I drive a 99 r/t 5.9L V8. I have two problems.

First, when i bought the truck, about a week later I noticed a little blue smoke coming from the exhaust when I start the truck. I havent taken anything apart yet, but i realized i'm burning about a quart of oil for every 300 to 400 miles, which is horrible. I'm thinkin maybe a/some piston rings are bad? has anyone ever had this problem with their D? I'm only at like 63,000 miles.

Second, I have some sort of air leak. When i was adding oil one day, I noticed a hissing on the passenger side of the engine. When i removed the cap from the valve cover, the noise dissipated and i didnt hear it anymore. However, the air is being sucked in from the hole where the cap goes. I'm no mechanic, not even close to one. But to me, that means that when i seal the air in at the cap, its pulling it in from some hole in the other side of the engine.

Has anyone ever seen any of this before?

Any advice would be greatly appreciated!

 

bust out the compression checker! without seeing it this sounds like you have compression leaking into the oil passages, and oil in the cylinder. if this is true then you have blown a head gasket. do a compression test on all of your cylinders and compare it against the specs in your manual. at 63k miles a head gasket should be fine unless you overheated or hauled something you shouldn't have.

 

Q: What's the most common problem with the 360? (and possibly 318 too, I dunno)

A: Intake plenum gasket failure/leak.


Take the plastic air intake hat off the throttle body, open the throttle blades and shine a light down into the intake manifold. If you can see any puddles of oil in there, your intake plenum gasket has failed and it's both a) a vacuum leak, and b) going to suck oil into the intake, which will then make it's way out your tailpipe.

At a quart every 300-400 miles I'd wager you've got a big puddle in your intake.

Check it out. It's free to diagnose yourself, and doesn't require much effort. If that is indeed the problem, there are several remedies.

1) contact hughes performance engines and get one of their heavy duty plates and gasket sets
2) contact hughes or whoever modifies the intake manifolds and have the runner lengths shortened for greater horsepower, and get the updated gasket set/plate
3) put the OEM stuff back in there and hope it doesn't happen again. It was supposedly fixed with an updated part number sometime in 2001 or so, but my 2002 had the problem. Mine was covered under warranty so I got the OEM stuff put back in and it was taken care of for $50 deductible.


Seriously, I'd put money on that being your problem.

 

not that i doubt the diagnosis but how does oil get sucked into the intake plenum?

 

How DOES oil get sucked into the intake plenum with a failed gasket? [sm=wtf.gif]

 

It's a good effin question. I believe the bottom of the intake manifold is where the gasket fails and it's directly above the lifter valley, which has oil slopping around due to the cam/lifters/pushrods/etc. The gasket iirc is a paper gasket and it seems to get soaked then sucked into the manifold itself causing the leak, which then pulls air and oil in.

I don't know who came up with this design.

It's not the intake manifold to block/heads gasket that fails, it's a gasket that seals the bottom of the intake manifold runners.

 

Thanks guys, I appreciate all the input. I bought a compression tester today, and i plan to look into the oil in the intake suggestion also. I'll let you know what i find.

 

OK. So heres what i came up with. I did a compression test and here are the results.

1-175psi
2-135psi
3-170psi
4-130psi
5-160psi
6-170psi
7-120psi
8-90psi

Correct me if im wrong, but isnt there only supposed to be 10% or less difference. This makes me think I need new head gaskets and who knows what else. I bought new plugs and wires. I am going to buy a set of intake gaskets, exhaust gaskets, and head gaskets.

And i did look through the throttle body and I saw my reflection haha.

Does anyone have any input or advice?

 

whoa

whoa.

Yeah there's supposed to be no more than 10, maybe 15% difference between the cyls. That's crazy.


And by seeing your reflection, does that mean it was clean or there was a lake?

 

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