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Ernest

Overheating

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Hi all

Seeking advice re. overheating on my 6. Caught is some heavy traffic last week and gauge into red -  so had to stop for hour or so then back on road. This is the second time this has happened over the past year

It looks like the car is prone to overheating. I have recently had a new radiator fitted by a TR specialist and I assume they would have flushed the system through at that time.

I have also changed the thermostat and this did improve the issue somewhat.

The car also has a supplementary fan (and an oil-cooler).

I had a six in daily use back in the early 70s and I don't remember any problems with overheating - and that one did  not have a supplementary fan.

Any ideas on what I can do to improve this issues? I seem to remember that back in the day when I drove mini coopers we used to just take the thermostat out to help cooling.

Best Wishes

Ernest

 

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In the  late '60's  used to cure  overheating vehicles by running with the thermostat out and a blind on the radiator- but that's just masking the problem.

Are you sure your timing is right and you have no airlocks in the cooling system? If those items look OK I'd have a look at the water pump .

The supplementary fan is rotating in the correct direction and  operating  before the gauge goes into the red?

 

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Ernest,

I would also ask the garage that replaced the radiator if they flushed the system an if so, how. If you can drain the block ( small tap above the starter motor) and clear coolant flows out you have an indication some effort was made.

If not, I would do this first, there is another active topic about this at the moment.

Waldi

 

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Hi

I had similar and it was the temp' sender sending wrong data to dial!  I tested heat on the block and radiator using a digital thermometer, you know the gun looking thing that chefs use for testing the heat on a pan or food.  Swapped the sender and all was good.

Just one step in the elimination process maybe.

Rich

 

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If you have an infra red thermometer you can do a fair bit to track down cooling problems.

A hot engine with a cold radiator indicated a water circulation problem.

A hot engine but a cold upper radiator hose is a good indication the thermostat is stuck closed.

A hot engine and a hot radiator and I'd be looking at timing, weak mixture or a clogged exhaust.

 

 

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Make sure the replacement rad is not a 3 row unit, this happened to me many years ago. I replaced a leaky radiator with new one from Cox & Buckles and the car ran hot and easiily overheated.

A 4 row fixed this......

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Mike C and Mark V 

Thanks for these suggestions - I think the circulation note and the three row radiator comment might well be relevant.

Best Wishes

Ernest

 

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Just got my 6 running after a long layup, I have had the radiator re cored and both block and head cleaned out thoroughly, replaced sender.  Found temp guage reads very high, but testing engine temp with digital thermometer reads around high 70's. Are these senders unreliable temperature wise. 

Mark

 

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Hi Mark,

I tested mine in boiling water and then while it cooled down, sensor connected to gauge. Made notice of the 100 and 75 degrees C location of the needle.

Also “calibrated” the pressure gauge against my air compressor gauge, so I had some idea if it was close. It was, fwiw.

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Thanks Waldi I'll test old sender first before removing new one. Never thought to test oil pressure gauge. 

Cheers Mark. 

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Hi Chaps, this is interesting stuff; Will the temp sender work if dipped in a cup of hot water, or does it have to be earthed (as it would be on the engine block)?

Best wishes,

Paul.

 

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2 hours ago, TR Paul said:

Hi Chaps, this is interesting stuff; Will the temp sender work if dipped in a cup of hot water, or does it have to be earthed (as it would be on the engine block)?

Best wishes,

Paul.

 

I’d wrap the bare end of a wire around the thread to make a full circuit Paul

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A job I have performed tonight, photo shows the new replacement sender temp reading, the vid shows the original sender reading in water at 77°. 

Another case of repo parts not up to the job. 

I wrapped cable around sender unit as Steve suggested above and connected to the earth tag on front valance. 

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Glad you got to the bootof of it Mark!

the sender could either be faulty or it’s just not the right sender.....

steve

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Your oil pressure is pretty high too.

Stuart.

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From your above clip thats quite high at tickover, usually expect around 70 running and about 25 at hot tickover.

Stuart.

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5 minutes ago, Mark69 said:

Is that good or bad, drops to just above 50 when fully warmed up. 

My TR6 is the same as yours cold. Hot it is about 60psi above 2000rpm and 30-35 at idle. That is fine. My TR2 has been running 70-75 psi hot for 43 years without any issues.

If you are worried put a separate pressure gauge on first to make sure your gauge isn't incorrect.

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2 hours ago, Mark69 said:

Is that good or bad, drops to just above 50 when fully warmed up. 

Hi Mark,

if your oil pressure reading is ok, and your oil pressure is high, it results in a couple of things:

1) The load on the cam gear is higher due to the higher required torque to drive the pump.

2) High pressure (resistance to flow) can also mean that some area’s will get less oil.

One grade lighter (like 20W50 instead of 20W60 will reduce overall oil pressure and increase flow.

The above shows that a high oil pressure is not necessarily better.

My oil pressure is very high too, I have put 20W60 in it, maybe with the next oil change I will use 20W50, but the engine has not run many hrs yet so first want to see what happens after some more running.

Before you change anything I suggest to first check your gauge is correct.

Waldi

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2 hours ago, John McCormack said:

My TR6 is the same as yours cold. Hot it is about 60psi above 2000rpm and 30-35 at idle. That is fine. My TR2 has been running 70-75 psi hot for 43 years without any issues.

If you are worried put a separate pressure gauge on first to make sure your gauge isn't incorrect.

4 Cylinder engines do run different pressures anyway as the larger the engine then the lower the required oil pressure is

Stuart.

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