The V8 Owners Forum -

mgbv8 wrote:Maybe you could remove the thermostat and do the test run again?

Yes I could but having just painted the whole engine I really do not want to unless I have to. It definitely opens at 74 although I suppose it may not fully open.

I'll ponder this and / or make up cowling to cool more.

richardpope50 wrote:

mgbv8 wrote:Maybe you could remove the thermostat and do the test run again?

Yes I could but having just painted the whole engine I really do not want to unless I have to. It definitely opens at 74 although I suppose it may not fully open.

I'll ponder this and / or make up cowling to cool more.

It's a puzzler. Your body and rad ain't that different from other versions of this car, so I'd guess airflow through it on the move is going to adequate.
Which really just leaves the rad itself not cooling things - for whatever reason.

It might be worth getting an Infrared thermometer (not expensive) and beaming it at the rad through the cowl opening, Left, right and centre and compare the readings. Without the fan on it should show uneven distribution and/or maybe confirm that the internal pipe at the bottom hose position is doing a good job or not.

If you have put in some rad cleaner, then things may gradually improve if the rad was fured up. Antifreeze/air/aluminium usual forms a white power so if the rad was semi dry for a time it may have suffered.

Using my multi-meter probe the inlet was 90ish, outlet 75ish. Bottom of uncooled rad was about 90ish and cooled area about 15ish. All at idle in driveway.

Unfortunately the rad cleaner needs to be in the car whilst it is used for one to two days. So whilst I may take out thermostat, I'm making a cowl up so hopefully I can at least get the car running around even if the fan is on all the time. That will enable me to get the other things sorted such as cleaner and mapping.

I'll update when I've done this. Thanks all.

DEVONMAN wrote:It would be benificial to source a different thermostat housing, one which exits straight out the front without a large kick up....

Anyone know of where to get one (or similar one) and what engines they come off?

If you know an aluminium welder its quite easy to just cut it off and reposition at at your required angle.

Tom

richardpope50 wrote:

DEVONMAN wrote:It would be benificial to source a different thermostat housing, one which exits straight out the front without a large kick up....

Anyone know of where to get one (or similar one) and what engines they come off?

I'd say there's more than enough head from a decent pump that such a small amount of extra height won't matter. Assuming no air in the system.

richardpope50 wrote:

DEVONMAN wrote:It would be benificial to source a different thermostat housing, one which exits straight out the front without a large kick up....

Anyone know of where to get one (or similar one) and what engines they come off?

http://www.v8forum.co.uk/forum/viewtopi ... e23ad8d55b

Perfect and many thanks. I did try to look around but obviously missed this reference.

So it’s not the fan cowling nor the thermostat as with that removed temperature still climbs. It therefore has to be not enough flow but with it being very unlikely the water pump and especially as the waterways around thermostat housing are very clean, it must be the swirl pot.

Have ordered a thermostat housing with horizontal outlet and will make a mod to the rad to make it a direct horizontal connection from block to rad. We shall see

Personally, I'd whip out the pump to check it.

Based on what has been stated so far, I understand that coolant is flowing around the heater circuit so the pump must be shifting coolant. A suspect pump would struggle to flow coolant through a small bore system like the heater.

The amount of flow could be checked by feeding a temporary hose from the heater feed into a bucket and giving the engine a rev.

My gut feeling is that there is a problem with flow distribution through the rad. This could be easily checked with an infrared thermometer.

Before the temperature is reached where the fan switches on, the core of the rad could be scanned to see if flow is even throughout. Naturally there will a drop in temp from top to bottom but left to right readings should be fairly equal.

Just a heads up have you checked the waterpump impeller is tight on its drive shaft and not slipping/spinning as revs rise? failing that I suspect your rad is not getting rid of the heat i.e clogged

SimpleSimon wrote:Just a heads up have you checked the waterpump impeller is tight on its drive shaft and not slipping/spinning as revs rise? failing that I suspect your rad is not getting rid of the heat i.e clogged

It's my guess too it's something pretty basic.

Just install some clear tube from the T/Sat to the rad.