I am in NC. Thanks for the link to car parts. I found one in state for $150. Now I have to decide if I want to go with the used one or with a new one from the dealer. Since the we are not sure of what caused the excessive vacuum and therefore the collapse I may go with the dealer part so that the work is under warranty.

Does anyone know how I can find out if the same tank is used in the SLK 320 as in the Crossfire? I think it will help me with my discussion with the dealer if they are the same.

 

This design article says the Crossfire 60 liter trapezoid shaped gas tank is made of steel and placed above the rear axle for safety.
Chrysler Crossfire

 

After reading about this unusual problem and the cost to fix it, should I be stopping every 1/4 tank of gas to open the gas cap and relieve any potential vacuum?

 

The shop manual says that is made of steel in one place and aluminum in another. The original post said aluminum so I'll go with that.

 

the dealer has had the car about three weeks now. they replaced the fuel tank and still get error codes. they have now replaced several sensors and the computer and still can not locate the problem. they have called the "Star" hotline several times and are not getting much help. they are still trying to determine what caused the tank to collapse so that it does not happen again.

 

Three weeks without yer Baby!
That's why ya gotta have two Crossfires!

Hope you get her back soon.
Thanks for the update. Keep us posted.

 

I'm sorry but this screams "We don't know what we're doing". If I was not on the road, I would whip out my Crossfire Speciaist Training Guide and bombard you with some schematics.

I'm thinking you want to find a real tech and get your car fixed properly.

 

Just another possible idea, check the fuel cap for a blockage or malfunction. As I understand the emission control requirements and fuel caps, the cap is basically a check valve designed to allow air to flow into the tank to replace the volume of fuel removed, but to block vapors from escaping into the atmosphere. I have had to replace three fuel caps over the years (not on crossfire) due to failing the local emission control checks required to renew the license plates. So if the cap is working properly, the tank can have a small pressure, but never a vacuum.

Just something to think about.

 

I don't know the emission laws in your state but here in CA the fuel tank is part of the emission systems and is covered under a separate emissions warranty. 5/50 or 7/70 depending on the year purchased. Be sure to check your warranty before the dealer hands you a bill. This might be covered 100%.

Good Luck

 

There is no such thing as vacuum.

you can reduce the pressure to zero in which case the max force is the atmosphere of 14.7 + - pressing on the sides of the tank.

Most nuclear blasts DESTROY buildings with an OVERPRESSURE of 3 PSI............
Over a square foot that is about 400 to 500 pounds of force.

Woody

 

It would appear to be a simple problem, fuel was sucked out and no air was allowed in. If the gas cap equalizes pressure its simple but as there is vacuum line to the carbon filter there has to be a route there, if that is blocked and you have a faulty gas cap that could be your trouble.

 

I concur.

Make sure you get a new gas cap now, and see if that helps with the trouble codes the shop is getting. Also, the charcoal canister should be inspected to see if it is full of gasoline. If it is, it needs to be replaced.

The way the emissions system works is after the gas cap is sealed, there is a valve in it that opens as a vacuum is created in the gas tank as the fuel is consumed by the engine. Then the vacuum reaches a certain pressure, the check valve opens, letting air in to replace the used gasoline.

The fumes created by evaporating gasoline, however, can not push their way out of the gas tank through the gas cap, and instead expand through a small hose towards the charcoal canister. There is a purge valve there that allows the engine to ingest these fumes under certain conditions, as the valve is controlled by the motor.

Since that hose is directly connected from the intake manifold to the purge solenoid to the charcoal canister to the gas tank, if the computer tells the purge solenoid to stay open, there is direct engine vacuum being applied to the gas tank. If the gas cap stays locked tight, the gas tank could collapse over time.

What I think you are looking at has been a long term failure.
The gas cap failed. The purge solenoid was told to stay open by the computer, and eventually failure.

What you might also have is a damaged hose between the engine, the purge solenoid, the charcoal canister, and the gas tank. They will need to test all of the hoses to see if there is damage done, and replace if needed.

So, replace gas cap, test all hose lines, test solenoid, test computer functionality for solenoid operation.

BC.

 

I would say that the greatest negative pressure applied to the gas tank would be the fuel pump. These pumps supply fuel to the injectors at a high pressure. Engines produce so little negative pressure via the venturi effect that rubber and plastic hoses are often used.

 

If this is a really possibility - how hard would it be to make a gas cap with a vacuum relief valve built in- it may already have a pressure relief valve in it - no reason you can't do both - . Guess this doesn't help the guy with the collapsed tank - but this scares me.

Em4ce shawn

 

This makes more sense to me than what the dealer has told me. I have the car back now (see today's update on page one) and the dealer replaced lots of parts but I don't think they replaced the gas cap. I will call them Monday to verify that since from what you say the problem could reoccur if they did not. Thanks

 

Hi,
The amount of fuel pressure delivered by the fuel pump does not matter to the gas tank. All the tank sees is that a volume of fuel is being removed and if air doesn't fill in then a reduction (vacuum) in air pressure will occur. As stated earlier, the pressure outside the tank at sea level is about 14.7 lbs per sq. inch. The difference in air pressure between the inside and the outside of the tank is what squished it.

 

If there were ZERO pressure in the tank, it could only have a 14.7 PSIG atmospheric pressure on it. Nothing other than some candidates can suck below ZERO. Aint possible .

WDY

 

There is such a thing as a vacuum we are just using it wrongly here. Space is a vacuum, it is the absence of matter that is called a vacuum.
I have used a vacuum pump that used an oil spray to collect most but not all air that was still floating around in a chamber after two previous pumps had evacuated the majority of the air. This was back in the late 70's making laser discs for DiscoVision (MCA) and the equipment was used prior to covering the plastic disc with a microscopic layer of aluminum which had been vaporized. This layer made the info molded onto the disc readable with a laser.
I am not sure what the closest we get to a true vacuum on earth is, maybe Maxichon will offer up an answer or we could use search on Google.

Meanwhile I'll get the vacuum cleaner (hoover in the UK) out and clean my workshop.

 

No such thing as nothing (vacuum).
https://en.wikipedia.org/wiki/Quantum_foam

 

Man Woody,

Did it really take you nearly 6 years to come up with that reply to this thread?
I know you were starting to creep up there in years, but this is a bit silly.

Hope all you guys here are still doing good.
Bat and I were zipping across the country and back in our brand new car, saw a few Crossfires and SRT-6's, and thought of you guys for a bit.

BC.