the.jake.is.real

Hey guys, so I am new to this, so I figure before I state the issue I'll go about with the details for the car. I have a 2001 Jeep Cherokee Classic that is painted silver. It does have the Infinity Sound System in it and it is the 4WD model with an automatic transmission. It is completely stock except for a trailer hitch, a new radio receiver, and I replaced the rusted muffler and exhaust pipe. It has 186,371 miles on it and runs perfectly fine except for this one problem...

When I am driving down any road (I don't typically rev over 2,000 RPM) and I come to a stop, my engine starts to shake a little bit and then smoke and a horrible smell comes out the driver's side of the hood. I check the thermometer and it's fine, it's not overheating or anything, because when it has done it I immediately try to feel the smoke to see if it's hot, and it feels just like air. I've taken it to have the check engine light read on it, and the codes are all misfire codes. The most prominent one is a P0303 (cylinder 3) misfire code. I've replaced the spark plugs, so I know it's not that. When I am cruising down the interstate at around 55-60 mph, my XJ starts to sputter a little bit. I've taken it to a mechanic and he looked at it and had it for a week, took it to what he calls "The Machine" and then gave it back to me and said that nothing was wrong with it. I don't know what else to do. Help!

extrashaky

Have you been losing coolant from your overflow bottle? Have you noticed your oil level rising between oil changes?

The "smoke" you're seeing. Is it white? Could it be steam?

The smell you mentioned. Is it a sickly sweet smell, like burning maple syrup?

Also, how is your oil pressure?

the.jake.is.real

I have not been losing coolant, and my oil has been fine through the changes. I honestly don’t know what’s wrong with it!!

It is white, I suppose it could be steam, but it smells nasty. I’ve never really smelled anything like it before, but it does kinda smell a little bit mapley now that you mention it. It’s definitely not sweet though.

Oil pressure is (on the dial) at like 40 while at idle and 60 while driving? I’m not totally sure what it means but i know it goes up when I push the gas pedal 😂

Thank you so much for helping!!!

extrashaky

I hate to say it, but this sounds like either a cracked head or blown head gasket. That would account for all your symptoms. That maple smell is what coolant smells like when it burns or boils, and there's really no place for steam to come from except the head. If coolant is leaking into your #3 cylinder and fouling the plug, you would get a misfire. The good news is that your oil pressure is still good, so it doesn't seem like you have damaged the bottom end yet.

The 2000 and 2001 XJs had the original 0331 head that likes to crack between the #3 and #4 cylinders. If you search for "0331 head crack," you'll find more than you want to know about them. Not all of them crack, but enough do that it's a concern whenever you have a cylinder 3 or cylinder 4 misfire, and the stakes go up if you have other symptoms of a head issue. If you let it go on long enough, coolant will get into your oil and ruin the camshaft bearings. Sometimes you can even see the crack by shining a light down into the oil filler cap and looking at the top of the deck there.

Some testing you can do at this point:

Test the compression. You can borrow a compression test kit from Auto Zone or similar store to see if your #3 cylinder (or any other cylinder) has lost compression. If you do have low compression, you'll have to figure out if it's a problem with the rings or the head.

You can test for the presence of exhaust gases in your coolant using a combustion leak test kit. You get this from Auto Zone as well. This test will tell you if you have a leak from the cylinder into the cooling system and vice versa.

You can also pull an oil sample and send it off to Blackstone Labs for analysis. They'll send you the test kit for free, and the test itself costs $28. You'll get an oil report that will tell you if coolant is getting into your oil.

If either of these last two tests are positive, the head needs to come off. You can take the head to a machine shop to have it tested for cracks, but honestly even if it only turns out to be the gasket, I would just replace it at that point rather than put a 0331 head back on that might crack six months later. Your easiest replacement option is a Clearwater 0331 head, which is a new casting with a thicker deck to resist cracking.

Even if those tests are negative, you still need to figure out exactly where that steam is coming from. Have you been able to get the hood open while it's still coming out?