Rover V8, are they too light to use as a boat anchor?

What radiator are you using?

It's a new Series 3 brass rad that's very clean and done less than 3 miles! It did have a new Series 3 modern style aluminium rad, that sprung a leak, replaced with the brass one.

Both have the same fan set up, which works very well, takes the temp down by 10C in less than a minute. However the fans didn't activate, don't remember them activating on previous boils either, but that may be because I didn't let the engine run for long enough.

Fan switch is in top hose, the silicone top hose was touchable, the rad just over touching temp. Also tried engine with and without a thermostat. It's got a new Gates on fitted at the moment.

So, bypass the fan switch ad have the fans running all the time to see it that makes a difference?

And a 200/300 TDI is looking better, the MPG gain will make the Landy more usable!

Going to ask an obvious question, but you've checked the water pump is circulating water?

For me, there are a number of things to ask here:

-Is there evidence of the water circulating around (i.e water pump)

-Is the correct thermostat being used? I doubt it would inhibit things too much, but if you need a bypass foot, to stop non-rad fed coolant from circulating around the engine when warm, this is going to cause issues.

-What gauge setup are you using? Do you know if the sensors are calibrated to work with the gauge? Stag ones now overread and have a different tempearature curve. I quite like the VDO gauges with a VDO sensor for this reason or a Smiths capillary gauge

-Where is your temp sensor located on the engine?

-Have you do a HG test with the fluid in it? (i.e a HG tester)

-You say the rad is new and only 3 miles old? Was it brand new or simply new to you? What core design does it have? Most rads of this age can have different cores, depending on who sold it, which can affect things. I doubt it would affect it here, but you never know.

-Where does the rad fill from? If the rad level is below the engine heads, it will be a pain to bleed potentially. A header tank put into the top hose, to try and get around airlocks?

Rad is brand brand new, it's the old fashioned brass type, just a replacement Series 3 one.

Filler is the highest point.

It's not just the gauge reading, it's the steam from the rad, that gives it away! The gauge probe is position is stock, in the front of the inlet manifold next to the thermostat. The gauge is a few degrees out (reads hot), but that might be down to the elevation here in the Brecon Beacons! Just moved here and, of course when I needed my thermometer probe, couldn't find it!

Haven't done a HG test, but the last few times I did it, was very inconclusive. However, you could see the bubbles in the coolant from (I think) a cracked head, even when the coolant was cold. No bubbles this time.

I'm wondering if the wrong water pump has been fitted, turns the opposite way. The pump looked nearly new when I removed it to change the camshaft.

The only other real difference is the Serps drive belt, it's missing a few pulleys (air con power steering), perhaps my new routing is turning the pump the wrong way? Is that possible?

It's not running massively lean or timed completely wrong?
I think they are generally tough old lumps it would be odd to have 2 duds.

Is water circulating through the heater circuit?

Does it have a degas vent hose behind the thermostat, usually comes out of a triangular boss screwed to the manifold. I had the same on my TR7V8, gas builds up behind the thermostat and it either doesen't open or does very late after the temp gauge has gone into the red.

Timing seems pretty close, haven't been able to get it running well or long enough to do more, likewise the fuelling.

Thermostat is opening, top of rad is hot.

Fan switch is in top hose, because of lack of space in and around the bottom hose.

So, I'm thinking one of 4 things:

Heads not sealing.

Water pump not pumping, (but it looked OK when checked).

Fans not working, either not switching on or the installation is poor.

When I first got the Landy, it had a big fan in front of the engine, blew very little air through the rad and looked awful.
So I replaced the big fan with 4 small fans behind the rad, mounted on a flat plate cowl. This is just a flat sheet screwed to the rad, a hole cut for each fan and then a fan, it does reduce the open space behind the rad by about 35%.
However, the fans do take heat out of the engine very quickly, 10 degrees in 60 seconds.

On the latest overheat, I don't know if the fans activated, because the exhaust is too loud and the Landy vibrates even with the engine switched off!

When it warms up bit (-4 today!) I'll check the fans are switching on.

I have tried it without a thermostat, on both the 3.5 engine with skimmed heads (skimmed to be flat!), the 3.9 with those heads, 3.9 with 3.9 10 bolt heads, 3.9 with 10 bolt heads and head studs.

Haven't tried it with these heads, but it does seem to be flowing. I can see strong flow across the top of the core and the top hose and rad get hot, with the lower part of the rad cooler as you'd expect. In fact just the same as without a thermostat.

My problem is that I've had the same problem across 2 engines and 3 sets of heads, the latest heads being from a very well respected V8 specialist!

So, either I've got no idea how to fit Rover V8 heads (very possible!) even though I've had a lot of practice lately or it's something else that's not in the engine?