Thread: Slowly dissapearing coolant.

Hi all,
Now that I've spent about a squillion bucks (reco gearbox, CDL linkage and switch, new clutch, new bits of exhaust, a couple of new hoses, etc) the beast is running really well. Shouldn't have said that should I....

Only problem remaining, if indeed it is a problem, is that coolant disappears at the rate of about 200ml / 1000km. There's no evidence of leaks, no steam from exhaust, no coolant in the oil, etc.

Question is. Should I be overly concerned or should I just let sleeping dogs lie ? I'm inclined to do the latter - wise move or not ? The coolant loss is about the same rate whether the weather be stinking hot or not or whether I'm working it all very hard or not. The temp gauge gets _slightly_ above half way towing at 110kph on a 40deg day but otherwise it's at the half way point and stays there so the cooling system appears to work well.

On a side note. Jeez it's quiet with a gearbox that's not busily destroying itself and a new rattle free flexible section in the exhaust...:-)

Originally Posted by peter51

There are 21 hose clamps on a TD5 - more of you have not removed the hose from the oil cooler to the radiator. There are three areas on the AC/PWR steering bracket where a small leak can occur - 2 weep holes on the air filter side and a seal between this bracket and the block

There are quite a few hoses weeping from the ends. Until I had a good poke around tonight I really didn't realise just how many hoses and clamps there are. I knew there was a lot but that many ??...:-)

Firstly make sure your coolant has plenty of colour to it. If you are using OAT coolant - it should be bright red. The benefit of this is you can find leaks easily either by visual means or with a UV torch - dried coolant will fluoresce. If your coolant is not a strong colour then you are up for plenty of corrosion in the oil cooler and various spigots BTW.

Coolant has plenty of colour to it - it's BRIGHT red...:-)
I used an old LED torch (very blue end of the spectrum). With the aid of a mirror blue-tac'd to a bicycle spoke I was able to see where the ends of hoses are weeping. Good trick which I'll file away for future reference.

To make the job easier make up the attached cap with a schrader valve and pressurise the system to 14psi. Then go round looking for leaks.

I've borrowed a cooling system pressuriser so I'll do that next weekend.

If you cannot find any evidence of external leaking - including all the others alluded to by Strangy, then it is head gasket.

I've found enough very small leaks to more than account for the coolant loss.

If you find the issue please report back. IMHO, too many people request help and never report back - which leaves a useless thread.

Agreed. None of the leaks have leaked enough for it to drip onto the ground which is what got me worried. But the fluorescing trick has shown lots of little splashes and leaks that evaporate before it gets a chance to drip off.


Thanks to all who replied. I'm somewhat relieved that I've got weeping hoses all over the place and that it's not the head or head gasket.


For a vehicle that's done in excess of 350k km I reckon it's doing quite well. It's still very capable, comfortable and economical to run and the added bonus is that it's still got the fun factor. AND it's a Land Rover...:-)