overheating????

my 3.9 v8 disco 1998 keeps overheating, no loss of power, have bypassed the heater matrix as i thought that was the problem (water not getting through) but have reconnected it now that is eliminated. it only overheats when putting the car under load e.g slight inclines and towing.

The car does run on lpg. someone did say that it will run hotter on gas but i ran it on petrol this evening and still overheated.

Please,please help me

It may be that the timing is retarded, thats why it may run hotter with youre foot down as there is no vac advance and the ign retards. Well doesnt retard but goes back to static setting which may be retarded.
just a thing to check.

not very mechanically minded, how do i check it or resolve it?

Thanks, Craig

it will over heat on gas and petrol

doncrag80 said:

it will over heat on gas and petrol

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The reason it runs hotter on gas is because you need more ignition advance to burn the gas and again the timing may be /could be/maybe not retarded.
You can always try to advance it and see.
Mark the dizzy and its clamp with tipex so you can go back to where you started.
Loosen the 15mm locking nut and twist the dizzy a little anticlockwise.
If it pinks on petrol then put it back
If not leave it and see haw you go.
Alternatively, check timing with a light or get it checked.

There again I might be wrong and it could be something else like a silted up radiator or summat else.

thanks will look at that tomorrow and keep ya posted for more info thanks.

Craig

if you can not get heater to work then classic head gasket failure.

otherwise check rad-flow test
viscous fan coupling

how will i check rad flow, and viscous fan seems to have a mind of its own and feels really tight, also puts alot of strain on the engine

MAny thanks

Craig

doncrag80 said:

how will i check rad flow, and viscous fan seems to have a mind of its own and feels really tight, also puts alot of strain on the engine

MAny thanks

Craig

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If you look for a local radiator refurbishes they should do a flow test for a fiver/drink. Is it auto or manual because I manual one here that we could do a deal on,because to have it refurbished is around £170 and a new one is £280+. I know this because mine was half blocked on my auto but only overheated under load i.e. up long hills or towing. You can check by getting your car hot and checking if the radiator is hot all over.
P.m. me your number if you require a few mor tips just being though the same thing or you want the rad Im in Kidsgrove so not to far from Chester

Thanks alot Smurphy,

Will defo check out the rad, i spoke to someone lastnight who said that it could be my viscous fan as he has been going through the same. do you mean auto or manual transmission?

Bloody thing has started heating up just driving round now. its drivin me mad any ideas how to check the viscous? or any other suggestions

has it just started to overheat? wot u say from viscous that sounds like its ok, is water circulating? if u checked the obvious and all seems ok get a sniff test done

I had an overheating disco 1, after all the assumptions about head gaskets, and other major problems proved to be a knackered radiator. Once removed it was obvious it was corroded and blocked. Don't dis regard the basics. I also replaced the viscous coupling as the disco had done 150k, £40 from Island 4x4.

Good Luck.

Bite the bullet. Get the radiator re-cored, replace the viscous coupling, put on a new water pump and maybe change the heater matrix. That should sort it. If after all that it still misbehaves then you could be looking at HGF.

I do think that radiator is blocked or maybe the water pump has gone. It sounds like poor circulation on the coolant.

radiators on V8 do block up quite quickly , due to having ali block and heads ,
If the fins on the cooling tubes are pretty good and no leaks on tubes , its worth having it serviced , eg they remove one tank and rod the idividual cooling tubes out whilst flowing water up thru rad then put back together , it becomes very apparrent which tubes are blocked when you flow the water with the tank off . Lot cheaper than a new rad . It is a common practice in Australia , as most vehicles soon show cooling probs due extreme heat.
Contrary to most beliefs most lpg vehicles actually run cooler due to heat absorbtion by vaporizer (liquid gas to vapour) . If it doesnot then quite often other problems eg timing ,weak mix etc . I ran a falcon 4 ltr estate (ali head) in OZ on lpg (as are all the taxis) no probs even with aircon on . 450,000km same engine .

Mine did overheating when towing and on hills....twas the stat.


Nick.