I think I might have to do a head gasket

[mickeytopher]

So lately I've been getting a P303 misfire code, plugs, wires, coil pack are all new. I put a new fuel injector on last night, and I still can unplug it (the wiring harness) and it doesn't effect performance, also I can pretty much take out the spark plug wire all the way out and it doesn't affect anything. Last night I fired it up, cold, and took the radiator cap off and there was a lot of little bubbles built up on the bottom of the filler neck. I have rough idle, poor power/acceleration, poor MPG, about 15/16 city. No fluids have been mixing, oil was low, but that could be other things too. I'll do a compression check this weekend.

[r/tguy02]

could also be a burnt or bent valve

[mickeytopher]

could also be a burnt or bent valve

[occasional demons]

If the bubbles stop and start with the engine being on or off, and the coolant gets a nasty brown residue to it, it could be the HG. Pretty much what our 1gn did. I did a coolant pressure test, and it held fine.

It would only bubble enough to get air pockets in the system and cause overheating issues. It ran fine tho. The brown crap is from the combustion gasses, not from oil mixing. It didn't take long to get nasty in there, so if the coolant is still decent looking, the bubbles might just be trapped air.

[mickeytopher]

If the bubbles stop and start with the engine being on or off, and the coolant gets a nasty brown residue to it, it could be the HG. Pretty much what our 1gn did. I did a coolant pressure test, and it held fine.

It would only bubble enough to get air pockets in the system and cause overheating issues. It ran fine tho. The brown crap is from the combustion gasses, not from oil mixing. It didn't take long to get nasty in there, so if the coolant is still decent looking, the bubbles might just be trapped air.

It's a nice pretty neon green...no pun intended

No over heating issues either, in fact it runs a tad cool

[05MoparSRT4]

what about a sweet smell with white smoke coming from the tail pipe? Any signs of wetness around the gasket too?

[mickeytopher]

what about a sweet smell with white smoke coming from the tail pipe? Any signs of wetness around the gasket too?

Haven't smelt anything, or seen any thing out of the normal

[occasional demons]

Well short of a huge difference in cylinder 3 compared to the rest of them, it's going to take some more hunting. Have you tried putting an incandescent light across the injector connector, (unplugged) to see if it is flashing, not lighting or staying constant?

Unless the cylinder is totally dead, I don't see the fuel mileage being that horrible. If the injector is fully grounded, that would kill your fuel mileage, not to mention your engine. No pulse to the injector would also cause a misfire, but you would probably only see a small drop in economy.

Either should give you a code, but that depends on the conditions. A bad ground on my 1gn was messing with #2 injector driver, (No fuel) and there was no code/CEL.

Short of a plug wire being off, it would not set a misfire code either. Number 1 cylinder was about 30 or less on a compression test, and that didn't do it.

As for the bubbles, get an old radiator cap, and remove the rubber seal on the pressure bypass. Make sure it is filled as full as you can get it dead cold, and run the overflow tube into a clear container filled with water.

A clear section of tubing would be better, dunking it into a pail of water, and pinching the ends off, until you have it slid onto the filler neck and the other end into the container.

Then start the engine and watch for air to start coming out, other than the little bit you can't prevent when putting the tube on. If that initial air is pushed out, and coolant stays bubble free as it expands into the container, and levels out with normal operating temp, then I would rule out the HG.

A CO detector would also work to detect exhaust gasses, at the filler neck, but I don't know that anyone rents those.

[mickeytopher]

I was checking the exhaust at idle this morning. There was a little white smoke, but I think that may have more to do with the cold. I did notice the muffler was making a "puff puff puff" noise and saw a lot of rust and some splitting on the muffler...could it be plugged just enough???

[mickeytopher]

So I took it in, and the guy did a compression test (30-40 psi) did a compression check with oil and didn't make a difference in compression, and he ran his scope in there and said he could see one of the valves stuck open a little bit so I'm guessing bent valve. So I called the junk yard and engines for this car are about $300, and heads are $91 (plus factoring in another $220-$300 for parts). What do you think would be better in the long run, motor swap, or a new head?

[r/tguy02]

called that one, at least you know now

i'd swap the head, at least you know the bottom end is good, and with new seals/gaskets the new head should be fine.
on a side note, if you know how to lap valves and assemble/dissassemble the head i can sell you some good valves and that would be even less money than a JY head.

[mickeytopher]

called that one, at least you know now

i'd swap the head, at least you know the bottom end is good, and with new seals/gaskets the new head should be fine.
on a side note, if you know how to lap valves and assemble/dissassemble the head i can sell you some good valves and that would be even less money than a JY head.

Being a bad valve what are the chances that it could have smacked the piston? Are these interference engines?

[r/tguy02]

it could have but typically it doesnt do much to a piston, usually just a knick. you'll know for sure once you take the head off. i've seen a fair share of these with bent valves and i've replaced valves and its just as happy as ever.
yes they're interference

[occasional demons]

It may be a burn't valve. Not sure how you would bend one, short of debris getting sucked into the intake. If the timing belt has never broken or slipped, the odds of the valves getting bent are pretty slim. Any timing related cause would bend them in pairs also.

If it is burn't, the seat may also be damaged. As far as used valves, you should get the seats ground, and the valves refaced. Lapping may not get them 100% correct, and you may burn some valves, and be back in the same boat.

Overall, it is cheaper/faster to just get a reman head, or a good one from a JY.

You can get new head bolts pretty cheap, so no sense trying to save a few buck re using the old ones. If one fails, it's going to cost you more than a set of headbolts if you mix oil and coolant. (Cost of fresh oil/coolant and flushing the gunk from the system, not to mention other little things like doing it again...)

[mickeytopher]

It may be a burn't valve. Not sure how you would bend one, short of debris getting sucked into the intake. If the timing belt has never broken or slipped, the odds of the valves getting bent are pretty slim. Any timing related cause would bend them in pairs also.

If it is burn't, the seat may also be damaged. As far as used valves, you should get the seats ground, and the valves refaced. Lapping may not get them 100% correct, and you may burn some valves, and be back in the same boat.

Overall, it is cheaper/faster to just get a reman head, or a good one from a JY.

You can get new head bolts pretty cheap, so no sense trying to save a few buck re using the old ones. If one fails, it's going to cost you more than a set of headbolts if you mix oil and coolant. (Cost of fresh oil/coolant and flushing the gunk from the system, not to mention other little things like doing it again...)

I was thinking burnt valve too. I don't think it would be driving as long as it has if it were bent.
As far as JY heads what do I look for so I don't have to do this more than once?

[r/tguy02]

Yeah unless debris got caught in the valve and bent it, I see no reason to regrind the seats. A simple lap job will work fine.

[occasional demons]

Any 1996 to 2005 SOHC head will bolt in place. Depending on the year, you may need an EGR block off plate if the head has the EGR drilled, and there is no plate.

You could also plug it with a 3/8 pipe plug, if you have a pipe tap available. If not, a plate will be cheaper.

2000 to 2002 heads should have a block off plate, 2001 is the best bet. They stopped drilling the hole out in 2002 sometime. Some 2000's still had EGR, but not many.

I would search for as new as a car you can find, because they are more likely to have less miles. Unfortunately, unless you have a way to power the system, you won't be able to check the odometer, if the car still has the cluster intact.

[mickeytopher]

(don't know how to pics on here)
I took off the valve cover and the exhaust valves are hanging down about 1/4"-3/8"
http://www.flickr.com/photos/33410244@N04/11891048066/

[r/tguy02]

You can't tell from there. You're just seeing the rockers being pushed down by the camshaft. You need to remove the rockers and do a leak down test

[NickKo]

What do you think would be better in the long run, motor swap, or a new head?

i'd swap the head, at least you know the bottom end is good, and with new seals/gaskets the new head should be fine.

..... Agreed !!

I have a friend who's son's car, blew the water pump & timing belt.
Rather than swapping the cylinder head, they decided to swap engines.
Unfortunately, the bottom end of the 'replacement' engine, had a nasty pin knock.

If you know the bottom end is good.... With good compression, and good oil pressure, it's better to just swap cylinder heads.


I swapped cyl. heads on my 1995 Neon engine (now in my 1998) when it was at about 155,000 miles..... Over 50,000 miles and 7-8 years later, it's holding up great.


- Nick

[mickeytopher]

Well since I'm tearing the head off...a few questions
1. Since I will be replacing the timing belt is there a way to check the water pump, or should play it safe and replace it any ways?
2. What is the torque sequence for the head, intake etc...?
3. When going to the junk yard what other cars can I scavenge a head from?

[caustic neon]

1. YES REPLACE IT, ITS ONLY $50 AND YOUR ALREADY IN THERE

2. GO TO AUTOZONE AND GET A HAYNES MANUAL, IT WILL HAVE ALL BOLT TORQUE SPECS AND THE TIGHTENING SEQUENCE FOR ALL BOLTS

3. REALLY DEPENDS ON THE YEAR CAR YOU HAVE, MOST WILL WORK BUT THERE MAY BE SOME ISSUED DEPENDING ON THE YEAR OF THE DONOR HEAD. (IF YOU USE A JUNKYARD HEAD HAVE IT MILLED TO MAKE SURE IT IT NOT WARPED, IF IT IS YOU WILL BE DOING A HEAD GASKET AGAIN SHORTLY

[mickeytopher]

1. YES REPLACE IT, ITS ONLY $50 AND YOUR ALREADY IN THERE

2. GO TO AUTOZONE AND GET A HAYNES MANUAL, IT WILL HAVE ALL BOLT TORQUE SPECS AND THE TIGHTENING SEQUENCE FOR ALL BOLTS

3. REALLY DEPENDS ON THE YEAR CAR YOU HAVE, MOST WILL WORK BUT THERE MAY BE SOME ISSUED DEPENDING ON THE YEAR OF THE DONOR HEAD. (IF YOU USE A JUNKYARD HEAD HAVE IT MILLED TO MAKE SURE IT IT NOT WARPED, IF IT IS YOU WILL BE DOING A HEAD GASKET AGAIN SHORTLY

It's a 2002 SOHC

Thanks everyone for your help

[occasional demons]

All years of SOHC heads are a bolt on. 1995 uses a different valve cover set up, and the holes are different. So for the simplest approach, just go with a 1996 to 2005 head.

Some Stratus's/Cirrus's/Breeze's had SOHC 2.0's. As long as the valve cover looks like the one you have, with the spark plugs to the front, and not in the center, you should be good.


A clean up pass is all the gasket surface should need. Have the shop check it for warpage BEFORE it is milled. If it is warped, it needs de warped, or another head. If it is milled before it is straightened, it is a paper weight.


In most cases, if the cam will turn freely in the bores without the rockers installed, the head is straight. But this is not a perfect method, just tells you that that plane of the head is ok. But if the cam does not move, look for another head.

Removing the rocker shafts and cutting the belt if you are removing it in the JY saves you some time/grief if it is warped. Check it before and after breaking the head bolts loose.

[caustic neon]

Removing the rocker shafts and cutting the belt if you are removing it in the JY saves you some time/grief if it is warped. Check it before and after breaking the head bolts loose.

THIS IS VERY GOOD ADVICE