Thread: TD5 Fuel Cooler leaks.

So, did anyone manage to find he "O" ring size type etc and if so would they mind positing the details. Thanks

Originally Posted by scott oz

So, did anyone manage to find he "O" ring size type etc and if so would they mind positing the details. Thanks

BS225 in Viton

My 99 TD5 was taken away on a truck this morning with what I think is a coolant leak from the fuel cooler - not real happy - it had its 120k service 10days and 250kms ago and was not picked up

I replaced all my hoses and thermostat and cap recently and I think all the pressure pulling hoses off and then pushing new ones on loosened the seals on the fuel cooler. Developed a leak on the front side of the cooler straight away, fresh red coolant is very easy to spot. Took the cooler out and apart, one o'ring on each side, appears to be a flat shaped o'ring, not sure if it started that way but didnt appear to be much difference between the OD of the o'ring and that of the plastic end fitting possibly contributing to the lack of sealing. Sourced two o'rings plus a couple spare from CBC for a couple of dollars. The biggest pain in the backend are the clamps holding the end fittings in place. Aside from that a very easy and cheap fix for me so far.

Td5 fuel cooler leak.

I have just done this repair and I will give you my slant on what’s what.
There are some pictures of the fuel cooler disassembled posted by some one else earlier in this thread. Have a look at them.

I took my cooler off the engine to repair it but I don’t think this is necessary.

Nearly always the front plastic cap leaks coolant. I believe this is because the front hose attached to it is very long and unsecured to the engine so it vibrates causing the O ring seal on the plastic end to flatten out and leak.

I bought the recommended O rings which the part number is (BS 225 Viton) from a bearing place but did not use them. I sent then back and got a credit. This suggested O ring that everyone is using is different to the original. Its actually a little big and not so wide but I tried it and it does fit and work.

If you have a leak from the front of the fuel cooler then I would place a screwdriver on the front clip clamp and knock it sideways with a hammer. This will release the clip without damage.

Grab the front hose and try to rock it up and down as hard as you can until the plastic plug works its way out of the cooler tube. Its hard to do because there is not much room, but if you can do it you don’t have to take the whole fuel cooler off the engine and you will save about two hours for a novice mechanic.

Remove the front hose off the plastic plug.

Once you have got the plastic plug free then clean the inside of the cooler tube up with rags and metho and then carefully pry the original O ring out of the plastic cap and clean the plastic groove with metho as well.

Put some silicone gasket maker on the inside of the O ring and carefully put it back in its groove on the plastic plug. Place more silicone forward of the O ring (that’s the cooler side). Slide the hole lot back in and tap it in with a small hammer and punch.

Place the clip clamp back in position by using some end cutting nipper pliers. If you have not got any then go and buy some. About 50 to 70 dollars for good ones. You will want some that have enough room to put your finger behind the blades when they are closed. You need to press the clip joint with your finger while pliering the clamp together. I found this really easy and got it the first time. If you can’t do it then use a new screw clamp. Don’t worry if the clamp hangs over the edge. It’s better if you can find a thin screw clamp but if not I don’t think it will make much difference. When its clamped nothing will move.

In my opinion you do not need to do the back seal O ring because the back plastic plug coolant tubes are much shorter and do not vibrate nearly as much as the front coolant tube. The back is not leaking because its not worn!!! Dont touch it!!!

Finally put the front coolant tube back on and tie off the front tube with a plastic tie to the engine somewhere so that it does not vibrate as much or you will be doing the whole repair again in 4 years time.

Originally Posted by mark td5

Td5 fuel cooler leak.

I have just done this repair and I will give you my slant on what’s what.
There are some pictures of the fuel cooler disassembled posted by some one else earlier in this thread. Have a look at them.

I took my cooler off the engine to repair it but I don’t think this is necessary.

Nearly always the front plastic cap leaks coolant. I believe this is because the front hose attached to it is very long and unsecured to the engine so it vibrates causing the O ring seal on the plastic end to flatten out and leak.

I bought the recommended O rings which the part number is (BS 225 Viton) from a bearing place but did not use them. I sent then back and got a credit. This suggested O ring that everyone is using is different to the original. Its actually a little big and not so wide but I tried it and it does fit and work.

The O'ring is EXACTLY the right size, and is as specified in the LR manual. It is also the correctly sized part based on its housing dimensions....

The old one is Wider due to taking a set from time/heat.

If you have a leak from the front of the fuel cooler then I would place a screwdriver on the front clip clamp and knock it sideways with a hammer. This will release the clip without damage.

Grab the front hose and try to rock it up and down as hard as you can until the plastic plug works its way out of the cooler tube. Its hard to do because there is not much room, but if you can do it you don’t have to take the whole fuel cooler off the engine and you will save about two hours for a novice mechanic.

Remove the front hose off the plastic plug.

Once you have got the plastic plug free then clean the inside of the cooler tube up with rags and metho and then carefully pry the original O ring out of the plastic cap and clean the plastic groove with metho as well.

Put some silicone gasket maker on the inside of the O ring and carefully put it back in its groove on the plastic plug. Place more silicone forward of the O ring (that’s the cooler side). Slide the hole lot back in and tap it in with a small hammer and punch.

Do NOT put silicone in the groove, nor in front of the O'ring.
An understanding of how an O'ring actually seals will let you know you have just rendered its function useless, and you're now sealed with a lump of silicone, not by the o'ring itself.

Better to use a rubber grease and smear it **lightly** on the o'ring and housing before re-installing.

When drifting it back in, do it SLOWLY to prevent the o'ring rolling over itself and pinching.

Place the clip clamp back in position by using some end cutting nipper pliers. If you have not got any then go and buy some. About 50 to 70 dollars for good ones. You will want some that have enough room to put your finger behind the blades when they are closed. You need to press the clip joint with your finger while pliering the clamp together. I found this really easy and got it the first time. If you can’t do it then use a new screw clamp. Don’t worry if the clamp hangs over the edge. It’s better if you can find a thin screw clamp but if not I don’t think it will make much difference. When its clamped nothing will move.

In my opinion you do not need to do the back seal O ring because the back plastic plug coolant tubes are much shorter and do not vibrate nearly as much as the front coolant tube. The back is not leaking because its not worn!!! Dont touch it!!!

Finally put the front coolant tube back on and tie off the front tube with a plastic tie to the engine somewhere so that it does not vibrate as much or you will be doing the whole repair again in 4 years time.

Other than that, excellent write-up!

Originally Posted by mark td5

Td5 fuel cooler leak.

I have just done this repair.....

Nice first post!! Not the usual "welcome" style

Just bought a 99' TD5 cab chassis, took it to the mechanic for a service, check over and replacement of all coolant hoses, get it home and a few days later discover this coolant leak from the front of the fuel cooler, called the mechanic, he says, yeah that's fairly common when it gets cold, can't be fixed and is about $800 for a new one.
So thanks fella's, I've just ordered from CBC two viton BS 225's for $4 each. would like to get it fixed before heading to Dalhousie Springs with the fam next week.