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post #1 of 30 (permalink) Old 12-03-2017, 22:40 Thread Starter
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Elusive Leak.

A couple of months back the car started to lose just a little coolant. Oil was clean, she ran well, couldn't see any dribbles. Topped her up and asked my (pretty) trusted garage to look. He couldn't see anything either.
Loss got worse, and on three occasions as I approached the car after a run (at the shops, after fuelling up) I saw a dribble of water passenger side just in front of rear wheel. Easy- must be a hose.
Asked the garage to look again last week when she went for MOT.
Couldn't find anything, but hinted I might have a dodgy cylinder liner.
Today I changed oil and had good look with the inspection cover off, and I still can't find anything.
Easily added 3 or 4 litres coolant (no, not just water) over last 6-8 weeks.
Now, I really don't believe I imagined seeing a dibble of water three times- so, anyone had weird, hard-to-track leak nearside?
Yes, I could just change all the hoses (13 years old) but there's a lorra lorra hoses in there, and it would still be an experiment.
Haven't driven her more than 10-15 minutes at a time, and about to lay her up unless I crack this.


ps- Oil level hadn't gone up and wasn't emulsified, so don't think it was going in there. Head Gasket done a year (8000miles) ago. Underfloor pipes were changed 4 years ago.



pps- Passed MOT. If only I dared drive her anywhere
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post #2 of 30 (permalink) Old 12-03-2017, 22:54
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Quote:
Originally Posted by skellum View Post
A couple of months back the car started to lose just a little coolant. Oil was clean, she ran well, couldn't see any dribbles. Topped her up and asked my (pretty) trusted garage to look. He couldn't see anything either.
Loss got worse, and on three occasions as I approached the car after a run (at the shops, after fuelling up) I saw a dribble of water passenger side just in front of rear wheel. Easy- must be a hose.
Asked the garage to look again last week when she went for MOT.
Couldn't find anything, but hinted I might have a dodgy cylinder liner.
Today I changed oil and had good look with the inspection cover off, and I still can't find anything.
Easily added 3 or 4 litres coolant (no, not just water) over last 6-8 weeks.
Now, I really don't believe I imagined seeing a dibble of water three times- so, anyone had weird, hard-to-track leak nearside?
Yes, I could just change all the hoses (13 years old) but there's a lorra lorra hoses in there, and it would still be an experiment.
Haven't driven her more than 10-15 minutes at a time, and about to lay her up unless I crack this.


ps- Oil level hadn't gone up and wasn't emulsified, so don't think it was going in there. Head Gasket done a year (8000miles) ago. Underfloor pipes were changed 4 years ago.



pps- Passed MOT. If only I dared drive her anywhere
I had a similar problem. Small loss. Eventually found it. Was the water pump
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post #3 of 30 (permalink) Old 12-03-2017, 23:15 Thread Starter
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Thanks- I've seen a couple of threads were water pumps proved to be the culprit. Wrong side of engine I think, and water pump changed when HG done.
Of course, quality of parts can be inconsistent, so will have a look in case.
Cheers!
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post #4 of 30 (permalink) Old 12-03-2017, 23:31
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Radiators are prime culprits when losing coolant in F's/TF's.
Both my previous cars, an F & TF suffered from this problem.
Luckily rads. are reasonably cheap.
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post #5 of 30 (permalink) Old 12-03-2017, 23:53
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The engine rail went on mine, underneath where the bleed screw is. Worth a look and sounds like the right side.
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post #6 of 30 (permalink) Old 13-03-2017, 07:44
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There have aso been several people over the years with similar hard to find leaks that have eventually found it to be a hose with a split that only leaks under pressure. Have you tried running the car until it is up to temperature and pressure and then having a close look at the hoses and pipes? Usually these slower leaks leave whitish marks on the side of the engine, as the coolant evaporates where it runs down the engine, leaving a residue. Don't forget that these small amounts of coolant may not run straight down the engine, but may result in the drip to the floor being some way from the leak. Look for damp or discoloured areas on the engine and if nothing is obvious think about putting dye in the coolant that shows up under UV light. UV torches are cheap on ebay.
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post #7 of 30 (permalink) Old 13-03-2017, 08:19
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As a basic test you could use an old pressure cap, drill it out and fit a tyre type valve and then use a foot pump to pressurize your system, worked a couple of times for me but not always, but for about £1 its worth trying, just don't connect to an airline as you'll blow a hose.
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post #8 of 30 (permalink) Old 13-03-2017, 08:47 Thread Starter
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Thanks Gents.
More useful suggestions than I hoped for. Will go digging after work.
Ta!
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post #9 of 30 (permalink) Old 13-03-2017, 11:14
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Please report back if you find it!

Could be useful info for the rest of us!
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post #10 of 30 (permalink) Old 13-03-2017, 13:12
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I've had 2 hoses at the back of the engine fail, one of which lead to HGF, it happened on a motorway and I only realised when I pulled off and was enveloped in steam. The hose that failed in both cases was PEH100940, it's quite close to the exhaust and has got a joint in it. Because of this I always fit a low coolant alarm to my cars.

My latest car is an F Steptronic, I wasn't sure how long I'd be keeping it so I developed an easy fit alarm. It uses a tank as fitted to 2005 cars and all the electronics including LED and warning buzzer are fitted in a switch blank.

If anyones interested I made a short(ish) video showing it.
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post #11 of 30 (permalink) Old 13-03-2017, 16:44
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Quote:
Originally Posted by mgbob View Post
I've had 2 hoses at the back of the engine fail, one of which lead to HGF, it happened on a motorway and I only realised when I pulled off and was enveloped in steam. The hose that failed in both cases was PEH100940, it's quite close to the exhaust and has got a joint in it. Because of this I always fit a low coolant alarm to my cars.

My latest car is an F Steptronic, I wasn't sure how long I'd be keeping it so I developed an easy fit alarm. It uses a tank as fitted to 2005 cars and all the electronics including LED and warning buzzer are fitted in a switch blank.

If anyones interested I made a short(ish) video showing it.
Interesting video. I would be interested which timer/processor you used for this purpose?
What I used is led and buzzer which is control with relay with timer for 10 sec delay, so no three marktimes and no ignition switch contact check.
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post #12 of 30 (permalink) Old 13-03-2017, 18:39
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A small leak on the molded joints of the hoses can be hard to spot. One of mine gave up, but it wasn't apparent till I gave it a substantial squeeze and pull.
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post #13 of 30 (permalink) Old 13-03-2017, 21:41
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Interesting video. I would be interested which timer/processor you used for this purpose?
What I used is led and buzzer which is control with relay with timer for 10 sec delay, so no three marktimes and no ignition switch contact check.

It’s an ATtiny85 based processor, they’re good because they’re easily programmable and reprogrammable. I've parameterised the timings so they’re easily changeable but I've found these timings work ok.

I had thought about making a small batch of these if there was any interest.
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post #14 of 30 (permalink) Old 13-03-2017, 23:26
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I had a similar leak on my zs. The garage looked at the problem several times. I found a a comment on the freelander site that pointed to the inlet manifold. I told the garage to change the gasket and that fixed the problem.
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post #15 of 30 (permalink) Old 14-03-2017, 12:09
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one of the problems, skellum, is even if you see the dripping of coolant under the car and on the passenger side.. that doesnt mean its where the leak is..

as ajsmith66 suggested " As a basic test you could use an old pressure cap, drill it out and fit a tyre type valve and then use a foot pump to pressurize your system, worked a couple of times for me but not always, but for about £1 its worth trying, just don't connect to an airline as you'll blow a hose."

i made a similar thing to pressurize the system, but in a bit of pipe that connects in series with the jiggle pipe return into the header tank.. with a 2 bar pressure gauge in it ( the system under pressure will vent through the pressure cap over 1 bar ) so i could check not only for leaks but the operation of the pressure cap..

Utility Gauges For Industrial and OEM Markets Dual psi/bar Scales

it cost me £11 then.. i see its gone up... to £18 now.. such is life..

here is the thread i started when i was investigating... and pick of the pipe in situ, before i fitted the omega pressure gauge...

MGF Header Tank and Leak Test Method


of interest, i did try driving the car with the pipe and gauge in place, to see if i could get it up to pressure and read that on the gauge when i stopped.. but even though i could get the car hot... i couldnt get the gauge to climb toward one bar at all...

i haven't pursued that ... but it should have told me i had a leak i couldnt see somewhere... which i did... HGF eventually, even though the car ran nearly a year on from that time.. without fault on emissions.. passing its mot...

the next mot after that it failed on emissions.. and i knew i had a leak i couldn't locate.. it was the head gasket..

thats now been replaced and dont loose coolant at all..

i think i should refit the gauge pipe, and see if that makes the pressure climb visible on the gauge..




of particular note. the vent caps are not reliably leak proof.. a fully working vent cap is designed in such a way it cant allow vacuum in the system. only the one i made by removing the vent in the cap and sealing it.. stopped leaks. a normal vent cap leaks.

Last edited by Incony; 14-03-2017 at 12:37.
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post #16 of 30 (permalink) Old 14-03-2017, 14:19
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Having read that the hose PEH 100940 or 100790 for non vvc, as in my case, can fail I looked it up in the Rimmers catalogue to find out which one it is so I could delve into the engine bay in my TF to see what the state of mine may be like.
Well, I had a good look, but I could not find one hose that looked anything like the picture in the catalogue so there wouldn't be much point in getting one to keep as a spare!
Lots of hoses and T pieces but none that look exactly like that one.

My TF is a 2004 135. Was the hose configuration ever changed ie with T pieces replacing the moulded in joints, or am I just not seeing it?

One hose runs close the exhaust down pipe, is it wise to apply a bit of heat reflective tape to it? Although it is probably a bit late now!
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post #17 of 30 (permalink) Old 14-03-2017, 14:44
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ok.. being Mr Dangerous again, i shoehorned the pressure gauge into my MGF Freestyle jiggle pipe return in the header tank line.

started the engine, checked for leaks... gauge didnt move at first the pressure takes time to build up.. but as soon as i revved the engine, the pressure started to climb.

1. the temp gauge climbing to normal.. idle revs,

2 the pressure gauge reading at that time.

it climbed to that point quite fast.. and was very rev dependent.. it didnt drop below, but at every idle point it settled a little higher up.. and over idle revs.. say up to 2000 rpm i could see 8psi

3.

revving higher to 4000 rpm i could see the gauge reading 13 plus psi.. near the 1 bar limit.. i couldnt take a pic of that and rev at the same time.. but it shows that the system pressure is pump force dependent.. as the pump turns faster, the pressure goes up .

at each time i let go of the revs and it idled, the gauge stabilised at about 7psi..

at idle.. engine warm.. no fans on..



at that point i had seen enough for this shoehorn example... i know now that the pump can push 13 plus psi into the system.. at normal operating conditions...

when i turned the engine off, the pressure dropped from 7 to 5 psi.. and stabilised.. sitting like that as the engine cooled... very gradually falling slowly.


i will post more... when i have some better hose connections and fittings..

i am pleased to see the gauge working... its a very useful bit of kit... i shall explore it further now i know it works.

of particular interest to me.. is now i understand what the normal operating idle pressure should be in a good sound system with no leaks... is a pressure switch to change a led from red to green... i.e. if there is a leak or low pressure below say 5 psi at idle something is wrong... the system cant get up to pressure... likewise it would also tell me of high pressure.. ( from a cylinder leak into the system.. )

much more useful than a coolant level switch.. since the system will change pressure before the fluid leaks low, and one would see abnormal pressure quicker... long before the vent cap vents at 1 bar.. just under 15psi. ie.. if 7 psi at idle is about normal, then 12 psi at idle isnt

it took 50 minutes today as posted this reply for the gauge to reach 2 psi... from stopping the engine..

Last edited by Incony; 14-03-2017 at 15:12.
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post #18 of 30 (permalink) Old 15-03-2017, 07:53
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i dont want to hog the OP post. so i am going to paste my efforts into my original thread... with the pics and info.. as i develep what ive found out..

MGF Header Tank and Leak Test Method

i hope this info will help folks looking for elusive leaks..
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post #19 of 30 (permalink) Old 15-03-2017, 18:44 Thread Starter
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Thanks Icony- over the last 3 days (50+ miles) my coolant has stayed almost static. Just a tiny loss you might not notice if you weren't looking.
From your thread it seems the pressure within the cooling system varies with revs, and so possibly any cracked/ leaky hose could behave differently under different driving conditions.
The next time I can get the inspection cover off will be Sunday. I'll have to rope in some help to vary the engine revs while I watch. I had the chance to park up over dry, light concrete the other day hoping for tell-tale drips.
Of course not.
We run two cars, and if I can't track this down this weekend I'm going to lay her up for proper investigation.
Cheers all.
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post #20 of 30 (permalink) Old 16-03-2017, 21:54
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"the pressure within the cooling system varies with revs"

YES.

so that means if you have a leak that only happens at certain pressure... then driving at the revs that turns the pump at that required pressure to cause the leak... will happen.. ie a hose that only leaks at certain pressure..

in effect.. you cool the engine because the pump pushes more coolant round the engine... but at the same time... you increase the leak.. ( more pressure ) and loose idle pressure when you stop driving... so if you loose pressure.. the coolant that wasnt boiling... suddenly starts to boil, as it reaches atmospheric pressure..


its a hideous cycle.... if you rev the engine... you increase the pressure... the water that was boiling.. now stops boiling, its under pressure... but the leak gets worse... more pressure more leak.. and what leaks.. is at atmospheric pressure.. so you get clouds of steam...


now.. so far - you are not loosing any significant quantity... and i suspect your pressure is still behaving normal.. but if the leak gets worse.. and you loose pressure.... you will make it worse by idling the car.. yet see some short term benefit if you drive it , ( you increase the pressure and stop the water boiling ) but in the end.. the pump will push coolant out... and you get air locks... boiling water in the head... etc etc.. bad news..


i saw nearly 1 bar pressure at 4000 rpm... certainly over 0.8 bar... i only tried that once.. this was a shoehorn example...

at that pressure the coolant wont boil... but its temperature might be over 100 degrees C at that pressure.. certainly over 98 degrees C..

so if it it leaks.. into the atmosphere... it will boil violently..

and why folks report clouds of steam when the vent cap vents..

so knowing that the system pressure varies with engine revs... is very important. and i might make a video to show the scale of revs, verses pressure and temperature...

as an aside.. i dont know yet that the pressures and temperatures around the engine head and the rad are the same in entirety... the head exit pipes might be very different to head entry pipes, and the header tank... one might not have the same temperature and pressure everywhere..

Last edited by Incony; 16-03-2017 at 22:08.
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