Coolant. How to check correct temperature

[Richmac]

My new to me TR4a is fitted with an alloy radiator, electric fan and over flow bottle. It reads high on the temperature gauge, not on the red but close to it but hasn't ventured into the red on 200 miles I've done so far. I wasn't too worried about the gauge reading high as long as its below red as it should have correct thermostat fitted and fan does kick in. However its melting the over flow pipe I bought for it from eBay ( sold as for purpose) so now I'm worried its running to hot. Any checks I can make please with no special tools, to ensure engine temperature is correct. I don't have a manual yet either to see what the temperature should be. Any tips appreciated 

Regards Richard 

[RogerH]

What value of Radiator thermostat do you have in the cylinder head housing.   TRy a lower value.

As for the pipe get a proper one.

 

Roger

[RobH]

The rad can't get much hotter than 100ºC and normal running temperature would be around 85-90 so that new pipe must be rubbish. 

If you buy or borrow an infrared thermometer you can check the temperature of the cylinder head. (Don't use the rad - those thermometers don't read properly on shiny metal).

Does your fuel gauge read correctly? If not the instrument voltage stabiliser may have failed, giving high temp and fuel readings.  

[trchris]

Hi Richard

As Rob advises try and get hold of a infrared thermometer it’s the best way to check the engine temperature 

Chris

[Lebro]

My 1st thought was the voltage stabiliser. Does the fuel gauge read overly high ?

Bob

[BlueTR3A-5EKT]

1 hour ago, Richmac said:

My new to me TR4a is fitted with an alloy radiator, electric fan and over flow bottle. It reads high on the temperature gauge, not on the red but close to it but hasn't ventured into the red on 200 miles I've done so far. I wasn't too worried about the gauge reading high as long as its below red as it should have correct thermostat fitted and fan does kick in. However its melting the over flow pipe I bought for it from eBay ( sold as for purpose) so now I'm worried its running to hot. Any checks I can make please with no special tools, to ensure engine temperature is correct. I don't have a manual yet either to see what the temperature should be. Any tips appreciated 

Regards Richard 

I’d be working that “suitable” overflow hose in the returns opening of the supplier.  Unless it is rubbing on the underside of the bonnet.……..then the radiator supplier needs chatting with.  

[Richmac]

Thanks guys for your help. The hose is not rubbing anywhere and my fuel gauge seems to be indicating correctly.

[Don H.]

Is that overflow hose “melting” or has it split, @Richmac?  The photo (on my iPhone’s small display) looks more like a split in the rubber. 

As others have said, get a proper hose and chase that eBay supplier for a refund. 

Pistol-grip infrared thermometer cost notalot. A good tool to have around for all kinds of things. Note the issues around emissivity and measuring shiny surfaces mentioned by @RobHand also that the laser pointer is just to help aiming. The infrared measurement is done via a much larger “cone” and isn’t remotely as small as the laser dot. 

[Richmac]

Thanks Don I'll look into infrared thermometer. On closer inspection it actually appears the bonnet box section is touching the radiator cap and hose outlet as blue above suspected. I guess the only solution therefore is to adjust the bonnet? Do the original radiators fit with such small margins please?

Edited June 19, 2024 by Richmac
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[stuart]

1 hour ago, Richmac said:

Thanks Don I'll look into infrared thermometer. On closer inspection it actually appears the bonnet box section is touching the radiator cap and hose outlet as blue above suspected. I guess the only solution therefore is to adjust the bonnet? Do the original radiators fit with such small margins please?

Original rads are close but dont rub unless theyre sited too far forward or too high with the insulators under the mountings being too thick or the body is mounted very low on the chassis. You cant adjust the bonnet without upsetting all the shut lines. Some of those ally rads arent a good fit at all. I would be looking at the rad mountings first of all to see if it can be lowered by using thinner insulating rubbers or if the mounting holes can be elongated slightly to move it back a little to clear but you do need to see how close it will end up to the fan then. This is sadly typical of some aftermarket bling.

Stuart.

[Z320]

1 hour ago, Richmac said:

Do the original radiators fit with such small margins please?

Interesting question,

maybe I put a piece of dough on there,

if it is still elastic.

No good idea to adjust the bonnet

because of a wrong radiator, IMO

Edited June 19, 2024 by Z320

[Richmac]

Thanks Stuart for your help. I can see my radiator sits on two spacers and an insulator. Is it ok if I take the bottom spacer out or better the top, or both?

Edited June 19, 2024 by Richmac
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[trchris]

Too much spacing you want to remove both metal spacers and leave just the rubber ones 

Chris

[Z320]

I bet they have a reason:

to get the neck of the thermostat housing and radiator in line?

 

[John Morrison]

50 minutes ago, trchris said:

Too much spacing you want to remove both metal spacers and leave just the rubber ones 

Chris

+1

plus have you considered a defective sender unit I ask because they are about?

John

[stuart]

Yes reduce it to the rubber one only but as Marco suggests be careful that the top hose hasnt gone out of line too much, if so then just remove one of the ally spacers, the radiators are close anyway but you do need just enough clearance to prevent rubbing.

Stuart.

[stuart]

1 hour ago, John Morrison said:

+1

plus have you considered a defective sender unit I ask because they are about?

John

Or incorrect ones, there are three different senders and they have different resistance values so give different readings.

Stuart.

[Andy Moltu]

If you are checking with an infra red thermometer, it might be worth painting a black area on the rad as reflective surfaces can cause mis-reading.

[Richmac]

8 minutes ago, stuart said:

Yes reduce it to the rubber one only but as Marco suggests be careful that the top hose hasnt gone out of line too much, if so then just remove one of the ally spacers, the radiators are close anyway but you do need just enough clearance to prevent rubbing.

Stuart.

Thanks Stuart but how much out of line is to much??

 

7 minutes ago, stuart said:

Or incorrect ones, there are three different senders and they have different resistance values so give different readings.

Stuart.

 

19 hours ago, RogerH said:

What value of Radiator thermostat do you have in the cylinder head housing.   TRy a lower value.

As for the pipe get a proper one.

 

Roger

This is the problem I don't know what to trust, engine thermostat, fan stat, sender or gauge 

[stuart]

Not so much as to strain the rad neck pipe as being ally it won’t be so strong. Mine just rubs the pipe from the overflow but it’s a thicker pipe as I run a header tank.

Stuart

 

[Z320]

No reason to worry with the original rad on my TR4A

[Z320]

Something is definitely „different“ with your aluminum rad

[Richmac]

So I've removed the packing washers and the bonnet now misses the rad, just. I don't think I am putting undue strain on the top hose. I'll see how I get on if need be I will go back and elongate the holes in the rad fixings. Thanks everyone for your help with this much appreciated. 

[stuart]

19 hours ago, Z320 said:

Something is definitely „different“ with your aluminum rad

They are a bit generic Im afraid.

Stuart.

[Lo100469]

On 6/19/2024 at 3:38 PM, stuart said:

Or incorrect ones, there are three different senders and they have different resistance values so give different readings.

Stuart.

Stuart, would you know a reliable source for a higher resistance sender? mine failed and the 2 i tried read too high. Laurent