oil leak

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Mar 16, 2011 | 01:12 PM

ewellman

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oil leak

I have a 92 F150 with 4.9 300. It has an oil leak that is getting bad. I changed the valve cover gasket a few months back and it's still leaking. I can't seem to find where it's coming from. the sides of the motor are covered in oil. On the passenger side under the intake and exhaust manifolds it smokes real bad after running. Is there anwhere other than the valve cover gasket that would leak oil on the sides of the motor? I'm trying to do this on my own as I don't have much money to spend on a mechanic at the moment.
thanks

Mar 16, 2011 | 07:14 PM

AbandonedBronco

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From: Boise, Idaho

There are a couple possibilities. First is that the valve cover didn't seal all the way. Is there oil down the sides of the head?
Next is the lifter cover on the driver's side of the engine. There are 6 bolts that hold it on and each has a rubber grommet around it, plus the gasket around the lifter cover.
The last is you might be leaking oil out of the oil pressure sender for the gauge inside the cab.

A rear main seal is another possibility, but I don't know if that gets oil up higher on the engine. Usually it just spills on the ground.

Mar 17, 2011 | 08:36 AM

ewellman

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Yes it's down the sides of the motor. Both sides, but the passenger side seems to be the worst. My first thought is the valve cover gasket but its a pain to get to all the bolts with out taking off the intake. The new gasket I put on is a rubber gasket. Can I use a silicon sealer with this or is that a bad idea? I just wasn't sure if there was anywhere else on the sides of the motor that i should look at for a leak. Right now the motor is covered in oil and with out cleaning it, it's hard to see where it's coming from.
Thanks again for any help

Mar 17, 2011 | 08:40 AM

AbandonedBronco

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From: Boise, Idaho

I use some RTV silicone on mine. My valve cover is bent from the years, and even though I've tried to straighten it, it still leaks without the help of some sealant.

Clean both surfaces with solvent first before applying it. Also, be very careful not to use too much. If it gets inside the valve cover, it'll get into your oil, and plug up small passages and lifters.

Lastly, what did you torque your valve cover bolts to when you put the gasket on? It doesn't take much. I think the manual calls for around 4 - 6 ft/lbs. Any more than that, and you'll crush the gasket and make it leak.

Mar 17, 2011 | 10:09 PM

4x4 Bart

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From: Middle TN

Be very careful using Silicone, if any gets loose into your engine it will ruin a bearing. Use only a thin coat with no excess.

The best way to find oil leaks is to soap and pressure wash your engine until its clean. Then run it for a few minutes, take a flashlight and look for shiny wet spots around the gaskets and seals.