Question : Sweet smell from exhaust

[alexbtango15]

I was reading a recent thread from a member water leaks in a Cherokee with a 3.4. Something was mentioned about a sweet smell from the exhaust.

I happen to have that very same sweet smell from the exhaust in a 95 Beretta with a 3100. I noticed it Friday as I was driving home from work. The engine had slighly rough idle when I first started it and then smoothed out. When I got home, 25 miles away from work, I noticed the sweet smelling steam from the tailpipe.

So.... Either a LIm or a head gasket is my problem?

[86FieroSEv6]

Most of the time it's the LIM, but I have seen cylinder wall cracks if they get too overheated.

[Schmieder]

You are getting coolant into the combustion chamber. Could be anywhere from the heads to the block.

But 95% says it is the head gasket leaking. Either the gasket was overheated and broke/cracked or the heads are warped.

When the coolant is cool, open the radiator cap and then start the car. Are you getting bubbles? It won't be many but you'll see a few.

When the engine is warm, preferably after a drive, hold a piece of paper up to the exhaust flow. If it gets wet you have confirmed it.

Tear into the block and find the leak. I would replave all gaskets and do NOT reuse the head bolts or you will ruin a new gasket fast. Also have the heads checked for warping. If you have warped heads and put them back on, that gasket will fail again in no time. You can get remaned heads for approx $250 on Ebay (not used, remaned)

If the car isn't worth that much to fix it, get a bottle of Blue Devil about $100. It will fix the leak for a while and when it does, sell it to a sucker or drive it to its death. Some people had Blue Devil last a year or so. But if you value your car and want to really fix it, don't use that clogging crap. It works well, but it isn't a good idea if you want to keep the car.

But for crap clogging products, Blue Devil works the best imho. I used it before on a Lumina. Stopped the leak very well, sold it.

[alexbtango15]

I think the car is worth fixing. I bought it just recently as a work car since the price of gas has increased and nobody from work can carpool with me because of my odd hours. It's actually in not in that bad a shape. Just mechanically neglected a bit. It still had the orange antifreeze, I've heard that it really eats up LIM's in older cars.

I hope it's just a LIM and not a head gasket or cracked cylinder wall.

Anyway, thanks for the quick reply guys, I'll keep you posted.

[pocket-rocket]

Does it steam as soon as it's started or once it's warmed up? I've seen 2 that only steamed after being warmed up and they both spit coolant out of the radiator at you, and both ended up being head gaskets. Also, I would do a cooling system pressure test when the car is steaming to see if you can hear where the coolant is going. Pulling the oil cap should let you hear if it's a LIM, a piece of tube down a spark plug hole will let you use it as a stethoscope to see if it's a head/gasket. Just don't pull plugs when it's at operating temp because aluminum heads don't like that.

[Schmieder]

If you are getting substantial coolant into the exhaust, like a drip that never goes away or soaks paper, it's likely the head gasket. If you are getting a lot of coolant into the oil, you'll have a milky chocolate or mayo looking filth under the oil fill cap, it's likely the LIM.


Don't worry about cracked heads or block. I hardly ever hear of cracked blocks unless your pushing some good boost into the engine. And cracked heads happen but aren't as often really. I think there needs to be catastrophic breakdown to crack a head, extreme heat (in the red for a while), valve train failure like valves breaking free or the seats flying loose. I had a valve seat come out once, chewed the piston and the heads like butter.

A proper head gasket fix is going to be a sure way of fixing this car up to snuff, more then likely. There is always the small chance of other issues.

Instead of buying a kit, just get the head gaskets and the LIM gaskets. The rest you can make your own tracing out gasket material to save $$ or use RTV properly. Some people torque RTV right away and squish it into the intake, restricts flow. Put the item on hand tight and wait 1-2 hours then torque down. Done right RTV makes a good cheap alternative to plenum and throttle gaskets.

You will also need new head bolts, roughly $25-35 last I remember. Reusing head bolts is no good. Thats asking for gasket failure. And Black RTV, needed for a part of the LIM gasket.

Never assume you know how to torque the Head Bolts by hand, use a torque wrench.

Oh, flush the coolant system and go green. Ditch that Dexcool crap, everyone hates it.

[RedogOnyx]

Yeah its a head gasket

[tractorman]

I gotta disagree with the consensus here.

Your problem COULD be a head gasket. But it also could be a lower intake manifold gasket. They can fail in such a way that coolant is sucked into an intake port.

Here's how I would approach it: I would remove plugs all the plugs and check them. If the plug for a cylinder next to a coolant port in the LIM shows signs of coolant entry (with coolant build-up and/or washed amazingly clean), then I would begin to suspect a LIM gasket. Basically coolant can be sucked from the LIM gasket into cylinders 1 or 2... or cylinders 5 or 6. If coolant is going into cylinders 3 or 4, then it HAS to be a head gasket.

I don't like doing unnecessary work, so at that point (regardless of what the plugs look like), I'd tear the engine down and remove the lower intake and look at the gaskets. If they're failed in this way (sucking coolant into an intake port), then it should be obvious.

Only if I tore down the engine to this point and didn't see anything wrong would I remove the cylinder heads. I'm not saying that head gaskets are NOT the problem (they might be- we just don't know yet). I'm just saying that it's quite possible that the problem could be limited to the LIM gasket. It might save you a LOT of work if determine exactly where the problem is.

And whatever you do:

KEEP THEM PUSHRODS IN ORDER. NEVER EVER EVEN THINK ABOUT CRANKING THE ENGINE UNLESS YOU KNOW THAT THE PUSHRODS ARE IN THE RIGHT PLACE.

Sorry for the yelling... I just feel strongly about that point. I've seen way too many engines fubared over this issue.

[pocket-rocket]

I have to agree about not wanting to do unnecessary work (hence my coolant system pressure test suggestion), but I have to disagree about LIM gaskets. I don't see a LIM gasket leaking bad enough on a 3.4 iron head engine to allow coolant to jump about 2 inches to get sucked into the runner and ingested into the engine without any other signs like severe oil consumption or really high/rough idle.

[tractorman]

Yep, you're exactly right. I was thinking of the aluminum heads. And now that I look at even those gaskets, I see that my proposed scenario is pretty unlikely.

So yeah, it's probably a head gasket.