overheat problems

philm4135 · Nov 22, 2013

hi guys just wondering if i can pick your brains i have a p38 2.5 dse 1998
been having issues with overheat runs ok then for no reason overheats i have changed the radiator for new brandnew one its had water pump and thermostat.
the oil is how it should be (not milky or bubbly) yet it still overheats really need some advice

Datatek · Nov 22, 2013

philm4135 said:
hi guys just wondering if i can pick your brains i have a p38 2.5 dse 1998
been having issues with overheat runs ok then for no reason overheats i have changed the radiator for new brandnew one its had water pump and thermostat.
the oil is how it should be (not milky or bubbly) yet it still overheats really need some advice

Check the viscous fan, if you can stop it with a rolled up newspaper when the engine is hot, it's fecked. Also check the RAD gets hot all over.
Repeated overheats will crack the cylinder head assuming it's not cracked already

philm4135 · Nov 22, 2013

viscous fan is good shreds newspaper and the rad gets hot all over if the head is crack wouldn't you get water in the oil turning it milky or creamy coloured???

really at a loss right now

Datatek · Nov 22, 2013

philm4135 said:
viscous fan is good shreds newspaper and the rad gets hot all over if the head is crack wouldn't you get water in the oil turning it milky or creamy coloured???

really at a loss right now

No, there is often no trace of water in the oil as the cracks occur round the exhaust port and the water is vapourised. You may get over pressured hoses and it may use water. Is the carpet wet in the drivers foot well by any chance. Also worth checking the cap on the expansion tank is fully screwed down, they often go tight long before they seal.

philm4135 · Nov 22, 2013

carpet is bone dry and it did have a new cylinder head in feb2013 prior to me buying it at an astronomical price.
see what i do not understrand is it overheated last week so i put a bits in it as stated been up and down motorway around town etc done a few hundred miles then last night just sat waiting to turn at lights and it overheats a week after the last one

what would be the scenario if i removed the thermostat i got mine from eurocarparts and it was cheap as chips the orig range rover one has a higher degrees c printed on it???

Datatek · Nov 22, 2013

philm4135 said:
carpet is bone dry and it did have a new cylinder head in feb2013 prior to me buying it at an astronomical price.
see what i do not understrand is it overheated last week so i put a bits in it as stated been up and down motorway around town etc done a few hundred miles then last night just sat waiting to turn at lights and it overheats a week after the last one

Was the cylinder head new or second hand?
If the RAD is good, it could still be the stat, there are lots of duff ones around especially the cheap ones. again it could also be the viscous fan playing up, the fan does nothing when you are the motorway. I can give you a mod to use the aircon fans for cooling, but it's not a good idea to try and use them to mask a problem.

philm4135 · Nov 22, 2013

not sure if it was new or not the paper says the giy paid 1700.00 for the job to be done.

and yeah the mod be great its work a shot

gfromleeds · Nov 22, 2013

Before you do the mod you need to be sure its a failed fan thats causing the problems
Get it up to operateing temp then shove a rolled up newspaper in the fan blades
If the fan stops its fecked if you get a load of confetti its something else

matt1987 · Nov 22, 2013

Does the temperature build up slow to overheat or does it jump up there sharply?

philm4135 · Nov 22, 2013

done the rolled up paper and it rips it to shreds as regards the temp rising its slow build up prob can do a few mile at present before it rises but notice that its steaming from the expansion tank screw lid even thou its a tight as it will go can't tight any more.

tomcat59alan · Nov 22, 2013

philm4135 said:
done the rolled up paper and it rips it to shreds as regards the temp rising its slow build up prob can do a few mile at present before it rises but notice that its steaming from the expansion tank screw lid even thou its a tight as it will go can't tight any more.

Get a new cap

gfromleeds · Nov 22, 2013

If the viscous fan works datas fan mod wont help
If the cap leaks It will boil at a lower temp as its not pressurised

Datatek · Nov 23, 2013

gfromleeds said:
If the viscous fan works datas fan mod wont help
If the cap leaks It will boil at a lower temp as its not pressurised

+1, but the fans mod could be used to eliminate the viscous as the source of the problem.
If it's steaming from the cap then the cap is not sealing.

merlinpjl · Nov 24, 2013

When you say it is overheating, is it actually overheating and throwing steam / water out, pipes under great pressure etc... OR is the needle on the dashboard saying that it is overheating?

overheat problems

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