Thread: TD5 Fuel Cooler leaks.

hi all i did the front O ring a few years back but know the rear one seems to be leaking, from memory i did the front with the cooler still on the car but has anyone done the rear without taking the cooler off and is there any precautions i need to take to remove the cooler if i have to.thanks,tony

hi all i replaced the rear one yesterday with the cooler still on the car only took about an hour being very careful and after a pretty cool night in melb no leaks this morning ya

Hi all,

Working through a few things tonight including a leaky fuel cooler. Got the fuel cooler out, and it was full of brown crud, like an old oil/water mix, but almost clay like in consistency. 3 galleries were totally blocked.

Rest of the coolant system always seems clean.
Any thoughts? Diesel leak in the cooler, or just 14 yrs of accumulated crud?

image-3274190695.jpg

lack of coolant flow?
The other end has a 2 way valve?

Yeah, could be lack of flow. There is a thermostat at the back end, so I suppose coolant hits a bit of a brick wall, dropping anything suspended.

I'm back again as well, I had a mechanic replace my seals whilst doing a few other jobs/checks prior to a desert trip 4 yrs ago, seals were put in without silicon and now done approx. 100k KM without leaking, for a further two years though I put up with loosing small amounts of coolant and had the coolant checked for ex. gas, nothing detected, decided eventually to bite the bullet and get the head gasket checked, lo and behold head was slightly warped and showed signs of leakage, once head was shaved and replaced no more coolant loss, just another coincident with fuel cooler leak???
My cooler was reported to also be full of crud.
No cable tie or anything to stop the vibration but sounds like a good idea.
Thanks everyone for your input, great to read about different experiences and learn from all the input. Cheers.

Just to add to marks comments about head gasket and pressure blowing hoses. If you maintain your car as it should be, the cooling system should be able to withstand pressure above 20psi at which point the fill cap will vent.

His suggestion to leave the cap loose if you have a blown head gasket will just result in all the coolant being pumped out.

I have left the cap loose for situations where I have had a leak, say a water pump, to stop the system pressurizing, therefore slowing the leak.

Just adding what I found when I replace front and rear orings in the fuel cooler
After changing out my radiator, thermostat and hoses (and plenty of gaskets, seals and o-rings here and there) I ended up with a leak from the front (and possibly from the rear) of the fuel cooler. (This may have been due to removing a hose that lead from the defunkt radiator 'bottom circuit'to the hidden pipe and then oil cooler - how so? Because the hose to the front of the fuel cooler had been cable tied to this oil cooler hose.)
So I bought BS225 viton orings ($9 for 4) at Allied Bearings and Seals Nerang and took a swing at it today.
I had intended inly to do the front end oring but could not access the front end clip to undo it with the fuel cooler in situ (The clic-r (ear) clips were done up with the clips hidden - I fuligure the previous mechanic did this in their previous 'service'). So I undid the four bolts holding it (finding the front top one stripped as it is steel into aluminum alloy intake plenum, slow clap for LR and previous mechanic) and found that I could manipulate the fuel cooler around enough to remove the clips and front and rear caps without removing the fuel lines. Nice.
Coolant wanted to spill everywhere, mainly from the rear hoses so in retrospect I should have prepared a proper sized hose clamp for the upper of those two. As it was I just tied the front hose high and clamped the rear top hose with pliers (sorry).
Anyways I opened up the caps and fond the old flat seal and a hole bunch of blue (rtv?) silicone. So what does this tell us? The silicone was a previous repair which did not use new orings and it HELD for at least 2 years (I've had the truck for almost 2 years) maybe more... Until it was disturbed by my work on the cooling system and/or movement due to not being cable tied. Okay, so silicone seems to hold back coolant when no moved about. Can an oring be moved about and continue to seal I don't know but will find out soon enough when I test it.
However... this silicone approach made me cry. Why? Because I spent over an hour in the cold, losing precious daylight and with coolant dripping al the while, scrapping silicon not only off the caps (easy 2mins) but off the inside of the fuel cooler - in particular the oring sealing surface. Silicon sticks real well to sheet aluminium of the fuel cooler and bakes on. This was not fun with the fuel cooler in the engine bay (fuel lines still connected).
It sucked.
In short I respect silicone could get you out of a jam and might even delay the onset of future leaks after oring replacement, but your next service to the orings might be a pretty awful. Moreover I have a feeling the silicone will only jold until disturbed. So if you're thinking of using silicone with orings you might keep this in mind.
Putting the lower bolts back on the cooler was pretty fun, particularly with the hidden pipe flange to factor in. It was so funny in fact that I want to travel to Solihull and give a big kiss to the person who made the decision to put it together like that, a big kiss from my ancestors - a Liverpool kiss.
Thanks Solihull, I hope one of you spilled your pint on yer missus' shoes at the pub tonight.
The Clic-r clips (ear clips) looked impossible to do up but when I got it it was easy. I tried with end cutters but found that the 'angled attack' of small side cutters worked better. You just pull them together and hook the female end over the hook about 12mm below where it will go, then bring the side cutters in from the side and get one end each within the tips of the blade, close it a bit, cheat some more purchase on the clip and then squeeze it until the female overlaps the male, push on it as you release the cutters and it should hold. This would have been easy on a bench. In situ the front was not too bad. The rear .... Was a right royal sh$&. Everything (fuel lines, air intake, coolant hoses) was in the way. After fifteen minutes of hard effort and furious creative swearing, suddenly it worked. I would advise anyone who is changing the back orings to do so on a bench not in the car, as you would have to be a zen master to get it without swearing so much the police turned up.