3.9 v8 overheating!!!

Hi guys i am new to this whole forum stuff so please bear with me :/

I have recently brought a 3.9 v8 disco 1 bobtail pickup, all was okay untill i took it to a pay and play and towards the end of the day it started overheating very badly!!! It was pis**ng the contents of the coolant system all over the place through the expnation bottle cap.

I finally managed to limp it home, were i cleaned the radiator and changed stat and gasket and re filled the system. i thought this had fixed it untill i took it out again on some local lanes and about 4 hours in.... BANG overheated again!!

it really confusing me as it can be okay for so long and then all of a sudden it overheats again

any suggestions as to what this could be would be much appreciated

possibly cracked block ,it is common , does rad get hot all over

That doesnt sound cheap!!! it seems to get hot all over but i need to get a lazer on it i think!!

Could it be an airlock?

discodom1 said:

That doesnt sound cheap!!! it seems to get hot all over but i need to get a lazer on it i think!!

Could it be an airlock?

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jamesmartin said:

possibly cracked block ,it is common , does rad get hot all over

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how would i find out if it was a cracked block? and what is required it fix it??

discodom1 said:

That doesnt sound cheap!!! it seems to get hot all over but i need to get a lazer on it i think!!

Could it be an airlock?

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possible , but check everything ,systems full ie all pipes and hoses ,heater etc get hot , theres no leaks ,expansion caps ok , you could check spark plugs

discodom1 said:

how would i find out if it was a cracked block? and what is required it fix it??

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often to prove the point you need to strip off heads and front cover ,seal water ways ,fill with hot water and pressurise a bank at a time ,similar symptoms to head gasket

jamesmartin said:

often to prove the point you need to strip off heads and front cover ,seal water ways ,fill with hot water and pressurise a bank at a time ,similar symptoms to head gasket

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This sounds like a pain in the bum, especially as i have no driveway space, tools or enough knowledge to do it!!!! What do you think i would be looking at price wise to take it to a 4x4 specialist to look at it??

Steel Seal - Head Gasket Engine Block Repair & Fix Pour-In Liquid | eBay


Cheapest way if its just an off roader , id check your rad fans and thermostat first and foremost

Festerer said:

Steel Seal - Head Gasket Engine Block Repair & Fix Pour-In Liquid | eBay


Cheapest way if its just an off roader , id check your rad fans and thermostat first and foremost

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Thanks for that mate, have you (or anyone else) used this before? is it good?

discodom1 said:

Thanks for that mate, have you (or anyone else) used this before? is it good?

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Ok the reason i posed this was i had a vauxhall vectra 20dti , it froze a few years back , the thermostat housing was 3 inches away from the head on a pedastal of ice (stripped theds in head , the rad was split as was the heater matrix , after it thored out i tred locked the stat housing back on and poured a can of the stuff in , it was worth a shot i thought before scrapping the car .

It worked ! i ran it for two years until the diesel pump failed (sold it to a mate)
turned out to be glowplug relay he fixed it and ran it for another year before flogging it on !
It says your gonna need 3 bottles and if it doesnt work they will refund (up to 3 bottles ) and it doesnt clog your cooling system as its chemical based not fibre based im no expert but id try it before spending more than the whole engine is worth on an old landy ( no offence intended)

I would check everything else before assuming cracked block. It is a seasoned engine and not that likely. Like James says check rad gets hot all over, change water pump, easy and only 20 odd from paddocks. Bleed system. I had exactly those symptoms on a rrc years ago. It was rad

Why change the water pump? impeller fins broken, shaft seal worn, shaft bearing shot all things that are easily identified, but theres no mention of any of these issues.

Save your £20 and at that price you would be changing it again, it won't be an OEM part.

cooltide said:

I would check everything else before assuming cracked block. It is a seasoned engine and not that likely. Like James says check rad gets hot all over, change water pump, easy and only 20 odd from paddocks. Bleed system. I had exactly those symptoms on a rrc years ago. It was rad

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your seasoned engines only need a poor cooling system to cause cracking ,some blocks may be less prone but they all are

If it hasnt been changed for ages, doubt it will be running at peak efficiency. The problem only occurs at off road speeds when the rad isn't drawing much air through. It could be a combination of factors. It could be a head gasket. Since it was limped home and goes laning, I assumed it is a road vehicle, and personally I wouldnt want to pour kseal or equivalent in.
I wouldn't care if it did need doing again, it's an easy access cheap job. I've got about 10k on mine and it cured what I feared was hg. Impellers were goosed.

Does your top hose and stat hose look new?
I would expect one of these to spring a leak when it overheated.
If one is new, the previous owner has had same trouble