributor install.

Since those parts from Buffman are no longer readily available at a good price (EvilBay) (Old post for reference, you can either use a socket as one member brought to my attention, which I believe was my Snap-On deep 7/16 since it has a step similar to the original tool, or what others have done is take the tip off a Sharpie marker, grind off the pocket tab/tang thing, and file smooth, and use this to install the seal.

The choice is yours.

With regards to the gasket set, yes that is the correct P/N. As an FYI Amazon has this gasket set for the same price, so if you have Prime, you can get it minus shipping costs.
 
#36 · (Edited)
Thanks, Junior and BALLSS, for the tool link and tool pics. I don't mind $30 for the tool if it'll help me guarantee that I don't spend hours redoing the project. Also, I do have Prime, so that's a bonus!
 
#38 ·
I did use the socket method . I do have a lot of info on the install pictures and some video on the seal lip issue. I did F up the 1st seal I installed . I took it out easy to take out and I knew I messed it up . the second seal went it perfectly but it is still working now 3 years later . on here there was/is good info on the install . like I said start engine no pump on see if the seal leaks ....................need opti in ! but not pump....

I got this gasket set at pepboys and also autozone .. perhaps advance has it as well .
 
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