Cooling System - 1980 3.5lt Range Rover

[dunno]

Have a situation where the cooling system is pressurising when motor is running forcing coolant into the expansion tank but not drawing it back as motor cools. Noticed the problem after seeing discharge from the expansion tank overflow pipe dripping on shed floor.

When you release the expansion tank cap the following day you can loose up to 1/2 a litre of coolant through the overflow pipe.

Vehicle starts and runs well through appears to run hotter on the guage than one would expect when warmed up.

Problem surfaced about a week ago after towing a trailer with 3/4 tonne of hay onboard.

Any ideas of cause or how to resolve ?????.

Thanks
Dunno :confused:

[scrambler]

Hi Dunno. Must confess I'd be largely guessing, but when my same age 3.5 Landy did something similar, it was just a small leak in the radiator - I think was basically pumping air in and water out over time.

[byron]

Have a situation where the cooling system is pressurising when motor is running forcing coolant into the expansion tank but not drawing it back as motor cools. Noticed the problem after seeing discharge from the expansion tank overflow pipe dripping on shed floor.

When you release the expansion tank cap the following day you can loose up to 1/2 a litre of coolant through the overflow pipe.

Vehicle starts and runs well through appears to run hotter on the guage than one would expect when warmed up.

Problem surfaced about a week ago after towing a trailer with 3/4 tonne of hay onboard.

Any ideas of cause or how to resolve ?????.

Thanks
Dunno :confused:

I hope I'm very wrong, but you're describing some of the early symptoms of a blown head gasket!:(

[DEFENDERZOOK]

it could be a faulty radiator cap......or even a thermostat......
and there is always the chance of a water pump giving its warnings......


you could also do as byron suggested and have the cooling system tested for exhaust gasses.....most workshops should have a t-kay tester.....
or you should be able to purchase one from repco or similar for around the $70 mark.......

[LukeV]

Sorry to bump an old thread, but did you ever sought this problem out? I have been having the same issue for quite some time. I have just finished putting new head gaskets on (heads machined also) and I am still having the same issue.
Seems that their is excess pressure in the cooling system which forces the coolant into the expansion tank and eventually out of the overflow pipe. Once left to cool, the expansion tank is still full however the radiator is half empty. A bit of a worry as the coolant light doesn't come on!!
AU Thermo's to go on in place of the 12" Davis, Craig units in the coming weeks, so hopefully this brings the temp and ie pressure down a bit.

Cheers,
LukeV

[dunno]

Luke,

Never sorted the problem. Took the thermostat out and this did ease the problem to some degree but was still likely to overheat on a hot day when under load. Need to check radiator that that is not causing problem but my guess is that it may be a hair line crack in the block somewhere.

Have since sold the rangie and bought a 2004 Discovery Classic. Nice unit but I miss the old rangie.

Let us know if you ever get to the bottom of it.

Cheers
Dunno

[PhilipA]

It's either a leaking head gasket or a slipped sleeve.
Seeing you have had the heads checked and a new head gasket, it is most likely a slipped sleeve although it is unusual in a 3.5.

You could try a new radiator cap of the correct 14 or 15 lbs , as Sometimes the heat soak after shut down will cause localised boiling if it is not holding pressure and then leakage from the cap.
Regards Philip A

[PLR]

Sorry to bump an old thread, but did you ever sought this problem out? I have been having the same issue for quite some time. I have just finished putting new head gaskets on (heads machined also) and I am still having the same issue.
Seems that their is excess pressure in the cooling system which forces the coolant into the expansion tank and eventually out of the overflow pipe. Once left to cool, the expansion tank is still full however the radiator is half empty. A bit of a worry as the coolant light doesn't come on!!
AU Thermo's to go on in place of the 12" Davis, Craig units in the coming weeks, so hopefully this brings the temp and ie pressure down a bit.

Cheers,
LukeV

G`day Luke

What size engine and is it EFI of carb ?

[LukeV]

Sorry guys, it is a 3.9i.

I've been worrying about it being a slipped liner for a while now. The head guy said the heads have been machined 5 times!

I have replaced the cap with a non-recovery system type cap. I am pretty sure it is 15 or 16psi.

Is there any way of determining a slipped liner? I had a good look when the heads were off but I imagine it is hard to see if they have been moving.

I'm still hoping it is just an air leak somewhere causing an air lock, forcing the water out of the cap but then sucking air back through the leak rather then the coolant out of the expansion tank. The radiator did have a slight leak between the RHS tank but that has seemed to stop after I did the heads (was off the road for 3 months :P )
The coolant seems to pass through the cap when at 90-95+ degrees, which seems to indicate the system is either getting pressurised either through trapped air or leaking gasses from the engine (slipped liner, gasket, cracked block, etc).

Thanks guys,

LukeV

[PLR]

Sorry guys, it is a 3.9i.

I've been worrying about it being a slipped liner for a while now. The head guy said the heads have been machined 5 times!

I have replaced the cap with a non-recovery system type cap. I am pretty sure it is 15 or 16psi.

Is there any way of determining a slipped liner? I had a good look when the heads were off but I imagine it is hard to see if they have been moving.

I'm still hoping it is just an air leak somewhere causing an air lock, forcing the water out of the cap but then sucking air back through the leak rather then the coolant out of the expansion tank. The radiator did have a slight leak between the RHS tank but that has seemed to stop after I did the heads (was off the road for 3 months :P )
The coolant seems to pass through the cap when at 90-95+ degrees, which seems to indicate the system is either getting pressurised either through trapped air or leaking gasses from the engine (slipped liner, gasket, cracked block, etc).

Thanks guys,

LukeV

G`day Luke

It`s very hard without being on the spot .

A slipped or moved liner is fairly easy to see if you have an idea what to look for , not just peering at but using a magnifying glass and feel the right bits but also before removing anything getting an idea which side and cyls to be looking at .

For yours to be a liner problem i would expect that you`d have seen something when the heads were off .

The liner problem will tell like a head gasket fault allowing pressure past and into the coolant system but this occurs in the later stages of the problem .

Generally but not always the engine need to have been overheated , for some engines once is enough , others a couple or three , some it won`t matter , there`s no telling just like lotto so none is best .

In the early stage there would have been coolant loss without external signs , one reason if it is an overheating 94mm engine ( 3.9/4.0/4.6 ) that it is important to fix any external leaks no matter how minor .
( Since yours had a leak in the radiator it`s hard to measure loss where a liner is concerned ).

Another sign is rust or strange coloured sparkplugs specially if any of the middle cyls , 3,5,4,6 , the 4 end cyls are harder because they are all near where the coolant passages are in the heads but none of the middle ones see any coolant that can get into the cylinders .
Some may suggest that a crack in the head could allow coolant into the mid cyls and they`d be right if it ever happened .

The only Rover head i`ve heard of doing this including ones that have been hot was one and only one that had been modified from factory and had the ports opened up too far so was nothing to do with a fault in the head but that it had been releaved too far so the wall between the port and passage failed .

Another sign of a liner problem is on first start up from cold and normally only from cold , is excessive moisture coming out of the tail pipe . ( untill later stages then it doesn`t matter hot cold or otherwise )

When the engine is shut down and is cooling , the pressure in the coolant system is still enough to push through the block cracks past the liner into the chamber .

The cracks are usually far enough down the block that the combustion pressure holds the coolant at bay while running , in the first stages in the last stages the combustion pressure makes it way into and pressurises the coolant system .

Most of the above will be signatured

The best way to know if you have an air lock when refilling is to use measured bottled with the right quantity for the L/R manual , this way if you don`t fit it all in you need to find out why not .

With the engine started and the thermostat open , with the cap/plug off/out of the radiator run it up to and hold around 1500 - 2000 rpms .

When or if the level lowers top it up and let the revs fall fluid may be lost , run it up again , do same , let it idle till it settles , the radiator should be full .

Always fill and check level at/in the radiator . Top up at the tank but check radiator .

If it has any leaks it can suck air and will be impossible to get rid of air till the leak is repaired .

If at idle for 10 or 15 mins and it starts to overheat could be air in system ( though generally show sooner ) or could be the cooling fan isn`t working as should . Could be a blockage and other things also .

If at speed it overheats under load ( trailer acceleration ) but not at cruise/steady gentle pace 100kph could be air , gasket liner etc .

Only suggestions and too much to take in i know .

Cheers

ADD........... just to make it longer .......
Our RR has falcon fans on it , i`ve fitted an idiot light so`s i can see when the gauge rises that they are working .

They only come on at a temp set by whoever sets/fits them .

The Viscos work at a different range of temp which is why the gauge doesn`t tell when it works . They do there thing before the gauge knows about it .

I didn`t like them when i first fitted them but being used to how and when they work now and knowing that if fitted correctly with a shroud that draws from the entire area of the radiator and is sealed properly and fitted so`s no damage can be done to the radiator tanks etc , by vibs etc , i think they are a good thing , they move more air than viscos , they allow under bonnet work with the engine running easier and they allow the engine to be heard easier etc .

For piece of mind a know working Viscos fan is also good , if going bush for more than a couple of days the visco would be my choice but for road and economy the electric .

Also i have a 110 amp alt which is part of electic upgrade ? The electric draw alot of current when working but they should only be working at lower speeds or something no right .

[mark2]

Peter,

What would you consider to be excessive moisture from the tailpipe when cold? When I start on LPG in particular, I notice a fair amount of moisture, but not sure it its 'excessive'
Would a 3.5 which has been stroked and bored to become a 4.3, be more prone to a slipped liner?

[PLR]

G`day Mark ,

Don`t know really , may sound silly but there are some things that are worth taking note of when everythings working as it should and i know these are the times that normal types don`t .

I can`t put it into an understandable quantity because if usuals not known ?

Lpg seems to give off more than petrol but in fumes mostly some but not alot of liquid and it`s dependant on the outside air temp .

I guess a stroked 3.5 is more prone to slip a liner because of the extra stroke or use of more of the length liner and also being 030 over for 4.3 .

3.5s if bored seem to be more prone to liner shift than std bore 3.5s but std ones that have been hot will shift also .

The thing about these engines is it doesn`t affect the block .

The liners can bang and rattle because it can move up and down but they don`t suffer like the 94mm bore engines because they have more than twice the amount of alloy surrounding the liner in some cases .

Liner shift , that is making a noise in a std or oversize 3.5 is not as sever as liner shift in a stroker because of the stroke . The std 3.5 has more room for error because of the crank weights .

It does depend which 3.5 also because some are stronger than others .

Most shifted liners i`ve seen in 3.5s have settled downward and if the case it is often possible to fit a 94mm oil ring side rail , which takes up the space and stops the movement . Probably not the best fix but short term and cheap .

So if you have an over heating/coolant problem unless your very unlucky it`s not liner shift .

Cheers

Most of this will be signatured

ADD ............... i forgot to say that i have an 030 3.5 in the shed was in the RR once it has 8 dropped liners , it had been hot on a couple of occassions .

It had no liner noise when running ever , even when over heated , it also never had any problem with coolant because of the liner shift .

It got hot enough to break rings but it ran for about 3 mths on those broken rings and still made no liner noise .

To break rings they have to get fairly warm .

[LukeV]

Thanks for the great reply Peter R :)

There is a noticable amount of water vapour coming out of the exhaust when the car is started. This does go away once you rev it a bit, but seems to be more then there should be (droplets of water form in the tail pipe). Haven't had a good test of this yet, so could just be when on LPG.

Good point about the fans and electrical load. I know with my current thermo's they are running most of the time (as far as I know). I like the idea of having the light to show when they are operating. Is this as simple as running another cable off the 87 prong on the relay?

I am thinking of trying the following:
1) Setup the AU fans.
2) Remove the gas system, eliminating any possible air leaks from the convertor or hosing.
3) Have radiator rodded and re-tested.

Is it worth trying any of the radiator stop leak products to try and seal up any cracks/leaks??

Cheers,

Luke

[PLR]

Thanks for the great reply Peter R :)

There is a noticable amount of water vapour coming out of the exhaust when the car is started. This does go away once you rev it a bit, but seems to be more then there should be (droplets of water form in the tail pipe). Haven't had a good test of this yet, so could just be when on LPG.

Good point about the fans and electrical load. I know with my current thermo's they are running most of the time (as far as I know). I like the idea of having the light to show when they are operating. Is this as simple as running another cable off the 87 prong on the relay?

I am thinking of trying the following:
1) Setup the AU fans.
2) Remove the gas system, eliminating any possible air leaks from the convertor or hosing.
3) Have radiator rodded and re-tested.

Is it worth trying any of the radiator stop leak products to try and seal up any cracks/leaks??

Cheers,

Luke

Hi Luke ,

I wouldn`t take too much notice of the fluid from the tailpipe unless you have a measure .

It`s like when there is an overheating problem , it`s one of the few times the bonnet gets lifted when everything`s hot and unless you have a measure they can seem very hot but the thing is they are very hot when the bonnet is opened even when the gauge is reading in the right place .

Another one of those things to do when everything is working as it should be .

Yes all 3 sound good to me though i`d probably do it in the reverse order and if you haven`t , put a new thermostat in at the same time .

If you rod the rad fit a stat and you`ve already done the gaskets , that`s 3 eliminations which you know are good .

If the Radiator hasn`t been rodded in the last 2 yrs , could be that it is the culprit and always a good idea to look at when any overheating problem . If it`s not allowing the coolant to flow at the right speed through the engine it will act as yours .

The current fans should only run either when the AC is on or when the engine is hot as in above normal running temperature .

It`s possible the fact that they are running they are trying to tell you something .

It may be worth taking note of what they are doing and when .

If not an electrical problem it may be air in the system is making steam ( sort of ) in the manifold which is causing the fans to initiate .

If it was from overheating without air in it i`d expect the gauge to be reading very high .

If the problem occurs at highway speeds the AU fans won`t alter much as far as the gauge goes , they will run all the time and this will limit their useful life span .
The AU fans will only do very much at idle and slow speeds also when slowing for towns , to 50/60 kph they will come on , short term .
In general any speed above around 70 kph will have no need for the AU fans , unless a very hot day and the thermastatic switch is set fairly low .

With the light i used a sole twin fused relay but yes i only ran an extra wire into the cabin , it could be inline but if it fails so will the fans .

I`ve heard of 3 people using chemiweld with good results but follow instructions , if after the radiator is rodded and the problem persists , i`d think about using it . I would only use it if everything else checked out ok and a block crack was a big possibility or if an engine had been overheated as a safe guard .

Only thing is that when used the LPG coolant ports need to be bypassed because the converter relies on heat dissipation and any of the gunk used can upset how the coolant works inside the converter , this also applies when any cleaners are put through the coolant system .

Cheers

Peter

[Davo]

Is it worth trying any of the radiator stop leak products to try and seal up any cracks/leaks??

Only if you're desperate. Some of them can work but can also gunk things up a bit.

[LukeV]

Thanks Peter :)

I will look at getting the radiator rodded as soon as possible ;)
Might as well get it done at the same time I fit the thermo's.

The Stat has been replaced, so if I can get the new fans on and the radiator rodded and it still plays up I think I might start looking at fitting a different engine.

Cheers,

LukeV