Smell of exhaust inside the car

[Dzekovic]

Hey everyone.
First of all, I do not know if this is the right place to post this, but merely posted it here, since i think its a technical question. If i'm wrong, then im sorry and will accept if the thread gets moved.(i checked the Polo forum, but it seemed inactive)
In fact i have 3 questions, which complicates it even more.
The questions:

Question 1: I drive around in a VW Polo from 1995, which I've had for precisely a year now.
This summer, before i went on a month of vacation, i left my car at a friends house, who i was suppose to go with on vacation, and at this point the car had no problems. My friend was only able to get 3 weeks off from his work, so when i returned from my vacation, i learned that my friend had been driving around in my car for a week(without my permission), and told me that a problem had appeared - 3 out of 4 spark plugs had burned out completely, and i was lucky i was able to drive it home. My friend seemed to have a bad conscience about something, and told me eagerly that he had cleaned my car totally and even gave me a gift - and this he does RARELY. So i couldn't help but thinking if he had anything to do with this, or was it something that happened because the car was inactive for 3 weeks?

Question 2:
I choose to believe my friend when he said he didn't have anything to do with the question above. I then bought 4 new spark plugs and replaced the old ones, and voila! it worked. Al tough, it didn't come without consequences. I would now experience that after I've been driving around for about 5-10 minutes, the entire car would smell of exhaust gas and all passengers I've had with me, has complained about it.
So why does my car begin to stink of exhaust after 5-10 minutes, and is it dangerous(probably yes, but i still do not know if it is even CO2 - everybody just says that it smells like exhaust)?

Question 3:
Is there a connection between the two problems?

Thanks in advance!

[DeltaP]

Ask your friend... theres something he aint tellin ya! Some friend. Might have run over someone and tore the exhaust off of it!
Hey, can I borrow $100 bucks? I'll be your friend.

[Dzekovic]

Originally Posted by DeltaP

Ask your friend... theres something he aint tellin ya! Some friend. Might have run over someone and tore the exhaust off of it!
Hey, can I borrow $100 bucks? I'll be your friend.

Haha
So you think he might have something to do with the exhaust problem? but what about the spark plugs?

[DeltaP]

Come on.... hell of a coincidence isn't it?

[Dzekovic]

Originally Posted by DeltaP

Come on.... hell of a coincidence isn't it?

I have always thought that he did something. My problem was putting words on it, as i cant accuse him of doing something without having knowlegde on the area. Thats why im asking in here, so i can find an answer to this mess

[DeltaP]

Now that ya got it running ya need to look underneath and inspect for exhaust leaks and damage.
Wheres Aalborg?

[MagicRat]

Originally Posted by DeltaP

Wheres Aalborg?

Wikipedia is your friend.
http://en.wikipedia.org/wiki/Aalborg

I do agree you need to inspect the exhaust for leaks and impact damage. One easy way: when the engine is cold, start it up. Go and cover the outlet of the exhaust with a rag in your hand. Use an old oven mitt so you don't get any burns. The exhaust gases should build-up some pressure and try and push your hand off the pipe.

If the exhaust is leaking, you will hear a whoosh sound as the exhaust rushes out the hole or gap.

Also, do you still have the old plugs? Their actual appearance of the electrode (the part where the spark appears) can give us an important clue as to any engine failure or abuse. Can you retrieve them and post a picture?

Some kinds of severe engine abuse can ruin plugs, such as hard acceleration when cold, poor fuel quality, detonation, overheating, continuous excessive revs etc.

Also, how old were the old plugs? I agree, it is a heck of a coincidence, but its possible your plugs were marginal to start with and your friend simply had bad luck they went bad when he "borrowed" the car. IMO this is a risk when borrowing anything - the borrowed becomes liable for failures that may not be his fault. This is why I personally hate to borrow ANY mechanical device, vehicle, power tool etc.

[DeltaP]

When I do borrow something,rarely, I tend to take better care of it than if it were my own.