At Wits End - Please Help..

DaveEFI · Post by **DaveEFI** » Sat Dec 05, 2015 12:15 am

I'd remove the thermostat and reassemble. You should then see the water circulating via the filler - and the rad should heat slowly, but evenly. If not, you need to find out why there is no circulation.

paul c · Post by **paul c** » Sat Dec 05, 2015 10:02 am

need4speed wrote:Wow. Lots of replies since I last looked..

Ok. Let me start by dispelling a myth. The amount of times I've read/heard "oh you can't make a 4.6 from a 3.9 block...." Etc etc. Yes you bloody can lol. You start with a 3.9 block, 4.6 crank/rods/pistons. You get an engine shop to turn the 2.5" main journals down to 2.3". Fit the assemblies. Get the lot balanced. Boom!! A 4.6!

Next thing I want to clear is, yes the blocks were a steal but that doesn't mean there is anything wrong with them. Keith Gott are an extremely reputable company in the 4x4 scene and would not have sold them to us if they knew there was something wrong with them. I've used them many times, as have a few of my friends and had nothing but great service and advice from them. They originally wanted £600 for 1 block but I knew they had been gathering dust for years and got both of them for the £600.

Next is the fact that I don't think it's a gauge fault as a gauge couldn't cause the top half of the rad/top hose to get roasting hot and spew water out the header..

Yes it is an edelbrock inlet manifold he is using but it didn't cause any overheating problems on the old 3.5.

I get a lot of parts from Keith Gott, my Solex carbs I bought brand new from them a few years ago. Before Ford dumped Landrover Jaguar on the market they cleared all the warehouses, lots of parts were sold off at cheaper than normal prices, Gotts were one of the larger dealers who bought up on them.

need4speed · Post by **need4speed** » Sat Dec 05, 2015 10:51 am

stevieturbo wrote:As others have said...

Test that water is actually flowing. Does the heater inside the car even work ?

Run un-pressurised for any tests if need be.

Does your thermostat actually work ?

Ignore OEM temperature gauges, they're always woefully inaccurate. Get an IR heat gun or some other means of measuring temperature with a more accurate reading.

Are you sure all hoses are plumbed correctly ?

Persistent air locks and subsequent loss of flow in the system are usually a sign of cylinder pressure entering the cooling system.

Usually this presents itself as unwanted pressure in the cooling system, but not always. A sniffer test for combustion byproducts in the cooling system can sometimes help.

And you keep saying the blocks are new....so brand new, never machined or used in any way and as they came from Leyland/Rover ?
From what base ? 3.9 or 4.0/4.6 ?

Yes the heater inside does work. Until it gets to the point of boiling over, then it doesn't.

The thermostat is brand new. Decent quality with toggle integrated.

All hoses are connected identically to when the car was running well with the 3.5 in it.

I will try and get a loan of a sniffer tester.

Yes the block is an absolute brand spanker. Still had factory storage wax all over it which was a pain and took ages to pressure wash off/out. It's the 3.9 flavour.

sidecar · Post by **sidecar** » Sat Dec 05, 2015 11:39 am

I doubt that its a liner issue with it being a brand new block, so assuming that its not a liner issue there are very few places where the coolant from the block goes up through the head gasket into the head, infact it is just one channel at the back of each cylinder bank and a very small hole at the front of each bank.

One other thing is what sort of fan are you using? The reason that I ask is that Muscle Manta has a 4.6 in an SD1 and we had no end of trouble with the coolant temperature going up and down like a yoyo, it would puke coolant out of the expansion tank. We spent ages messing about with it. in the end it turned out to be the viscous fan that was the problem, it was knackered which caused it to be engaged all the time. I think that this was setting up an 'over cooling' cycle which caused the thermostat to slam open and closed. We fitted an electric fan controlled by a 'box of tricks; that I made up using a Maplins temperature controlled switch and the car has never overheated again.

JSF55 · Post by **JSF55** » Sat Dec 05, 2015 6:38 pm

Is the heater mounted higher than the engine, could it be air locking there ?

mgbv8 · Post by **mgbv8** » Sun Dec 06, 2015 9:17 pm

Coops wrote:right so it is using water then,
have you tried it with the stat removed?

I think there is confusion here over what "using water " is?

Using water in my mind is an engine thats not overheating but loses water without it spitting from the exp tank due to high system pressure which could be due to internal leaks that allow the water into the sump or into a chamber to be burnt.

I think what we have here is an engine block that has insufficient water flow. The rad temp issue is the clue ? Especially as the obvious parts have either been replaced or removed.

If the old engine had good water flow and the new block has all the old cooling parts fitted there should be adequate coolant flow to make the rad hot from top to bottom. Even assuming that the old rad was not good enough to cope with the bigger displacement, it should have boiled over when the top and bottom of the rad was red hot and not as described above.

I have no idea who the Eric chap is though. Does he sell brand new RV8 castings for a living ? The only guy I know who does is John Eales !

mgbv8 · Post by **mgbv8** » Sun Dec 06, 2015 9:22 pm

DaveEFI wrote:I'd remove the thermostat and reassemble. You should then see the water circulating via the filler - and the rad should heat slowly, but evenly. If not, you need to find out why there is no circulation.

I thought he had already tried removing the stat? Maybe I misread. But yes! Remove the stat and try again to rule that out eh ?
Relying on the stat being new is no guarantee that it actually works.!

v8250 · Post by **v8250** » Sun Dec 06, 2015 10:41 pm

mgbv8 wrote:
DaveEFI wrote:I'd remove the thermostat and reassemble. You should then see the water circulating via the filler - and the rad should heat slowly, but evenly. If not, you need to find out why there is no circulation.
I thought he had already tried removing the stat? Maybe I misread. But yes! Remove the stat and try again to rule that out eh ?
Relying on the stat being new is no guarantee that it actually works.!

OP, as above, plus do post some good clear pics so we can see your hose layout. Plus, I have come across this problem before albeit on another engine type so I want you to do the following as process of elimination, you need to know your base status before starting to change any components...

1. remove stat and run atmospheric [no rad' cap]
2. know the total system coolant volume including all hoses and heater matrix
3. make sure your heater valve is installed in correct flow direction and that the heater bypass works when the heater valve is closed.
4. depending upon inlet manifold...is there a constant bypass hose? if so, make sure it's fitted and not capped off.
5. premix your known coolant volume, make sure the heater matrix is fully open and fill the system very slowly...it drives me mad the number of times i've seen engines with over heating, the owner saying the system's full and it's not it's full of air and :. too many high pressure points where the water boils resulting in system pressure that equals the pump flow rate and stops effective circulation.
6. with known coolant volume in system run the engine...if there are no internal blockages [block, head and/or inlet manifold] your engine will not overheat/have high heat spots/low temp spots as you're running atmospheric...rad' cap still removed.
7. if you're still running too hot, and you haven't yet stated precisely what temp' the water is when 'too hot', then check the rads total water volume against req'd for an RV8...I'm assuming here you've already compared this and ideally increased rad volume for the engine?

Come back with results once the above is completed...

need4speed · Post by **need4speed** » Mon Dec 07, 2015 2:22 pm

Thanks for replies so far. Little update.

As Ian suggested I filled a bucket of water, put bottom rad hose in and aimed top hose at same bucket.

Started engine to check flow. Nothing. I'm stumped. Pump is brand new from Rimmers. And not the cheap one either.

In order to check for a blockage somewhere I used a 2nd bucket for the top hose and submerged both hoses. When I forcefully blew into the bottom hose I could see bubbles in the bucket containing the top hose. So there's no reason for lack of flow as far as I see....

Eliot · Post by **Eliot** » Mon Dec 07, 2015 2:28 pm

Even if the block is porous - you wouldn't have a cold radiator at the bottom.
Plus I've owned more than one 4.6 that pressurises and consumes water but they never overheat and run fine - as long as you keep the header tank at the correct level. Allowing it to drop and then boil over dues to lack of coolant is the big problem - but keep it topped up and it will run for years.

So I would ignore the porous block route for now and get the layout and basics understood.

As asked, some photos are required.

minorv8 · Post by **minorv8** » Mon Dec 07, 2015 2:31 pm

Which water pump do you have ? Sounds silly but does it run the correct way ? I have had my share of correct but incorrect parts... I would not be surprised to see that the blades of the pump are the wrong way

r2d2hp · Post by **r2d2hp** » Mon Dec 07, 2015 2:55 pm

Will a Rover pump actually suck water from a bucket. I thought they are very much like a central heating pump and just move fluid

Spongo · Post by **Spongo** » Mon Dec 07, 2015 3:02 pm

Maybe the impellar is just spinning on the shaft?

SimpleSimon · Post by **SimpleSimon** » Mon Dec 07, 2015 4:32 pm

r2d2hp wrote:Will a Rover pump actually suck water from a bucket. I thought they are very much like a central heating pump and just move fluid

It wont draw fluid

I would be flow checking that rad thoroughly IMO

v8250 · Post by **v8250** » Mon Dec 07, 2015 5:03 pm

Spongo wrote:Maybe the impellar is just spinning on the shaft?

had this happen on a 2.5 V8 once before, it took ages to work out why circulation was at standstill as the pump was in perfect working order before the rebuild.

And as per Simon's note, check radiator flow throughput. The radiator may have the volume req'd but if poor flow rate it's of no use. You mentioned the radiator's been re-cored/rebuilt, could you contact the radiator Co' and get the flow rate of 1. the core i.e. a Nissen unit and 2. measure the overall flow rate between i/p and o/p.