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Another problem: overheating


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My car never over-heated except in traffic in hot weather. I exchanged the short engine, years ago and had over-heating problems, so installed oil cooler and electric fan.

 

I have a problem with the electric fan that seems to be on the whole time. On Monday I had the carbs overhauled and having found-out about the problem with the electric fan, turned it off.

 

On the way back, on an empty motorway, at around 70mph and 24/25º outside temperature the car started overheating to the point that steam was coming out of the bonnet by the time I arrived home (some 15miles).

 

Not being a mechanic, I know enough not to blame the mechanic's work with the carbs. The car is now running nicely and I assume that the timing, points, etc is ok as they were done recently,

 

Where should I start looking? Could it be the engine itself?

 

qim

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Is there Anything blocking the radiator ? Outside and inside tubing ? Thermostat ok? Is it the correct bellows skirted thermostat?

 

The electric fan is off now, is the mechanical fan still there or was it removed when fitting the electrical?

 

Is your waterpump ok ?

Edited by EdwinTiben
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Don't be too quick to exonerate the mechanic. An overly lean fuel mixture (as well as dozens of other things) can cause overheating.

Tom

 

+1 on this.

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What car is it and what mods has it got? If its a 3A does it have the 'cardboard' radiator shroud fitted?

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Could do with a lot more information

+1 for Carbs need checking for being lean. Also

 

What model car is this Tr2/3/3a (matters because of the different bonnet /cooling configurations) ?

Has it got the cardboard tunnel IN FRONT of the radiator pushing the incoming air through the rad ?

Do you still have the original mechanical fan fitted ?

Where is the electric fan situated ? in front of the rad or behind the rad ?

Is the fan almost touching the rad (within about 5mm max, if too far away the air "buffets" and stalls causing overheating) ?

Your signature could do with more detail are you in Norway ? or in Sri lanka with 43deg heat and 98percent humidity ?

 

All these things matter please supply for accurate diagnosis.

 

Mick Richards

Edited by Motorsport Mickey
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Hi Qim,

where abouts are you. 70mph on a motorway sounds like the UK.

 

You need to go through things in a methodical way. All the tips above need looking at. Do not rule out what the mechanic did.

 

Take plugs out - what colour are the centre electrodes (4 plugs) - very light = weak (hot mixture). Chocolate is good. Black = too rich - would help to run cool.

Ignition timing - too retarded will increase the temp - but may make the engine feel nice and run easy.

Thermostat - could be stuck shut - remove and place in a pan of hot water to see at what temp it opens.

One assumes the head gasket is OK.

 

Roger

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Hi

 

Lots to think about

 

1959 TR3A with (I hope) 2200 cc engine. TR4 carbs; mechanical fan still there.

 

As for lean mixture I would expect sluggish power but it is better than it has been before overhauling the carbs.

 

I am going to run the car tomorrow with the electrical fan permanently on to see if the overheating returns. If it does then it must be like some of you said too lean mixture as it ran without overheating before.

 

many thanks all

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There should be a cardboard air-guide in front of the radiator which funnels air from the wide '3A mouth and into the radiator. If that is missing then a lot of the air just goes past each side of the rad instead of through it. It might not look like cardboard as it is usually painted- often body colour.

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Your signature could do with more detail are you in Norway ? or in Sri lanka with 43deg heat and 98percent humidity ?

 

 

Mick Richards

 

Hi

 

I'm in Portugal (Lisbon area, by the sea)

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Just a thought, I suppose the flow of the fan has been checked ? ie if in front of the rad which it probably is if the mechanical fan is there, then it obviously needs to be blowing the air THROUGH the rad into the engine bay.

If the blade is fitted the wrong way around or the electrical connections reversed then it's trying to pull the air backwards through the rad out of the engine bay and the cooling is severely compromised.

 

Mick Richards

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The car was NOT overheating before having the carbs (and nothing else) overhauled. The only other thing that was changed was the turning off of the electrical fan.

 

So, maybe it would have overheated if I had switched off the fan BEFORE the work on the carbs; or, as has been suggested, the mixture is too weak.

 

I'm going to try out the car with the fan switched on (permanently as before) and if it still overheats I will go and see the mech about the mixture

 

Thank you, all!

Edited by qim
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Here is a photo of my cardboard air duct. If you have one it should be painted body colour. If you have a TR2 or a TR3, it is included as part of the body work welded into the front apron.

 

I bought my 1958 TR3A brand new in May 1958. There was no air deflector and it overheated every time that hot summer. When S-T re-designed the front apron (valance), they made no provision for an air duct. I can visualize the engineers working very late every night to design something that could be retrofitted by the dealer and which only cost pennies. That's why it's made of cardboard. All the TR3A customers were complaining about overheating.

 

As for your electric fan, maybe it's turning in the wrong direction. Try changing the electrical connections so it will turn in the direction that sends cool air into the radiator. You can see my 12" diameter Kenlowe fan that I mounted as a pusher fan in front of the radiator. and also the details how the air duct is secured by the inner end of the supports for the top of the front over riders. I had to trim the air duct so the fan would not scrub on the cardboard. I have the fan high enough that I can still use my hand-crank to start the car.

post-1056-0-79844500-1468443377_thumb.jpg

post-1056-0-95461100-1468443468_thumb.jpg

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Hi qim

I am your neighbor in Spain, so I know all about overheating in my TR3A, After many attempts to cure it I took the centre only out of the thermostat and removed the restrictor in the bye pass hose. My water pump has a six blade impellor and I have a suction Kenlowe fan with manual over-ride, since I removed the mech. fan.

All helped to cool it down but only when I fitted the air duct behind the grill did I cure my troubles. If you look carefully at the first picture below you will see the duct fitted and painted body colour, However mine is made out of 2mm aluminium and in addition to the cardboard type (ex Moss) I have a top plate as well, and I have two holes in the one side plate up the top rear corner for the cold air pipes to take pre rad. air to the carbs.

 

Dave

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If you look carefully at the first picture below you will see the duct fitted and painted body colour,

Hi Dave

 

Thanks, but I cannot see what you mean... Do you mean you blocked both ends of the grill to direct the air-flow into the middle?

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Hi Dave

 

Thanks, but I cannot see what you mean... Do you mean you blocked both ends of the grill to direct the air-flow into the middle?

 

The ductwork is a folded piece of heavy paperboard that directs airflow to the front of the radiator by funneling it better through the apron. It prevents air from heading down the sides or the top of the TR3A/TR3B grille opening.

 

Here's a view into a TR3A/B apron without the paperboard air deflector. One can see how much place there is for air to go that isn't through the radiator. The inverted "U" shaped deflector -- either paperboard (my preference), aluminium (nice idea but brings more risk of radiator damage), or as done in one of our forum friend's works car, custom-made aluminium side panels -- makes a difference and should be fitted to these cars.

i-3VPZtqJ-X3.jpg

Edited by Don H.
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  • 5 weeks later...

Hi

 

I'm still battling with overheating problems, while driving in empty motorways in temperatures that should not present these problems. I can only drive if the electric fan is on the whole time

 

I have decided to take out the radiator and have it cleaned and serviced; I will also change the thermostat.

 

Meanwhile, I wonder...

 

In the late 80s I had a problem with oil being thrown out via the breather and unable to find anyone that could solve the problem (I think now that it was nothing more than piston rings) I drove the car to the UK and had a new short engine put in by a TR specialist in the Twickenham area. As soon as I collected the car, it started to heat up. I took it back, they put yet another short engine but the problem continued. To solve the problem and so that I could drive back to Portugal they fitted an oil radiator and a Kenlowe fan.

 

I did not use the car regularly and then a baby came along. The car was pretty much abandoned for some 20 years. Now, that I am trying to get everything working again, I wonder if my major heating problem has something to do with the engine itself. How can a new short engine cause overheating?

 

Thanks

 

qim

 

 

P.S. Thank you Don H and Iain for the images above. I will try them if everything else fails!

Edited by qim
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Hi Again Qim

If you send me a p.m. with your e mail address I will send you the same pics that I sent Lebro (Bob) and Yves.

 

Iain

 

Does your ducting have a top plate as well? mine does, as I thought that with the side plates only in position the air might be forced over the top of the radiator being the least line of resistance. Also do you have pipes to take cold air to the carbs direct?

 

Dave

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Does your ducting have a top plate as well? mine does, as I thought that with the side plates only in position the air might be forced over the top of the radiator being the least line of resistance. Also do you have pipes to take cold air to the carbs direct?

 

 

 

Hi

 

I don't have any sort of plates top or side; as for the carbs I have no idea. I will have a look next time I go to the car (at my mother's...)

 

But right now I am trying to understand if the short engine (the bottom block with the pistons) could cause overheating by itself.

 

Thanks

 

 

 

 

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if the block is heavily silted up it will restrict the coolant flow and possibly overheat.

 

 

Do you believe that a supposedly TR specialist would fit a "heavily silted up" block that they sold as newly reconditioned? Thay told me that they fitted yet a second one, but maybe they did not...

 

Anyway, two questions.

 

1) if that is the problem how could it be solved?

2) any other possibilities for the block, itself?

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A decent engine builder would have cleaned the block.

 

The water pump may have issues - corroded vanes, cheap repro pump where the vanes do not fit very well Seized thermostat.

 

If you open the drain valve on the side of the block (near the exhaust pipes) does water flow out easily.

if not then it could be silted. To remove - head off, poke arund #4 liner to dislodge any silt. OR remove liners and do a proper job.

 

 

Roger

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Hi RogerH

 

Many thanks. Next on the job list.

 

Unfortunately, my limited tool-box only includes a cheque-book!

 

I will start with the thermostat and check the water pump. This is no longer the original one. Are there reconditioned ones?

 

Thanks

 

qim

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