alanrichey

Thanks for the reminder nikki. Form printed off to send tomorrow.

Application sent for the Saturday

Sorry, forgot to mention the system was primed full of fluid so pump has something to circulate. No way of Topping it up though so RH must have assumed it didn't leak. I have often thought it might be safer if it included some sort of tank though.

Odd. As far as I know the kit was issued out of the RH factory without the bottle and cooler fitted. And there is a simple short length of pipe running from the pump output to the input to form a closed loop. Removing the pump itself its not really an option as the same spindle also drives the water pump.

Thanks to all for the support. Nice to get everyone together again and I think we all had a decent run out, and for some it was the first run of the year. Looked good in the car park too

Good, weather looks as though it will be superb. Too late to book a table, might have to sit outside

OK, Sunday looks as though it might be OK in between rain showers. So let's give it a go, Muskham Ferry (http://www.muskhamferry.co.uk/) ( NG23 6HB) at 12:00 on Sunday 10th Apr. See you there Al

Mine's the same. The default map runs the engine a bit rich and with a working lambda sensor the ECU leans it off between 3% & 6 % Fascinating stuff.

Probably not, and as I have now found out I had been running for 2 years with a broken lambda sensor so the ECU wasn't controlling the fuel/air mixture at all and I was running in Limp-Home Mode it is really academic. But like you with my cooling problem, now I have the extra information available to me I can't bear to leave something not quite right. (Why do they call it Limp-Home Mode when the car actually performs rather better in that mode (apart from the emissions) then under normal conditions?)

More cars coming off their winter hibernation so time to get out more (not me, I have been doing run-outs 2-3 times a week since Xmas and am in danger of exceeding my mileage allowance ) We are actually spoilt for choice this month with the Stilton Cheese Run (http://stiltoncheeserun.webs.com/), and HorsePower at the Hall (https://www.facebook.com/horsepoweratthehall) Unfortunately they are both happening on the same day, Sunday April 24th. Personally I will be on the Stilton Cheese Run. So I will watch the weather for the 9th/10th and 16th/17th and if either/both are good we will meet up somewhere. Be nice to go in middle of the county again so we have our old favourite the Muskham Ferry. But if anyone fancies anywhere different let me know. Watch this space. Al

Good point, although to be honest, as long as it doesn't boil over, I am not all that bothered about the absolute temperature value of the engine.. My initial concern over the the cool running was that all the things the ECU controls that use temperature as a parameter (fuel/air mix, ignition timing, idle speed.....) would not be working correctly because the engine was not running within the optimal 80C-100C band. So in made more sense to use the temperature used by ECU as the guide, regardless of it's accuracy and do something to get that value into the optimal band.

Careful, it's not a 'K' it's a 'T', and it uses the standard cooling method, not the peculiar one used by the 'K' so don't get confused by that. I agree, So far no-one has explained that RHE mod to me. Eh ? Jumping the gun a bit here That was the test Jim recommended, and I have yet to carry it out. At this stage we don't actually know the stat is being bypassed,. And even then I would have thought that would affect the warm up time, not the final stabilsing temperature ? If you require a coolant flow of X through the radiator to keep the engine at a constant temperature I see little difference between a water flow of X through a full opened thermostat and a collant flow of 90% of X through a partially opened thermostat and 10% of X via other means. Same overall effect . Sorry, I'm not really interested in redesigning at this stage, although I am happy to try temporarily blanking of lines for testing. As I said in my last post this has moved from a problem (which it was at the beginning of the thread and has now been fixed) to an intellectual discussion on the workings of the system. You misunderstand, I am now totally content with the new design. Car is running absolutely perfectly for the first time in months. I think my next redesign will be to make the grill blanking plate adjustable so I can then adjust the running temperature to the EXACT value I want. Maybe just up it from 88C to 90C. Show me another car where you can do that

Makes sense, although actually I don't regard it as an issue any more as the car is behaving perfectly. It's now moved from being a problem to an intellectual exercise in thermodynamics.

You would think so, but with a 20psi cap it seems to work OK. Probably just pretends to be a sealed system instead

Shouldn't really get involved in this with all my problems but with the Superspec design, that uses the same principle, you have to fill the expansion bottle to within 1" of the top to ensure the top hose and radiator are full.

Can't give an instant answer, and having spent so much time analysing my ECU I am probably biased But what I have found is that for the first couple of minutes the engine is run on default settings. Once it starts to warm up the lambda (O2) sensor starts to work and the ECU then switches to a different mode whereby the fuel/air mix is actively controlled based on the default setting and the lambda sensor output. Unfortunately if the sensor isn't working the ECU should just drop back to the default settings and should not stop the engine from running. And I am assuming you have a lambda sensor fitted ?

Hi Jim Not really. I think my previous overheating problems were actually caused by a leak of the coolant under pressure from a dodgy connection. And as the water level dropped, that caused the temperature to rise and the pressure to rise, and at 13psi she started dumping water overboard and the situation just ran out of control. And it was during this period I removed the thermostat to try and cure the problem. It then came to a head when I fitted the 20psi cap and in that case instead of the water being dumped overboard the pressure just kept increasing and it blew the dodgy joint apart (In the middle of the A6 ). So I fixed the joint, and that was when she started to run very cool (stabilising at 62C). I assumed that was because of the lack of a thermostat so put an 82C one in and she then stabilised in the low 70s. So moved to a 87C stat and then she stabilised in the high 70s. So I think we can safely ignore all the previous problems as a red herring, and assume that I now have a cooling system working as it was originally designed to run (Whether that is a correct design or not) and start from that point. I should also clarify that I am not using the in-car temperature gauge for this work I am analysing the output of the ECU as it is much more accurate. And as a precaution I have already changed the ECU temperature sensor with a spare one, and they both read identical values. So I think we can safely assume the temperatures I am seeing are genuine. But I do take the point about water going into the top radiator when it shouldn't, so unless someone can explain to me why those extra pipes are there I will try temporarily blocking them off. And thanks for the offer to chat but first I will run all those test you suggested to make sure everything is opening/shutting/warming up as it should. Might even treat myself to an infra-red measuring gun That way we may be able to eliminate other things. But at the end of the day I am still waiting for someone to point out the flaw in my logic that says that having fixed everything I now have a very efficient cooling system and that at 78C with the thermostat partially open I fulfill the equation: Heat dissipated by radiator = Heat created by engine. so she just doesn't get any hotter. And the only way get her to run hotter is to reduce the left hand side of the equation by blocking off part of the radiator. Al

The Rover manual agrees with you, pump takes water from bottom hose and pumps through engine block and inlet manifold before coming out underneath the thermostat. No, Red line appears to be permanently open All under water, particularly when engine running when expansion tank appears to be full. Sounds logical. I guess I could try temporarily blocking the red and blue lines out of the top of the radiator,

OK, you asked for it so here it is Obviously everything in black is a standard core system used by all cars. The Green pipe running from above the thermostat to the top of the expansion bottle is standard Rover design and allows the coolant to expand into the bottle The part of the red pipe that runs from underneath the thermostat to the expansion bottle is also Rover standard and I assume that is the return path for the coolant when the engine cools off. In a normal Rover the rest of the red pipe feeds the ancillaries (Heater, aircon..) but in the Superpec it goes across the top of the engine and into the top of the radiator. I have no idea why, but the presence of the bleed valve leads me to believe it to assist in filling the system. And I have absolutely no idea what the blue pipe on the left is for. Maybe the radiator (anyone know what it came off ?) had a spare outlet on the opposite end of the top of the radiator to the top hose, and the expansion bottle also had a spare inlet so RHE just decided to join them with a tube ? That's all I can figure out.

This thread has become so contentious I was going to shut up and go back in my box. But maybe one last thing. No-one has yet explained to me why my theory is incorrect. We have to remember my thermostat doesn't suddenly snap open at 88C and snap close if the temperature drops to 87C, it is a very gradual process over 10-12C. As I see it, my engine starts to warm up until the thermostat starts to open at 76C (Actually if I look carefully at my graph I think that happens at 73C, probably just down to manufacturing tolerances). At this point water starts to flow through the thermostat and is cooled by the air flowing through the radiator. Now, if by the time the temperature reaches 78C the thermostat has maybe opened about 30% and the resultant flow of water and the cooling via the radiator is sufficient for the system to reach a steady state so it remains at that temperature. What I have done by masking the grill is to reduce the amount of cooling air going through the radiator so that the thermostat is forced to open a bit further to allow more water to flow through the radiator and so the steady state raises to about 85C. Where is the flaw in that logic ?

Maybe up to 45 degs but I don't think so at 70 degrees

I don't want to get into a slanging match about this, but if I quote directly from the Rover manual "..Thermostat starts to open at 76C, and is fully open at 88C.." you will see the top of the rad will start to warm up well before the Stat quoted temperature.

Have to admit my 88C thermostat, bought from Rimmer Bros, does have the 'jiggle' hole in the stat. So maybe I should try another thermostat without the hole ? I didn't realise this subject would cause such a heavy reaction, but in my defence can I reiterate that I have made NO modifications to the basic plumbing, it is exactly as it left the Robin Hood factory in 2001 .

Sorry Jim but I don't think you can compare the Superspec with a 'normal' 2B. Although the pipes are routed differently to the Rover 420 (because the engine, radiator and expansion bottle are mounted in different places) looking at my Haynes manual it is still fundamentally the same system. And I haven't made any modifications to the cooling system. And as I said before, our radiator is almost twice the size of any normal one (including the 420), but angled back almost 70 degs to compensate. The Superspec doesn't have a heater fitted so that is not a player in the equation. The only major difference is that Richard Stewart fitted an extra pipe from the top of the radiator across the top of the engine (with a bleed valve brazed on) into the expansion bottle, as the bottle is almost level with the top of the radiator. I suppose you could get reverse flow through that pipe from the expansion bottle to the top of the radiator, but it is a very narrow bore. Anyway, bottom line is that for the first time in 3 years I seem to have a perfectly working cooling system so I don't really care how it is working, I'm just enjoying driving around without having to continually watch the temperature gauge

The long term story is that I suffered overheating problems for 2 years and tried everything, including, as you say, trying to force the air through the radiator (which on the Superspec is absolutely HUGE), and running without a thermostat, but at the same time found the coolant was also leaking under pressure from somewhere, One of the modifications I tried was to change the pressure cap from 13psi to 20psi and that resulted in a rather dramatic breakdown on the way back from last years end-of-season bash when one of the rubber cooling pipes blew off a stainless pipe. In hindsight I suspect that was where the coolant was leaking, as since I fixed that the leakage has been minimal. That was when the car started running very cool, mainly because it was full of coolant and with no thermostat, so I started playing with thermostats. So at long last I think I may be there and I will now remake the grill blank so it is a bit more adjustable for various conditions.