Help required with a coolant leak ....please

[Woody68]

I've just had a pressure test done today on my 1999 xjr because every 4 to 5 days the coolant drops to just below the sensor in the expansion tank triggering a warning on the dash

after running the test for 2 hours the local garage could not get a drop in pressure or any water leaks which is great news in one sense but frustrating in the fact that the water level has been dropping for the past few weeks now every 5 days or so ...

So has anybody else had this happen to them or has anybody got any pointers as to what might be the reason behind the drop in coolant ..??

I don't mind topping up the fluids but I just want peace of mind that if I go on a long journey I wont have any problems ....

Any help will be gratefully received

Phil

[J44EAG]

Take a good look under the water pump. You may find a leak as I indeed did on my S-type which has the same engine and pump. Early pumps were not good. Later pumps have two prominent 10mm bolt heads on the front behind the pulley. Those are the later 4.2 units which have a moded impeller, housing, drain and bearing assembly.

Try this post of mine which explains my saga and water pump replacement.

http://www.jec.org.uk/forums/viewtopic.php?f=201&t=4685

Investigate those matters first and make sure you don`t have the same faults.

I`ve had these issues myself, so know the frustrations.

Mike

[robv12]

they can also leak around the plastic cooling "tower" situated at the front of the engine, there is an alloy upgade for this item, I think Mike J44EAG has one fitted to his car

whatever the fault is it will need sorting as your car should not need topping up with such frequency

[J44EAG]

Rob is correct. I do have one fitted. Details and pics in the above link to my post.

The original plastic units can crack and fall to pieces due to age and heat. The captivation threads for the front thermostat nozzle can also spin in the plastic tower and make dismantling difficult. The after market tower gets around those problems. Here is an image of the aluminium unit.

Mike

[Diavel]

hi check the blow off water tank its located on the nearside front under the abs unit you have to remove the front plastic guard on the underside of the car you need to get on your back to have a good look for any coolant leaking around this area.let me know if you see signs of coolant theres a few things to check.

[Woody68]

Many Thanks everyone for your helpful reply's ...

I think the first thing I need to sort out now is a local jag mechanic who knows these engines ..

Anyone know of one around Hastings East Sussex area (I don't mind traveling if I have to )

Cheers

Phil

[Woody68]

Just to update this thread I've now found my water leak

Pulled up outside home last night and noticed steam coming out from under the bonnet

Popped the bonnet and low and behold there was coolant dripping on to the drivers side cat just where it meets the manifolds ..the pipe just above the said point was leaking from the joint where the rubber hose connects to a metal pipe

Booked in tomorrow morning to have her sorted out so hopefully that will be the end of my coolant problems

Will update this once I know the outcome

Phil

[J44EAG]

That is good, Phil. Glad to hear you have found the problem.

I really do recommend changing the thermostat tower to an ali job and checking the water pump to ensure you have the latest 4.2 unit. This is distinguishable by having two 10mm bolt heads at the 8 and 2 o`clock positions at the front of the pump. The pump is made from two parts which can easily be seen.

Older type pumps can shed or break their plastic impeller blades and develop leaks from the pump spindle bearing and a drain hole under the lower part of the outer spindle/pump casing.

Mike

[Woody68]

Thanks Mike for your info will get those bits looked at and sorted out asap ...

Better to be safe than sorry

The repair on the leaking hose cost a grand total of £37 including vat ....so very happy and so far no more leaking coolant

Happy Days