Hi All,

I just bought an 86 XJ6 (7/85 build date with no 3rd brake light) for $1,000. I had seen it around my neighborhood for a while and knew it wasn’t driven much and sat outside all the time. It has 129k miles, minimal rust — although some is becoming evident around the front windshield — and the leather seats are trashed from heat, sun and neglect. All the fluids are clean and topped up, it runs at 80-85c after fully warmed up and the transmission seems to shift fine.

I figured I would be in for fuel system woes due to it sitting outside with irregular use. The car drove fine for the first 15 minutes and then started to get progressively slower. I could smell a sulfur smell and suspected a clogged catalytic converter (still do).

But I also wanted to drain the fuel tanks ASAP and did that last night. The right tank drained fine but did spit out some dirty gas and debris initially. The left side tank drained much more slowly until I stuck the head of a nail into the drain and removed some debris. After that tank had drained, I poured an additional gallon of clean fuel through the tank in an attempt to flush out more debris. Then I put the drain plug back on, added two gallons to each tank and started it up using the left side (slow drain) tank. It started, idled for a moment and then died. Restarting it several times replicated the same scenario.

The previous owner had installed a single prefilter before the fuel pump but after where the lines for each tank meet. It was clogged with debris. I removed it this morning and Installed prefilters for each tank.

Then I started it up using the right side tank (faster draining) and took it for a 15-20 minute drive. For most of the drive it ran fantastic — better than ever since I have driven it. But within 1.5 miles of returning home, it lost significant power and barely made it back.

I plan to replace the right tank prefilter again

tomorrow and see how it does.

The fuel pump also was buzzing the entire time.

Am I foolish to keep replacing prefilters (and maybe the pump and main fuel filter) until the system is clean of debris or should I just bite the bullet I don’t want to and pull the tanks?

So far, I actually like this car a lot and hope I can get it going reliably. It’s my first Jaguar and first car with an automatic transmission; I’m 44.

Thanks for any help and advice you can offer. I have a lot to learn.

 

A pal of mine went thru a half-dozen or so pairs of pre-filters on his Series III.

The first pair went maybe 10 miles. The next maybe 50. Then next, a few days. Then 2-3 weeks. Then a month.

Eventually all the serious crud was trapped and he had clear sailing after that.

It was a bit of a nuisance but a lot less work than pulling fuel tanks. For him, it worked out OK.

In answer to you're question I'd say "Give it a try"

Cheers
DD

 

Thank you for replying, Doug. I’ll give it a try for as long as I can increase my mileage intervals between filter changes. Glad to hear there has been a positive precedent for this approach.

 

did you only remove the small drain bolt in each tank? or did you remove the entire large nut assembly when draining the tanks?

There is a screen filter mesh which comes out off the tank complete with screen mesh when you remove the large nut assembly. Rmove and clean those in gasoline, the screens are usually clogged.

NOTE: you need to have new rubber seals in advance, the old seals are probably rotted.
Order them from SNG BARRAT USA store, they're under a dollar each.

When you have the tanks fully opened., open the chromed filler caps and spray water with pressure into the tanks with a garden hose, let them drain and dry overnight or use a blower or hair dryer to force them dry from above and from below through the hole at the bottom. Use new seals, two per tank, to reassemble.

Refill with gasoline and add a can of STP Gas Tank Conditioner to move and burn any water dropplets remaining.

 

I have been through all this with my '86 S3 the last two years. I did what Doug suggests above, as well as the flush recommended by Jose. But instead of replacing the two filters (that I had installed near the outlet of each tank), I washed them out to save money. I only had to do this twice, and now the car is running beautifully, reliably. I do carry a pair of new filters and some tools in the trunk however.

PS I love the colour of your car, not seen very often. And I happen to feel that the Borg Warner 66 auto does a fine job in these cars.

 

Mkii250 I carry one spare of each belt and one spare of each radiator hoses. And yes, the BW66 is an excellent transmission.

 

Awesome. Thanks Jose and MKii.

I drained the left side tank a second time and the whole plug came out. The gasket was indeed bad so I have yet to refill that tank until I replace it.

I’ll also go through the additional steps you recommend. And thanks for the tip about washing the clogged filters out! I’ll definitely give that a try.

John

 

you bet.
The good news is that you only do that once every 30 years.

regarding the 3rd brake lamp, they are easy to install. I don't like to glue the two aluminium brackets to the glass, in my '84 I used Gorilla Mounting Tape, the black tape, eliminating the two brackets.

 

For a new tank drain plug gasket, consider this

https://www.jaguarforums.com/forum/x...c26310-196039/


Cheers
DD

 

Great tip, Doug. 👍

I was able to get the last drain gasket all the NAPAs in town had. I’m ordering the other one tonight.

I started on the left side tank this afternoon with a garden hose. I found by rocking the car side to side while the water flows more junk came out. I’m not 100% satisfied with the process though and plan to run the hose through the tank again tomorrow evening to see what else comes out. After that I’ll let it dry out for a day or day and a half.

Then, on to the right side tank.

Thanks again for the help everyone. There is some aspect of ridiculous joy in running pressurized water through a gas tank. Hopefully it all works out, but if it doesn’t at least it was fun.

John

 

for the best access to the tank's insides:

remove the tailight lens, remove the tailight housing, then remove the Float sender.

to remove the float sender, disconnect the two wires connected to the sender, back up the metal ring with a brass tool and wood mallet, (don't use steel tools, bad idea), then attack the tank from the hole behind it with the garden hose.

NOTE: disconnect the battery FIRST.

Service the float by lubing its pivots with thin oil.

 

That proved to be very helpful advice, Jose. I removed the tail light and float (and disconnected the battery) and alternated between flushing it out from the back and the top. A lot of crud came out initially. Now it’s more sporadic, but I’m still getting occasional small chunks coming out. I am going to give it another round tomorrow night or the next evening that time permits. Hopefully I can get it to a point where there are no small chunks and few to no tiny but visible deposits.

I’m not looking forward to this month’s water bill, so I hope this process ultimately works out.

Thanks again for all the help.

John

 

John you are welcome, I am glad to help.

It's the best way to get the years of grime out short of removing the tanks, and they would have to be cleaned the same way anyway. Tank removal is a p.i.t.a.

I'm getting one of these:

​https://youtu.be/wAJ-QqRLpA8​​​​​​

 

Lets hope the tanks don't leak after all that clean-out activity !

 

"Thanks again for the help everyone. There is some aspect of ridiculous joy in running pressurized water through a gas tank. Hopefully it all works out, but if it doesn’t at least it was fun."

A good attitude to have working with these old cars

 

For added fun and enjoyment,in addition to the suggestions already employed, use a pressure washer instead of a mre garden hose
Are you using a pressure nozzle on the garden hose?

enjoy!!!

Carlh

 

absolutely, there are small water pressure electric machines that are great for washing engines, cleaning siding, and tanks.
Some have flexible extensions, adapters with brushes and scrapers.

 

absolutely, there are small water pressure electric machines that are great for washing engines, cleaning siding, and tanks.
Some have flexible extensions, adapters with brushes and scrapers.

 

Hey everyone, I’m still at it with the left side tank.

The last few washes I did came out clean with no discernible deposits. I’ve been draining into a light color, open 5 gallon pan to observe what comes out. If I can do what I should and keep at it, I’ll spend another evening flushing the tank through until I get 5 clean pans in a row. Or I might just call it and put gas and the STP tank treatment Jose recommended and hope for the best.

That’s not to say the worst won’t happen. I won’t be too surprised if the tank ends up leaking. There were some sizable rust deposits that came out of it.

I have been using a good high pressure nozzle, although a pressure washer certainly would have been better and in hindsight I wish the me from four days ago would have made that investment.

Thanks for the encouragement everyone. The beauty of this car is that even if this tank goes to hell, there’s one more left that might not. 🤞

 

I diligently keep both tanks filled and cycle between tanks as soon as one gets to 50%. This I believe exercises the switching solenoids and never allows fuel to just sit in a tank, as it is constantly being replaced with fresh juice. So far (3 years now), I've yet to have an issue.

Now that I've said that, I expect I'll go into the garage and find a gas puddle somewhere!