Fuel cooler on M103
 

On my M103, the fuel line runs inside of the air conditioning refridgerant system before entering the fuel distributor. I have to assume this is to cool the fuel. Is this absolutely necessary in a temporant climate? My "manifold", for lack of the correct name for this thing, is cracked and I wonder if it can be eliminated or must be replaced.

Fuel Density
 

Brother of The Benz, Capt. Carageous
The fuel cooler servse two functions;
The most obvious is cooling the fuel to eliminate vapor locking,
But I believe the best return for the cooler is fuel density.
By cooling the fuel your engine recieves a denser fuel charge than the heated fuel you would recieve without the cooling.
What does all of this bumbo Jumbo relate to?
More horsepower from the greater charge of fuel at compression and combustion.
Do you need the cooler in your area?
Not for vapor lock prevention but yes for the denser fuel charge.
If you decide to bypass the cooler you may get less performance output from your engine.
Consider the dragsters of time past, they used a container with coiled tubing inside and a coolant in the container trying to increase the fuel density.
Your engine would not die without it but may perform less than designed.
Happy Trails Beep Beep from The Spiderman in Houston!!!

I suspected it was designed for hot climate operation. Internal combustion engines have performed well for over 110 years without a gizmo like this. It looks to me like another example of over engineering. :rolleyes:

Over Engineering?
 

Brother of The Benz, Capt.
Being an Engineer serving The Auto Industry for over 20 years, I can say that the M/B automobile is a classic example of "Over Engineering", but that's what seperates the least from the most; the Kia from the M/B.
Just observe the electoless nickel on all of the fasteners. Or the brown ground wire for every circuit not a common earth.
Just look at the M/B texture material used for seat coverring, that is so sought after by other manufacturers(Mooney AirCraft for one).
Over Engineered?
I think not just ENGINEERED.
Happy Trails Beep Beep from The Spiderman in Houston!!!

Now, if only MB would take Honda and Toyota's lead and make them dependable . My 89 300 E MSRP was $44,500. For that kind of money I would have expected a lot more dependability and features in addition to nice seat cover material.:D

Is there an End
 

Brother of The Benz, Capt
Noticing you too have a w124030.
Apparentally you haven't had the reliability you think the other manufactures offer.
I don't know what you class as reliable?
I have a 1987 W124303 with 188,000 miles and it's major components are original never been touched.
The engine has yet to have the cam cover removed, likewise the transmission is original. I'm still on the original exhaust system. Have had 1 waterpump. Nothing in the steering mechanism with the exception of a $25.00 stabilizer.
It has had the normal brakes and tires.
I could go on and on.
My 15 year old Benz is still a joy to own and drive; it still has that eye appeal of a Benz.
You don't see many M/B on the used car lots, sure they don't sell as many as the T & H cars, but they aren't the disposable car either.
When will it end?
I guess when yoy sell your Benz and buy what you class as more dependable.
Hasppy Trails Beep Beep from The Spiderman in Houston!!!

I have driven over 700,000 miles on on five cars, A Datsun, three Toyotas and a Honda. I have replaced two water pumps and one clutch and two front rotors. I have only driven my MB for 32,000 miles and have replaced;
foglight lens (2)
window switch
stereo
AC compressor and dryer
Climate control elements (5) (entire dash out)
OVP
Fuel pump relay
Fuel pumps
Thermostat
O2 sensor
Coolant sensor (fuel injection)
CIS-E unit (ouch)
door checks
Fan pulley, tensioner and shock and fan bracket
Rear window regulator
Flex disc (front)
radio antenna
transmission
Valve seals and guides
headlight lens (50 bucks for a piece of glass)
Timing chain and so on
This by no means fits my definition of the words dependable or durable.:mad:

Per my shop manual, the W124 fuel cooler ONLY works when the A/C is actually turned on & refrigerant is actually circulating.

So in a temperate climate I don't think you need it.

BTW, PermaCool makes a dedicated fuel cooler (air-to-air, a simpler design) for under $30 bucks.

:-) neil
1988 360TE AMG
1993 500E

I know mine works.
 

When my fuel pumps were dying they were temperature sensitive. They would act and sound worse the warmer it was outside, to a point. When it got really warm they were alright. I’d have been really confused but thanks to this site I remember surfing over the fuel cooler and made that connection.

You Win!!!
 

Brother of the Benz, Capt.Heart Break
What can I say, I totally agree with you in that you either have a piece of junk or a well rebuilt prece of junk.
If possible;
Happy Trails Beep Beep from The Spiderman in Houston!!!

Sounds like you got a car that was not well maintained before you got it. The newer Honda's and Nissans (what was Datsun) are not the reliable cars they once were. My daughters Nissan has gone through a few starters and alternations.
Some of the things sound like normal maintenance or caused by damage. By the way have you checked on the price of a new headlight for a Honda or Toyota? 250 to 400 and that is for plastic!
Thermostat
O2 sensor
foglight lens (2)
headlight lens (50 bucks for a piece of glass)
How many miles on the car? Most of these components have a life of at least 200,000

Read Between The Lines
 

Brother of The Benz, SilverBoat
I see you too realise that the Capt. is cursed with an unfortunate condition Benz.
Possibly when all of the gremlins have been chased away and he drives it for a while without any of these dollar you to death repairs he'll have a second opinion.
Happy Trails Beep Beep from The Spiderman in Houston!!!

I took the cylinder head to the machine shop yesterday to be reworked. As soon as I get it back I will put in new timing chain and reassemble the the engine. Then I'll purchase the reman transmission and install the drivetrain as a unit. All the wiring harness connections will be resoldered by then. After the air conditioning system is recharged I will turn the key. If that damn check engine light comes on...... well, it just better not come on.;) ;)

does anybody else offer a fuel line cooler in their cars? I find it incredibly cool!!! Perhaps it was a way to regain some lost hp when you enganged the ac. The compressor draws a good amount of hp, and perhaps the benz-heads thought that they could cool the fuel, make it denser, and perhaps get a few hp back... genius... pure and simple...

I think they had a slow day in the engineering staff meeting! "O. K. people, let's make something really ridiculous that adds cost to our cars. Any ideas?":rolleyes: Seriously though, I can see it helping in Saudi Arabia or Arizona to control vapor lock, but I can't see it as a performance enhancement. If cool fuel was beneficial we would have refrigerated fuel tanks.... (light bulb above my head)...anybody know the phone number for MB Engineering??:D :D

hehehe... yea, I think you should drop them a line... I have to find more reasons to justify owning a benz... I mean... what do you tell people when they ask why you drive a 10 year old box thats slower than a civic? So far I have... real wood trim, heated windsheild wiper fluid, air conditioned fuel lines, and light wipers. Sometimes I tell them that I can floss in my benz.. at which point they laugh at my face saying maybe I could if my car was worth anything....

Just for info, most diesel engines in trucks,tractors etc have fuel coolers now although they are air to fuel coolers. I would say MB has done a very efficient job on a problem that has been around for years. Over engineering???:confused:

I believe the cooler is there to reduce evaporative emissions by cooling the fuel so it doesn't build up to much pressure and vent to the atmosphere.

You're Right
 

Brother of The Benz, badinfo
You're correct on the making the fuel denser, more HP; in addition you lower the vapor pressure of the fuel, no vapor locking but with electric pumps we shouldn't experience that. In some countries they aren't privaledge to the advanced refining of the fuel(I bet that statement will bring the booger bears from under the covers).
I'm not aware of anyother manufacturer cooling the fuel, but I'm not up on the other brands.
Happy Trails Beep Beep from The Spiderman in Houston!!!

Again, the fuel-cooler is ONLY in operation when the A/C is turned-on, its function is to reduce the formation of vapor bubbles on the RETURN/EXCESS fuel from the fuel-distributor as it returns to the tank.

Note- it's for USA cars because of the extreme heat in our SouthWestern states (e.g., DeathValley, CA; Arizona, Nevada, etc.)

This was taken from the M104 and M103 Engine Service Manual from Merceds-Benz.

:-) neil
1988 360TE AMG
1993 500E

http://www.silcom.com/~neilv/sportli...uel-cooler.jpg

How can you debate that last post!

Debate?
 

Brothers of The Benz,
How can we carry on as we all have?
Happy Trails Beep Beep from The Spiderman in Houston!!!

Thanks Neil!. I'll probably replace it anyway. It would be my luck to take it out and then have to go to Death Valley!! :p