Oil Leak Identification Help

[jastewart25]

i'm a total newbie when it comes to anything mechanical. i've read a few threads on identifying leaks but i could use your help!

will start tomorrow with cleaning the undercarriage as best i can as well as wiping valve covers down. i know not to wet the air filter and carb -anything else i shouldn't get wet?

here is what the floor looks like after truck has been driven and parked for a few hours. each time i move it, the oil drips in multiple places.

any thoughts? thanks!

[enaberif]

Could be lots of things but most common is rear main seal, transmission pan gasket or the oil pan gasket.

Others could be intake manifold leaking as well.

[greg64]

Do you have an automatic tranny? If so, that fluid (atf), gear oil (rear diff) and engine oil will all smell different. Might allow you to tell which major part is leaking.

Alas, they all leak, eventually. It took the Japanese to show people cars didn't need to leak everywhere for US companies to design better sealing surfaces.

[rich weyand]

Here's a big hint. It will never drip forward of a leak, but it can drip behind a leak because the leaking oil gets blown back along the bottom of the truck. Left and right is usually correct in terms of where the leak is. That looks too far forward to be a rear main seal, and toward the passenger side. I think it's the passenger side valve cover.

[jastewart25]

thanks guys. appreciate the feedback.

yes-auto tranny. i tightened valve covers 2 days ago and it seems to be worse if that is possible.

another clue that may help, i couldn't see anything leaking while the truck is running. only after it has been parked for a few hours.

there was pooling on the rear main seal but everything underneath is a complete mess fluid wise so i didn't want to jump to that conclusion.

is it normal to have so many different leak spots? the first day i noticed it, i remember seeing just one spot. now, quite a different story.

is it possible for it to be leaking from one place but drip as it's doing? and those drips were 100 percent in the park position.

[rich weyand]

Everything behind the drip will be wet from drops getting blown backwards while driving. So you probably only have one leak, and all the drips are from places behind the leak; that is, the real leak is from the most forward place where you see oil.

Yes, it is possible for it to get worse from tightening the valve covers, because the flange may be bent at the hold down holes, and it will bend more, pushing the rest of the flange up.

The leak is also from the highest place that is wet with oil, because the oil isn't going to go uphill.

So find the highest, most forward wet spot. For me, it was the front of the passenger side valve cover. You should look around below the valve covers, and see if the heads are wet with oil anywhere. That's your leak.

I tried a bunch of things people suggested on forums, and I got tired of them leaking, so I went a little nuts. I used Proform hold-down looms, together with pressure spreaders, new steel-core rubber gaskets, and then I sealed both sides of the gasket with an aviation product, TiteSeal, that is a non-hardening gasket sealer. You rub it on both the gasket and the mating surface (valve cover, head), on both sides of the gasket, and then you stick them down. Clean them with lacquer thinner first, because TiteSeal won't stick to oil and then you'll leave a track for the oil to leak again.

Oh, and I also used T-handles, so I could get them just hand-tight, and not over-tighten them and bend the flange.

One reason I had so much trouble is that I run full synthetic oil, and if there is any place it can get out, it will.

http://www.jegs.com/i/Proform/778/66292BKC/10002/-1
http://www.jegs.com/i/JEGS+Performan...21100/10002/-1
http://www.skygeek.com/gunk-t25-66-1...-1-lb-tin.html

[jastewart25]

thank you rich! all of what you say makes perfect sense.

off to do some cleaning and drip tracing.

thanks again.

[enaberif]

Also off of what Rich said too tight is also bad. You can warp flanges and gaskets which can also cause leaks.

I just replaced the pan on my truck with a new gasket and I got a small leak at the front of the pan that I will sort out. But this could also be a result of the pan being slightly overfilled.

[DPowers]

you might want to check your oil pressure sending unit.

[Bigstevex4]

Valve cover Gaskets are always leaking on older vehickles theres a
reason chevy changed the hight of the lip on heads and went to center bolts.

[jastewart25]

i removed my valve covers today and cleaned them. came back tonight with a flashlight and took a few pics.

does this look like oil mixed with water?

i'm honestly not even sure about what i'm looking at. are these cylinder heads? i think i've identified them as rocker arms?

should i clean the oil from them before putting the valve covers back on?

i found some stamped numbers as well on drivers side by the hole where the oil goes.

B106
333882

anyone know what that means?

thanks so much!!!

[74CustomK20]

No that looks like Normal Oil. Yes those are rockers. No don't clean them they will just get covered again... those are casting numbers, means you have standard truck heads pretty much.

[jastewart25]

Originally Posted by 74CustomK20

No that looks like Normal Oil. Yes those are rockers. No don't clean them they will just get covered again... those are casting numbers, means you have standard truck heads pretty much.

thank you. i got worried for a hot second. i'm learning slowly.

[Dead Parrot]

Yep, that is normal. Oil goes in the lifters, up the push rods which are hollow, out the little hole in the bump, and down and off the rockers. If you don't mind the mess, you can watch it all work by running the engine with the valve cover off. If you try it, do just before an oil change.

[buddy_1]

Originally Posted by Dead Parrot

Yep, that is normal. Oil goes in the lifters, up the push rods which are hollow, out the little hole in the bump, and down and off the rockers. If you don't mind the mess, you can watch it all work by running the engine with the valve cover off. If you try it, do just before an oil change.

Also, don't stand right in front of the holes in the rockers. I have seen them spray oil over the fender and into your face if your in the way.

[Gregski]

Welcome to the Pavement Lubrication System club, I am battling something similar. I would recommend cleaning with Mineral Spirits (from Home Depot) and some paper towels, instead of spraying with a garden hose, or pressure washer, that only scatters stuff all over the place, start at the top and work your way down, also front of engine to back. Check to see if the top of your bellhousing is wet, remember that what ever the fluid, it likes to run down and follow what ever metal it can flow down, so the leak may be off by a foot or so of the source.

[mrolds88]

Before replacing the valve covers, make sure the flanges aren't warped around the bolt holes. If they are, you'll need to straighten them out. And you have so many options for valve cover gaskets. There should be a good option for you to find a set that you can get that wont leak on you.

['76 Big Block]

Just a trick I learned many moons ago, is to take common thread and tie your valve (rocker) cover gaskets to the cover (through the bolt holes. This will help keep gasket aligned when trying to reinstall covers----seems like the gaskets sometimes shift when you're putting things back together...

[85/Silverado]

so you don't use any kind of gasket sealer on valve covers?

['76 Big Block]

I use a "light" film of Perma-tex #2 between gasket and cover, but not between gasket and head. I alos prefer the cork gasket over neoprene---
I feel that the cork gasket gives me a better feel for when the bolts are snug enough---neoprene has never worked as well (for me)....