1991 300ce Poor gas mileage after headgasket job,need Help please ?

valvar · 11-05-2009, 07:39 PM

Greetings to all !
I just had my 1991 300ce in the shop for a headgasket job and it seems to be burning more gas than before now. !
It seems to give me 11 miles per gallon just driving around town ,
that seems very bad and I did not have this problem before the work was done ,

any ideas of what the problem could be ?
you're input would realy help me .
thanks.

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ps2cho · 11-06-2009, 01:04 AM

What were you getting before ?

Any other info on work done along with head gasket?

valvar · 11-06-2009, 07:01 PM

Quote:

Originally Posted by ps2cho

What were you getting before ?

Any other info on work done along with head gasket?

thanks for you're reply !

yes the time chain was replaced as well , spark plugs replaced , added a K&N air filter also

The mileage I was getting before the Head job I am not sure about , but I know for sure it was not 11 miles to the gallon .

if something was done wrong from the mechanic what could it have bein ?

ps2cho · 11-06-2009, 08:45 PM

My bet is you have the wrong spark plugs. There should be no other reason why it would drop. Pull one out and see what type of spark plug he put in there. It may also be a good measure anyway to make sure after the head gasket swap everything is showing up fine on the plugs.

valvar · 11-08-2009, 04:00 PM

I will check that out !
I think I went with the NGK platinum plug
I hope that's the problem and it does'nt escalate to anything bigger .

neanderthal · 11-08-2009, 08:36 PM

You want non resistor copper plugs. The platinum plugs are not the correct ones and are designed for the much newer cars with the high capacity/ voltage/ whatever ignition systems.

Change your plugs.

I personally don't think that is the problem, but it solves one thing that is wrong.

valvar · 11-14-2009, 03:43 PM

Well my mechanic called and said he could not find anything wrong with the car ,
he said the timming is right ,and that everything is working properly ,
I heard that a bad exaust system could also be causing this.
He said that if it were the exaust system or the catalytic converter the exaust tips at the back would be firing very uneven ,wich he says is not happening to my car.

ps2cho · 11-15-2009, 04:34 AM

Get the plugs changed man!

If all of a sudden your MPG dropped its not gonna be anything in the exhaust system....I'm surprised he even said anything like that.

11-06-2009, 01:04 AM	#2
ps2cho MBWorld Fanatic! Join Date: Apr 2007 Location: SoCal Posts: 1,391 Drives: 1988 300TE, 1987 260E	What were you getting before ? Any other info on work done along with head gasket? __________________ 1988 Pearl Grey Metallic Mercedes 300TE - 98k miles 1987 Black Mercedes 260E - 86k miles

11-06-2009, 08:45 PM	#4
ps2cho MBWorld Fanatic! Join Date: Apr 2007 Location: SoCal Posts: 1,391 Drives: 1988 300TE, 1987 260E	My bet is you have the wrong spark plugs. There should be no other reason why it would drop. Pull one out and see what type of spark plug he put in there. It may also be a good measure anyway to make sure after the head gasket swap everything is showing up fine on the plugs. __________________ 1988 Pearl Grey Metallic Mercedes 300TE - 98k miles 1987 Black Mercedes 260E - 86k miles Last edited by ps2cho; 11-06-2009 at 08:47 PM.

11-08-2009, 08:36 PM	#6
neanderthal Super Member Join Date: Dec 2003 Posts: 804	You want non resistor copper plugs. The platinum plugs are not the correct ones and are designed for the much newer cars with the high capacity/ voltage/ whatever ignition systems. Change your plugs. I personally don't think that is the problem, but it solves one thing that is wrong. __________________ 'O=00=O' BMW 2002. LONG LIVE THE LEGEND.

11-15-2009, 04:34 AM	#8
ps2cho MBWorld Fanatic! Join Date: Apr 2007 Location: SoCal Posts: 1,391 Drives: 1988 300TE, 1987 260E	Get the plugs changed man! If all of a sudden your MPG dropped its not gonna be anything in the exhaust system....I'm surprised he even said anything like that. __________________ 1988 Pearl Grey Metallic Mercedes 300TE - 98k miles 1987 Black Mercedes 260E - 86k miles

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11-08-2009, 04:00 PM	#5
valvar Newbie Join Date: Oct 2009 Location: California Posts: 10 Drives: 1991 300ce	I will check that out ! I think I went with the NGK platinum plug I hope that's the problem and it does'nt escalate to anything bigger .

11-14-2009, 03:43 PM	#7
valvar Newbie Join Date: Oct 2009 Location: California Posts: 10 Drives: 1991 300ce	Well my mechanic called and said he could not find anything wrong with the car , he said the timming is right ,and that everything is working properly , I heard that a bad exaust system could also be causing this. He said that if it were the exaust system or the catalytic converter the exaust tips at the back would be firing very uneven ,wich he says is not happening to my car.

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