Advice on Cooling system V8

[HoggyN]

If you need fans while you are moving, your rad isn't big enough or it's blocked up.

You could try taking the grille off to improve the airflow and see if that improves things. Also make sure that as little air as possible can bypass the rad around the sides etc.

[Bowie69]

OK, taking a step back a mo, how do you KNOW it is overheating? Gauge? Is it matched sender and gauge? If not, buy a proper one, gasp yes even digital, and then you will properly KNOW what your engine is doing.

Do you KNOW the condition of the water pump and thermostat?

I get the feeling you may be chasing your tail here, and the stick is elsewhere.....

Photo of the radiator with the grill removed and your fan set up would be good to see, to assess condition and whether cowling is in appropriate place...

[HoggyN]

I had an overheating problem with my standard S1 when I first got it. I used thermocouples poked into the hose joints to work out what was really happening. Cheaper than buying a new gauge and sender.

[FridgeFreezer]

What Bowie said, unless the gauge + sender are matched there's no point looking at anything else until you've got some method of finding out what the temperature really is.

If it's got a standard Series temp gauge then 99% chance it'll be reading wrong with a V8 fitted.

[Jon W]

Just dragging this thread back up again. 

I have just got my series V8 back on the road. Carb V8 i have put a new 4 core rad in it so i know the rad is good. Looked at the thermostat and it appears to be a 74C thermostat. I have a 14inch push fan on the front of the rad, controlled by an x-eng switch in the bottom hose switching on at 88C and off at 83C. Running 30% antifreeze and a water wetter. Running the standard series overflow tank. I have the pipe at the top by the carb blanked off at present do I need to connect this or can I just bleed it?

I have a new gauge with match sender in the top hose.

Running this temperatures are fine when driving 30mph + and remain about 85-90C. If driving in 2nd or 3rd gear and below 30 it will soon heat up to 100C on the gauge. Like wise if stationary the temp will creap upto 100C at which point you will hear the fan kick in. The fan will run for a while and then cut in and out. The longer you leave it the longer the fan runs before cutting out, as I guess everything is warming up around it. I haven't let it get much hotter than this before stopping and switching off to let it cool or getting onto faster roads to increase air flow. 

My question is, is this getting too hot? as obviously it is being fed water which is 88C or 83C but kicking out hot water 100C so should I be worried or is it just where my gauge is? 

So should I put a lower temp switch in the bottom hose so the fan kicks in sooner to prevent it getting so hot. But I don't want it to be running whilst driving at a sensible speed. If so what temperature?

Should I connect the pipe at the top??

I have a remote oil filter so am planning on putting an oil cooler on so that will be the next thing I think. 

I am just looking for easy quick fixes as am using it for a few small trips in the next couple of weeks. A 50 mile trip where I can keep the speed up so am not worried about it and then a couple of 3 mile runs as it is my wedding car in 12days time, so I think it will be fine as long as we keep an eye on it

 

Thanks 

 

Jon 

 

[Bowie69]

Sounds all pretty normal to me...

[Jon W]

But is running it at 100C going to damage it? As I have hear that 85-90C is what they are meant to run at but it doesnt state where the temperature is taken. 

Thanks 

Jon

[Bowie69]

100C is not really that out the ordinary for a Rover V8 in my book, but hotter than some would like I suppose.

You could try a different stat, could be faulty... Make sure your one has a jiggle pin in it, and fit at the top.

 

As long as it doesn't go over 110C you are unlikely to kill anything.

[FridgeFreezer]

Why fit an oil cooler, spend a couple of quid on a temperature label stuck to the filter to see if your oil is even getting hot. Cold oil is bad for your engine, after all.

[bodumatau]

dragging up this thread instead of starting another one.

I had an 88 degree thermostat in my V8 before I installed megasquirt and it would drive me nuts "yo-yoing" during normal driving, so my temp would fluctuate between 85 and 95/100 while driving, only pushing it hard in summer (german summer = 30max) would the thermostat stay open. I have a VDO gauge installed not the LR one.

to remedy this I installed a 74?72? degree thermostat when I installed my megasquirt, but now it never reaches more than 85!! even pushing hard in summer.

looking at my old 88 degree thermostat it is a "MotoRad" so strongly assuming it is NOT OEM, it also has no bleed hole.

now my questions:

1. surely this yo-yoing is not good for the engine? 

2. is there an advantage installing a thermostat in the "middle" 82 degree?

3. or should I just go for the 88 degree standard? OEM, I am assuming a proper quality one won't yo-yo? (and my heating will work better again!!)

can anyone help me out with this?

 

Edited November 22, 2016 by bodumatau

[Quagmire]

By yo-yo do you mean it would literally bounce up and down whilst cruising along at a constant speed on the motorway? If so that's weird...

Both my rv8 powered vehicles will sit in the low to mid 80's at cruise, with little fluctuation, but the temp will rise when i stop in traffic. After that (and as you might expect) the temp then does fluctuate as the electric fan does its thing and cycles on and off. 

[FridgeFreezer]

Could be the motorad was slow to react, hence the temperature regulation being unstable as it failed to keep up with the changes.

My RV8 behaves much as per Quagmire's, with the standard 88deg stat in and a standard defender V8 rad.

[bodumatau]

yep literally, I have since learnt the word "hysteria", it showed a hysteria of between 10 and 15 degrees which I can't see being beneficial to the engine, I think that the cheap and nasty thermostat wasn't linear with its opening, or it was starting to stick, so would stay closed until slightly over its 88 degrees and then "spring" open.

I am going to order an 88 degree then and install it, might just clip off the breather toggle one way thingy so there is just that little bit more circulation around the thermostat and the engine doesn't get that cold shock as the thermostat opens, and have less cavitation on the water pump (not sure how much this will help but surely must help a little

thanks for the input FF and Quaggy

 

 

[FridgeFreezer]

You mean hysteresis, hysteria is something different

[bodumatau]

yes, that one, I get hysteria when my thermostat shows hysteresis 

you are dealing with a colonially raised child here Fridge, need to be patient with my Souf Efrikan english

Edited November 23, 2016 by bodumatau

[Davo]

1 hour ago, bodumatau said:

yep literally, I have since learnt the word "hysteria", it showed a hysteria of between 10 and 15 degrees which I can't see being beneficial to the engine, I think that the cheap and nasty thermostat wasn't linear with its opening, or it was starting to stick, so would stay closed until slightly over its 88 degrees and then "spring" open.

I am going to order an 88 degree then and install it, might just clip off the breather toggle one way thingy so there is just that little bit more circulation around the thermostat and the engine doesn't get that cold shock as the thermostat opens, and have less cavitation on the water pump (not sure how much this will help but surely must help a little

thanks for the input FF and Quaggy

 

 

Buy a good quality thermostat, and leave the little jiggle pin alone. It's only there to help bleed air out in one direction. Trust me, I must have the equivalent of a degree in these cooling systems after several years of working on mine and the less changes you make, the better. All the components, especially the radiator, must be top quality.  

[missingsid]

On 23/03/2016 at 6:51 PM, tacr2man said:

On 22/03/2016 at 9:28 PM, tommobot said:

Thanks for the replies guys! Lots of good information flying about

So, the 'easiest' solution, with what i've got at the moment I guess would be something like this:

Blue - hose from carbs to top hose or heater hose This pipe needs to go to t piece on top hose or to t piece on yellow pipe that attaches to spigot on rad cap socket

Yellow - Rad to header tank ok as long as header is above rad

Red - Blanking cap on radiator

This would mean i'd only need a T junction on the lower hose, alternatively as suggest I could add it into to 1 of the hoses going to the heater unit, with the addition of a 1 way valve.What for ?.. thinking about it, that actually sounds easier?

So, does this all sound feasable, sounds ok in my head, input welcome..

I have a vertical version of this tank which is lower than rad top it uses suction when cooling down to pull in water from the bottom of the header back to the rad and air bubbles rise to top. Only difference to the pic is that I have a brass pipe soldered to the rad top tank for this, easy to do solder the pipe flange to the rad then drill inside the pipe to the rad.