Hi all,

I have a 2004 with the 3.0 Vulcan @ 125K. CEL on and rough idle. Codes P0300, P0304, and P0316. I started down the normal route of looking for the cause. Injectors all within specs, coil pack within specs, getting spark to the plugs, new wires and plugs. So I went ahead and did a compression test to check the health of the cylinders before I went any further. Here are the results:

1 - 180
2 - 175
3 - 170
4 - 115
5 - 160
6 - 165

Cylinder 4 seems to be the problem as reflected by the CEL codes and the low number. Added oil to 4 and compression rose slightly to 125.

I have done some research and found the service bulletin and tons of others with low compression and the valve seat issue with these motors. Also, I'm unsure whether the slight rise in compression in 4 after adding oil means anything. Doesn't seem like a great enough rise to suggest the rings in 4 are the issue as opposed to the valves.

Some questions:
I would appreciate some opinions on the my results and the next step? And if I proceed with the head replacement what other things I should do in the process (timing belt, water pump, etc.)? I plan on buying a haynes or chilton manual to go through the process - any recommendations on which is better? Anyone have a good how to?

Thank you.

Adam

 

If the compression shot up to what the other cylinders are putting out after putting oil in cylinder #4, then you have bad rings. If it only went up a few psi like you said it did, then I'd suspect the head/valves.

I like the Haynes manual better than the Chilton. The Chilton just isn't laid out well, IMO.

I would replace both heads (go to ebay and buy the Dover heads, you get both for about 300 some bucks) Replace any push rods or parts related to the valve train if needed.

It wouldn't be hard at all to do the roller rocker swap at this time either... since you're thinking about fixing the top end of the engine and keeping the truck, maybe 20 hp would be a good thing to add as well...

 

probably burnt exhaust valve....do a leak down test

 

Thanks for the suggestions. I plan on doing a leak down test to confirm but have to find a compressor to work with.

Any suggestions on regular maintenance that absolutely must be performed when removing the heads? As always money is a huge concern here as I'm helping out my parents with their only vehicle right now. The truck runs perfectly other than the miss and has never had any major work done.

 

Not really a must, but good preventative maintenance would be to replace the timing chain and the timing cover gasket.

A must do (and a very good idea) is to check the cam synchro, if it's still good, I would oil the upper bushing (right under the camshaft position sensor) well and work the oil in by spinning it by hand. Keep doing that until you feel comfortable with how well it's oiled... the more oil the better... Just be sure the oil doesn't get onto the camshaft position sensor, which is the little plastic doodad that bolts on top of the synchronizer.

Otherwise, you shouldn't have anything else to worry about. Unless I missed something which I don't think I did.

 

Based upon the good compression numbers on the passenger side bank, does anyone think just rebuilding the drivers side head is a good idea or is it a must to do both?

 

If you find out the piston rings are the culprit, I would just replace those. 125k isn't really all that much mileage these days. If you do have the money, there is nothing wrong with replacing the heads and like the earlier post said, 300 is not too much for a head. If 300 is for both heads, I would go that route!

 

Ok guys, leak down test confirms leaky exhaust valve on #4. But interesting thing happened once I restarted the car. I performed the leak down test twice to confirm so I rotated the engine a few times in order to get to TDC on 4 twice. Upon startup I heard a very clear and loud tapping coming from the head above #4 which cleared up once the engine warmed back up and the oil came up to temp. Anyone think this may be a bad spring or sticky lifter rather than a valve seat issue?

 

pull the head, if the valve is burnt, then u know its that...if the valve looks fine, might be a bad lifter.

 

you probably wont be able to see a burnt valve or cracked seal with the naked eye. take the head off and pour water into the valve chambers. if it weeps, you have cracked seals.

 

do a leak down test this'll give you a better idea

 

he already did a test.

and u can see a burned valve...even at a mild burned level its noticeable



youll see the heat marks in a specific section on the edge of the valve....since you already know #4 is bad, you should be able to see something like the pic above. either way, the leak down test already told you somethings wrong and its good practice to look at every possible cause.

 

Thank you. She's half way torn down right now. New heads from dover in the mail. I pulled the valve cover early to see on the off chance that there was something obviously wrong with the spring but it appeared normal. I'll let you know what results.

 

UPDATE:

#4 Exhaust valve proved to be the culprit as the leakdown test showed earlier. Pretty obvious recess when compared to the other cylinders.





#6 For comparison


Any ranger specific suggestions for cleaning the gasket mating surfaces?

 

Larger Pic.

 

first pics failed

 

Sorry, first time. I can see them in preview and they appear for me. Here's another try. First two are #4, third is #6 for comparison.

Any tips for cleaning mating surfaces?

 

Ah, that will cause problems...

So did you go with the Dover heads or get yours rebuilt?

 

I ordered the Dover heads. WIll finish the install over the next few days when I get some time. This will be my first time bolting up a head so I want to take it slow and do it properly.

 

Never hurts to take your time. Rushing a job almost always results in some sort of screw up, lol. Been there, done that.

If you haven't ordered valve cover gaskets, I highly recommend Fel-Pro Permadry... they won't leak when installed properly. Ever.

 

How clean should the block deck be? Any body have a pic for reference? I've put in about 4 hours of razor blades and acetone so far and still have the faint outline of the old gasket. Any tips?

 

Can anyone confirm the torque specifications for an 04 3.0L. My Haynes manual shows:

Step 1: 37
Step 2: Loosen one full turn
Step 3: 22
Step 4: Tighten an additional 90 degrees
Step 5: Tighten an additional 90 degrees

I ask because it is different from all of the other years in my book and there are conflicting numbers on the net.

 

Just go with the Haynes numbers.

Sometimes certain bolts require being torqued like that. Confusing, but it works.

If the gaskets and/or bolts that came with the heads specifies a different way of torquing, (not likely, but be sure to double check the papers that came with the heads) then perform that procedure instead of the one in the manual.


As clean as possible. Some gaskets are a PITA to remove. Permatex sells a gasket remover in an aerosol can with a brush tip, should be available at Napa or Autozone for about 10 bucks. Looks like this... and might make things a little easier.

http://permatex.com/products/Automot...et_Remover.htm


Just get the surface as clean as you can. Making it as level as possible would be more important than having a surface clean enough to eat off of. However, it is sorta like painting... the more prep work, the better results. Don't remove too much metal (especially in one area) and you'll be fine.

Another option to make this go a lot faster would be to get a right angle die grinder and get some iron/steel 2" surface prep discs, along with the proper 2" disc arbor. (maybe about 30 bucks or so for all of the stuff at HF Tools) This would make the whole thing go faster, if you have a compressor that can run a die grinder decently. This does raise the risk of removing too much metal.

 

Thanks for all the feedback.

Got it all back together over the weekend and it fired perfectly on the first turn of the key. Always a relief :). Put 100 miles on it over the last two days and it is running great so far with no leaks or CEL. All in all a pretty straightforward job.

 

Good to hear things went well.

And it sure is a good feeling when an engine starts up and runs properly after such a major operation.

I started mine up after putting the new fuel filter on and the gas tank in, and it seemed to idle a little better. A month of sitting... waiting to taste gas again, lol. We'll see if that lack of power was a result of a plugged/almost plugged fuel filter or not, after I get the bed on sometime this week.