hot and bothered

before any one asks yes i have done a search my 4,0se is getting warm , its hotest ive seen it just idleing on the drive the temp went right up just touching the red i changed the water pump and stat a while ago and its been fine , i topped the coolant up by removeing the top hose and replaced it before starting today and its all gone wrong ,, we have,nt driven it for around 3 weeks and started it up today to see the temp climb ,, and thats at idle ,, theres no white **** on the oil filler cap and theres no oil in the water but the system seems to be pressurising im gutted any advice please

do they suffer from air locks ??????

I don't think they are as bad for airlocks as the V8 classics but don't rule it out just yet
Where did you get your thermostat from ? - I have had NEW thermostats fail to open in the past (not on a P38 mind) - does your top hose get hot when the engine is showing hot ? - if not, suspect the thermostat
Does your viscous fan work as it should ?
Is your radiator in good condition or maybe clogged (been off roading lately ?)
Does the engine cool down significantly if you turn the heating onto max ?

v8kenny said:

I don't think they are as bad for airlocks as the V8 classics but don't rule it out just yet
Where did you get your thermostat from ? - I have had NEW thermostats fail to open in the past (not on a P38 mind) - does your top hose get hot when the engine is showing hot ? - if not, suspect the thermostat
Does your viscous fan work as it should ?
Is your radiator in good condition or maybe clogged (been off roading lately ?)
Does the engine cool down significantly if you turn the heating onto max ?

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i got the stat and water pump from p38 spares and i have replaced the viscous coupling , and yes when i put the heater on it did cool it down quite a bit ,, could it be a blocked rad ??????

Well as long as the thermostat didn't come in a Britpart box you will be alright !
If I were you I would whip the rad out and have a good look at the state of the cooling fins for rot, and the rad in general for muck
This hot weather's the boy for showing up faults !
Give it a good hosing to clear the fins and back flush the rad with a hose
When refilling the system fill VERY slowly - this will help stop air locks
Once filled, run up to temp and feel the hoses every few mins to feel when (if) the thermostat opens
Crank the heating up to and check you have hot air - this will circulate water around the heater matrix and associated pipes so you may need to top up the water level
If in doubt about the rad - change it !
We all know what happens if you cook the V8's !

well ive been pressure testing at 14psi for around 40 mins now and the needle on the guage has dropped about a needle width , is that relaventor should,nt there be any drop ???? gonna do a chemical sniff test on it later

I would say a tiny pressure drop like that is acceptable - sniff test is the one you really want to pass !
Reason I asked about the heater cooling it down a lot yesterday was because I used to have a 110 with a 3.9 engine from a rangie - it was a bugger for air locking at the heater pipes - it would go to red very quickly but switching on the heater brought the temp right down quickly and this seemed to cure it till next time the system was emptied
It's a pity P38's dont have a filler cap on the rad like the classics, it was much easier to fill from here and with the expansion tank cap off and engine running up to temp you could watch in the rad cap for water starting to circulate indicating that the thermostat had opened, then just turn the heater on, top up rad and put the caps on.
If you pass the sniff test it still could be an air lock
Have you checked the fins on your rad yet ?

ive done a sniff check well i done it twice and it past every time i had it running for about 30 mins earlier to do the sniff check it woz fine temp went up a bit when i put the cap on ,, i kept watching the needle and when i put the heater on the needle seem to waver a little just cant get my head around it ,, i pumped the pressure tester up when it woz off the car and it did drop a little on its own ,,,, just got the rad out full of brown ****ty water ,, im flushing it as i type

If the rads full of brown ****ty water, so is the engine - flush that out too
Did you put anti freeze back in when you changed the water pump ?
V8's need a 50/50 mix of the correct type all year round to stop rust forming

v8kenny said:

If the rads full of brown ****ty water, so is the engine - flush that out too
Did you put anti freeze back in when you changed the water pump ?
V8's need a 50/50 mix of the correct type all year round to stop rust forming

Click to expand...

im gonna flush the engine tomorrow and the give it a try ,, thanks for all of the advice

its all flushed ,, big lumps of brown **** were coming out of the rad ,, but than it woz , spanked it to luton at ,,,,mph and it got up to next digit on from the middle dont know where normal is ???? loads better still running a little hotter than i remember so im wondering if the rad may still be a little blocked ,

throw the fookin rad in the bin and fit a new one mate !!!!, while your at it check the vent pipe from the top of the rad to the header tank for blockage not forgrting the nipples that the hose goes on to , if you have brown crud in the cooling system this is the route i would take , its cheaper than a recon motor by far .
rick.

As Rick says - bin the rad !
If it's that rusty internally then no way can water be flowing efficiently enough to cool it properly
Summer is on the way - you are just asking for a major engine rebuild !
Try Here :-
Range Rover - Cooling System

new rad on order , thanx gents