Hi all,

Strong exhaust smell In cabin and my inlet air temp raises over 170 when idle. I have no oil leaks (knock on wood). This is not the “all D2 smell funny” I’m getting light headed while driving, it’s a problem.

I did connect a leaf blower in the tail pipe and sprayed soapy water all over exhaust system, I only saw bubbles in the manifold y-pipe connection (see picture) in both sides. Leak is small enough to not create a ticking sound.

I have taken the nuts from stud on both sides and replaced y-pipe gaskets, retightened to 22-24 lb-ft. I didn’t remove studs as nuts came off easily and studs seemed to be just fine. The leak persisted as if I had done nothing .

i tried copper gasket maker on the outside of the flange and it held for couple days until the gasket came off, during those days the smell disappeared which sort of confirmed the leak location. I disassembled the connection again and used the gasket maker on top of the metal gasket, that was a terrible idea, the gasket maker pulverized away and left a bigger leak of course. I removed the gaskets again and cleaned the mess (lucky cat didn’t go kaboom) and reassembled, I’m back to square one. Smell is there.

I did replace the moulding cawl since it was broken, I was hoping it would minimize the smell but it didn’t. I have also checked carefully for cracks in the y-pipe flange and there is none.

today I decided to taken it to a muffler shop, the said he couldn’t find a leak, I showed him the picture (after he tried to diagnose the problem to avoid bias) and he said that leak was very small and that I should check the AC vents as they might not be closing for proper recirculation.

im guessing y-pipe connection is warped or somehow defective and I need to replace the entire exhaust system, but I don’t want to spend that amount of money without checking all options.

can someone share any suggestions on how to fix this issue?

thanks!


Old gasket

 

Do you have SAI system? Tubes crack sometimes. Some folks double up yhe manifold/y-pipe gaskets with success.

 

I do have SAI, and they do leak a bit on the connector, tubes are not broken though.

I haven’t tried double gasking, will
definitely give it a try.

 

I'd repair the SAI system first. The minor leak you have at the manifold/y-pipe is down low and normally wouldn't cause you to get fumes in the cabin while driving. Because air moving past it carries fumes under the vehicle and away from drivers compartment. Now, a major leak would be noticable.

Whereas, the SAI tubes are up higher on the engine, more inline with your cabin inlet air duct. Air coming through engine bay from radiator would push exhaust fumes towards firewall, and again, towards your air intake opening below cowl. Which would make more sense to me, if you are getting exhaust smell/fumes while driving.

 

It makes sense, thanks for taking the time. I spent 3 hours this weekend trying to figure this out. Connected a leaf blower to the tailpipe and sprayed exhaust and SAI. Couldn’t really see any bubbles on SAI. The exhaust had the usual small leak in y-pipe and something new to me was the leak in the muffler connection to the pipe (see video). I don’t know if that leak is designed to be (muffler breather to drain condensation) or is a genuine leak. The fact I don’t hear any rambling sound makes me think is a small leak but not sure if that would cause the smell in the cabin? Perhaps when idle fumes would get in? Not sure. It is definitively not the cause of rising inlet air temps.

I checked the engine bay this morning on cold start, hovered over engine and manifold to try to find a huff or puff that might be the reason not only for smell but for rising inlet air temp and couldn’t really feel anything out of the ordinary. No strange sound either. It is Running smooth.

I’m thinking on getting a cheap smoke machine from Amazon and smoke the evap and SAI system, there might be a big leak that I haven’t found with leaf blower and soapy water method, although I don’t have any codes

Any suggestions? @The Deputy

Thanks

 

And you're sure it's exhaust? If it's a sweet smell, could be heater core leaking. Just seems weird that you can't find a substantal exhaust leak. I'd almost like to point you in the direction of your cats, they can really stink when plugged. But you say it's running good and you'd be getting codes...so...this is a weird one. Maybe the smoke test will show something.

 

I had a Dakota with plugged cats. It ran fine, only less power than I thought it should have, and it didn’t throw any codes. When I removed them, I got an extra 12 km/hr up a nearby hill.

 

@The Deputy I ran the smoke test, first time I do such a thing so I will describe what I did for process scrutiny.

I disconnected the MAF sensor bracket from air intake hose and plugged the smoke machine (SM) to the inlet, stuck the throttle body valve open and pumped the smoke. Smoke immediately leaked from brake servo hose and breather hose on top of inlet manifold (see picture), leak was big. I sealed it with some RTV and retested, leaks are gone and no smoke leaked from inlet manifold or valley and nothing on SAI pipes or valves.

I then proceeded to disconnect RH oxygen sensor and plugged the SM, plugged tailpipe and pumped smoke. To my surprise there was no leaks, just a mini leak in cat to muffler connection (see pic). I know the system was pressurized because the rubber glove I used to plug the tail pipe was inflated holding the smoke.

I went for a ride and noticed inlet temp raising but at a lower rate and exhaust smell was still there. So im at loss now

I did head gaskets 2k miles ago, no leaks, oil level stable, no valve cover leaks, nothing, the engine is 60k miles, but there is layers of what seems to be oil sludge from valve cover leak before the HG job(PO, I bought recently), the top of transmission is also soaked, I have seen people suggesting a vcg leaking on top of exhaust manifold would smell but how about oil sludge in the back of the block, would that smell when engine is hot? I know it would but I would assume light fractions of oil have already evaporated and the residual sludge shouldn’t really stink that bad. In will clean/degrease the block and assess of course but wonder what you all think about it?

thanks,

@Extinct

 

Follow up:


sealed upper manifold leaks and the smell subsided substantially, I think you were right @The Deputy, the air inlet temperature increase also slowed down but still gets pretty hot (150 deg) it just takes longer to get there.

i think I can deal with smell but want to focus the discussion on the raising AIT, I found something new I hadn’t identified. Look at this hole on the back of the passenger side bumper



I have no idea why that is there, hole was made during Prior ownership.

2 questions:

- any clue why someone would cut a hole there?

- would the hole have any impact on raising AIT?

@Extinct