Coolant leak

[mike123]

My 2006 STR is proving eccentric at the moment, having had a leaking oil cooler pipe replaced it started to drop coolant which was traced to the top hose. This had split where the small pipe tees off to the heater, this too was replaced.
Having got the car home and driven about 60 miles I noticed two drips one from the duct to the right of the under shield and one from a hole behind the duct.
As it was a pleasant week end I removed the shield and cleaned it, (first time I have personally done anything on this car in 2.5 years - its been looked after by my local independant) and saw the coolant was dripping down the right hand side of the tightly packed area infront of the engine. The cross member was wet and the oil cooler pipe and oil filter was coloured.

However I could seen no 'origin' for the leak. Monday I called the garage and they collected the car tested it and could find no leak, so home it came again. The next morning there were more drips; I'm told it was dripping about once every 10 seconds. (I was away in the MX5 - Lancashire to Dorset and back in 2 days in that 22 year old car is a long way !)

So it seems that the system doesn't leak when hot, then when cold leaks more quickly and then slows. The water loss is small, perhaps a few 100 mls per day.

I am monitoring the fault and our collective thoughts are that it could be the water pump gland heating up expanding and sealing, then leaking when it cools down.

Has anyone else got any thoughts ?

Mike

[oldtimer]

Hi Mike123,
Your garage should have a radiator pressurising kit which comprises of a selection of adaptors to fit the cooling system header tank and joins to a small hand pump by a length of plastic hose. The pump has a built in pressure gauge and pressure should not exceed pressure cap setting.
Applying pressure to the system should help identify the leak, this can be carried with hot or cold coolant.

I'm afraid I can't remember the trade name of the kit supplier and it's to late to get to the top shelf in the garage - will make the effort if you need to know

Hope that helps a little

Oldtimer

[mike123]

Hi Oldtimer,
It was tested by the garage hot, and left under pressure but nothing seen. Problem was getting the car to them cold; but that's what I expect we will do next week.
Don't expect I will be driving it much in the next week, by the time I've driven it to them and allowed it to cool overnight !
Mike

[Martec]

This is quite a common problem, new rubber takes sometime before it seems to slick permenantly to metal/plastic, so when the metal cools down it contracts a little so the jubilee or spring clip hasn't quite got the same nip and it leaks.

I replaced all the hoses on our MkII and fortunately the easiest to get to leaked when it was cold, when everything was warm I managed to tighten the jubilee clip about a quarter of a turn and all is well.

I always put hoses on with a smeer of vaseline now as it requires less effort and less damage when they need to come off again.

Best of luck

Brian

[J44EAG]

I`ve replaced several spring type hose clips on J44 with conventional stainless steel Jubillee clips. I distrust the spring clips and it worries me that I would be unable to tighten them whilst out on the road and perhaps be under gun fire, ie on the shoulder of a motorway. At least with a Jubillee you can tighten the clip to get you home.

Mike

[mike123]

Final update on this one. The leak was quite small and unless something unusal happensI will never know what it was. On impulse (sorry chaps) I replaced it with a 2.7D XF, so now don't have a bulletin board to post to !

However in the last week I drove the STR to the Kent coast and back about 600 miles and it hardly lost any coolant. I opened the header tank every morning when the engine was cold and measured the level. One morning after short local runs it was low so I added about 350 ml of water, the next day after the run to Kent the level had risen by several mms. After a few moments panic and checking for oily scum etc, I worked out there must be a second tank , later confirmed by Preston Jag, which takes the expansion liquid and allows it to be sucked back on cooling / contracting.
This rather confused the change in levels I was measuring; but maybe the info will help someone else one day.

All the best
Mike

[MCALLISTERABERDOUR]

Hello,
I too have a problem with my cooling system. When cold the cap on the header tank releases pressure when opened. I get the Low Coolant level warning coming on now about every 200/300 miles. Garage has checked this out twice now and can't find any signs of a leak. Don't know if they pressure tested the system the last time but they did the first time and it was okay. Only takes a couple of hundred mls of water to top it up and no signs of overheating at all. Seems to be worse when I have the caravan on tow.

We have now resorted to radiator leak sealant but that has proved ineffective as the light came back on today.

The garage suspect it could be something sinister like a head gasket problem but I can't see any evidence in the oil or from the exhaust as to that. The car is running superb as well which is really frustrating.

She has only done 86000, 2.5 v6 automatic, 2004 vintage and is the last of the pre facelift models sold.

Any ideas.

[MCALLISTERABERDOUR]

Hello,
Been a while since I wrote about this issue. Still got the problem but even worse now.
One new radiator and expansion tank plus all the time and labour costs incurred getting to this stage - down about £800. Radiator had shown signs of extreme pressure at bottom end (virtually melted some sections of it), expansion tank was also leaking at top. Using even more water now with no visible signs of a leak either through the exhaust, oil or underneath and with no apparent loss of power.
Anyway, kept the car rather than trade in for a pittance, suspension is all sorted, body is good. nice colour and I have invested a small fortune in this car. Bought a Freelander 2 TD4 now with 28k on it for towing the caravan. Brilliant motor but no style in comparison.
Down side now is with Jag not getting used is the Gremlins are moving in ( ABS warning plus engine malfunction warning now flashing on last short drive ).
Next stage with the Jag ( after our holiday in September ) is a compressed air test down the cylinders apparently and I dare say we are in the area of potential engine replacement. It might be a leak on the hose that is located around the inlet manifold, this will be checked before the step above but doubtful.
Any thoughts/comments ?

[J44EAG]

Take a check on any coolant related pipes, thermostat tower, water pump front seal/bearing, tank etc.

My V8 got leaks last year. \water pump replaced and leaks got worse.Thought a strip out might be required to find the issue.

Then I was recommended K-Seal. A miracle in a bottle and worth every penny of around a tenner. Dumped a can in the coolant system and within a day or so, no more leaks and that was a year ago.

The AA use this stuff. It does what it says on the bottle. Give it a try. Its completely changed my life. Thinking of drinking a bottle myself after a Saturday night session!

Mike

[MCALLISTERABERDOUR]

Hi Mike,
Suspect there may be a problem with this top hose as I detected water dropping from the back of the engine rear under tray at the back of the engine when I parked up on my drive ( it's quite a steep gradient ). Going to get the garage to check it with the ramps at an angle with the engine running because every time it's been checked it's always been on the level on the garage ramps or on the floor. I think it may be dripping down onto the tray and probably lying there until I drive it again. Water pump and Themostat all have been checked be fine according to the garage.
Anyway if the hose theory proves unsuccessful then I will certainly give K-Seal a go before throwing any more money at it. Any idea what the difference is between heavy duty K-Seal and the normal one at £10. There is special HD stuff for Jaguar advertised along with others on ebay for around £18 and I am not sure what to go for.

Thanks

[jeff1954]

I think the heavy duty K Seal is for trucks and the like as the haulage firm I work for has it in there stores.

Jeff

[MCALLISTERABERDOUR]

Thanks Jeff,
I was kind of thinking that, it was just when it was advertised for Jaguar and other makes. Then again it's Ebay.

[MCALLISTERABERDOUR]

Sorry if it's boring but I have a new perspective on this on going problem. Car been in garage again. No obvious leaks at all found, left the under tray off for a wee while whilst I use it again to monitor the situation. Used the car after getting it back for a couple of days for running to and from work, round trip of 30 miles each day. Coolant light went on and off a couple of times (especially when stopped at lights or when going slow), staying on for around a couple of minutes each time. Took a litre of water after these trips to bring up to level. Same today took it out for a run of about 30 miles, light came on and off as before and even more noticeable when pulled up at the junction on leaving the motorway after about 10 miles at around 80 it came on and went out again after about half a mile. Getting loads of pressure in the water system which I presume is exhaust gas from a head gasket leak. Releasing it very slowly and carefully through the pressure cap when hot brings the water level up slightly.
Time for K seal I think, if it works great. If not then its time too have the cylinders air tested to find out where the leak is. Think this might be expensive. Still can't understand :
Why no obvious lack of power
Why no sign of anything out of the exhaust
Even after around 8000 to 10000 miles since this started no water in the oil issues.

[J44EAG]

Short of a strip down for examination and diagnosis, K-seal may be the way to go. If it works, it is happy days. If not, then stripping may be the only answer.

Take some encouragement in that K-seal has been totally successful eradicating a leak I had on J44. It did what it said on the bottle and has been effective now for around a couple of years. Not topped up since.

Try it and see and please let us know how things have panned out.

Mike

[MCALLISTERABERDOUR]

Will do Mike. Going to try the K seal this week and monitor it. Hopefully it will improve situation but if no success then I am taking it over to the RR/Bentley/Jag specialist in Dalkieth again after our holidays in September.
Presumably some big bucks to be spent.
Pics under L17MCA in register, maybe explains why I want to keep it.

Cheers