another p38 overheating

ok so iv never had any serious problems that iv not sorted,until now.

it started 2 weeks ago,it is a p38 4.0 hse 2000 year with an lpg conversion,it overheated so thinking it was just short of coolant hastilly topped up,same the next night,so i ordered a thermostat which made no difference.

When it overheats it normaly takes about 6 mins when stood and about 10 when driving,although im aware of slipped liners im telling my self its not that,if i let it overheat when stood the top hose to the stat is soft yet when the stat opens it gose significantly harder,then if i switchoff and take the cowl off above the viscous van and feel the rad it is cold or cool all over which i would say is not normal as hot water should be flowing through it,

Also as the top hose goes hard when the stat opens that rules out the water pump im pretty much sure about,would the cold rad point to it been blocked and how would i go about clearing it and how can i make sure i have no airlocks in there

sorry bout my long post.

thanks for any input any one gives.

chris.

Best to replace the Rad - they do get silted up quite badly and you'll never shift all of it!!

To reduce airlocks - bleed the system as per RAVE and I have always found raising the front of the car to the tank is the highest point in the system helps too.....

The top hose should be hard/firm but not solid...if you can't compress it with reasonable ease, it could be a dodgy head gasket...

Check for Water in the Oil and Oil in the Water etc.....

Check the operation of the Viscous Fan Unit too using a rolled up newspaper.

If it overheats just sitting and idling, I would suspect HGF, pump or blocked Rad....

cheers for the reply im going to take off the rad and price one up.

thanks again.

chris

Island 4x4 are the best I have found on prices (no affiliation just a satisfied customer)

Radiator P38 4.0/4.6 99 on (XA410482 on)PCC106850 Island 4x4 - Specialists in Land Rover and Range Rover Parts and accessories for all models. UK and worldwide mail order.

Hi chrisall69,

sorry to hear about your overheating problem, i know what its like. I have a P38, 4.0l Yr2000 petrol and not wishing to takeover your thread i thought i would post a reply with my own situation that someone may wish to recommend a next step as it may also help you.

I originally changed o rings on matrix due to wet footwell, left an air lock that overheated engine and took out gasket.Replaced gasket,water pump and thermostat at same time as a precaution.Also removed and thoroughly flushed out radiator.Refitted - all ok. Travelled 265 miles over next few days all ok - then bugger me it overheated. allowed to cool,refilled and then every 10mins of driving or driving under load ( ie up hill etc) she overheated. Replaced viscous fan coupling - all ok - took up up the steepest hils in my area and floored it - all ok. Did this for next few days whilst keeping eye on coolant level - minor tops up needed as air exited the system. Really happy - thought everything was ok, then yesterday, took her less than 5 mins drive - calm drive - she then over heated and spat coolant everywhere as she normally did.

Not sure what to do next - no exhaust smell in coolant so don't suspect faulty gasket, its not mis reading temperature as its definitely overheating - its intermittent so why would a radiator be the cause, i now am thinking that i may have faulty hoses ie - de-laminatied internally and causing restriction.

Any suggestions or recommendations from anyone ?

n18rks said:

Hi chrisall69,

sorry to hear about your overheating problem, i know what its like. I have a P38, 4.0l Yr2000 petrol and not wishing to takeover your thread i thought i would post a reply with my own situation that someone may wish to recommend a next step as it may also help you.

I originally changed o rings on matrix due to wet footwell, left an air lock that overheated engine and took out gasket.Replaced gasket,water pump and thermostat at same time as a precaution.Also removed and thoroughly flushed out radiator.Refitted - all ok. Travelled 265 miles over next few days all ok - then bugger me it overheated. allowed to cool,refilled and then every 10mins of driving or driving under load ( ie up hill etc) she overheated. Replaced viscous fan coupling - all ok - took up up the steepest hils in my area and floored it - all ok. Did this for next few days whilst keeping eye on coolant level - minor tops up needed as air exited the system. Really happy - thought everything was ok, then yesterday, took her less than 5 mins drive - calm drive - she then over heated and spat coolant everywhere as she normally did.

Not sure what to do next - no exhaust smell in coolant so don't suspect faulty gasket, its not mis reading temperature as its definitely overheating - its intermittent so why would a radiator be the cause, i now am thinking that i may have faulty hoses ie - de-laminatied internally and causing restriction.

Any suggestions or recommendations from anyone ?

Click to expand...

Radiator.... it's about the only thing thats left...

Flushing out you could have dislodged the baffles(depedning on how hard you did it but it wouldnt take much.) Therefore you're coolant might be going straight in and out of the rad without transferring any heat or getting the benefit of the viscous fan. When its at operating temp is the top hot on the rad and the bottom cold? If its an old rad then there's nothing lost in replacing it.


Replace the rad then you pretty much have a new cooling system.

it is impossible to successfully flush a parallel flow radiator.you can have half off the cores blocked and you will still get an apparantly decent flow with a hosepipe.replace it.

i think you're all right,

flushing could has dislodged the muck/baffles, flushing probably managed to only flush half, it is an old radiator - the top get very hot hot and cannot keep hand on it - the bottom is much much cooler.

n18rks said:

i think you're all right,

flushing could has dislodged the muck/baffles, flushing probably managed to only flush half, it is an old radiator - the top get very hot hot and cannot keep hand on it - the bottom is much much cooler.

Click to expand...

there en lies your answer

well in my case iv sorted it as id not kept an eye on my coolant level which was very low as soon as i topped up after it spat it all out i created an air lock and everytime i drained it and retoppedup i still created an airlock i think because i top it up into the top hose down into the rad,but the final time i drained and topped up i topped up down the hose down to the thermostat,and now i have no problems it runs fine no overheats been out thrashed in sport mode up hill down hill left on tick for ages,im happy now.

although i do have a slight weep from my o rings but can live with it till i pluck up courage to have a go.

As long as your heater matrix o-ring don't weep enough water to kill the BECM you'll be fine...

Where is the becm exactly I m thinking its under the passenger seat

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Under the drivers seat