Burst radaitor/ overheating - Please help!!

Hi all,

Wonder if someone can advise me.
I own a 2000 P38 2.5DHSE automatic. Last week i was driving and after about an hour i notced the temp light had come on and a loss of power. I pulled over and waited a while then opened the water tank and as the water was still hot, some of it bubbled out. I topped it up, and drove the car home, as i got home i obviously pushed the car too much, and the radiator split from the top.

OK- had a new radiator fitted, and was told the car was still overheating and the viscous fan was the cause, had a new viscous fan fitted today.
The garage called to say as they were running the engine to ensure that the fan was working the Radiator split again. They said there was obviously a build up of pressure. They recommended that they should remove the head etc to check that.
I spoke with an independent LR dealer who told me that the garage should have also replaced the Pressure Valve/Cap as that may not be working and could have been the cause.
I have already had 2 new radiators fitted and a viscous fan. Before i spend more money i just wanted to ask is there anything else that could be the cause.
I am in west London and cant seem to find any independent LR/RR specialists near me to work on the car for me.

these engines can get cracks in the cylinder head,this can then cause the problem you describe.

I'm afraid Gemsdad is right. You've got classic symptoms of a blown head gasket/cracked head.

One of the other members here split a rad lately and it was the water pump that had failed but a competent garage should be able to diagnose that pretty quickly. They should do a few tests such as sniff tests etc before taking off the head.

One of the often ignored golden rules with DSE's is if they start to overheat replace everything. Rad, water pump, thermostat, pressure cap. The pump impeller is plastic and goes brittle with age or overheating so that should be done if anything else goes. Also I'd be very slow to put in a spurious rad.

In your case you have to ask yourself why/how is it building pressure.

BTW I'd be pretty pee'd off with a garage that didn't spot a build up of pressure on a car that had just split the rad as they were running the engine to ensure that the fan was working What the hell were they watching for? That's verging on negligence.
And a broken Viscous fan will only cause over heating at low speeds in hot weather, not while you're driving along the road in May, the DSE also has the aircon fans as well so I'd be slow to diagnose that as the real root of your problem (i've run a V8 RRC with no VC fan for the last 2 years without a single problem)

if its still got the original water pump on they have got a plastic impellor which goes britall and brakes when mine went it took the top hose out (split it and took a chunk out of it) i put new hose on still doing the same really quickly then sussed water wasnt being pumped round the system

Water pump if you are lucky, otherwise head gasket or cracked head. It is just possible that the replacment rad was a cheapo with the centre baffle missing, but if it oveheated whilst stationary thats unlikely.