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Discussion Starter · #1 ·
Hey everyone - first time here!!!
Sorry put the thread the wrong discussion area. So im posting it again.

I’ve got a 300 with he 3.5L and my sister filled it up with diesel fuel :pat: . This happened like 3 weeks ago. Well it was towed to my mechanic and he drained the tank and everything but didn’t change the spark plugs or fuel filter. Our gas mileage went from an average of 20 to about 11 now. I heard the fuel filter is in the tank would it be that hard to change it out?


I removed a spark plug and it was very brown for a car with 20K miles. The mileage is probably shot since the plugs are fouled up. What are the best plugs you guys recommend? Champion? Im waiting for a nice day to change them out. The intake manifold must come off to access the plugs on the passenger side right? Is this a strictly air manifold? On my car (mustang) when you remove the intake manifold you must also remove the coolant. Is this the same?

Last question what should I torque the plugs down to? 20ft lbs?

Thanks in advance,
John
 

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Champion plugs are what comes in it but any brand is fine as long as it is the correct plug as specified by the plug manufacturer. If you don't trust your parts guy to look them up right, go with the Champion 'cuz the part number is on the emission label under the hood as well as on the plug itself.

Remove the intake manifold to change plugs?? I don't have a 3.5 but I can't imagine why you'd have to do that. Possibly the plenum or "upper" intake manifold????.....

If you don't know the exact torque spec on the plugs, run the plugs down until they stop, then with the palm of your hand on the head of the ratchet (not at the end of the handle) tighten them "Snug". Also a good idea to use some anti-seize on the threads since the heads are aluminum. In 25 years I've never used a torque wrench to install plugs and never had a problem doing it this way. Never use air tools to install spark plugs.
 

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Discussion Starter · #3 · (Edited)
kevenj said:
Champion plugs are what comes in it but any brand is fine as long as it is the correct plug as specified by the plug manufacturer. If you don't trust your parts guy to look them up right, go with the Champion 'cuz the part number is on the emission label under the hood as well as on the plug itself.

Remove the intake manifold to change plugs?? I don't have a 3.5 but I can't imagine why you'd have to do that. Possibly the plenum or "upper" intake manifold????.....
I went to autozone and got the Champion plugs this morning hopefully Ill get them in once the car comes home.
Sorry I guess it’s the upper manifold. The intake runners cover all the plugs on the passenger side so i don’t think I have a choice. Does anyone know where I could get torque specs for the upper manifold in case i have to remove that. I don’t want any leaks.

Has anyone changed the fuel filter on these cars yet???
 

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stroked4.6 said:
I went to autozone and got the Champion plugs this morning hopefully Ill get them in once the car comes home.
Sorry I guess it’s the upper manifold. The intake runners cover all the plugs on the passenger side so i don’t think I have a choice. Does anyone know where I could get torque specs for the upper manifold in case i have to remove that. I don’t want any leaks.

Has anyone changed the fuel filter on these cars yet???

I don't believe there is an external fuel filter, just the one in the tank. Most chrysler products have been this way for several years.
 

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the fuel filter is the tank in these vehicles. we had a customer do the same thing as far as filling withe diesel fuel. we replaced both the fuel pump and the transfer pump. replaced the plugs and cleaned out the lines. this was on a hemi, but the fuel tank/pump set up is the same. there are holes in the floorboards under the rear seats to gain access to the pumps, one on either side. i had to remove the tank to do both, had a hard time with the transfer pump hoses that go accross the tank to the other side of the tank through a small opening on the top of the tank.

if anyone is wondering about the transfer pump, this is used due to the design of the tank. the tank is under the rear seats but ontop of the driveshaft. the shape of the tank goes around the driveshaft therefore part of the tank is very small and when gas is getting low there will be gas on either side of the tank. they use the transfer pump to pump the fuel on one side to the other side of the tank which is then pumped by the actual fuel pump to the motor.

sorry for such a long post but i tried to explain as much as possible and not confuss everyone.
 

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How often are you supposed to change the fuel filter? Can you use an in-line filter in lieu of the one in the tank? That setup seems very absurd if you have to drop the tank every 30k miles or whatever to change the fuel filter.
 

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John,

Sorry to hear of your misfortune. It sounds like you have already received some great advise. Pardon me if I'm wrong, but, isn't a diesel nozzle (with a green handle vs. black handle) too large to fit into the regular gasoline tank filler hole? (I realize this might not be the situation if you live somewhere in Europe.)

Anyway, I hope your vehicle will soon be back to new.
And, welcome to the forums! We're glad to have you aboard.

bruno


stroked4.6 said:
Hey everyone - first time here!!!
Sorry put the thread the wrong discussion area. So im posting it again.

I’ve got a 300 with he 3.5L and my sister filled it up with diesel fuel :pat: . This happened like 3 weeks ago. Well it was towed to my mechanic and he drained the tank and everything but didn’t change the spark plugs or fuel filter. Our gas mileage went from an average of 20 to about 11 now. I heard the fuel filter is in the tank would it be that hard to change it out?


I removed a spark plug and it was very brown for a car with 20K miles. The mileage is probably shot since the plugs are fouled up. What are the best plugs you guys recommend? Champion? Im waiting for a nice day to change them out. The intake manifold must come off to access the plugs on the passenger side right? Is this a strictly air manifold? On my car (mustang) when you remove the intake manifold you must also remove the coolant. Is this the same?

Last question what should I torque the plugs down to? 20ft lbs?

Thanks in advance,
John
 

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Dutch said:
How often are you supposed to change the fuel filter? Can you use an in-line filter in lieu of the one in the tank? That setup seems very absurd if you have to drop the tank every 30k miles or whatever to change the fuel filter.

As long as you don't put diesel in it and don't habitually run below 1/4 tank you should be fine. In 150,000 miles or whenever a fuel pump goes bad change it then.
 

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Discussion Starter · #9 · (Edited)
bruno said:
John,

Sorry to hear of your misfortune. It sounds like you have already received some great advise. Pardon me if I'm wrong, but, isn't a diesel nozzle (with a green handle vs. black handle) too large to fit into the regular gasoline tank filler hole? (I realize this might not be the situation if you live somewhere in Europe.)

Anyway, I hope your vehicle will soon be back to new.
And, welcome to the forums! We're glad to have you aboard.

bruno
Yes the nozzle is bigger but my sister didn’t think of it since she went to a new gas station (Gulf). She just picked up the nozzle in the middle since we always get 89 oct. She angled the nozzle so the gas would flow in. Well she knows now -- lol

The filter was not replaced so that’s next on my list.

Are there any shop manuals out yet for these cars? Like a Haynes manual or something along those lines?

Thanks Guys
 

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stroked4.6,
Sorry to hear about the misfortune. I am sure everything will work out OK. Here's the spark plug removal/installation procedure for the 3.5 engine. This is out of the shop manual. Hope this helps.
3.5L
Always remove the ignition coil assembly by grasping
at the spark plug boot, turning the assembly 1/2 turn
and pulling straight back in a steady motion.
1. Disconnect the negative battery cable.
2. Remove the intake manifold, (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL).
3. Prior to removing the ignition coils, spray compressed
air around the coil area and spark plug or
contaminates from spark plug tube..
On 3.5L engines, it is necessary to loosen the screws
by alternating back and forth. Do not lose the spacers
under the coil when loosening the screws.
4. Remove the ignitions coil.
5. Remove the spark plug using a quality socket with
a rubber or foam insert.
6. Inspect the spark plug condition.

3.5L
1. To avoid cross threading, start the spark plug into
the cylinder head by hand.
2. Tighten spark plugs. Tighten to 28 N·m (20 ft. lbs.).
3. Install ignition coil assembly onto spark plug.
4. Hand tighten coil screws.
5. Tighten ignition coil screws to 6.7 N·m (60 in. lbs.).
6. Connect and lock the electrical connector.
7. Install the intake manifold, (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - INSTALLATION)
8. Connect the negative battery cable.

MANIFOLD - INTAKE
REMOVAL
UPPER INTAKE MANIFOLD
1. Disconnect negative battery cable.
2. Disconnect the IAT sensor electrical connector.
3. Remove air inlet hose from the throttle body.
4. Disconnect the MAP sensor electrical connector.
5. Separate the engine electrical harness connectors
from the intake manifold.
6. Disconnect the EGR tube, PCV, Purge and power
brake booster vacuum hoses from the upper intake
manifold.
7. Disconnect the electronic throttle control electrical
connector.
8. Remove the throttle bracket (4) fasteners from the
throttle body and cylinder head.
9. Disconnect electrical connectors from the Manifold
Tuning Valve (MTV) and Short Runner Valve.
10. Remove the right intake manifold support
brackets.
11. Remove the upper intake manifold retaining bolts, insulation foam pad and manifold. Clean all gasket sealing
surfaces.

INSTALLATION
UPPER INTAKE MANIFOLD
1. Clean and inspect gasket sealing surfaces.
2. Position new gasket.
3. Install the upper intake manifold insulator foam.
4. Install the upper intake manifold. Tighten bolts to
12 N·m (105 in.lbs.) starting in the center working
outward in a cross sequence pattern.
5. Install the right manifold support brackets. Tighten
fasteners to 12 N·m (105 in.lbs.).
6. Install the throttle bracket. Tighten fasteners to 12
N·m (105 in.lbs.) at the throttle body and 28N·m
(259 in.lbs.) at the cylinder head.
7. Connect the manifold tuning valve and short runner
valve electrical connectors.
8. Connect the electronic throttle control harness connector.
9. Connect the engine electrical connectors to the
intake manifold.
10. Connect the EGR tube, PCV, Purge and power
brake booster vacuum hoses to the intake
manifold.
11. Connect the MAP sensor harness connector.
 

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Discussion Starter · #11 · (Edited)
magnuman said:
stroked4.6,
Sorry to hear about the misfortune. I am sure everything will work out OK. Here's the spark plug removal/installation procedure for the 3.5 engine. This is out of the shop manual. Hope this helps.
Awsome info. Thanks :fing02:
John
 
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