OVERHEATING Problem P38, Please Help Guys!!!

Hi everyone, I'm really new on this forum, and only recently became a Range Rover owner. It would be great if someone can help me out a little bit...
I bought a 4.6 V8 HSE Auto, drove home for about 200 miles fine with no probs and temp gauge sitin right next to the blue mark on temp gauge. After 200 odd miles a temp went up to the middle, and stayed there constant, at around 250 it got just above the middle mark but again stayed constant. Got home fine, next morning went for a drive, engine got warm within 5 minutes of being started, temp gauge stayed in the middle, after bout 20 min suddenly shot up to the red and the light came on the dash. I pulled over straight away, expansion tank wasn't spilling, tried to unscrew expansion cap and a lot of air and bubbling sound came out together with water, and straight away the temp went down!!!! so put the bonnet down and drove off, 2-3 miles down the road started to go up again, so i ave don the same thing. Managed to get back home ok, but by the time got home, looked in the expansion tank to see no cooling fluid left, poured 2 litres in with out any indication of water level raising up!!!! no visual signs of any leaks.... im really puzzled as to whether its the head gasket, crack in the engine or just water sipping out somewhere where i cant see it.... but engine sounds nice pulls as it should, seems to work ok....

I ll be very very greatful for any of your suggestions guys!!!!!! Thanks!!!

there are loads of threads on here about water related issues, i'm not gonna tell you to read em all but it will be worth while have a quick scan of em just get get a background.

you need to establish where the water is going. first thing i would do is get a sniff test done. this will tell you if the head, head gasket or liners have problems.

you need to download rave cd as a must, use power iso to mount it let me know if your not familiar with .iso and i'll talk you through it, its a great reference and it will tell you where all the pipes are on the cooling system, if there are any small leaks this will be evident by a white scale usually around the pipe joints.

the fact it is bubbling over suggest its either compression related side going into coolant or air expanding under heat. most fellas on here report the guage coming up to temp pretty rapid but then sitting at half way or thereabouts. a little under or a little over is fine.
it took 200 miles to get warm, this i cannot explain as even on short journeys in cold weather the engine should get warm within 10 mins or so.

have a look to see if the seals are ok on the expansion cap, when mine was ill i took the o rings off and it calmed it down a little but my liners suffered a severe slip! try not to use the car and if you do have to keep some water in the back. at least you can then fill it up. running while the engine is overheating just about guarentees liner slip as the metals expand the ductile liner parts company and moves down. the only real cure is a new block or flanged liners in that case.

also blocked rads, air locks and knackered vicious fans can cause o/heat.

also if its lpg i would suggest you check its not that that is putting pressure in the system. turn gas off at the tanks, there will be a small valve. close it and run on gas till it stalls then run on petrol. if symptoms still there then its not the lpg system.

also report back as to what the exhaust is doing, if its white steam then its deffo h/g or liner related etc. if the exhaust is clear, cannot be seen on a normal warm ish day then its not h/g etc.

also at the base of the exp. tank, have a look with cap off(obviously you need to fill and be confident most of the air is out) if there are bubbles pulsing up look carefully between brake res. and exp tank. if its constant then its prolly just air in the system, if its pulsing rythmically then again its comp. side

sounds like alot but its the difference of hundreds if not thousands of pounds!! and for the sake of a couple of hours diagnosing its worth it!!

regards, Gav

I had exactly the same problem with mine about a month ago. Exactly the same symptoms. I had to fill it up with about 3 litres of water to get the bottle registering any level at all. It drank another bottle the following week, but now all of a sudden it's fine.

I have concluded that I have a small leak, and the level had slowly dropped and I missed it until it was low enough for some air traps to cause overheating. Having refilled it, I have only had to top it up once in the last couple of weeks and not by much. Also, it does smell of coolant when hot after a run.

Like gav says, for peace of mind you should eliminate head problems. Check for oil/water contamination, remove the plugs and see if any plug looks different. I've also been told there's a type fault with the bottle cap which lets steam pass slowly, thus letting the water level drop slowly. You could change that for £14.99

Personally, I just drive around with 2 x 3 litre Highland Spring bottles of tapwater in the tyre well just in case. I'm waiting for the big bang...

Hey thanks GAVBRIGGS and BigJock2005!!!! I went through a lot of threads yesterday, and there are many ))) but thank you so much for the replies!!! Today in the morning i actually went and got a system leak sealer, some anti-freeze and yeah i did get the spring water... top uped the coolant and went of. engine temp raised to normal, and stayed there throughout the whole day :confused2: now i've done about 50 miles today and water level hasnt moved yet.... it seems to run very smooth, but as Gavbriggs said, out the exhaust comes a slightly greyish/whitish smoke, not a lot and not constant, for example when driving its ok!!! my friend was driving behind me and noticed no smoke what so ever while driving!!! so Im even more confused now!!!! :5bwilly_nilly:
And in the oil there are no signs of water...like those yellowy white substances kind of thing, with the water theres no oil in there, it looks pretty normall too.... the gas sniff test ill probbly do tommorrow to make sure its not h/g. If it is do you recon it might be worth fixing? or if fixed is there a big chance of it going again? I also read something about the crack in the engine, hope its nothing to do with that!!!

If it's a h/g then its very probably worth doing - esp if you can do it yourself.

The worse problem is a slipped liner whereby the cylinder steel liner has slipped within the alloy block casting. That is a nightmare scenario as you are defo looking at engine out, rebuild, refurb or replace. Probably £2k and thre rest. However, that's less common. Plenty of threads here on "slipped liner", and there are some serious experts on the subject too.

Problem is you can't easily tell the difference between a head gasket and a slipped liner as the effects can be the same - you can only tell when you get the heads off.

If the water loss has stopped you might be lucky to have just let it drop too low. Just keep an eye on it, and the temp gauge!

Jock

Thanks Jock!! yeah i'm going to have a look at the "slipped liner" threads, otherwise will probably start on head gasket after the sniff test tommorrow... really like the car but its a shame it started playin up a bit... i have a friend that has been a mechanic at some point,and he would probably be able to maybe help me out if its the h/g... so its all down to the sniff test tomorrow then.. If its a slipped liner would the sniff test show up the exhaust gases too?

Yeah I try to keep my eyes constantly stuck to temp gauge!!! really really dont want it to overheat...

thats a slipped liner, notice the step in the black and silver bits on both pots, that was a serios one on mine, 3 of the 8 had gone. the block should look like one piece of metal across the top or deck. this caused severe pressure in exp tank and bubbles to come up from bottom of tank!!! if its that bad then you will need a block or flanged liners!!!

hi gav mine is blowing up in the hether tank heads ok h/g ok liners all look ok no water in oil no water leek i am f..... as to what it is any clues thanks j

i didnt notice the slip the first time i stripped it, just slammed a gsket on and then put it back together. obviously it was my first v8 so i was a bit unfamiliar with em.

i always guage the amount of water that goes in, standard system is 11 litres and then theres a bit for lpg pipework, i only ever fill with water first to confirm its sealed and run it for a bit to get it circulating then fully drain and replace with a tub of antifreeze and top up with water. this gives around 50/50 fill.

is yours lpg? if so check the lpg isnt passing into the coolant. do this by turning off the gas at the tanks or isolating the power to 1 or more solenoids on the tank/pipework before the vap/reducer.

get a sniff test to confirm hydrocarbons in coolant.

with all that done then you should be able to establish what the bubbles are.

obviously that determines the next action.

lpg, refurb or replace vap.

air(hydrocarbons test negative) requires bleeding/replumbing if its lpg and air locking there are several methods to get air out, my most succesful is recent, and ive got a blled valve next to the vap from thae pipework from a transit van.

if none of the above (hydrocarbon test positive) it got to be the combustion cambers leaking into the coolant. first job is heads off pressure test em, skim em too if they prove ok, next is block out and pressure test that/or if there is anything obvious replace/liner it. if that tests ok then get a good quality gasket. if the gasket wasnt leaking then feck knows cos thats the only ways air can get into the system!!!.

the only other way is what is known as kettling in domestic boilers, i havnt heard of this before in cars but there are no other ways gas can pass into the system.

have you had a sniff test done(hydrocarbons test)???

Thanks Gav for the picture!!! i have done a sniff test today and it showed no signs of gases at all in the system. But water level still drops so there must be a leak somewhere on the system... no noticable marks where i usually park the car, maybe its only when driving??? its like a puzzle now.... and im puzzled too..... probably will take tomorrow into garage to trace the leak....

do a pressure test on coolant, if no leaks show up i would change the exp tank cap!!

i noticed on mine, at the bottom hose to the rad from the stat, water was seeping out of the centre of the hose wall, i assume the hose has delaminated inside and i'll be replacing them all as soon as i can find a kit.

look on the bright side, the block is ok so you will be spared the massive cost and hassle of replacing it!!!! i'd be more than happy to have a leak instead of the block problems!!!

hi gav yes after we did heads skimed new h/g new rad new them tested therm and then we sniffed it still showing gases in water no got lpg as i like the smell of petrol this got me f....d may have to go down the road of new block forgot to say it had gen engine in 2004? bet it got you going now thanks j

was the new block linered?( it shouldnt have gone yet but its not impossible) was heads pressure checked?

if there are products of combustion(poc) in the coolant then there has to be a leak from the pots into the coolant, there is only 3 ways it can get in, block, h/g or heads.

if not done already i would compression or leak down test it, and/or have the heads tested, then after that it can only be block. there is no other way poc can get in there!!!

yes heads tested again yesterday dont want to put them back on again till i am sure what is wrong think it time to take block out more fun oh joy let you know what i find thanks for your help j

the only way forward really is to test the block. its frustrating when you build engine up only to find it was all a wast of time!!! the only good thing to all this, as i have found, is that once done you know the engine is good for a long time!!!

it might be worth your while getting the block re linered. theres a firm(i think most will) who re line and bore to the original size allowing you to use your existing oistons if they are good. depends how much you want to spend.

give as many details as you can about the block, i will be interested to know if it was one of those coscat ones???

does it have engine number on? if so pm it as you can get an idea of the age from it.

i get engine number later today it is the thour engine and yes sending me mad starting to think about giving it to some body to finish it for me going to ring guy in engine center see what he has to say about price let you know still thanks for help r/r only done 88ooo from new think thats what doing me in j

its certainly not a good situation to be in, its low milage to have 2 engine knackered!! mine did 170k on what i believe is the original, if it does another 170 on this one i will be more than happy!

i will try and find out the origins of the block from the number. the block i have has no number. i assume this was either a cast block for the purpose of replacement or more likely has been removed it the process of having liners installed.

Thanks Gav!!! Yeah that is very true!!!!! I think there must be some problem somewhere close to heating because the heating got worse its blowing out hot air when set to cold and it messes around constantly, giving hot and cold air when ever it likes, maybe theres a fault on thermostat too....
Gav you got huge amount of knowledge, how did you get all this experience? You'r really good!!!!

Hey gav, tell me how do reckon land rover managed to end up producing a block that can either do 60k and slip a liner and become a basket case, or do 170k with no bother? achieving that kind a quality variance is a bloody mystery to me.

Jock