Overheating Issue? & Cutting Out?

During the recent snow the other week i was sat in traffic for 4 hrs (journey normally takes 25 mins!!!) and my 1997 4.6 HSE on LPG started to overheat and to keep it from getting too high i had all the blowers on warm and get the revs at about 1500 (automatic) and this kept in th middle of the guage as it should. I was at mcdonalds last night and sat in the drive through waiting for my fries (supposed to be fast food...but that is another story!) and the temp started raising again very quickly and i was only stood still for 2-3 mins. When i am driving normally it is fine.

Then another issue happened last week - on a cold day i was driving to the PO round the corner and when i approached a corner to turn left the whole thing cut out and would not start - i had to really turn the key to get a bite. This is the 2nd time this happened in cold conditions - i have topped up the oil and recently had a new water pump, bottom pulley, alternator, PAS pump, air con pump and an auto tensioner (after replacing all of that it turned out it was none of the original parts!!! doh! so i have replaced all those bits for no reason! again another story).

Has anyone got any idea on what it could be?

thanks again people for any comments or help.

Like I said to another member have you checked your viscous fan. I keep mentioning this as it cost me a lot of money when my head cracked as a result.

check the radiator isn't bunged up with mud, or it could be blocked internally? My series one did the exact same thing, put a new rad on and it was fine, back flushed the old one and you wouldn't believe what came out of it!! Worth checking, I think the P38 rads have particularly fine innards and are prone to blocking up.

classic Viscous fan failing!

Get it change pronto as the v8's dont like getting too hot!

viscous fan coupling is fairly cheap at island 4x4. good service from them too.

the cutting out on gas can be quite confusing, it does sometimes take mine a bit to restart if it stalls (usually if i switch over too early and the coolant isnt warm enough)

i have found swithing on then off a couple of times helps.

check your coolant levels.

also check the earths. get someone to watch guage and wiggle earth straps. mine o/heated on the guage (although engine temp wasnt rising) when i wiggled the earths the guage went to normal and o/heat etc. i added another earth strap and all is fine.

once again all the forum members have come up trumps with their detailed answer and suggestions and in double quick time! thanks!

will try and look this weekend at the fan - i have used island 4x4 before very good and efficenet - so i second that. Although the fan at first was tough one it is now easier as i have removed so many time time replace all my parts (see my previous posts opn this forum).
Not being a mechanic so this might sound daft but can i flush the radiator out while insitu? how do i do it?

thanks again

do i need the fan blades too? or just the viscous coupling (http://www.island-4x4.co.uk/viscous-coupling-4046-err4996-p-106.html)?

Just the coupling unless the fan is damaged

i would take yours off, strip it down, inspect the fan and if its ok then just buy the coupling!

how do i flush the radiator out as suggested in earlier post? thanks again

Take off top and bottom hoses, put hose in the top and wait to see all the crap come out of the bottom!

sounds so simple! legend try this weekend

Might be worth testing the viscous fan coupling to see if is faulty before buying a new one. This extract from my article on Viscous couplings

# The first of two common fail conditions is when the fan does not speed up due to insufficient bond between the wheel and the housing resulting in overheating especially in slow traffic, urban driving, towing or running air-con. Lightly loaded at normal driving speed there is sufficient air passing through the radiator to cool the engine. There are three reasons for such failure. Faulty bimetal coil, oil control shaft/valve siezed, or loss of oil. A simple check is to press a rolled newspaper against the fan blades when a hot engine is idling. If the fan can be slowed or stopped it is probably faulty.

# A second fail condition when the fan becomes permanently locked is potentially very serious. Because the grooves are thin they can break due to age, internal corrosion, vibration, etc, with debris jamming between wheel and housing resulting in an over speed fan. The air roars loudly and continously, more so at high engine speeds and such a condition may result in a thrown fan blade, resulting in severe imbalance and further breakage. If this happens broken parts are projected forwards into the radiator. Never drive a car with a locked-up viscous fan.

# There is a third (possible) fail condition whereby the coupling is quite stiff when cold and upon start-up the fan roars at high speed for a short while, say from thirty seconds to two minutes, before it slows to a normal freewheeling speed. This is due to the internal fluid leeching into the grooves, usually over-night, through poor internal seals and locking up the fan immediately. However the fluid soon reverts to its normal routine and the clutch lets go of the fan until such time as normal heating of the mechanism engages the fan again when hot, as previously described. Perhaps not a true fail condition, but certainly a pre-cursor to total failure when the fan will eventually fail to engage, sometime soon.

More here Rover SD1 Efi Viscous Fan Coupling

Be v.careful with replacing the fan.
The pre serpentine belt fans on the 3.5 and diesel spun in the opposite direction to the 3.9. I assume the 4.0/4.6 are the same as the 3.9. If someone replaced the fan/VC before they may have used one from a scrap yard. The fan blades are pitched in the opposite direction and will blow air out through the rad instead of sucking in. This causes o/heating at slow speeds but not at high or stopped.

Also in your case the aircon temp switch must be dud, otherwise the aircon ans should have cut in to prevent overheating.

guys i am back again! this time so annoyed! as my beloved range rover decided to overheat again so i cant make my 705 tee off time saturday morning!!!!

i am going to try again all the suggestions but today was different than the last time. the engine out of know where decided to overheat so i whacked the heater and blower on full (my air con has never worked since i got it a year ago as it needed gassing i was told - not sure if you need to know that!!) to try and keep the heat down but it did not work but then it did and then it did not and this carried out until i got home *not far away from home when it started. but at the same time a heard some clunking noises like something falling in the engine bay snf the blowers were blowing really really hot and then they would go to luke warm or even cool and then back up to hot very hot again. Each time it went very very hot the temp began to drop but then when it became warm it rose again. When i got in a checked for leaks and there was a water leak dripping from the oil sump but it was not oil. the oil level was a bit low so it is above min at mo but tomorrow will top up. the water level was topped but seemed ok. Also lots of gurgling and even hissing from the expansion bottle.

I have had to cancel my bros birthday golf game tomorrow so please see what you can do advice wise to cheer up a gutted RR fan.

thanks again

if you have done the fan and the rad is working ok that either sounds like a failing water pump which would be the cheapest or a dreaded headgasket or porous block.

Is yours a 3.9? a 3.9 or a 4.0 or 4.2 or a 4.6 are all prone to failure of these items when run on gas the 3.5 is a bit better at surviving gas but they have also been known to fail.

I wouldnt have thought it would be the thermostat breaking up as the heat was intermittant form you blower.

If you never changed that fan coupling , in this weather it could have gradually cooked the engine in traffic to hasten the headgasket/block failure???

Hi Guys,
I'm having the same problem with my 98 range rover DSE. I just had it overhauled like few months ago, the engine is perfectly fine and all, but there is a fault on my range something is wrong with the cooling system or my engine. I'm having trouble starting the car after i using it for like 30 mins or so, the temp gauge is on the normal middle part. It does not want to start, i have to cool it down like water the radiator for until the temp cools down. And when i'm using the rover on traffic when the AC is on its overheating as well and i have to shut down the AC. for its to cool down. Let me know what to do guys need help badly! Thanks

thanks fett!

mine is a 4.6 and i have 90,350 on the clock and i replaced the water pump (from island 4x4) 5 months ago - just about to take bottom & top hose off and flush with hose to clean and also inspect fins. i hope it is not the gasket but the following has been done on the car before i got it:

1. engine reomved, rear cam shaft core replaced & rear camshaft oil seal also.Engine oil pump replaced.
2. cylinder heads removed (o/s gasket blown???? it says on report?), heads taken for machining, gring valves, fit new valve stem oil seals, refit valves, refit heads to engine with new gaskets and seals. refit all ancilliaries.
3. rad replaced june 2006.

any more thoughts guys?

sounds like it may be the old porous block- I hope its not!

Depends how well that work was done, did you do the fan clutch yet?

fett said:

sounds like it may be the old porous block- I hope its not!

Click to expand...

I agree. There is no exact science to this as (obviously) the best way to check the pourous block would be to pressure test the block and that isn't practical as the engine needs to be out of the vehicle.

An island4x4 part is likely to be of questionable quality, although it should last more than the months you've had it in. The radiators are the biggest problem, the early original ones were redesigned as they were blocking up. The lifetime of a p38 radiator is 4 years. It may be worth puting a new one on anyway. Theromostats tend to be OK but can cause problems. If K-seal has been used in it, some of the return pipes can block and ideally need replacement as coolant can't circulate.

From the description, you are getting airlocks in the system somehow. I'd bet it is a pourous block. You may even find the stalling issue related to the running hot. Possibly.

My p38 is now on its 4th engine at 176k. Thankfully it's a Tuner Engineering unit with the top hat liners (as it should have been at Land Rover back in late 1994) so I hope to be able to get more than 60k out of it this time.