Kv6 new thermostat leaks?

[Terryf]

Originally Posted by Aidan Collingwood

Hello again,

I've been doing a bit more searching around the forum and I followed a link to the DMGRS website. They sell the "Kaiser" housing and hoses etc. (currently out of stock till August) which is supplied with a Lucas thermostat already installed. However, they also supply a "Vernet 6773 Equivalent" thermostat which says 87C which I suppose is suited to the UK climate? DMGRS' phone lines are already closed but I'll contact them tomorrow, have a chat with them and report back.

Regards

That is the one Kaiser told me to get, works fine. Can't remember where I got it, but found on internet.
Terry

[kaiser]

Originally Posted by biffa75

Thanks shuriken, my previous thermostat sat at 82°c regardless unless stuck.in traffic.

The new one sits higher but it fluctuates.from.84-96°c. I'm just going to ignore it and keep and eye on the level. Make sure there's no air locks and.be done with it.

Regards

Of course it fluctuates! What on earth are you expecting?
This is perfectly normal!
Why don't you just enjoy your car and stop worrying?
The time to worry is when it overheats!

[biffa75]

Thanks for your reply kaiser

With it fluctuating, I would have thought it would hit the operating temp of around 88°c and at least stay there at the very least or go a few degrees above, not fall back to 84°c surely at 84°c (motorway speeds) it would either partially shut or fully causing a flow restriction wouldn't it?

[kaiser]

Originally Posted by biffa75

Thanks for your reply kaiser

With it fluctuating, I would have thought it would hit the operating temp of around 88°c and at least stay there at the very least or go a few degrees above, not fall back to 84°c surely at 84°c (motorway speeds) it would either partially shut or fully causing a flow restriction wouldn't it?

There are a lot of factors to work in. If you are using the heater, you have that as an extra radiator. In cold weather that can almost cool the engine by itself.
As the water runs through the heater at all times, this is not something the thermostat can adjust for! You might also have a jiggle valve, a small hole or even a rubber flap in the thermostat. That also will allow water to pass uncontrolled. The thermostat itself will only start to open at the set opening temperature, and gradually open more and more, until it reaches fully open, about 10 to 15 degrees later.
The load on the engine varies, the ram cooling effect varies and the water temperature can therefor never be constant.
And what temperature is right?
The reason for later years higher running temperatures has a lot to do with modern technologies. There is less space in the engine bays, there are smaller radiators, less excess capacity, higher specific output and a tendency to run higher temperature for two main reasons. One: emissions and Two: better evaporation of water inside the engine.
But to claim that fuel economy is affected by running the car at 85 rather than say 95 is just idle talk. There are no fuel adjustment made at any temperatures above 60 degrees on any system I have ever heard of or seen. I guess maybe down to about 55 degrees.
So be happy your car does not overheat, and don't let some 5 or 8 degrees spoil your life. It is for all intends and purposes a safety factor and beneficial!!
I could think of many many other things in life much worse than that!

And for anyone to claim otherwise, just ask them to prove it. Simple as that. Relax, enjoy and watch out for high temperatures!

[biffa75]

Hi Kaiser

Thanks for your reply, if this is the stance on current kv6 thermostats (that they may run a little cooler) for whatever reason could this information not be made a sticky or something on this forum for people to read through. As stated in the rave manual and by xpart. The thermostat minimum opening temp is 86°c. As myself and others have found.. new thermostats clearly aren't operating at this temp so.. here lies the confusion (perhaps by parts being updated or simply out of date information).

If the ECU isn't over fueling the engine, due to the lower coolant temps being recorded then I don't have an issue at all..
But who would have this information as I'm sure sure Siemens won't release this info..

Anyway.. the new stat doesn't leak, the level appears stable, I have even heat flow from the dash vents..



Regards

[kaiser]

Originally Posted by biffa75

Hi Kaiser

Thanks for your reply, if this is the stance on current kv6 thermostats (that they may run a little cooler) for whatever reason could this information not be made a sticky or something on this forum for people to read through. As stated in the rave manual and by xpart. The thermostat minimum opening temp is 86°c. As myself and others have found.. new thermostats clearly aren't operating at this temp so.. here lies the confusion (perhaps by parts being updated or simply out of date information).

If the ECU isn't over fueling the engine, due to the lower coolant temps being recorded then I don't have an issue at all..
But who would have this information as I'm sure sure Siemens won't release this info..

Anyway.. the new stat doesn't leak, the level appears stable, I have even heat flow from the dash vents..



Regards

So, there you go. No problem.
If you want to know the operating temperature on the thermostat, you can open a discarded unit and see if/what is etched or printed/stamped on the unit.
I have a 80 degree unit in mine. Today we have a cold day here, 13 degrees. I made sure the car was filled with coolant, and off I went. Leisurely driving. Heater off. Temperature on dash showed 80 degrees rather quickly, within 2 km I guess. And then it sat fairly constant at 84 degrees for maybe anther 5 km. After that it started to rise to about 95 and go up and down with stops starts and speed.
So to me it looks as if when the first batch of cold water in the radiator is being used, things are pretty stable, and you will see temperatures of maybe 5 degrees above opening, until the water in the radiator has been through the engine. Then the flat spot moves up another 5 to 10 degrees.

I think the Chinese have started fitting 80 odd degree thermostats in their units as well. And to me, that makes a lot of sense.

And I promise you, that will never make the fuel mixture rich!

So I hope you now feel much better!!

[DMGRS]

We did ask someone 'in the know' some time ago (the name escapes me, but if it comes back to me I'll report back) at what temperature the ECU will start to adjust fuelling.
The answer was quite complicated but ultimately above 75 degrees (mid-way on the temperature gauge) the ECU will be fuelling 'normally' and not adjusting for the running temperature. I think the actual temperature for the cut-off was a few degrees lower, but I can't remember the exact number.

[Aidan Collingwood]

As much as I'd love a Rover 75, it seems to me that there are just too many issues for someone in my situation to deal with.

I am searching for a reliable and relatively simple second car and, although I can do a lot of work on cars myself, I'm not in a situation to deal with a car that seems to have such complex problems such as over-heating and inlet manifold faults.

I wish I was in a more fortunate situation where I was able to own a Rover 75 as I've wanted one since they were released but, such is life.

Happy motoring to all you 75 owners. I hope you are all able to use your collective knowledge to resolve the issues of these desirable cars. Maybe oneday, to quote a famous Austrian...aahll be buck.

Regards
Aidan

[SD1too]

Originally Posted by biffa75

At motorway speeds the temp was.coming back at 84-87°c.

Originally Posted by biffa75

The new one sits higher but it fluctuates.from.84-96°c.

These results indicate that your cooling system isn't perfectly sealed. Have you checked the expansion tank cap 'O' rings? They flatten over time.

Originally Posted by biffa75

With it fluctuating, I would have thought it would hit the operating temp of around 88°c and at least stay there ... or go a few degrees above, not fall back to 84°c ...

You're spot-on here Rob.

Originally Posted by kaiser

But to claim that fuel economy is affected by running the car at 85 rather than say 95 is just idle talk.

I'm afraid you're mistaken there Kaiser. Recently the fuel consumption of my urban car increased by about 3 mpg and, at the same time, I noticed that the engine was slow to warm-up and was barely reaching normal running temperature. I tested the thermostat on the bench and it was opening early, at around 82˚ (the spec. is 89˚). When replaced, the fuel consumption and coolant temperature returned to normal.

Simon

[kaiser]

Originally Posted by SD1too

These results indicate that your cooling system isn't perfectly sealed. Have you checked the expansion tank cap 'O' rings? They flatten over time.



You're spot-on here Rob.

I'm afraid you're mistaken there Kaiser. Recently the fuel consumption of my urban car increased by about 3 mpg and, at the same time, I noticed that the engine was slow to warm-up and was barely reaching normal running temperature. I tested the thermostat on the bench and it was opening early, at around 82˚ (the spec. is 89˚). When replaced, the fuel consumption and coolant temperature returned to normal.



Simon

You are always able to talk, Simon. Now let's see some proof! Show me a system that will adjust air/petrol mixture for engine temperature above 60 degrees!