Where do you think my coolant leak is?

I have a 97 300 tdi with a coolant leak, I've tried everything to find the leak but can only isolate it roughly.

When standing level and once the engine is hot there is a constant dribble down the front nearside of the block (under the alternator).

However, if at this point I squeeze the top house a jet spurts forward from under the serpentine belt tensioner.

I've removed the tensioner and the spurt is coming definitely from under the tensioner mounting.

I had a new P gasket about 2 years ago, could it be this again?

I've attached a photo, it's a bit poor off my mobile phone but shows the splash.

Did you get someone else to do the p gasket or do it yourself? The bolts can be siezed and shear, im hoping that did not happen. If so the housing might be warping a little bit when it gets hot, or it could just be the gasket. Try using a mirror to see exactly whats happening if you can.

I friend who was LR trained and worked for a main dealer did it for me. He's too ill to do anything for me now.

Will have a go with a mirror later on like you suggest.

Hi all again, had some fraught times recently and the Disco has been parked up till now.

The leak, to the best I can see, plus a little advice locally, might be coming from the bottom of the thermostat housing.

To re-cap when I'd been for a run she lost the majority of coolant and the top hose was pressurised. When I squeezed the top hose a jet of water shot straight forward from underneath the mount for the serpentine tensioner. Obviously a pressurised jet can ricochet from anywhere and give the appearance of a forward jet but this is the symptom.

Looks a right sod to change the thermostat housing gasket, all the water pump housing off by the looks of it as per p-gasket.

She drives and sounds OK but is there a chance this is head gasket related instead? Would a head gasket ever go in such a way as to give an external "jet" of coolant?

All advice greatly appreciated to get the old girl running again.

Disco Magic said:

Would a head gasket ever go in such a way as to give an external "jet" of coolant?

All advice greatly appreciated to get the old girl running again.

Click to expand...

I have serious doubts it would do just that.

hi disco magic,
i have got to change my thermostat housing as a pervious owner rounded off the bleed screw thread and have leak.
i have a new thermostat housing ang gasket and with what i can see you don't need to remove the water pump as that wil not gain you any more room.

from the shape of the thermostat housing and gasket there are four bolts that hold it on.
two at the top, two bottom, two bolts are at different heights.
the two bottom bolts look as if you undoo them as much as space allows and remove the top two.
remove thermostat housing sliding up wards, as the two bottom holes are sliding fittings.
clean area replace gasket and refit,
top up and bleed as needed.

if any one as replaced this any more comments would be good before i start mine.

hope this helps,
any further comments would be great.

have you removed the fan on the pic?
is that where the serpentine belt normally sits on your engine?
who removed the tensioner?
the stat housing can be removed by slackening the 2 lower bolts but its fiddly.
even fiddleir to replace with new gasket an a dollop of hermetite.
how old is the disco?
how old is the radiator?
do you run it without the fan?

more questions and answers later

nrgserv said:

have you removed the fan on the pic?
is that where the serpentine belt normally sits on your engine?
who removed the tensioner?
the stat housing can be removed by slackening the 2 lower bolts but its fiddly.
even fiddleir to replace with new gasket an a dollop of hermetite.
how old is the disco?
how old is the radiator?
do you run it without the fan?

more questions and answers later

Click to expand...

I removed the fan and tensioner and just dropped the belt down. This is just how the engine looks whilst investigating the area of the leak.

1997

Radiator approx 3 to 4 years

Don't run it without fan.

Disco Magic said:

She drives and sounds OK but is there a chance this is head gasket related instead? Would a head gasket ever go in such a way as to give an external "jet" of coolant?

Click to expand...

Hi, i used to have a rover 414si (totally different vehicle i know) and when the head gasket blew on that a tiny jet of water shot out of front of the block.


I thankfully now have a disco 300tdi but i also have a similar leak and cannot find where it is coming from. not only that i was just drving down the motorway only to notice that my temp gauge was maxing out. as i was only 1/2mile from home i carried on. also my heater was not working. then as i came off the slip road and went round a roundabout my temp gauge leveled out to normal and the heater started blasting out hot air instead of cold. very strange

does anybody have any clue why this may have happened?

Disco magic, if you have any luck finding the leak any information would me most appreciated. im gonna have a quick look again tomorrow but not holding out much hope.

grunta-22 said:

Hi, i used to have a rover 414si (totally different vehicle i know) and when the head gasket blew on that a tiny jet of water shot out of front of the block.


I thankfully now have a disco 300tdi but i also have a similar leak and cannot find where it is coming from. not only that i was just drving down the motorway only to notice that my temp gauge was maxing out. as i was only 1/2mile from home i carried on. also my heater was not working. then as i came off the slip road and went round a roundabout my temp gauge leveled out to normal and the heater started blasting out hot air instead of cold. very strange

does anybody have any clue why this may have happened?

Disco magic, if you have any luck finding the leak any information would me most appreciated. im gonna have a quick look again tomorrow but not holding out much hope.

Click to expand...

head gasket symptoms.
it'll only get worse.
D1 300tdi water loss.
probably caused by loss of coolant due to the leak, but may not be related to it

nrgserv said:

head gasket symptoms.
it'll only get worse.
D1 300tdi water loss.
probably caused by loss of coolant due to the leak, but may not be related to it

Click to expand...

ah crap :doh:

I feel a expensive week ahead!

I just picked up a thermostat housing gasket today from my local LR dealer - ERR3490. Will try and find time to attack this tomorrow or Wednesday.

If that doesn't work then back to square one. As the leak is the other end of the p-gasket to the waterway I'm not too convinced that's to blame which to me would only leave the head gasket.:frusty:

Fingers crossed.....

grunta-22 said:

ah crap :doh:

I feel a expensive week ahead!

Click to expand...

Seconded, crap - crap - crap

How many hours for a mechanic to change the head gasket?

Disco Magic said:

Seconded, crap - crap - crap

How many hours for a mechanic to change the head gasket?

Click to expand...

i'm going to pop into my mates garage tomorrow he should give me a pretty good idea of how long it will take. i'll update ya as soon as i know.

grunta-22 said:

i'm going to pop into my mates garage tomorrow he should give me a pretty good idea of how long it will take. i'll update ya as soon as i know.

Click to expand...

Cheers. Before doing the thermostat housing gasket I'll bleed it through again and stick a latex glove on my expansion tank with an elastic band (don't have any condoms). No doubt it'll stick two fingers up at me!

Disco Magic said:

I just picked up a thermostat housing gasket today from my local LR dealer - ERR3490. Will try and find time to attack this tomorrow or Wednesday.

If that doesn't work then back to square one. As the leak is the other end of the p-gasket to the waterway I'm not too convinced that's to blame which to me would only leave the head gasket.:frusty:

Fingers crossed.....

Click to expand...

Or a freeze plug or plugs. One of mine was just starting to leak just before I sold it.

Disco Magic said:

Cheers. Before doing the thermostat housing gasket I'll bleed it through again and stick a latex glove on my expansion tank with an elastic band (don't have any condoms). No doubt it'll stick two fingers up at me!

Click to expand...

Well i think someone must be smiling down on me. took the old girl to the garage this morning and we are almost 100% sure its the p gasket. slight furring round the joint and coolant on the engine block near the alternator. heater problem was simply that there was no coolant left for the heater to use.

i assume that it has never been done before and i understand it is a very common part to go on 300tdi's as land rover have since modified the gasket from a fibre one to a metal one.

gonna clean the engine around the joint and where it is wet. hopefully this should mean i can see where its leaking and confirm my suspicion.

gonna be a long day methinks

dont want to be a damp squib with all this, but.....

from experience, it doesent take long to cook the head if its been run without / low on water. first time ours did it (due to knackered radiator) was new years day green laning. stopped to open / close gate, then down road for dinner. tried to get heater on hot while sat eating, which was when we first noticed problem. tried and better tried to get air out of system to no avail.
.......later on in conversation our lass sez "that gate before dinner? well musta bin cold outside cos when i shut the gate the snow an ice on the road had turned bright blue"
sez i "my f**kin antifreeze........."

got home keeping rad topped up (30 mile ish)
head off, pressure tested ok, skimmed (3 passes with machine at bradford engine units)
rebuilt, no problems. (also new rad....)

did a mates similar situation- water pump went. he drove 5 mile ish, pressure tested ok, skimmed.....12 passes at bradford engine units!! well bent!

pressure test and skim- £40. payne or elring head gasket (dont fit owt else!) £15 - £25
make sure you get the right thickness head gasket.
bout 2 hours to remove head. 2 days for head test as i had to farm it out. 2 hour ish to put back together.

have got 2 300s in with headgasket failure caused by p gasket leaks, one has seized no 3 piston and requires reboring tother 1 just needs head skimming.

grunta-22 said:

Hi, i used to have a rover 414si (totally different vehicle i know) and when the head gasket blew on that a tiny jet of water shot out of front of the block.


I thankfully now have a disco 300tdi but i also have a similar leak and cannot find where it is coming from. not only that i was just drving down the motorway only to notice that my temp gauge was maxing out. as i was only 1/2mile from home i carried on. also my heater was not working. then as i came off the slip road and went round a roundabout my temp gauge leveled out to normal and the heater started blasting out hot air instead of cold. very strange

does anybody have any clue why this may have happened?

Disco magic, if you have any luck finding the leak any information would me most appreciated. im gonna have a quick look again tomorrow but not holding out much hope.

Click to expand...

Thermostat sticking......I had the same problem.....totally remove the thermostat and no more problems