aging diesel fuel query; & when is cleaning out fuel tanks also recommended?

[mjeremy]

As previously posted, we have a 1998 Holden badged (Chevy) K2500 suburban, and which we have replaced the engine with a P400 6.5 turbo diesel, among other engine bay improvements, and needed to get the best out of our new engine, as well as safeguarding it. We are now finishing off installing last inter cooling piping etc, before we look at starting it. My husband Michael intends on separately siphoning off some of the old fuel to check for any signs of poor quality. My query now is more to do with the overall fuel system for this vehicle.

We have now had it off the road for about six months, and mostly during our winter months with average day temps not exceeding 25 degrees c, until more recently (day time temps can be over 30 degrees and more) At the time we last drove, the fuel tank contained half of its normal 160 litre capability, and we are aware of the need to visually examine its suitability for cont'd use. I understand 'old' fuel can develop gums/sediment from contact over time with natural occurring water condensation in tank;(worse in humid climates), and/or contact with oxygen; or reaction with any metallic contents in tank itself etc. Personally, I am tempted to completely dump the existing fuel; ( husband, Michael not so sure!!), so as not to risk causing any remote issue with our new replacement engine etc, but do read that diesel fuel can last up to 12 mths anyway.

As well, our vehicle is now approaching 17 years old, and I have read that fuel tanks should be periodically removed from any vehicle and cleaned out, for they can harbor damaging fungi and other bacterial growth etc accumulating over time, which of course doesn't sound too good. We only acquired this vehicle 18 mths ago, and am unsure of whether tank has been prev. cleaned out or not, but in the absence of knowledge here, would assume the tank has never been done.

Can anyone on the forum offer their own opinions as to how best we should proceed, given the outlined details of our situation? Thank you!

[bowtiebutler]

If I was investing in a new engine as nice as the P400, I would want to drop the fuel tank to make sure its clean inside. You also have a filter sock inside the tank that can get plugged over time. At the very least, I would replace the filter sock. You can also remove the filter sock, and put an external 30 micron filter inline before the lift pump, then you don't ever have to worry about removing the fuel tank again do to a plugged filter sock. There is a place on the web called Leroy Diesel, and he sells a nice pre lift pump filter kit for our trucks. I've bought several items from him, and he's a nice guy to work with.

Matt

[mjeremy]

Thank you Matt for that timely advice, as we are finalising currently the last little jobs to do with our P400 install, and besides other things, ensuring the overall fuel system is in order is naturally important to us.

I have also been meaning for a while to reply to your very informative last posts to us, on another post, inclusive of your link to pics of your own rig, and which Michael and I were really really impressed, and particularly to your under bonnet work. All credit to you. Further, and which I should probably go to that particular posting, you raised some interesting points which we didn't understand at first (thus prompting us to do some follow up reading, e.g. differences in boost pressure, say 15psi, and your reference to drive psi, and where overall pressure can rise twice that of boost.) We are forever learning about this vehicle - huge huge learning curve for us over the long while, but getting there, bruised fingers; mental ache and all - we are getting there!!LOL

Michael took some pics yesterday so will have to post. There is still so much we will do with this vehicle, but am trying to ensure most importantly that mechanically this vehicle will be in top order before we go ahead and start it.

On your ref. to the fuel sock/tank, will definitely look at this. I looked at an official BP fuel website the other day as well, and they recommended that fuel tanks be cleaned out at least every 10 years, but a specialised sock filter as you mention sounds definitely worth looking at, and will check out Leroy diesels. Also as it is our intended plan to do some outback travel with this vehicle, it can be an issue here coming across remote fuel suppliers with questionable fuel (say old fuel, with possible contamination with water etc). Here, many people put fuel management systems/alarms on their 4wds, which apparently not only alert drivers that there is an issue with the fuel, but prevent water from entering the fuel system. Michael knows more about it - but yes, really do want to ensure that we give our P400 the best working environment we can. Cheers to you, and I'll put some pics up. Again, thank you for posting!

Regards, Anne and Michael!

[HeavyChevy95]

Technically speaking..

Anytime the lift pump is found faulty and replaced, your supposed to drop, clean and inspect the fuel tank, test the fuel sender, and replace the OPS and fuel strainer.

Having our lift pumps mounted externally is a convenience thats all to often taken for granted by pros and DIYrs alike. Much like aging rubber fuel hoses and o-rings found throughout the fuel system..

Be sure you replace the fuel strainer with the correct piece (see pic).
Beware- Its not uncommon for new diesel fuel senders to come with gasoline (finer) strainers or part pushers telling you theres no difference. How to spot a gas strainer? typically both ends are flat and lack the bypass valve.

[mjeremy]

Thank you for your response HeavyChevy95. Michael reminded me that when we first got our suburban over 18mths ago, our fuel system filter was checked and found to be very clean; & in good order. Yesterday was startup for our vehicle, and prior to this, we took over 3 litres from our fuel system needed to inspect it. It was found to be a nice 'straw' coloured; pale yellow and free flowing liquid, no adverse signs of murkiness or sludge present. A BP depot Manager where we regularly buy our fuel from (BP outlets charge a bit more, but are viewed as having the most consistent & best quality fuel), anyway he reckoned that diesel fuel should last for 12mths. Ours is about 6 months old, and where 'most' of our vehicle has been undercover - and through our winter months, where humidity levels also modest. Thus, whilst we prefer to play things conservatively, we think our system all good, but am still looking at installing a suitable Fuel Manager type system, with its alarm and better filtering abiility, for those times when we might travel to remote areas, and capably encounter possible dodgy fuel. Our fuel tank will be also checked and cleaned for this.

As for our re-start, everything appears to be working as it should electrically - fuel pump making the right sounds etc. Just a lot of air still in the system. At a point, my husband undid the small valve at the top of our engine, where for a while a lot of air bubbles were seen, before finally diesel fuel oozed over. Later, he also 'cracked' (I understand that is the correct term for undoing the injector? for no. 8, and where diesel fuel has yet to emerge. It was getting late, with diminishing natural light, and obviously, we need to give our batteries sufficient time in between starting, to re-charge. I understand this process of re-starting can take a while, as diesel fuel works slowly forward through our system. We hope to do a bit more today. Here, I'll post a few pics. Cheers!

[a5150nut]

Have you removed the glow plugs and tried cranking until you see fuel spay coming out the glow plug holes? Much easier on the starter to get everything primed and ready to run.

[bowtiebutler]

That is a beautiful Suburban, and I love the work your doing on it! Very Top Notch! I am curious what your going to do for your front grill, as I doubt it will clear your new intercooler. Glad to here you got it running, and looking forward to your next post.

Matt

[mjeremy]

[
Gidday BowtieButler,

Will need to take some more photos to better show you the lastest on our suburban, (it is now night time here), but for your interest, our front grille was slightly trimmed in one area that looked likely to rub against the intercooler if left unchanged. We then purchased a small 'lip' strip of black rubber which was placed over the cut/trimmed area, allowing for both a smooth finished look, as well as provide some soft insulation between the intercooler and the grille. It is barely noticeable:

Before we drive this vehicle, just need to now install some black brackets, which will give a type of lift kit to the front of suburban, but being chiefly used to give more space between the front diff and modifed sump. As of this afternoon, and after removing the front wheels for cleaning, will be both replacing the rotors, with a view to replacing the wheel hubs as well - thus there will be a minor delay before we actually drive our dear suburban.

We will certainly keep you posed Bowtie with continued improvements to our vehicle. Thank you as well for your kind interest. We were both very impressed with your own suburban - really love the colours given to your engine in areas. Everything just so well done! Cheers to you and kind regards, Michael & Anne: