After driving my truck a few miles or further when I turn off the engine it smells like burning oil. The smell does not last long and it goes away but it is there. I don't know where it is coming from, I have looked under the truck with a flashlight, did not see any leaks, I saw no leaks up top either. What I do see is a film of grease/dirt/maybe oil all along the edges of both valve covers. Is it possible the crankcase ventilation system is bad? My PCV valve is brand new, and I replaced the hose from it to the intake about a year ago, it had a bad crack in it. The right valve cover has more gunk built up on it than the left. It has always been that way but I just recently started noticing the burned oil smell after I shut it off.

I changed my oil today and noticed a glob of some kind of black fluid on the front edge bottom of the transmission. I think it was water mixed with dirt or grease. It did not smell like oil or transmission lube. It had no smell at all. There were no trails leading down to where the drop was hanging there on the transmission either so that made me think there is no leak. In between the front of the oil pan and back side of the engine has a coating of grease and dirt too. I figure that is normal for a 13 year old truck with over 163,000 miles on it.

Any thoughts on this one? Is it blow-by from that hose on the right valve cover? Seems to me if I had a bad valve cover gasket the oil would be dripping at a higher amount, hitting the exhaust and smoking/stinking up the engine bay. I don't have any of that going on. Oil level is always OK, truck does burn about half a quart over about 2500 miles. My truck has never dripped any oil on my driveway or in my parking space at work. I always park in the same space at work.

I will try to get a better look at this tomorrow in the daylight. Thanks for any help.

Jimmy

 

Sounds to me as there is some slight leak or seepage getting on the exhaust somewhere and burning off. Therefore nothing to see when you are looking. Next time you are searching look at your exhaust manifolds and system for dark spots. That SHOULD be your culprit...or maybe not. But it's happened to me before.

 

power steering pump/flluid?

 

Thanks Magnet but it's not the ps, not so far as I can tell. I crawled under the truck again today and there was another drop of water hanging on the bottom edge of the front of the transmission. It was not in exactly the same spot as the one yesterday, it was a few inches over but it was clear and was definitely water. Maybe the cooler weather here caused that, IDK. I didn't see any spots on the exhaust Jeff but I did not have time to remove the heat shields to get a good look.

There is no greasy gunk around the front main seal. I wonder if I have a slight leak in the rear main seal. I need to spend more time on this, first thing to do is clean the valve covers up and also clean that space between the trans and oil pan the best I can, drive it a few days and then see if i can spot any leaks. I have other stuff to get done today and get togethers with my family for Christmas this week will keep me from having much time to work on it. I plan to buy a few cans of brake cleaner and compressed air next week and get after it on Saturday. I need to change out my rear differential lube on Saturday as well. I bought gear oil yesterday but did not have time to change it. Still, an oil change, tire rotation and a good detailing and wash was a great way to spend a cool sunny Saturday.

Thanks for the help on this. I will keep after it till I find the problem.

Jimmy

 

I think I found the trouble. I believe I have a bad crankcase breather tube grommet in the right valve cover. I drove the ruck this afternoon and when I got home I smelled oil again. I popped the hood and had a good look, there was a small stream of oil running out from under the edge of the grommet so I am pretty sure it is shot. The PCV grommet seems to be OK.

It also looks like I will be replacing my valve cover gaskets this week. Both covers have a film of gunk on the edges and there are spots on both exhaust manifold where oil is dripping down. It's not enough to cause smoke but it is enough to stink like burned oil. Thanks to AlaskaJeff for the tip about spots. I took some pics, do you guys think I am correct on the valve cover gaskets?

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As always, thanks for your help on this.

Jimmy

 

I suggest a good steam cleaning before you start I cant believe how dirty you folks let your engines get?

 

Happy New Year Everybody....I thought I would post an update here.

On Sunday the 22nd I had a no start. That was the first no start I have ever had since I have owned my truck. There were no codes stored but it just would not start here at my house. I tried it a few times and eventually it did start but the idle was real low, almost cutting off unless I goosed the throttle. I had that low idle problem a couple times in the week or ten days prior to the no-start too. I just figured it was the cool/wet weather whacking out my IAC because it did start on the first try, it just had to idle low a few seconds and then it came up to a normal idle and ran OK.

So last Saturday I replaced my valve cover gaskets. I cleaned and vaccumed the dirt/grease/sand/gunk off the top of the engine as best I could and took a rag soaked in brake cleaner and cleaned all the grease and dirt off the valve covers and heads. Here is a pic of the old valve cover gaskets. They both had oil saturated on them in the same location:

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I am no expert but I replaced the vc gaskets anyway. I think they may have been the source of the leak because since I put in the new gaskets the valve covers are still clean and I do not smell the hot burning oil any more when I shut down the engine. I also replaced the breather tube elbow and grommet and I bought a new PCV grommet at the dealer. The PCV grommet is not leaking but for peace of mind I will replace it anyway when I re-check the torque on the valve cover bolts.

I do believe this oil leak problem is fixed now. It may have been the gaskets but also could have been the bolts in the left side valve cover. The two that are regular bolts, not studs, were both very loose when I removed them. I probably could have removed them by hand if I had been able to reach them without a socket and extension. I torqued all of the bolts on both valve covers down to 95 in-lbs when I reinstalled the valve covers and plan to re-torque them again later today and again on Saturday to be sure they are all still OK.

Just as a precaution I also replaced my spark plugs and wires. I had read online that the no-start *could* have been the result of an oil-fouled plug or wire boot damaged from the oil leaking down on it from a bad valve cover gasket. I also read that if a plug gets oil on its insulator it makes the plug unable to dissipate heat correctly and ruins the plug. I did not see any obvious problems with the old plugs or wires but I replaced them anyway for peace of mind. My truck starts right up and idles perfectly now.

Here's a pic of the right head with valve cover removed, before I cleaned it up:

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Same head cleaned up and with new gasket in place:

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It's not nearly as clean as 98DakAZ's engine but it is good enough for me. So far my truck is running very fine and still getting 18 MPG. I plan to check out the underside of the truck this weekend, see if I can find out what that stuff was on the front of the transmission.

Thanks to everybody for your help on this. I will update the thread again if any other problems come up.

Jimmy

 

Well I'm originally from southern CA. and most in CA. like keeping our engines sharp and clean.

Plus I have been around a Lot of custom shops most my life so its natural to keep engines sharp and clean.

Just a habit that stuck with me all these years

 

Move up north, guaranteed your engine won't stay as clean as you have it!

 

I second that. If you live up north it is damn near impossible to keep vehicles clean, especially during the winter. The only clean ones are garaged cars that rarely hit the streets.