Blocked cat / exhaust overheat engine and increase consumption?

[rowan194]

The whining noise in my AUIII is becoming more prominent. My father in law reckons it may be the exhaust.

Recently my trans has overheated a couple of times, and I also noticed the coolant temp was higher than normal at the time. Fluids are normal.

So I had a thought, maybe the two are related... especially since an exhaust leak developed recently in a join where I hadn't tightened the bolts enough. I had gasket cement on the join, I'm thinking the cement sealed it for a while, but eventually the backwards pressure caused the cement to fracture and subsequently leak because of the loose bolts.

So if there's blockage, the engine itself is overheating, which is then raising the temp of the coolant and overheating the trans...?

I haven't noticed any loss of power, but the engine has been drinking 10-20% more fuel than normal for months. This change happened suddenly.

Is there a way to check the cat converter? What's one of them worth?

[T3man]

It does sound like the symptoms of a blocked exhaust. It may be the cat has collapsed and the guts have found their way back to the muffler and have jammed.

Give it a good long rap through the gears out on the freeway where you can safely take it up to say 120 a few of times from a standing start. On the second or third run (after you've got some heat through the system) if you see a heap of sheeeet billowing out your exhaust it indicates bits of dead cat being expelled. If you're lucky it will all be cleared out and you can continue driving for years even before you may have to actually replace the cat. But if the heat continues and fuel consumption doesn't stabilize then the cat/exhaust blockage will have to be addressed.

However, there are other things it could also be such as blocked radiator, slipping clutches in the auto, lock-up clutch in torque convertor; just to name a few.

[rowan194]

Originally Posted by T3man

However, there are other things it could also be such as blocked radiator, slipping clutches in the auto, lock-up clutch in torque convertor; just to name a few.

Would that just be the cause of overheating? Remember there's the additional whine noise (more like a drone) and the increase in fuel consumption.

I'll give it an italian tuneup when things are quiet and see what happens.

Found a quick way to test a cat using a non contact thermometer - trying to remember where mine is...

http://www.youtube.com/watch?v=Qrj_ioWCkQI

[LTDHO]

Get the car on a hoist and hit the cat and muffler. I have to agree, sounds like a collasped cat and/or muffler.

Time for an exhaust upgrade!!

[Day-mow]

ditch the exhaust. sounds cooler with out

[rowan194]

This is interesting...

http://www.youtube.com/watch?v=5icTmYItwiE

Of course, these two methods of cleaning are for a cat that has clogged slightly, not one that has totally crapped itself like mine probably has.

Day-mow: did start the engine briefly when I last had the exhaust manifold off. It was, hmmm, shall we say an interesting note.

[Day-mow]

i ran my car @ the drags with just extractors. was pretty rad.