The V8 Owners Forum -

Hi,I'm new on here,I hope you could be of some help.
I have a V8 rover 3.5 engined trike.Up until friday ,it was running fine,keeping cool etc...
Then it decided to over heat...Fans working fine,but rad was cold.When i opened up the pressure cap,it spewed out all over the roadside..
I let it cool a bit,the added hot water from kettle to top it back up.started it again,it still got hot,and bottom hose was solid...
When i released the cap again,it boiled over again making gurgling noises and rad got hot.
After that i took out the thermostat to see if it was closed.and put it all back again without thermostat,refilled it and still it overheated.Rad always staying cold until I remove cap..
.Can anyone help me with a diagnosis,or solution please.
Kev

Could be a blown head gasket leading to the system pressurising.....or simply an airlock in the cooling system.

Unfortunately if it was running alright and then overheated I'd put money on the former rather than the latter....

Oh and welcome to the madhouse

Hi.
If you have removed the thermostat and the rad is staying cold then either the rad is blocked or the water pump impeller is not working or an airlock somewhere in the system.
Regards Denis

Does it have a "cabin heater" arrangement installed? (Perhaps as a screen demister?)

If so you may be getting most of the flow through this circuit and not enough through the rad.

Try closing the circuit to the heater matrix

Ian

Many thanks.I will go get it compression tested,and if so replace head gasket.Hope it isn't any block or head cracked.....

haystax wrote:Hi,I'm new on here,I hope you could be of some help.
I have a V8 rover 3.5 engined trike.Up until friday ,it was running fine,keeping cool etc...
Then it decided to over heat...Fans working fine,but rad was cold.When i opened up the pressure cap,it spewed out all over the roadside..
I let it cool a bit,the added hot water from kettle to top it back up.started it again,it still got hot,and bottom hose was solid...
When i released the cap again,it boiled over again making gurgling noises and rad got hot.
After that i took out the thermostat to see if it was closed.and put it all back again without thermostat,refilled it and still it overheated.Rad always staying cold until I remove cap..
.Can anyone help me with a diagnosis,or solution please.
Kev

If you've removed the thermostat and there's still no water circulation to the rad (it should get warm with the engine without one) I'd guess the water pump impeller has disintegrated, or you have a severe blockage somewhere.

Hello Kev, Bit difficult to visualise your trike cooling system layout but assuming something near conventional, as you had the stat removed and the rad did not heat up at the same rate as the engine then, as already stated, there is no flow thro' the rad due to either a blockage or water pump failure. If the pump is toast, one might also see water leaks from the pump bearing.

By the by, even if it is not pumping, the natural convection of hot fluid would percolate upwards and be felt in the top hose and top of radiator. So, with no heat felt thereabouts, a blocked radiator is your most likely cause.

You can deal with that issue first, quite easily, by forward and reverse flushing the two main elements of the cooling system separately, radiator then engine block (assuming no cabin heater matrix) using a domestic garden hose on full water pressure.

As you perform this you would notice if there was loads of crud ejected and assuming you are able to clear the passages and galleries, do the forward and reverse two or three times to get all the crud out, then refill the whole system with plain water and test it for integrity with thermostat in.

If the system behaves normally, you can now drain it and refill with your chosen coolant mixture. That way, it saves a lot of wasted coolant if things are not OK.

If, sadly, the system is not blocked then the mechanical causes, already mentioned on the thread, are next in line.