There is expoxy specifically made for plastic fuel tanks. Just do an interent search for "plastic fuel tank repair".

 

So far, found 2;

Permatex 09100 and ITW Performance Polymers.

*** SEE POST 34 BELOW ***

Neither of these have advertised descriptions of the exact plastic materials they work for; they just have descriptions like "plastic fuel tank repair kit", but as we all know, there are lots of different materials which can be used for plastic fuel tanks.

After more digging through the service manual, for future reference;

The material of the fuel tanks is:

* HIGH DENSITY POLYETHYLENE (HDPE)
* SAE code stamp "PE", usually found on the rear of the part
* A rigid thermoplastic (not thermoset) polyolefin
* Floats in water
* Melts or frays when sanded
* Flammable
* Heat resisting temperature is 176 deg F
* Gasoline and most solvents are harmless
* Best repaired with hot iron plastic material-feed welder, but
usually replaced instead
* Common trade names; Alathon, Dylan, Foriflex, Hi-fax, Hosalen,
Marlex, and Resinox.

Thermoset plastics (but not the fuel tank material) are recommended to be repaired with epoxy or other more rigid 2 package repair material. I.e., the service manual doesn't recommend repairing the material the fuel tanks are made from by using any type of epoxy - only hot iron plastic welding.

On page 8-1348 there are GM part numbers and vendors identified as sources for cosmetic, structural, or bonding adhesives, but they are only identified as for "most rigid plastic parts" and not for specific materials or parts (i.e. these adhesives may or may not work for high density polyethylene polyolefin thermoplastic).

Adhesive bonding: GM Goodwrench Structural Bonding Epoxy, GM P/N 12345726, GM Dealer.

Adhesive bonding: Dynatron Dyna-Weld Plio Grip (OE structural adhesive), Refer to local paint supplier.

Adhesive/Strucutural bonding: US Chemical and Plastic System 2000 Structural Adhesive, P/N 82007B = 30 min, P/N 82014B = 9 min, Refer to local paint supplier or US Chemicals customer service 1-800-321-0672.

This information found on pages 6-1055, 8-1348, 8-1372, 8-1373, and 8-1374.

 

This help? I have others if you need them.

 

JB Weld

 

[QUOTE=2000C-5;1568415891]This help? I have others if you need them.
QUOTE]

Thanks, but is this from a 2000? My fuel tanks don't look exactly like this - they're similar, but not exactly the same. My crossover tube is a smooth black rubber hose. The FLVV valve on top of the right tank is colored blue (not white) on mine.

Does anyone have pics of 2002 coupe fuel tanks out of the car?

 

I read on the JB Weld website where they claim this stuff works to repair fuel tanks and that it is impervious to gasoline.

But I've also read on several other automotive forums where people have tried this for plastic tanks, that it works for a while but eventually cracks right where the repaired crack was - implying that JB Weld isn't flexible enough, once it hardens, to compensate for expansion and contraction of a plastic tank.

How long has your repair been working for you? No leaks since?

 

If the leak is coming from the evaporative emission controls system, it may be covered by warranty. As I recall the air pollution controls on the vette are warrantied for 75000 miles.

How many mile on your car?

 

About 62,000. LOOOOONG out of normal warranty. I've never heard about this 75K mi emissions warranty.

 

GM provides extended warranties on some emissions controls system parts if you have the California compliant emissions package. My 2002 Z06 is California compliant as were all 2002 corvettes. Search for GM warranty data for your car. You may get a pleasant surprise. For example, my fuel tanks are covered for 7 yrs or 70000 miles. Catalytic converters for 8 yrs or 80000 miles

 

OK, since your car is a 2002 it is a non FFS fuel system. GM changed to the FFS fuel system in the 2003 year model. The main visual difference is your fuel lines are located at the bottom of the tanks. That's why the access to the FLVV is blue. I've not had a non FFS system out, but on the one above, the access on top is a twist lock type with a large rubber O-ring.

Have you tried spraying some brake cleaner on the tank to clean it, then see where the fuel is coming from?

 

Bell:

I fixed the fuel tank about 5 months ago and so far the fuel smell has not returned. The reason most epoxy type repairs crack at the same location is because most individuals apply the epoxy material right over the crack without exposing the crack via grinding, smiliar to what you would do to perform a base metal weld repair on structural steel, piping, or a pressure vessel.
If you are not familiar with the what to do I suggest you stay away from it. As far a heat welding is concerned, I would not put any heat to that fuel tank without having completely flushed it several times and removed every trace of gasoline left in it.

 

OK, Tim,

Now we're on track. This is what my fuel tank looks like.

However, I need some educating here. What is an FFS fuel system and how is it different then the one my 02 has? What do you mean when you say "That's why the access to the FLVV is blue." When you say "the access top is a twist lock type with a large rubber O-ring." are you talking about the FLVV which is about 3/4 way up the tank or the small blue fixture on the tip top of the tank. BTW, installed in the car, I cannot see any of the tip top of the tank. I haven't needed to spray any brake cleaner on the tank. When I wipe it with a paper towel, it looks dry immediately, then the fuel on the surface seeps back VERY quickly. The highest wet surface is the horizonzal plateau where the large blue FLVV is located. The vertical surface just behind it is NOT wet, so I don't think the leak is at the tip top of the tank. I believe it is coming from either the FTP sensor (which is mounted through the flange of the blue FLVV) or the FLVV joint where it mounts into the tank.

 

my 04 coupe had a leaky driver side tank. when the dealer dropped it and we looked at it it was not evident where the leak was coming from(no visible crack) but it was definitely leaking. replaced the tank and the problem was solved. even doing it myself i would not try to repair the plastic tank. it is a bear to pull on jackstands and do again.
Dave

 

I went to AutoZone - scratch BOTH products that I mentioned in post #22 above. The Permatex 09100 is for plastic tanks that are NOT used for fuel. The ITW Performance Polymers is for METAL fuel tanks. I also stopped at Advance Auto - same story; products for plastic (non-fuel) tanks and products for METAL fuel tanks. AutoZone did have one that was for plastic fuel tanks called;

CarGo QuikSteel Plastic Tank Repair Kit, P/N 6522K.

The manager actually opened up the package for me so I could read the instruction page inside (got to love AutoZone). Outside of the package says it works on all types of plastic. Inside there is a separate SPECIAL STEP section which says;

"TANKS MADE OF POLYPROPYLENE AND POLYETHYLENE PLASTIC. Tanks made of Polyproylene and Polyethylene are very difficult to repair. Two things must be accomplished to make a repair to tanks made of either of these two types of plastics.

a. The surface must be vigorously sanded leaving grooves in the plastic. The grooves are necessary to achieve an effective QUIKSTEEL bond.

b. The surface must be warm when the QUIKSTEEL is applied.

IMPORTANT! Unlike other types of plastic, Polypropylene and Polyethylene tanks need to be empty when being repaired.

After cleaning and roughing up the area with the sandpaper provided, heat the plastic and apply QUIKSTEEL while the plastic is warm.

One way to heat a Polypropylene or Polyethylene tank is to place the tank in the sun until it becomes warm. Mix and apply QUIKSTEEL while the tank is in the sun. Leave the tank in the sun for one hour after applying QUIKSTEEL."

It sounds to me like this is not going to be an easy fix, even with a product that's designed for it.

 

I would certainly rather have a whole new tank also. But I'm WAAAY out of warranty and the dealer wants $804 for the tank and $275 labor to swap them out.

As long as I don't fill the tank (keep it under 3/4), there is no visible leak and the vapor smell is negligible.

A week after Christmas, I just don't have $1,100 spare change. Got to try repair first, then replace with used and install myself, then buy new and install myself. Either way, lot's of work and aggravation.

 

The fuel tanks were the same from 1999 to early 2003. In early 2003 GM changed to the type of fuel system in the first picture I posted. The fuel filter was integrated into the fuel pump assembly and the fuel pump assembly is mounted vertically where the FLVV access is on your tank. FFS is just the RPO code for the new fuel system.

What I meant by the FLVV access being blue is that is what differentiates it from the fuel pump assembly in the FFS, which is installed in the same location. The FLVV is an internal part of the tank and is an integral part of the fuel pump assembly in the FFS system.





Since I haven't had a non FFS system out of a car, I was hoping that the FLVV section of your tank would be removable like it is on the FFS tanks and your problem was just the O-ring.

Have you checked to see if maybe there is just a crack in the plastic hose that is connected to the blue piece?

 

I've wiped dry the two EVAP tube connections that attach to the side of the FLVV. The vertical surface of the blue FLVV immediately below the tubes re-wets almost immediately, but from the bottom up, not from the connections down. I.e. the leak doesn't appear to be coming from the tubing connections. In the FFS system you show, the FLVV/pump assembly has 5 tabs around the perimeter of the connection which undoubtedly are the locking tabs to make is a twist lock (as you've described). My tank has no such tabs, so must be friction/heat/sonic welded. It's just smooth with a circular seam around the blue FLVV. I've tried and tried to wipe the area dry and see where the wetness comes back from and it seems there must be a crack in this weld seam.

I've been posting back and forth with c4c5Speacialist on CorvetteMechanic.com but am only getting suggestions to take it to the dealership and let them verify the leak by pressurizing the tank with nitrogen "smoke". I keep trying to explain to him that I KNOW the tank is leaking and that it's coming from the FLVV area. I've asked him whether that is friction welded or if it's the twist lock type, but he claims there are 4 different types and doesn't know which I have. After looking at your pic above, I'm quite sure that mine is NOT the twist lock type, but is friction welded. ARRRGHH.

Right now my plan is to get the tank out of the car, which I will do next weekend to verify where the leak is (hopefully that will be much easier with it out of the car) and try the QUIKSTEEL plastic tank repair putty. I'll put it completely around the entire friction weld seam. If I can't get it to stop leaking, I guess I'll be looking for a used tank. Sounds like (from your post above) that any tank 02 and earlier would work. I may also give some more thought to trying to determine whether a late model one (with the twistlock) could be retrofitted with the guts from my tank (as we've discussed earlier), although initially I see lots of challenges with that approach.

 

If you do end up taking the tank out, I would suggest that you take it to a local body shop and have it plastic welded. It would be very easy to weld and, it being a small area, they would probably charge very little to do it. Maybe even take it to a dealership and just drive around to the body shop, walk up to one of the guys and ask if they can plastic weld something for you. You could probably get it done for a little beer money. Plastic welding is extremely strong if done correctly. Years ago, I used to repair motorcycle bodywork and repaint it to help support my habit when I was racing motorcycles. A guy brought me an upper fairing that was in 4 separate pieces. I repaired and painted it for him. About a year later, he wrecked it again. It busted up the fairing again, but not one of the welds was broken.

Worst case, you get it out and mail it to me and I'll weld it for you and send it back. All you would be out is postage.

 

Dropping the tank wont be very difficult. Actually, it is held in place by the coupling hose !
Make sure the car is close to empty fuelwise, then jack up the rear so you can reach with a screwdriver to the clamp. Place a jack under the tank because it will drop when the coupling hose is out. Unto the connections to the top of the tank and the electical lines. Remove the aluminum bracket that holds the tank underside, then undo the clamp and pull strongly on the coupling hose until it comes loose.
At that point the tank will drop and remove it gently.
Good luck

 

Latest update:

With all the warnings and special procedures called for to get the plastic fuel tank repair epoxy to work, I decided to avoid that route if I could. I purchased a used right tank for $60 from Protrax, who was parting out a 2001 Z06. The tank from his car appeared to be the same as mine, and after comparing the two, they are the same (2001 Z06 and 2002 Coupe). He also sent me the fuel pressure sensor already mouned in the top of the tank.

Yesterday, I did the tank swap in my garage on jack stands.

To gain the only access to be able to reach the cross over tube, I had to drop the right muffler. I've never done this before, but for future reference, with the car about 20 inches up on jack stands, I still did NOT have enough room to get the pipe totally out from over the axle - I just dropped the muffler to the floor and got the pipe as far out of the way as I could. I also had to remove the right mid section pipe - fortunately I have the ARH system and it can be removed individually behind the cat. If I still the stock midsection, it would have required the ENTIRE midsection, cats and all, to come out.

I also had to disconnect several other things that were competing for the limited space, including the EVAP vent valve and another electrical connector - just pushed them up out of the way.

The large cross over hose is connected to the tank with a regular worm gear hose clamp. But where it's located, you can't quite see the screw - it winds up just above the structure that separates the tank and the differential. At first I tried working on it using a mirror on a long stick, but that was just too confusing. I couldn't get both hands up into the area to work, but after about an hour of cussing, finally got the clamp loose. Initially I had to use a 7mm socket with universal joint to get it loose enough to use a short screwdriver. Major PITA!!!

Then the hose has to be manually manipulated with ALOT of force to get enough clearance to reach above it to disconnect the EVAP tube that comes across the top of the tank. Man, this would be so simple if GM would have just thought the put a removable panel in the floor of the hatch area. Anyway, I finally got that off.

When I dropped the tank out, I inspected it very closely all around the FLVV area, but I couldn't see any obvious cracks. I pryed out the pressure sensor and the rubber grommet has several accordian sytle ribs and one of those was torn about half off. I don't know whether it was like that in the hole and that's what was causing the leak, or whether I accidentally ripped it while removing it. If I ever have a leak from this area again, I will definitely trying replacing the fuel tank pressure sensor first (which is about $60-$80 depending on where you buy it), before resorting to replacing the tank again. I left the pressure sensor in the used tank without prying it out to look at it. I swapped the siphon jet pump/sending unit from my tank to the used tank and put the used tank in.

Again, a major PITA was trying to get the cross over hose out of the way to put the EVAP tube back on, then manipulating the cross over hose back onto the tank and then trying to get the hose clamp back in place - all with one hand and no room to work. The problem is that if you put the hose on first, you can't get above it to attach the EVAP tube and if you kink the hose to the side to allow the tank to slide over so you can get the EVAP tube on, then it's very hard to get the hose onto the tank stub; but that's the only way I could see to do it, so that's how I did it. As I said, a major PITA and a lot of cussing. I applied a little dish soap on the end of the hose and around the fuel tank stub - this was VERY helpful because it lets the hose slip onto the stub easier. Then the biggest aggravation - it's very difficult to tighten a hose clamp when there is not enough room to get your free hand up there to hold it still while you're trying to tighten the screw. I wound up using a piece of old broom handle to stick up there and wedge it against the clamp to hold it still until I could get it tight enough to stay in place while I finished tightening it. Wound up doing most of the tightening with a short screwdriver, then finished up with the socket again because I wanted to make dang sure it would be tight.

The whole tank swap took me about 5 hours. It was not complicated, but definitely very aggravating because GM put ALL the connections you have to get to in very awkward locations which are difficult to get to.

Drove to the gas station, filled it to the brim and now it has sat overnight with no more fuel smell, no more puddles underneath. I guess it's fixed. Hope I never have to do that job again.