My first post! I’ve had a problem with water in fuel as well as strong fuel smell in boot and in cabin of my sII Daimler Sovereign 1975, uk build. The tanks are each vented by a rubber tube at front of each fuel cap. The drain points at fuel cap recesses are clear and draining and the fuel cap seals appear fine.
I started to remove passenger side fuel cap assembly to check the rubber flat seal between fuel filler cap base casting and car body and it was present and intact, though appeared thin. I did not fully remove the cap assembly, as it was fiddly to release. But, in this semi removed state, I could not see any o ring between the fuel tank neck and the filler cap base assembly. Should there be one? If it’s missing, would this be the likely cause of the fuel smell and rain water entry?
Can anyone advise what the oring spec would be?
Also, is there any advice on best way to clear water from a tank full of fuel?
to drain the water out you need to remove the small plug on the bottom of the tank, then the large one to flush out the rust while you are at it.
If the tank is very full you could directly power the fuel pump to a container and only then remove the bottom plug.
The way I know it there’s an O ring around the tubular part of the filler neck, and a gasket below the filler (where the four screws pass through). When there’s water getting in, either the drain is blocked which it is not and the cap seal is not tight, or the cap seal is completely gone.
The vent that goes out towards the front of the cap makes a loop in the C pillar and is not a likely water source.
Do yourself a favor and replace the fuel hoses and filter. I hope it’s not a rusted tank.
I don’t think water will come in around the outside of the filler neck. There’s the gasket, then there’s the O ring… most likely candidate is still the sprung seal inside the cap itself.
Many thanks David. I’ll drain fuel into a spare container using the pump, then crack open the bottom drain point, replace the filters after I’ve flushed it. And I’ll take the cap fully off when the tank is empty to see what is going on.
what VIN is your car - mine is 2T 12048 BW and was built in late 74/early 75. Our cars may have met at Browns Lane!
The most common way for water to get into the tank is through the front door and caused by blocked water drainage lines from the fuel filler recesses. - Don’t know for how long you’ve had the car - just in case you haven’t noticed yet - there are holes in the recesses to which rubber tubes are attached. Once these tubes are blocked or if there is just a couple of leaves collecting in the recess and blocking the drain the water level will climb within the recess if the car is parked outside during extended rain and any longer period of water pressing against the usually worn upper rubber seal of the fuel filler lid will be sufficient to get some water inside the tank. Clean the recesses and poke through the drainage tubes with an old bicycle brake wire or similar to re-activate the drainage.
Now, as for the fuel smell: Is it raw fuel or burnt fuel, i.e. exhaust gas? Exhaust gas fumes may get “pulled” into the cabin as a consequence of a shot air ventilation: there should be some over pressure in the cabin pressing air out through the extractor underneath the rear parcel shelf and through the trunk. If over pressure doesn’t exist or the one-way system of the extractor (foam padded flaps) is ineffective exhaust fumes may go the wrong way.
Raw fuel smells it seems are mostly caused by slight leaks at the tubing, fuel pumps, t-valve behind the spare wheel. Just open that compartment, run the engine in idle and switch tanks to-and-fro. Feel the banjo bolts at the fuel pumps and the clamps at the joints. Any dampness will cause smells.
“Older” cars - in particular if unused for longer periods may have developed pin holes rusted into the tanks, caused by water in the tank. That kind of damage typically can be identified by exclusion: run the car with one tank empty - does this affect the smell? Vary the filling height. Chances are you reach the level of the pinholes and the smell is strongly reduced. If that is the case though you’ll have to pull the tank.
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As water is heavier than petrol, it collects in the ‘sludge sump’ at the drain plugs - together with tank debris…
As per David; water will drain by opening the small plug - it’s arguable whether draining the tanks is really necessary for small plug draining. If you use fuel pump for draining; fuel pressure and flow rate is very high - so be prepared…
You can reuse petrol by filtering out water and debris through chamois leather…
Great to hear from you. My Daimler Sovereign has VIN 254804BW (format looks a bit different to yours, I’d better double check it) – yes was probably built on the same line as yours. My grandfather purchased it in Guildford UK and brought it back on a ship to Australia. I now live in Australia, so I inherited it, and did a major restoration (90% my work!) in 2004. She’s still looking good, other than some vandal scratching the bonnet some years ago and the leather seats falling apart.
When restoring, I took out the tanks, replaced one with a second hand better one, then cleaned and sealed them both with a fuel tank repair kit from POR15 (something like that). I also replaced the fuel pumps, filter and piping at that time. I recall the fuel smell was bad in the car before I did the work, and I also lowered the rear parcel shelf vent and restored that with new flaps and felt. It’s quite possible I have introduced an error on assembly, or not fixed something that had gone wrong (though I did my best). Bit frustrating, but I’ve been living with it. I’m pretty sure its fuel, not fumes.
My plan is to initially remove most of the fuel from left tank, then drop the tank plug out and check out the condition of the bottom, where any water has been sitting. If it’s OK, then I’ll take the cap assembly out, replace its lower gasket and O rings, and make up a new upper gasket in the cap. I’ll check hosing condition and see if I can find where the vent hose (the forward facing one coming off the cap body) is going. Wondering if it’s somehow venting fumes into the cabin or near that drain point of the parcel shelf assembly. Would that be the cause?
Anyway, those are my thoughts for now and thanks for the tips below. When problem solving, it’s always great to have the experience of others and encouragement.
Pic of car below in about 2005 (out of date plate). It used to be lavender with black roof, but I decided to change to black at that time. It’s done about 140,000 miles I’d say.
could it be that this is not “25” in the beginning of your VIN, but “2S” - that’s what Daimler Sovereign SII 4.2 LWB RHD should start with? Car nos. then begin with 1001 in Sept. 1973.
With everything done so far you’ll know your way around the tanks. I doubt you would have messed up anything - the extractor is fairly self-explanatory.
If you smell fuel, not fumes anyhow, I seriously start with the plumbing though - anything is easier than pulling a tank. What you did on your tanks is pretty good preparation and in a dry climate this should make the tanks hold on forever. By contrast, I’ve been at the plumbing a couple of times over the last 13 years: once a fuel pump was leaking, once a metal tube coming from the tank through the exhaust box had developed a leak, once I had to retorque the banjo bolts on a fuel pump (maybe the one I replaced). Each time fuel smells were really obnoxious.
A lovely looking car Eddie - I Don’t think there is a Vent pipe from the filler neck . The one to the rear is the water drain that comes out at the low point inside the tank valance - the forward one from the filler neck just has a rubber bung (this on a S1 V12).
However on the top of the tank you may recall there is a pipe which has a rubber cap fitted and for sure if this cap was missing it would stink out the whole car. I have only just got rid of my fuel smells after 20 years! … early culprits were the steel pipes that run from tank outlets to spare wheel well pump locations (but these were pinhole rust which started as a smell but turned into drips). My final action was to replace all my R6 flexible hose with Gates R14 barricade which seemed to finally rid me of the smelly boot (I was told the higher volatility of ethanol in todays fuel could permeate through R6 hosing ?)
None of the above solves the water ingress issue - I would try carefully pouring water into the filler neck area (not the tank obviously) to check that it drains freely down into the tank valence area.
This would have to be the tank ventilation - leading out to the atmoshere in ROW, while being connected to the vapour neutralization system on US cars. Usually, a long tube leads outside the car. If the tube is missing or ends inside the trunk it will smell.
Yes, exactly. I have that on both sides on our 2J50041DN (LHD XJ6C) and the LH side was seriously blocked when I bought the car in Milan in 2007. No water going in but no air entering the tank either. All fixed long ago. Yes on all classic XJ’s the drain tubes block easily and need regular cleaning, the worst are the T- and Y-joints found on some lines. Nothing impossible but sometimes in very difficult to access.
When washing the car it’s a good idea to check the holes mentioned, that water comes out where it’s supposed to and observe how fast the fuel filler box, the rear screen vent box, the front fresh air intake etc all drain.
For sure that cap C37021 should be in place for UK cars. Venting of the tank vapour pressure, or vacuum as contents of tank are consumed, is only via the vent built into the filler cap itself.
never occurred to me to check this part - even though I should know better for my Spitfire has a similar vent tube on top of the tank. Hope I can peek in through the rear light opening and an endoskope.
Thanks Mike, this little pipe on top of tank I need to inspect. I have this terrible feeling it has no bung on it. Assume the tank has to drop to access it. I’ll look at the fuel hoses as well, this Barricade product looks the biz.
Cheers Eddie
Good question. I don’t know really, condensation when using the A/C? Bad trunk seal?
I recently replaced the trunk seal, it wasn’t terrible and I had not noticed any leaks, but my wife had started to complain about luggage and shopping bags starting to small like exhaust. As I didn’t know how old it was (we have had the car for 14 years now) I thought I could just replace it with a new one.
collective experience confirms that the air extractor is prone to rusting as during cold weather the cabin air is warmer than the ambient temperature and will carry water which will condensate when led through the relatively cold metal air extractor box. There are full reports on clean renovations (Paul Novak, I think). The parts catalogue shows something looking like drain tubes (BAC2806). I don’t know though where they are supposed to be going.
