More Overheating

[Guest Paul J B]

Gents,

I have been closely following Tim's story for the past few weeks. I have a 1970 CP car with unleaded conversion and a Kenlow fan fitted. I too have have a hot running engine. At normal cruising the needle is perhaps 5mm above centre it then creeps up during town driving and settles about 5mm below the red mark in stop start traffic with the Kenlow fan running.

 

I have fitted a new standard thermostat and radiator cap. I have checked the new water pump I fitted last year which seems ok. I don't appear to have any leaks. The heater works ok so I guess there are no airlocks! How can I tell?

 

The last time I bought fuel I used BP premium unleaded and having read some of the replies to Tim's problem advanced the timing by 3 turns of the vernier. The gauge now settles at the mid point of the gauge but still runs hot in traffic. I am tempted to revert back to super market fuel next time but is this likely to be the cause of running hot in traffic? How much influence will the timing have on engine temperature in stop start traffic conditions?

 

I don't think I have any electrical problems the engine bay does feel hot when I stop and lift the bonnet.

 

Any suggestions would be much appreciated. Thanks

 

(Muted response (only one, thanks) when posted with Tim's original question so I decided to add it as a new topic)

 

Paul

[Andy Moltu]

How hot does it run on the open road rather than in traffic.

If it runs cool/normal in open condtions it may well be an airflow issue (worth checking the Kenlowe is blowing the right way)

If it runs hot either the votage stabiliser is playing up (that was Tim's problem) or you'vr got a bigger problem. Is it using water - in which case you have to consider head gasket problems if not then it may be a clogged radiator.

[badshead]

Hi Paul,

 

My TR6 engine (standard in every respect) temp settles just below mid point and barely rises even in traffic with original mechanical fan only. This suggests to me that TR cooling is perfectly adequate rather than marginal, so problem is probably down to water pump problems or radiator partially blocked with crud. Many Triumph Snag owners (famous for overheating) find their problems disappear when they fit a new radiator core and/or 12 vane water pump.

 

I alternatively use bog standard unleaded or Optimax, but apart from the latter eliminating the occasional episode of running on, it makes absolutely no difference to engine temperature.

[millsie]

Hi Paul - not sure if this will help.

 

I fitted a Kenlow fan a few years ago, shortly after, I had the car serviced by Cox and Buckles who advised me that the fan has to be fitted very close to (read almost touching) the radiator - I had fitted it so the blades were about 2 inches away ... they told me back then that I would have had engine temp problems if it was left that way. At least a quick and easy check ... good luck

[Guest nco]

HI ,

 

I had similar porblems with my car - it would overheat in traffic.

 

I cleaned out the coolent, swapped the thermostat to one that opened at lower temperatures and even then it wasnt great.

 

On the open road fine but in traffic useless.

 

The Kenlow fan was old and I eventually found the fan was slipping on the motor spindle. I tried all sorts to get it to work but evenutally the thing broke loose and punctured the radiator.

 

Swapped the radiator and hey presto - problem solved! I also went back to the original mechanical fan. It works, its not complicated and the car reaches normal temperature quickly and sticks there.

 

Swapping radiator seemed to fix the problem for me. Costs a bit but better than damaging the engine/cylinder head.

 

Neil

[graeme]

I had a radiator recored a few weeks ago after damaging it with a disintigrating electric fan. The guy doing the work on the rad, said that 90% of overheating problems on old cars are caused by the radiator sludging up. I know he has a vested interest, but my cars temp has been rock steady since the rad change and the fan hasn't been on.

 

Graeme

[Red 6]

Paul,

 

I have only once had an overheating problem with a 6 and it was an air lock which occured regularly whilst i was trying out different bits on my car which meant i had to drain the rad a lot.

 

The air lock is in the cylinder head how it gets there or why it occurs i do not know but it happened, and to several of my friends and the solution is as follows.

 

Fill the rad and replace the cap when full.

 

Disconnect the hose from the heater to the valve at the valve end, and with that valve open fill the hose until water pours from theopen valve, i.e you are back filling the head through the heater and purging any air.

 

Refit hose.

 

A frequent cause of overheating is where the water system is not properly or under pressurised. Pressurised water has a higher boiling point

 

Check for even the slightest leak and whilst you are at it make sure you have a 13 or 14 lb radiator pressue cap. Finally dont rely on the guage.

 

I am assuming you have flushed the rad with 2 stage flush and that the rad is in good condition.

[Guest Paul J B]

Gentlemen,

Thanks for all your replies. I will work through them all over the next week or so. An update on my symptoms - I went for a 50 mile drive on Friday afternoon. while travelling at 60-70mph the gauge is just above half way, when I slow down to 30-40mph it starts to creep up and in stop start traffic it goes up higher still. Each time the speed changed the temp reading went up or down accordingly. I stopped by the roadside and let the engine idle when the gauge crept up towards the red line. The fan kicked in about 5mm before the line when the temp reduced slightly. At no time did it reach the red line. I had to keep driving as fast as possible to keep the temp down - what a bummer!

 

Thinking logically. I do not have the original fan fitted so I guess when I stop the car the engine is not receiving any cooling air until the fan starts. Should it start straight away? In which case do I need to adjust the cut in temp? How do I do that?

 

I have drained and refilled the system a couple of times lately so I will try filling from the heater hose incase of an air lock.

The radiator was reconditioned a few years ago so I will flush it through.

The Kenlow fan is mounted in front of the rad and very close. I can feel some air at the back of the rad when it is running although not a huge amount. I will check its not slipping.

 

Thanks for all your help I will keep you posted on my progress and look forward to any other suggestions in the mean time.

 

paul

 

 

 

Paul,

 

I have only once had an overheating problem with a 6 and it was an air lock which occured regularly whilst i was trying out different bits on my car which meant i had to drain the rad a lot.

 

The air lock is in the cylinder head how it gets there or why it occurs i do not know but it happened, and to several of my friends and the solution is as follows.

 

Fill the rad and replace the cap when full.

 

Disconnect the hose from the heater to the valve at the valve end, and with that valve open fill the hose until water pours from theopen valve, i.e you are back filling the head through the heater and purging any air.

 

Refit hose.

 

A frequent cause of overheating is where the water system is not properly or under pressurised. Pressurised water has a higher boiling point

 

Check for even the slightest leak and whilst you are at it make sure you have a 13 or 14 lb radiator pressue cap. Finally dont rely on the guage.

 

I am assuming you have flushed the rad with 2 stage flush and that the rad is in good condition.

[TIMS]

Paul

 

As the paranoid who had the earlier problems I feel empowered to reply.

 

What you are experiencing sounds quite normal apart from the electric fan not cutting in early enough. In normal road running you should not need any fan assistance, and you do not seem to. But as the air flow through the radiator goes down as your speed slows so the need for the fan goes up.

 

You say you have a Kenlowe, but where is the thermostat and is there a regulator in the line. If you look at the Moss catalogue their Kenlowe can come with a sensor linked to the "bulb in the top hose" which you can use to alter the cut in temp.

 

If you search the forum there have been threads on the place to fit the sensor, top hose v in the stainless pipe in the bottom hose.

 

As a final thought, jury rig a separate feed and switch to inside the car so that you can turn the fan on to override the sensor. Do a similar run and when the temp starts to rise as your speed drops, switch the fan on and see if it brings things under control again. (I have done this as a permanent wiring anyway)

 

Good luck

 

Regards

 

Tim

[vanflyer]

I have to agree with Graeme on this one, my car has had a re-cored radiator installed and the overheating disappeared. even when it hits 35 degrees C in summer, the original 8 blade fan and radiator shroud pulls plenty of air through the rad. The electric fan is sitting on the shelf in the garage.

[JohnC]

Paul,

Just to emphasise a point van made in passing - the original radiator shroud makes a big difference to the cooling. If you don't have one, then get one.

 

Secondly, I have a Kenlowe, and I'd say the airflow it provides is quite strong - there is even a noticeable upwelling of hot air around the car with the bonnet closed & fan on. How are the electrical connections to the fan? The earthing?

 

Finally, I refitted the engine-driven fan a year or so ago, and since then the Kenlowe has hardly ever kicked in, even on 35-40deg summer days in traffic. It eventually comes on if the car is stationary for a while, but not for long.

 

Cheers,

John

[Guest Paul J B]

Gents,

Hi. I am taking a methodical approach a replacement radiator being one of my latter options. I made a tenative start at the weekend.

 

What I have realised is that the radiator cap I fitted new a few weeks ago is the standard 7.5psi for my car CP52597. I checked the one I removed (kept it just in case) which is 10psi. This is confusing, should I fit a 13.5 psi cap as mentioned in Tim's question or stick to the standard one?

 

I tried Red 6's suggestion and disconnected the heater hose, poured water in until it flowed out of the heater valve about half a jam jars worth with some glugs and gurgles. During a road test it made no difference to the temp gauge, perhaps I should allow more fluid to run out!

 

 

I wanted to check the voltage stabiliser but after removing the knurled nuts on the speedo it wont budge. I am afraid to push and pull too much because the veneered dash flexes as I push and I don’t want to break it. Any ideas?

 

I have adjusted the Kenlow fan setting from Normal to Cold, which has helped the tick over temperature but have not tried it on a longer run yet and consider it a temporary measure only. The Kenlow sensor is attached to the top hose, oh and I have a radiator shroud fitted. There doesn't appear to be any oil mixed with the water or visa versa.

 

Any tips on removing the speedo and which cap rating to use would be much appreciated. I would like to exhaust all options before removing the radiator.

[Bob Stubbs]

I agree with John C and Van. Having a good rad shroud and recored radiator helps no end. I replaced the original shroud with the tighter fitting fibreglass version from Racetorations and it certainly keeps things cool on a run.

 

I have an internal illuminated switch rigged up so I can see when the electic fan kicks in or not and under normal road conditions, it doesn't come on at all, only when you are in a queue or stopped does it come on.

Which brings me to another thought. Presumably, once you switch off the engine to park up, there's still heat in the system that needs to clear. Should the fan be wired independently of the ignition circuit so that it can operate until things have cooled a bit? (If so how?) But then, the water isn't circulating anyway and it could be a good way of flattening the battery...... Any thoughts out there?

[badshead]

Should the fan be wired independently of the ignition circuit so that it can operate until things have cooled a bit? (If so how?) But then, the water isn't circulating anyway and it could be a good way of flattening the battery...... Any thoughts out there?

 

Bob,

Simply wiring the thermo switch directly to the battery (via a fuse) will let fan run independently of the ignition. I've got this set up on another car and the fan typically runs on for a minute or so after a good run, but not enough to flatten a healthy battery even using a 16" fan which draws 20A, where the 12" or 13" fan typically fitted to the TR6 draws about 12A. From my memory of schoolboy physics, I reckon that there is some circulation still going on due to thermo/syphon action as cooling water in the radiator will want to sink allowing the hotter water to replace it.

[Tom Fremont]

But then, the water isn't circulating anyway and it could be a good way of flattening the battery...... Any thoughts out there?

 

There should be some convective migration of water through the block after shutting off the engine; this due to the relative densities of cooler/warmer water. I've heard that some early engines did without water pumps for this reason.

[unclepete]

Which brings me to another thought. Presumably, once you switch off the engine to park up, there's still heat in the system that needs to clear. Should the fan be wired independently of the ignition circuit so that it can operate until things have cooled a bit? (If so how?) But then, the water isn't circulating anyway and it could be a good way of flattening the battery...... Any thoughts out there?

 

Bob

All the TRs up to the TR6 only had an engine driven fan fitted as standard even the ones going to the States and Australia! Once turned off - no cooling. The electric fan came in as a petrol and power saving device, saving yourself 10hp driving a fan that is not needed. Don't jump at a Kenlowe, there are other makes with much better performance.

Unc

Edited May 16, 2006 by unclepete

[JohnC]

Paul,

I gather from your email that you haven't solved this problem yet. Rather than rely on my opinion alone , let's reawaken the collective consciousness!

 

To be honest, I'm not sure you have a problem at all ! Your engine temperature is very sensitive to road speed, but that's normal, as you have no engine-driven fan. Your electric fan keeps the temperature out of the red even at idle, so what's the problem? I've probably missed the point somewhere, so please feel free to point out where...

 

Incidentally, it seems to me that you still don't know if your engine is really overheating (notwithstanding my point above), as you haven't been able to check the voltage stabiliser and therefore the temperature gauge. My experience has been that the speedo is easy to remove, so I'm puzzled. You haven't missed a fixing? Unlikely, as my speedo has only two. Alternatively, can anyone suggest another way to test the vs? Does it have an impact on the fuel gauge for example? How about removing another gauge and checking the voltage it's receiving?

 

Stay cool !

John

[tr4-thomas]

hi John,

yes it has an impakt on the fuel gauge, as both gauges are powered from the same stabilisator. so if the fuel gauge reading is ok its unlikely that the stabilisator is defekt. its not easy to test the stabilisator if you still have the bimetall operated one, with "normal" multimeters you will never get a proper reading. with the elektronik stabis its easy: output has to be 10volts.

regards

thomas from germany

[dendres95693]

I haven't seen anything mentioned here talking about the water pump and the amount of blades there are on the impellar. I too have had this mysterious running hot problem. My machinist tells me that he too had a similar problem and once he put in a pump with 6 blakes, the problem was resolved. Have any of you gone this route?

[Ade_TR6]

As JohnC says the speedo should pop out assuming all the fixings have been removed, It is likely the problem is down to the original rubber gasket gumming it into place - a little 'rotational' force on the body of the gauge from behind should break the little blighter from the dash.

[John L]

Has any body out of a matter of interest filled the system with Evans coolant, seems expensive, as in the new magazine to one that was showing running hot before?

What should be the correct pressure cap setting?

John

[RobIsaacson]

I think you may be looking for a problem which doesn't exist.

 

Mine runs at mid point on the gauge at normal road speeds but in town and slow traffic the temperature rises and the fan kicks in bringing it back down.

 

I have a low temperature stat so it opens earlier.

I don't have the original fan fitted, I just rely on the electric (Pacet - very good) fan.

The radiator was replaced last winter.

The engine was completely rebuilt 2 winters ago by someone very experienced.

The water pump was replaced with a new unit.

 

Yours seems to run the same as mine and I don't have any issues. Stop looking for a problem and just drive it. ;-)

 

Regards

 

Rob

[dan-t]

Hi no one has suggested temp sender if you have a tr4 one fitted these make it look like you are running hot, also is your expansion tank topped up

these were my problems up until this weekend. the clue is temp sender should not have the red ring.

 

best wishes Dan

[John L]

I have just checked mine and it has a red plastic ring before the terminal, is this definately the wrong one. I ordered and fitted a new one about a year ago now, and yes it does run at the top end more but never goes into the red.

What colour should the TR6 one be then, and there should be some markings on the side of it to identify the correct one, could somebody check theirs please.

John

[stuart]

TR6 one is usually green ringed, though it depends on the supplier as I have seen black ringed as well. What you need is 110 degree full scale rather than 100 degree full scale.

Stuart.