Hey guys,

My Q45 '94 (176K) threw something at me I haven't seen before during my ownership of 8 years. The car started vibrating pretty violently both at stop and while driving. The vibration is not very rhythmic. There is obvious loss in power. The other obvious sign is the smoke that appears to be coming out from the engine block itself. By the smell I can tell it is oil (similar to burning oil smell I had when my valve cover gasket was leaking 6 years ago). It is coming from the driver side of the bay somewhere from just above the headers. It is not smoking all the time either, appears to be in bursts ... no smoke then a small cloud ... then pause again.

I also noticed a stronger than usual gasoline smell in the cabin this morning, probably injector leak but not sure its related. Before all this happened the car was driving really good (just a few days ago). I haven't had any problems with it for at least 4-5 years related to engine.

My question is what in the world is going on there? Is it a head gasket that's blown? Any ideas?

Hate to see it die like this

Thanks,

Andre.

If I had to guess, I would say you have a valve cover leaking onto the exhaust manifold - and an injector problem. Two unrelated issues that you're noticing at the same time since the injector started acting up. You will need to pinpoint both issues and see where it leads you. Head gasket failures are very rare, and would probably show up as coolant mixing with the oil rather than an external leak.

If you have a dead injector, it tends to feel like a bounce at idle, and a vibration at speed. I would start by ohm testing your injectors.

http://www.q45.org/ohminjectors.html

Good luck!

Heath

Hi Heath,

I think you right. I took the vavle cover of today and my last cylinder was all dirty. What happend I think was a leak inside the vavle cover. It leaked into the spark plug then leaking through the thread into the cylinder. BTW, I haven't replaced my spark plugs for a very long time and most of them were pretty loose (i.e. I could unscrew them without a wrench). I suspect that's due to normal vibration?

I ran into adminstrative problem with getting a new gasket. Called my local dealer who quoted $31 and had it in stock. I picked it up and it turned out to be a wrong part. So I came back to this guy and after checking and double checking his inventory he told me that Infiniti shipped them wrong gaskets for the part number that I need. He will order another one on Monday but that does not guarantee its going to be the right one either. Where should I get mine from, everythinginfiniti? How quick do they deliver?


Andre.

They can ship overnight for a price...

The spark plugs being that loose is not normal. I can only guess that they weren't torqued correctly when installed? Hopefully you're using the OEM specified NGK plugs... lots of members have had major problems with other brands - especially Bosch.

Heath

I had NGK plugs. Bought new set of NGK IX iridium.

The metal house that sticks out from under the plenum is going to make it a bit hard to put the cover back I think. How did you deal with it?

Andre.

It might be worth a picture to let us know what part you're talking about is in the way... it's been a long time since I did this, but having a rubber gasket makes your life a lot easier than those of us with the 90-93 that have to use RTV.

Heath

I actually took a few pictures but I can't find a way to attach them here. Let me know how to post 'em and I will do that. Today I got the gasket from a different dealer and it was the right one this time. Took me probably 5 hours to put everything back. The hardest part was to put the cover back in place without rubbing the gasket. There isn't much room at all to maneuver because of the metal hoses that stick out there. Once I put it in, I tripple checked the gasket sit tight but really hard to tell since the far end (the one that's closer to the cabin) you can't really see the gasket there only feel and touch. Makes it a bit risky, because to test it you have to put everything together and 5 hours later to find out ... .

Test drove it and seems to be driving well althought I do smell that burning oil a bit (hoping it just burns whatever spilled over before). Also put new spark plugs for the driver side. Need to find energy some other day to replace plugs on the passenger side.

In summary, this job is a pain to do for the driver side. Passenger side looks much easier.

Thanks for your help Heath,

Andre.

If you want to post pictures, you have to host them somewhere on the internet. I like google's picasaweb.

Then you take the picture's web address and surround it with image tags in the body of the message like this:

{img}www.yourimageaddress.com{/img} but using "[ and ]" instead of "{ and }" around the "img" and "/img"

Congratulations on getting it all back up and running!

Heath