Oil leak, and maybe need a new motor

[79vette]

I had my K5 for ~4 months 3k miles of mixed city/highway driving, and no leaks. About a month ago I moved from UT to CA, and on that trip the truck ran hot and started leaking a quart every 200mi or so. Big trails of oil down both sides of the engine, up to the valve covers. So I swapped those gaskets and was leak free for another 1k miles.

I just made the drive to UT and back to SoCal again last week. Like the first time, the truck ran hot and is again leaking oil like a sieve. The block is dry at the VC corners, but the starter/bellhousing are completely covered in oil.

I have no idea where this is coming from. Distributor hold down is tight (shouldnt really leak that much, even with no gasket at all IMO), VC gaskets are good, and the motor is dry around the oil pressure sender. Is it possible for a head gasket to cause an oil leak, because I've checked everything else up there that I can think of.

The photo of the trans pan was taken after a 10min/4mi test drive, and everything is completely coated in oil. Basically the truck is undrivable. Other pics show the leakage as well as I can document it. And the last one is of the oil change I did this afternoon. Last oil change was clean and clear, but this time it looks like the filter was full of bearing material.

Can you guys help me out? Guesses on where the leak could be (and is it possible to be a head gasket?) and how bad does the last pic look?
EDIT: could be the back of the intake I guess, but it seems unlikely that would just suddenly start leaking like this. I'll check that out now and update with what I find

[mongocanfly]

One picture makes me think rear main seal...the other pictures make me think valve cover gasket or maybe intake gasket..I'd start with valve covers..new gaskets are cheap enough...
There shouldn't be any oil pressure on the head gaskets..oil is carried to the valve area thru the pushrods and gravity flows back down thru the head

[mongocanfly]

Here's a article explaining a head gasket.http://www.badasscars.com/index.cfm/...rod/prd119.htm

[79vette]

Thanks both for the info on head gaskets. I knew the valve train is oiled through the push rods and the heads had drain-back holes, but I swear that is where it looks like the leak is. I guess I will do the VC gaskets again, and hope it lasts longer than 2k miles.

Anyone have experience with FelPro PermaDry or other gaskets of that type (rubber molded around steel inserts)? I'm going to get cast valve covers as well, as I wouldn't be surprised if my tin ones are warped.

Also, any thought about the last pic? Looks like bearing material to me, but IDK if it is enough to get all worked up over.

Originally Posted by mongocanfly

One picture makes me think rear main seal...the other pictures make me think valve cover gasket or maybe intake gasket..I'd start with valve covers..new gaskets are cheap enough...

Which one makes you think RMS? The one of the trans pan? That was my thought a month ago, and then swapping the VC gaskets made the problem go away temporarily.

Originally Posted by mongocanfly

Here's a article explaining a head gasket.http://www.badasscars.com/index.cfm/...rod/prd119.htm

Thanks. I've read a bit on that site before, but that article was new. It was a good read.

[geezer#99]

Do you have a pic of the top of your motor?

[79vette]

Originally Posted by geezer#99

Do you have a pic of the top of your motor?

I can get one. Its a mess in there though; what do you want to see?

[geezer#99]

Top of the motor with the air cleaner off.
Looking for something missing or wrong.

[79vette]

Originally Posted by geezer#99

Top of the motor with the air cleaner off.
Looking for something missing or wrong.

There's a lot of wires and hoses sort of going everywhere that makes it hard to see. If there is something specific you suspect I can get a pic of that area, but in general these are about the best I can do. Thanks for taking the time to look

[geezer#99]

I thought it might be a crankcase pressure problem.
But I see you have a pcv and breather.

Have you checked for blowby?
Pull the breather and pcv off and rev the motor to see how much oil fumes blow out.

Excess blowby can still cause gasket failures if the pcv won't handle it.

[mongocanfly]

Oil on trans pan is what made me think rms..but since its coming from higher up that narrows it down to intake or valve covers if you've positively ruled out oil pressure sender....as bad as that leak is can you clean it up real good..crank engine and get some mirrors and a good light and tell where its coming from?..if you know someone with a borescope they work really well also for seeing where you can't see

[79vette]

Originally Posted by geezer#99

I thought it might be a crankcase pressure problem.
But I see you have a pcv and breather.

Have you checked for blowby?
Pull the breather and pcv off and rev the motor to see how much oil fumes blow out.

Excess blowby can still cause gasket failures if the pcv won't handle it.

I'll check on that tomorrow. I guess that could cause valve cover gasket failures, and both times this problem has occurred during 12 hours of sustained highway operation (80mph +/-). I changed the PCV after the first round of leaks, so it is new within 2500 miles. Breather is old, but I dont know if they can fail at all.

Anyone have thoughts on the oil pic with the metal shavings?

[79vette]

Originally Posted by mongocanfly

Oil on trans pan is what made me think rms..but since its coming from higher up that narrows it down to intake or valve covers if you've positively ruled out oil pressure sender....

I am going to replace the sender anyway because it is wired to an aftermarket POS gauge and I want to go back to the stock gauge. Do I want thread tape or anything like that, or just screw in the new one?

I bought cast valve covers and the high-dollar rubber FelPro gaskets, so we'll see if that solves it when they come in this week. I've used cork gaskets and cheap tin covers on my Corvette for years with no issues, but IDK. I'm tired of fighting this and need it fixed asap.

[mongocanfly]

Although thread tape works I prefer a rtv style thread sealant...

[geezer#99]

I also noticed the intake gasket on the front china wall shows no sign of silicone. Which makes me suspect the cork gaskets were used at both ends. You could have a china wall leak at the back that only shows up under long drives.
And oil breathers can get plugged up.

[79vette]

Originally Posted by geezer#99

I also noticed the intake gasket on the front china wall shows no sign of silicone. Which makes me suspect the cork gaskets were used at both ends. You could have a china wall leak at the back that only shows up under long drives.
And oil breathers can get plugged up.

So now it leaks like mad even driving a few miles. The problem started during a long drive and I fixed it by replacing VC gaskets, and now its back again (after another long drive). But that first pic of the trans pan was after running the engine for 10 min, and I really cleaned it well right before.

[mongocanfly]

as bad as that leak is can you clean it up real good..crank engine and get some mirrors and a good light and tell where its coming from?..if you know someone with a borescope they work really well also for seeing where you can't see

I can't tell what I'm looking at in your metal shaving pic..is that a cut open oil filter or just oil dumped out on something..

[79vette]

Originally Posted by mongocanfly

I can't tell what I'm looking at in your metal shaving pic..is that a cut open oil filter or just oil dumped out on something..

Its the oil that was in the filter, dumped into my catch pan. here is a better resolution pic, the attachment on the site made it hard to see

[mongocanfly]

If its leaking that bad it shouldn't be hard to narrow down...have you checked the shaving with a magnet?...

[geezer#99]

Cut the filter apart and have a look.

[toolboxchev]

Rear China Wall on back of intake manifold is what I have been thinking. What year truck is this motor in?

Appears to be set back like a 67-72 4WD vehicle??

If you put oil back in it with a new filter to run it get a large magnet and stick it to the bottom of the oil filter for a safeguard.

[midniteblues]

Check your breather of it dont flow well you might build pressure.
That could explain a china wall gasket blow out if thats the case.
Also aluminum intakes are notorious for loose mounting bolts checkem i bet some are loose.

Ive seen the bolt hole for the fuel pump push rod spew oil all the way back too the trans and further. for your sake check too make sure that hole is plugged with the rite size bolt.

Oil guage lines can crack and spew the oil too and it never looks like its the line leaking.

Those chunks dont look like bearing too me but its hard to tell from pics.
Could be plastic timing gear chunks.

I notice a body ground hanging loose in one pic and no bolts in the exhaust manifold. tic tic tic.

['68OrangeSunshine]

I don't know how many miles you have on your engine, but on a 292 I ran for 25 years, I had the curious problem of it losing a quart an hour when on the freeway, but not much oil loss in-town driving. When we did tear it apart, I found the Harmonic Balancer had worn a cut in the top arc of the timing gear cover, and at high speed, this was bleeding oil.
Something to check out.

[cadillac_al]

When my valve covers sprung a leak I was losing a quart every 100 miles. The oil and engine were clean so it was hard to find it until I got home. Those are some serious metal specs in the oil. If that catch can was clean then I would be worried.

[Warrens69GMC]

Look at the 5th bolt on the intake (passenger side) as compared to the 3rd bolt (front to rear). It looks as thought its not tightened down as much. You may just need a new intake gasket.

[garyd1961]

You also need to find out why it was over heating, the two problems may be related.. Maybe you have a blown head gasket or cracked head.