E38 Fuel Tank Sealer Rusty Hole DIY

How to seal rusty gas tank

If your car seems to loose fuel and you can’t keep it up filling at gas station maybe the fuel tank is leaking through tiny hole. My car (BMW E38) consumes a lot of fuel (about 13MPG) so small leak would be difficult to notice, but if your trip computer and actual consumption, which you can do dividing miles driven by total fuel consumed, tells the story.

Signs that your car might be losing fuel without burning it in the engine:

  • You can usually smell gasoline when approaching car first thing in the morning. If the hole in the tank is small enough, you cannot always see visible clues.
  • Look underneath for unusual clear or shiny spots. Gasoline is a perfect solvent and can be used as a cleaner. When it seeps through the hole in the tank it most likely will wash away any dirt and oil. Wet gasoline stain can travel further down the tank bottom to the lowest point. If it doesn’t evaporate until this point, fuel drops will collect on the ground.
Fuel Tank Sealer

Fuel Tank Sealer

There are special products for repairing small leaks on the tank. Usually it is a 2 part plastic compound sealer which you have to mix and apply on the rusty hole before it hardens and seals it.

Steps to patch your rusty tank:

  1. Locate the spot and evaluate hole size. What might seem like a little weeping hole at first could become large falling part when you remove dirt, paint and rust from this spot. Rust on the car is like cancer, you can’t see the whole picture until you investigate. If you find the hole is quite big and you can even stick a finger or 2 in it maybe you should consider replacing whole tank instead of trying to repair it. Driving with this condition could be dangerous.
  2. If the spot is reasonable or you are tight on the budget continue with cleaning the area with a wire brush or coarse sand paper. You can also apply brake cleaner and wipe with paper towel. Clean until all rusty parts will fall off and you are left with a semi clean area. It doesn’t have to be perfectly shiny but the smoother it will be the easier to patch.
  3. Read the instructions on the package on how to prepare the patch. Usually you have to take 2 equal parts of the material and mix it by hand until color will become uniform. Make a pancake in your hand and apply this to the hole. At first, it might be lose and seem like falling off, but tap it with your fingers until it begins to stick better. You can make the patch fatter on the hole area and even push it in a bit in the tank to get a stronger seal.
  4. Wait at least 10-20 minutes before driving the car to not disturb the hardening phase. The patch might feel hot to the touch. This is because chemical reactions are taking place and new bonds with the metal are created during curing phase. After a while, the patch changes color and might blend with the rest of the tank color, so no one could even notice without close inspection.
  5. Periodically check the patch area every few days to make sure you don’t have any further leaks.

Fuel can disappear not only from the tank with a hole in it but also from lose fuel hoses in the engine bay. It took me a while to notice this on my car during winter season. When I first started the car in the cold morning I could smell gasoline for the first few minutes, but after stopping and checking under hood, nothing was apparent. Only later I managed to catch the area where fuel was leaking. It was near the fuel injector on fuel rail return hose connection. The hose clamp was loose from the previous fix where I changed intake manifold gasket. I didn’t tighten hose clamp enough and fuel was able to seep through the tiny opening. When the car warmed up, rubber hose did to and expanded thus making leak harder to find. It was tiny leak and caused some idling issues, but otherwise you couldn’t tell at first. So this example only shows that with cars you have to be creative and curious because not every problem is the same.

If the tank is full or fuel level is higher that the hole you found it is better to siphon fuel out first before patching. This is because leaking fuel can inhibit the compound from proper adhesion and the leak might reappear later on.

There are other ways to repair rusty fuel tanks like welding a patch. But this usually involves taking fuel tank apart and it is not very DIY if you haven’t got MIG welder at home or garage.

LPG Transfer Pump DIY From Fuel Pump

If your car is running on LPG and you want to save even more money you can run on propane from cylinder propane tanks sold for domestic use (heating, food cooking). In this article I will explain how to transfer LPG from cylinder tank to car LPG tank.

LPG or liquid propane gas is a mixture of propane and butane. Different proportions are used in countries from as low as 40% propane 60% butane to as high as pure 100% propane.

Why propane is better fuel than butane?

Firstly, propane boiling point is much lower than butane. Propane boils at -43.6°F (-42°C) while butane boils at 30.2°F (-1°C). Why it matters? In cold weather you need steady supply of gas to your engine or else it will stall. If you have open loop system LPG could actually backfire breaking your intake manifold or air filter box. Running on butane your LPG reducer can freeze instantly and cut the supply of gas. Some northern countries change the LPG proportion in the winter to help drivers avoid such problems. Usually from 40% propane 60% butane it switches to 60% propane 40% butane.

If you consider transferring LPG from domestic cylinder tanks you must know that gas composition is probably worse than what you get at the gas station. Hovewer in theory you can drive on pure butane as long as it is in gas form. But keep in mind that at freezing temperatures you will probably have many problems. If the air outside is for example –20C it would again liquify butane in the intake manifold even if the reducer supply butane in gas form. Continue reading ‘LPG Transfer Pump DIY From Fuel Pump’

Subaru Speedometer Not Working

Jan’s Question: The speedometer on my 1999 Subaru doesn’t work. My husband tried replacing the sensor on the transmission for the speedometer, but it made absolutely no difference. He thinks the problem is in the dash, but that costs a lot of money. Is there something else he can try?

Answer: Yes, the problem should be in the dash, unless the wiring has been broken somewhere between the dash and the sending unit (so have him check the wiring at both ends, because it’s generally the ends that have problems unless the car has been wrecked.) Now he doesn’t need to replace the whole expensive dash. Subaru does offer the speedometer circuit board. And if he doesn’t feel comfortable replacing that, he could just take the dash to a speedometer repair shop and they can do it for him. It’ll save a lot of money not buying that whole dash.


1998 Chrysler Concorde State Emission Test Fail

Alberto’s Question: My 98 Concorde failed the state emissions test last week. It had the code for misfire on cylinder # 5. I changed out the spark plugs, the wires, and even the fuel injector on number five. Still won’t pass the test with the same misfire code. What am I missing?

Answer: Well, you covered the common problems for misfires on one cylinder. But of course, there can be many other causes–like a bad main computer, bad wiring, bad valve springs, or even a crack in the engine head. BUT, I was once bitten by a Concorde with the same problem as yours. I eventually fixed the car by replacing the intake manifold gasket. There was a TINY crack on the intake runner for the number five cylinder. I could only see it when I removed the intake manifold. There was carbon black around the crack where it had been leaking. SO, you might find someone with a smoke machine and see if they can smoke out a leak in the intake system. Since it’s misfiring on number five, pay close attention to the manifold gasket around number five.


Toyota Corolla 2003 Transmission Oil Change

Peter’s Question: Hi, Michael I have a Corolla 2003 at 52 000 miles. Yesterday I changed the transmission oil second time. The first time it was at 30 000 miles. The oil level has always been OK but now when I try to change to rear gear from parking only there is a jam. When I go to neutral first and then back to rear it is smoother. It have not had a problem like this before. What could it be? Regards, Peter

Answer: OK, IF you had no problem like this before changing the fluid, you may have either added the incorrect amount of fluid, or have used the wrong type of fluid. Those newer Corollas use a special Toyota fluid. I go to the Toyota dealer to buy this special Toyota fluid, or to a quality foreign auto parts store that sells the same exact fluid. If you didn’t use this fluid, then I would advise going to a transmission shop that has a flush machine. Have them flush the tranny out completely and refill it with the Toyota fluid. You can’t get it all out yourself, because most of the fluid will be inside the torque converter and you can’t get it out yourself. As a note to everyone out there, ALWAYS check the type of fluid used in automatic transmissions these days, because there are a bunch of different fluids used in different vehicles which are not compatible. Good Luck


2001 VW Beetle Transmission Poor Shifting

Jacob’s Question: The transmission in my 01 VW Beetle is shifting poorly. I took it in, and was told I needed a remanufactured transmission installed. 5300 dollars was their quote on the job. I’m floored. What options do I have?



Answer: Of course, get a second opinion from a transmission expert, you never know what someone else will say. BUT, they’ve had a lot of problems with the automatic transmissions breaking down in VWs (and I assume you have an automatic, since a standard tranny is much cheaper and they rarely break down anyway.) A factory rebuilt (not even new) unit costs big money on those Beetles–that’s just how most German cars are. If you don’t like the cost, my advice for others is basically don’t purchase a German car.

You already have the vehicle, so now you’re pretty much stuck. You could gamble with a used automatic transmission (realizing that they do break down a lot so a used one may not work too well either) but that’s taking a relatively big chance if you plan on keeping the car for years. You could find a mechanic who charges less labor cost for replacing the VW rebuilt transmission, BUT you’d still have to pony up for the expensive factory rebuilt transmission. Or, you could look for a good transmission man who could rebuild the transmission for you.

Just realize that those VW trannies are really complicated and only a person with a LOT of experience rebuilding them is going to do a really good job repairing it. I personally wouldn’t trust some national chain of transmission repair shops to do this job. I’ve seen too many horror stories of people who’ve tried that route and then had nothing BUT problems after the “rebuild” was done. I’ll give you an example of what I did with one a few months ago. I took a gamble and got my customer a used transmission. It worked OK, and I convinced the customer to then sell the car before something else went wrong. They got enough money out of the car to buy a nice used Ford instead. And if the Ford transmission ever goes out, it would cost him one thousand something dollars to repair it instead of five thousand something dollars.



Cadillac CTS 2004 Broken AC Knob

Freddy’s Question: The AC knob on my 2004 Cadillac CTS has broken off. I tried super gluing it back on, but it won’t hold very long before it breaks off again. Am I going to have to buy the whole expensive control unit?


Answer: No, you won’t have to buy that VERY expensive entire control unit just because the knob has broken. So many of those knobs have broken that the Caddie dealers now sell just the knobs themselves. SO, you might just mosey over to a dealer and buy a couple. Keep one as a spare in the glove box.



Kia Sephia 2000 Catalytic Converter

Dwayne’s  Question: Hey, I’m back again. This time it’s my wife’s car. It’s a 2000 Kia Sephia, and it won’t pass the inspection test due to trouble code PO552. It’s the code for inefficient catalytic converter. BUT, this Kia has two converters on it. How do I know which one is bad (they aren’t cheap.)

kia-sephia 2000

car kia sephia 2000

Answer: Yes, the first one is built into the exhaust manifold, and it is known as the “warm up cat.” The second cat is under the middle of the car. I’ve seen a few guys mistakingly think there was only one, the one under the middle of the car, and when they replaced it the code didn’t go away. It’s normally the front one that goes bad and sets that code in a Sephia.



Fuel Heater Fuse Blowing Ford Diesel

ford-f150-truckWilson’s Question: My 2003 Ford Diesel pickup keeps blowing the fuse for fuel heater. Even when I replace the fuse, it’s hard to start and stalls. What should I check first?

Answer: Yes, I had one like that a couple weeks ago. I ended up changing out what Ford calls the “horizontal fuel treatment module”–which is in reality a fuel pump module assembly. And interestingly enough, the new replacement fuel pump module did NOT have a heating element in it like the last one. They must have been having problems with the heater in the original design and have now left it out.



Nissan Quest Distributor Problem

Question: My 2000 Nissan Quest runs fine for about 15 minutes, then it dies. After about half an hour sitting, it will start up again. I had the computer checked and no codes were stored. Have you fixed one of these with this same problem before?

Answer: Yes, I’ve seen that quite a bit. Many times the electronics inside the distributor will short out when the engine gets hot, and then you will have to spark and the engine will die. The next time your Quest dies, quick have someone check the spark plugs to see if they aren’t sparking. If they aren’t, then replace the distributor. So many of them have broken that you should have no trouble locating a quality rebuilt unit to save a bunch of money versus buying a brand new distributor.