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Engine Temps and Cooling


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So, engine flushed (lot’s of crud) and had to clear out the block drain and flush some more. New radiator core and move to 4Life coolant. Revotec fan fitted, working fine. In general running the temp gauge stays around the halfway or slightly above. The minute you stop/ queue, then it rises quickly, is that unusual? It feels like you have to be constantly moving to keep the temp normal, what are other peoples experiences? My car is a ‘73 CR. 

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I guess it all depends whether the fan can keep the temp under control when stationary. If it can’t then there is something up.

Tim

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Most engines, certainly most Triumph sixes, seem to heat up speedy when stationary or at very low speed. I also use 4Life coolant and don't think that's the issue.

With my TR6, the Kenlowe kicks in when stuck in traffic and keeps the temp under control. Just!

Nigel

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My temp gauge reads just below half way. It has the engine fan and that keeps it cool for every uk scenario. I installed a back up electric fan too on a switch for continental touring when stuck in queues in 35+ temps.  I routinely don’t need it - it’s merely there for my nerves.  In my experience, a well maintained standard cooling system should be good enough for uk temps. 
 

cheers

 

dave

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I have an electric puller type fan, but no engine driven fan. I (still) have not run the car, but if left idle when warm, the electric fan kicks in regularly, but not too long.

I think with a mechanical (engine) fan, which is designed to keep temperature in normal range, also in slow traffic, it should not go “hot”, unless there is an issue.

This aligns with Neils wise words above.

Waldi

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I have no mechanical fan, only the electric fan that is turned on via a 180 degree fan switch in the bottom of the radiator. Under normal running the temp guage sits at the 1/4 mark which strikes me as a bit cold, probably due to the thermostat. If I sit in traffic on a hot day the fan kicks in when the guage reaches the half way mark and it never goes above that. If I see that I am going to get stuck on a hot day I turn on the fan manually as my cheap junk meccano set bell crank accelerator linkage tends to bind when it gets hot.

Stan

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4 hours ago, aardvark said:

My temp gauge reads just below half way. It has the engine fan and that keeps it cool for every uk scenario. I installed a back up electric fan too on a switch for continental touring when stuck in queues in 35+ temps.  I routinely don’t need it - it’s merely there for my nerves.  In my experience, a well maintained standard cooling system should be good enough for uk temps. 
 

cheers

 

dave

My TR6 is very similar. Soon after I bought it 4 years ago I got stuck in heavy traffic on a 40 degC plus day here in Sydney (I recall it hit 43 that day at the time I was in the traffic). The temperature gauge got up to the red but didn't boil, even after shut down.

I had an electric fan in the garage which I fitted with a manual switch under the dash. I also flushed the system a few times .

Since then even on the hot days (mid high 30s) I've never had to use the electric fan. I turn it on to make sure it is still working.

My radiator looks well used so I reckon when it is recored the electric fan will be superfluous.

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Thanks all, so my stat is an otter unit which screws into the stainless down pipe between the block and the radiator. I will check that it is cycling properly, after that it looks like something that I am just going to have to keep an eye on (along with loads of other things as per usual). I did fit an override switch which should help, but ideally I would have liked the car to ‘manage itself’, looks like I will need to use that in traffic.

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When you drained and flushed the block did you remove the drain plug from the block at the back closest to the bulkhead? I believe I am right that there is another plug here and this is often also clogged up. I believe there have been other threads on the forum related to this so it might be useful to perform a search.

Also might be worth checking the water pump is in good health? Mine had a rumbling bearing which whist not stopping it working completely didn't help! It was the original water pump which I managed to get rebuilt by EP Pumps who did an excellent job for a very reasonable price.

My1973 CR TR6 tends to sit just under halfway on the gauge and rise to just over halfway in traffic. The engine has been fully rebuilt by TRGB to 'fast road' spec with a high capacity radiator and standard fan set-up.The block was chemically dipped and cleaned as part of the rebuild which I understand removed quite a lot of accumulated silt. I hope this and my earlier thoughts might be helpful.

Best Regards, Peter

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SGP,

Forgive me, but:

1/ is the fan as close as possible to the matrix?   The outer cowl should be on the matrix.

2/ are the electrical connections the right way around?   So that it is drawing air in the same direction as flow from movement.

3/ Have you calibrated your temp sensor/guage?   The rise when stationary is normal but does the fan keep it within the acceptable?   Take the sensor out, use some jumper leads to extend the wiring (supply and earth) and suspend it in a pan of water on a  camp stove.    Note the gauge reading when the water boils.   Your engine coolnat will oprtae at or near to that, as it's under pressure.

       If you have a thermometer you can documen the response curve, which can be informative.    Sensors have odd physics - they decrease their electrical resistnce as they heat up, when most materials increase.    Modern repro sensors are often poor quality with a short life, and an unsmooth curve can show that - see yellow below.

Temp.sensor responses.jpg

Edited by john.r.davies
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I also run a Kenlowe fan on my 6 ,as it came without an engine mounted fan and a strange heath robinson  electric setup mounted on the engine, which was soon removed. With mine I found the best point to set the thermoswitch was just after the gauge moves from normal, which in my case is halfway.  The fan comes in quickly when stationary but does prevent excessive heat build up  before coming on and has worked well for the last eight years. 

I have noticed a variation in gauge position at normal temp on several other six cylinder cars so perhaps these are not particularly accurate in respect of needle position to actual temp.

Brian

 

 

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26 minutes ago, Peter Cobbold said:

Does it matter ? 4-life cannot boil.  Burn, yes.

An airlock in the pump will stop fluid circulating and carrying away heat. The air collects in the pump at low engine speeds and stops circulation. At high speeds the sheer volume of fluid circulating carries the air along with the fluid.

I assume the engine was initially filled with coolant with the heater valve fully open?

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How about a little electronic circuit that will bring the rad fan on when the speed drops below about 30MPH.    Modern cars do something similar I think (or their sensors are much more sensitive/stable.)

 

Roger

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Good idea Roger. If I see a Jam up ahead, I'll switch the fan on to avoid heat build up as I slow to a crawl and whilst stationary rather than let the heat build and THEN allow the fan to cut in on Temp.............

But its a TR4 with the smaller rad anyway, sorry to intrude !  B)

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1 hour ago, RogerH said:

How about a little electronic circuit that will bring the rad fan on when the speed drops below about 30MPH.    Modern cars do something similar I think (or their sensors are much more sensitive/stable.)

 

Roger

Great idea Roger. Let us know when you figure out how to do that.

Stan

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I also felt mine was running two cold (1/4) when driving which meant that the heater wasn't great (yes it has been flushed). I changed the thermostat to a higher one this winter and now it runs almost perfectly at 1/2. I have an electric sucker fan (the largest you can fit) and it works great. Even at 30+ temps in the summer sitting on a motorway with a load of cars cooling it keeps the temp close to 1/2. Mind you it also pulls a lot of amps! 

In the past I also just ran the mechanical fan and this is more than up to the job if the radiator is in good knick. If in doubt get it recored!

Tim

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If your car cools adequately when moving it suggests that the basic cooling system is OK and the rad is quite capable of cooling the engine when running under load and generating much more heat than under load..Also effectively rules out the airlock theory although these are profoundly uncommon on a 6. So when you are driving, the fan isn’t operating and the engine temp is governed by the thermostat. Likewise an engine fault like a blown head gasket will cause more problems under load.

Is your Revotec fan switch set low enough? If it is in the top hose it should switch on at about 5 celsius above the thermostat temp. (You need it to be above the thermostat temp or it will be running continuously once the thermostat has opened.

Is the electric fan up to the job? A significant number are marginal.

Is the fan running in the right direction? Easy done.

Some of the waterless coolants don’t transfer heat as efficiently as a good water/antifreeze mix.

Theoretically a failing water pump with a knackered impeller or one where the impeller is slipping might struggle to produce enough flow at tick over but these are rare issues.

 

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27 minutes ago, foster461 said:

Great idea Roger. Let us know when you figure out how to do that.

A challenge!

Well the main trick would be in getting a signal proportional to road speed.

The easy way is to buy a pulse generator that fits between the speedo cable and the speedo (at a price!).

https://transmissioncenter.net/shop/54mg-eight-pulse-signal-generator-for-your-electronic-speedometer-head/

If the cost of the pulse unit it is a problem then a cheap crank position sensor looking at a rotating component - perhaps a brake drum flange with a hole in it would do, though there's more work in getting that going.

It's fairly simple to make a circuit that will switch on a relay if the pulse rate drops below some threshold value. 

 

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Thanks all, collective eye roll at the ready, I had disturbed the positive feed to the fan whilst on another project, it looked connected but on inspection wasn’t. I did take the time to burp the coolant system on the ground and then after a forum search I raised the front, it was surprising how much More air escaped. I cycled the system a couple of times to be sure. Temp guage is on half normally now and does rise in traffic but the fan now cuts in to restore order. I appreciate everybody who responded.

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As a footnote, I recently had a faulty sensor, the first replacement had a red collar and was faulty, the second has a black collar and by new normal running temperature is now nearly ¾ up not ½ way as before. It's a little disconcerting.

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