Running Hot!

[Richard '69 Saloon]

I know that this has been covered before and yes I've done a search but I'd like some opinions on the running temperature of my 1969 P5B Saloon please.
These two pictures show the steady running temperature -



I apologise for the blurred image, but as you can see the needle is right at the top of the N. Not in the middle, but right at the very top right hand corner of the N.
The car runs consistently at this temp, it doesn't get much hotter, rising very little in traffic even on warm days. I have a reconditioned radiator with 3 cores, and a new high compression water pump. The cooling system is in good order as far as I can tell (although the front heater doesn't seem to put out any warm air) and there are no signs of overheating. The engine runs well and has been diagnostically tuned.
My question is, although I know these cars run hot, should it be this hot? It's a little unnerving to say the least. My Dad has a 1971 P5B Saloon and his seems to run much cooler, at least if the temperature gauge is to be believed. Did Rover sort out the hot running on later cars?
I've changed the thermostat and temperature sender but that made no difference. I even run Water Wetter in the cooling system which is supposed to transfer heat better.
I'd really appreciate your thoughts gents. I could be being over sensitive, maybe they all run this hot and it's not a problem. Or is this too hot and does it therefore need a flush through with some kind of limescale remover?
Any ideas would be most welcome as summer is on the way and I want to use the car with confidence.
Best wishes,
Richard.

[harvey]

In my experience I'd say that was fine, and I wouldn't say that was "right at the top of the N", rather a bit over centre. Wait and see what it's like in really hot weather and traffic.

[Kev]

Seems fine to me.
Big Kev.

[johnwp5bcoupe]

Looks fine to me

[Deleted]

I recently purchased a non contact laser thermometer from SC Parts for only £35 plus P & P and this reads up to 520 degrees C and would be ideal to point at the engine or engine parts in order to read out the temperature of the thermostat housing, cylinder head, radiator etc.

www.scparts.co.uk/index/lang-2/lkz-195/markenid-23/katnr-194/kat_sprache-2/hrubnr-1847/rubrik-5893/tpl-clickable_vertikal.tpl,x-a.htm

On this page you can also see the manual choke conversion kit for the AED fitted to some of our cars.

The reading you are getting seems fine to me but I wonder if there is a voltage stabiliser for the instuments that may be giving a slightly odd reading or even that the temperature gauge is slightly 'out'.
If I were you, I would simply regard this reading as the norm. for this car and keep an eye on any abnormal variations from this.
These gauges are only meant to give indications and are not scientificly accurate instruments.
Enjoy driving this fine vehicle.

Regards

Freddy

PS Try setting your digital camera to MACRO for close up shots!

[stantondavies]

I wholeheartedly echo Freddy's comments - these instruments are crude, not scientifically accurate. Regard it as a rough indicator and watch for CHANGES.

[Phil Nottingham]

If the engine is running Ok and no other signs of overheating then do not worry - all the gauges are very inaccurate. The only way to be sure is to use a reliable calibrated electronicor capillary gauge. Mine never moves from the first leg of the N actually unless in crawling traffic for a half hour or so when it goes up the the last leg of it like yours. I have tried different senders but not the gauge with no difference.

I was once stuck for a hour in a jam and it go up to the red and then it was clear it was getting too hot!!

[Richard '69 Saloon]

Thanks to all for your comments.
I'll try to stop worrying!
Richard.

Freddy - believe it or not the camera is set to macro mode! Problem is, the infa-red autofocus is focussing on the instrument glass, not on the actual instrument face, hence the slight blurring. I wasn't able to rectify that. Thanks again for your help. R

[Richard '69 Saloon]

Does anyone know what the running water temperature should be?
I can't seem to find it in the workshop manual and want to test it with an external gauge.
Cheers,
Richard.

[Phil Nottingham]

As the stat s/b fully open at 82 deg water temperature between 83-88 deg should be regarded a normal at the top of the rad/cylinder head

In winter I used to put a 88 deg stat in as I found it ran better and the heater was hotter - the winters have got too warm recent years!

[harvey]

The cooling system has the thermostat to allow for rapid warm up to the temp at which it opens but from this point on the temperature will still rise. If it ran at 88 deg or thereabouts all the time there would be no need to pressurise the system. Running at 15lb pressure,the temp can get up to 115 deg before it blows out under the cap. The 15lb pressure allows the system to run over 100 deg as and when req'd,without boiling the coolant.

[Richard '69 Saloon]

So what temp should is stabilise at Harvey?
R

[andymaslen]

When I took delivery of Babs, the gauge was "set" to read on the limit of the green and red sections of the scale. It would move up to that point within five minutes of starting and then sit there all day eg over a ninety minute run to Henley from Salisbury.

When I had a bit of extra work done, the guy said the engine might be running hot from the gauge reading but you should always question the gauge first!

In the end, he ran a flow test on the rad - fine - checked the Kenlowe (which had actually fused) and, finally, got a thermal imaging camera, which confirmed that all was absolutely fine.

He then recallibrated the temperature gauge to sit dead centre - which it was doing till it failed last week!!

So I'd say, first, your gauge looks OK; second, trust your instincts - if there's steam pouring out of the engine it probably IS running hot!

[harvey]

spellacy29 said:

So what temp should is stabilise at Harvey?
R

There's no answer to that. There's far too many variables for a definitive answer because all cars are different, as well as ambient temp,there's cooling system efficiency to add in.
And temperature at tickover on a cold day will always be less than stuck on the M25 in a jam on the hottest day of the year. In normal use the temp will vary according to how you use the car.
If you're worried check the cooling system over, top it up correctly, then use the car with a temporary catch tank on the overflow and see if it gets any coolant in it.

[Phil Nottingham]

88-90 deg is optimum mean running temp for any modern petrol engine - as this is an average it can safely run at betwwen 82 and 110 without loss of coolant. Much higher would cause localised hotspots round exhaust valves etc

[Richard '69 Saloon]

So, for the temp gauge to read in the green, are we saying that the temp range should be between 82 and 110? And if over that, ie. in the red, then loss of coolant will result as it's over 110 degrees?
Cheers,
R

[Phil Nottingham]

More or less but the gauge is not linear or very accurate - I would not bother unless it actuallly gave signs of overheating, with a 3 core rad especially - have you got the standard pump on and was the block descaled?

When the cooling system is designed probes are inserted through the block and rad to make sure everything is running efficiently at as high a temp as prctical.

Running cool causes more probs in the long run

[Richard '69 Saloon]

Thanks Phil,
Do you think I should de-scale the block then, in case there's a blockage or limescale build up?
If so, what would you recommend I use? Can I use a regular household de-scaler, or is there something specially designed (and twice as expensive) for cars?
Thanks again,
R.

[Phil Nottingham]

Vinegar - or the proper stuff for ALLOY engines.

I would try changing the sender!

[eightofthem (Andy)]

Going back to the original question it says that the heater is cool, if the car is at its normal operating temperature then the heater should be hot!. My heater will melt your feet at half way on the gauge so i would check your heater matrix out.

[harvey]

If the heater matrix is blocked and inefficient that will also cause an increase in the temperature the engine runs at. A nice efficient heater switched on to hot when things start overheating can often avert a boil up.Another reason the heater can be inefficient is as it's the highest point in the cooling system gas from a blown head gasket forms an air lock in it.

[Warwick (Ozcoupe)]

I can identify with a couple of threads today.

The previous owner advised me that the car ran with the temperature gauge in the red zone although it didn't overheat. It was due to a fault with the gauge or sender that he hadn't been able to solve.

Since I had to drive it from Brisbane to Melbourne through the heat of inland New South Wales, I decided to take my IR non-contact thermometer so I could keep an eye on it. The trip was last week.

The gauge did indeed run with the needle in the first part of the red and it varied very little whether in traffic in Brisbane on a 27 degree day, or doing 110kph on a hot day in the middle of NSW. It would sometimes move almost to the end of the scale. However, whenever I stopped and checked, the radiator tanks read about 87 degrees with the laser-aimed thermometer.

So my gauge/sender is indeed faulty, and the car's cooling system can easily maintain normal operating temperature on a warm Australian day. (I'll have to wait until next summer to see how she handles high 30s with the aircon running).

About halfway home, in the middle of NSW near the Parkes radio telescope (900km for Brisbane and 900km from Melbourne) I discovered a small pool of coolant on the ground under the rear seat. One of the rubber elbows for the rear heater was leaking. I found the valve under the bonnet, but it was seized. Fortunately Repco and Sunday trading came to the rescue and I by-passed the whole rear system before the valve using a length of 5/8" heater hose. I had to use about 800mm of hose in a large loop to avoid putting strain on the aluminium tubes behind the engine.

Incidentally, my tag photo was taken in the area and if you were able to enlarge it you would see the dish on the horizon where the sky meets the road at the lower edge of the photo.

I hadn't visited the telescope since the early 70s just after the moon landings so we stopped to have a look in the visitors' centre. A large posed photo on display taken shortly after construction was completed in the early 60s shows the farm paddock in which it was built, the dish in the centre in the distance, the farmer from whom the land was acquired with his tractor in the foreground on the right, and his P4 parked in the middle distance on the left.

So was a P4 the original Lunar Rover?

[Phil Nottingham]

P4's were quite advanced for their day and especially so for Rover.!!

The gauges despite the Jaeger badge were no better quality having been made by Smiths than those fitted to almost every British car made then and now? Even some Rolls Royces so they are quite primitive and rough and ready

[Warwick (Ozcoupe)]

Speaking of gauge branding, why is the ammeter branded as Lucas when the other 3 identically-styled pod gauges Jaeger?

[Phil Nottingham]

Perhaps - Rover did not enough influence with Smiths who made them for Lucas ?! This is yet another Rover oddity as my 3 Litre Coupe also has a 30A Lucas ammeter (not the shunted "60A" version on the V8's)

Rover's cars were virtually all assembled by them from off the shelf parts makers and fron subcontracted assemblies eg axles, bodies, subframes. They manufactured very little of their cars apart from the engine/trim and even then Birmid Qulacast did the castings both alloy and cast iron leaving the essential machining for Rover