Overheating Issue

Land Rover Discovery 1998 V8 4.0

The car is fine at idle, but when driven the temperature started to rise, so I stopped immediately then steam started billowing from the bonnet. Opened it up and it’s coming from radiator hoses. Tightened the clamps/jubilee clips, and it was fine at idle but then the issue happened again when I tried to test drive.

The coolant holds until the steam billows out and then a puddle appears underneath. No smoke out of the exhaust, no coolant in the oil, no power issue. Could it be the head gasket? Would have it pressure tested but hesitant to risk driving it to the garage as don’t want to cause warping issues if the head gasket hasn’t gone yet..

Not sure if relevant.. but the internal heaters have also stopped working, coincidentally at the same time..

Firstly Welcome .

Not knowing the discovery, But the V8 in a P38 can take some bleeding to get the coolant properly full. With what you have said and the heater not working I would have to say you have a lot of air in the system.

Does the viscous fan work?
Does the rad get hot/warm all over?
Could be a water pump, but get it full first. some park up with the front up some lift the expansion bottle higher.

Coolant pressure test kits can be brought at a reasonable price on the tinternet for DIY use.

What area of the world/uk do you live in?

J

marjon said:

Firstly Welcome .

Not knowing the discovery, But the V8 in a P38 can take some bleeding to get the coolant properly full. With what you have said and the heater not working I would have to say you have a lot of air in the system.

Does the viscous fan work?
Does the rad get hot/warm all over?
Could be a water pump, but get it full first. some park up with the front up some lift the expansion bottle higher.

Coolant pressure test kits can be brought at a reasonable price on the tinternet for DIY use.

What area of the world/uk do you live in?

J

Click to expand...

Thank you for the information!

marjon said:

Firstly Welcome .

Not knowing the discovery, But the V8 in a P38 can take some bleeding to get the coolant properly full. With what you have said and the heater not working I would have to say you have a lot of air in the system.

Does the viscous fan work?
Does the rad get hot/warm all over?
Could be a water pump, but get it full first. some park up with the front up some lift the expansion bottle higher.

Coolant pressure test kits can be brought at a reasonable price on the tinternet for DIY use.

What area of the world/uk do you live in?

J

Click to expand...

thanks for the reply!

The viscous fan works but the pusher fan doesn’t engage at any point. The rad and hoses get very hot but there’s no boiling at the reservoir cap.

I have been advised that it is likely to be the thermostat or as you say an air pocket so the plan is to flush it through with the return valve open and then drain the system and re flush. Do you think this would be worth it?

The return coolant when at idle is clear with no brown substance either which suggests to me (with the other points) that I may be lucky and it not being a head gasket problem.

Thanks again for your help!

RDH1994 said:

The viscous fan works but the pusher fan doesn’t engage at any point. The rad and hoses get very hot but there’s no boiling at the reservoir cap.

Click to expand...

Are you sure the viscous is working when hot, will it chew up a newspaper?
The "pusher" fans are for aircon, they will come on when at a high temp from engine sensor (if its in contact with coolant I guess)

RDH1994 said:

The return coolant when at idle is clear with no brown substance either which suggests to me (with the other points) that I may be lucky and it not being a head gasket problem.

Click to expand...

What return coolant can you see?

RDH1994 said:

I have been advised that it is likely to be the thermostat or as you say an air pocket so the plan is to flush it through with the return valve open and then drain the system and re flush. Do you think this would be worth it?

Click to expand...

It is possibly a thermostat, but the heater would be hot , a flush will not hurt , but as I said they seem to be difficult to fill/bleed.


What work have you recently done? or was it fine then this happened?

J

marjon said:

Are you sure the viscous is working when hot, will it chew up a newspaper?
The "pusher" fans are for aircon, they will come on when at a high temp from engine sensor (if its in contact with coolant I guess)

What return coolant can you see?



It is possibly a thermostat, but the heater would be hot , a flush will not hurt , but as I said they seem to be difficult to fill/bleed.


What work have you recently done? or was it fine then this happened?

J

Click to expand...

In the reservoir, when the cap is open the coolant from the return pipe. Albeit only at idle as when it got hot the coolant all dumped from the reservoir via the steam and also a puddle formed beneath the car located near the water pump area. At this point the car has been switched off to prevent damage.

I did notice hot air coming through the heaters in the cabin but this I assumed to be form the heat of the engine (I may be wrong as I’m learning all of this as I go) but point noted regarding the thermostat. The viscous fan was spinning at idle but to be honest I didn’t check when it was hot as I was distracted by the steam, so it is possible that it wasn’t spinning. At idle it does spin very quick.

No work carried out - the vehicle has been running perfectly up until now to the point that I was surprised how there aren’t any rattles or knocks when running even with the issue.

Pictures often say a thousand words .

RDH1994 said:

I did notice hot air coming through the heaters in the cabin but this I assumed to be form the heat of the engine

Click to expand...

So in your first post there is no heat, now there is?

Until you fill with no air, and seal any leaks its a bit of a guessing game.


J

marjon said:

Pictures often say a thousand words .



So in your first post there is no heat, now there is?

Until you fill with no air, and seal any leaks its a bit of a guessing game.


J

Click to expand...

Apologies, badly worded - the heaters don’t function independently to heat coming from them if the vents are opened.

I will get some photos tomorrow. Thanks for all this information btw - it’s invaluable